Friday, June 16, 2006

New data links global warming and major storms

We can expect stronger and more frequent hurricanes in the summer and worse storms in winter as the result of climate change, according to a group of top climate scientists in Canada.

That country's leading scientific society on climate has urged the Canadian government to take prompt action on climate change. The appeal comes on the heels of new scientific studies presented at the 40th annual Canadian Meteorological and Oceanographic Society congress in Toronto.

The executive director of the society, Ian Rutherford, told the Inter Press Service: "Climate change is real, the Kyoto Protocol is an important first step, but we need to do a lot more."

A statement endorsed by the Society's membership of more than 800 public and private scientists, said: "The scientific evidence dictates that in order to stabilize the climate, global reductions in greenhouse gas emissions need to go far beyond those mandated under the Kyoto Protocol."

The Society has been very vocal about climate change of late. Part of the reason is that Canada's new conservative government has adopted a position in opposition to the Kyoto Protocol in line with the Bush administration in the U.S., which claims adhering to the Protocol would damage the American economy.

The new government also opposed stricter emissions standards for a post-Kyoto agreement at a United Nations meeting in Bonn, Germany, last month.

Part of the reason for the new government's opposition to these programs is a small and previously unscrutinized group called Friends of Science, which is skeptical of climate warming. The group is drawing attention from the government and the Canadian media.

The U.S. government opposes the idea of global warming at the behest of ExxonMobil and other big oil companies who hope for melting of the polar icecaps to drill in the Arctic regions.

Rutherford said: "The conservative government is listening to them because they tell them what they want to hear." He added that no member of Friends of Science has presented any papers, viewpoints or even attended a Society meeting. "They never present their arguments in front of scientists and should not be listened to," Rutherford said.

Likely they would have not enjoyed hearing the first physical evidence tying global warming to increased hurricane activity and intensity, which was presented at the Toronto conference.

Robert Scott, an oceanographer at the University of Texas, used surface temperature data on the tropical Atlantic Ocean over decades to show the area that spawns hurricanes is dramatically enlarged in recent times.

His data reveals that since 1970, the eastern side of the Atlantic, touching the African coast, has grown warmer, passing the threshold of 26.5 degrees Celsius, which allows hurricanes to form. That data demonstrates that the traditional area where these storms are birthed has grown by hundreds of kilometers. In fact, Scott said, hurricanes are originating an average of 500 kilometers farther east since 1970, spending more time over warmer water. That means the storms are getting stronger because they draw their strength from warm water, and the pool of such water is now larger.

Scott believes global warming has made the storms stronger, a still controversial view, but one which is accumulating more supporting data. Steve Lambert, a climate expert at the Meteorological Service of Canada, told the conference there is convincing new evidence global warming will result in more powerful winter storms over the mid-latitudes of the Northern and Southern hemispheres.

Using current computer climate models, Lambert studied how future greenhouse gas emissions will affect low pressure systems in the winter. The models all agreed as levels of greenhouse gases in the atmosphere climb, low pressure systems, or cyclones, become stronger but develop less frequently.

"There's a direct relationship between the changes in magnitude of cyclonic events and concentration of greenhouse gases," Lambert said.

Hurricane loss could total $130 billion: forecast

NEW YORK (Reuters) - As the first of 2006's tropical storms came ashore in Florida on Tuesday, an catastrophe-loss forecaster made a gloomy prediction: a Category 5 hurricane could hit Miami and cost insurers $130 billion.

AIR Worldwide Chief Executive Karen Clark said scenarios developed by her Boston-based modeling group foresaw a 155-mile-per-hour storm banging into Southern Florida and a major earthquake in the central United States that could cost property casualty carriers $150 billion.

Clark was testifying before a congressional seminar on whether a federal disaster insurance program is needed as a backstop for insurers that experience major losses.

Such a fund is supported by carriers like Allstate Corp. and by states such as Florida, which has been hardest hit by hurricanes in recent years. Allstate and other insurers are trying to move out of areas with hurricane and earthquake exposure.

Clark said increasing insured property values in high-risk areas, such as coastal Florida, pose a financial threat to insurers, policyholders and the economy.

"There is 1 percent probability of an insured property loss exceeding $100 billion this year," said Clark. "That may appear small, but the probability of experiencing this loss -- or greater -- over the next 10 years is almost 20 percent when the continual growth in the number and value of exposed properties is included."

Florida officials have said that more than 100 people a day are moving into their state, and insurance costs in some areas have risen 90 percent since last year, when both Hurricanes Katrina and Wilma hit the state.

Tuesday, June 06, 2006

Study: Clean Air, Global Warming Mean More Hurricanes

Cleaner air and more Atlantic hurricanes may come as a pair, according to a new study comparing rising global sea surface temperatures with sun-blocking pollution particles.

It turns out that the recent decline of small manmade pollution particles called aerosols in the North Atlantic might be allowing hurricane activity to catch up with the effects of global warming there, reported climate researchers Michael Mann and Kerry Emanuel in a new study in the journal Eos.

The newfound powerful role of aerosols throws out the need for a largely theoretical "Atlantic Multi-decadal Oscillation" (AMO) that's been called on by some researchers to explain North Atlantic temperature changes over the last century.

"It's kind of an Occam's razor argument," said Emanuel, an atmospheric scientist at the Massachusetts Institute of Technology, referring to the maxim that the right explanation is usually the one that's least complicated, requiring the fewest assumptions. "It really fits beautifully."

Emanuel and Mann modeled the warming effects of accumulating greenhouse gases in the atmosphere along with changes in aerosols, which filter sunlight and cool the ocean surface. The researchers found the observed sea surface temperatures could be easily explained without any AMO.

Instead, according to this new view, the recent rise in hurricanes can be traced to the end of World War II, when the US, Europe and the Soviet Union kicked up industrial output.

"From the 1940s to the 1970s aerosols increased enormously in the Northern Hemisphere," confirmed Gavin Schmidt, a climate researcher at NASA's Goddard Institute for Space Studies. The aerosols essentially dimmed sunlight over the North Atlantic and masked the effect of global warming there over those decades.

Then in the 1970s and 1980s, the US and Europe instituted clean air regulations and the Soviet Union collapsed. These changes reduced or flattened aerosol emissions trends in the western Northern Hemisphere.

Since aerosols have a lifespan of only a few weeks in the atmosphere, the effect on the climate was almost immediate: Clearer air over the North Atlantic allowed more sunlight to reach and warm up surface waters.

Meanwhile, much longer-lived greenhouse gases have continued to mount - also supplying more heat to the oceans.

"There is a very good correlation of North Atlantic hurricanes and the temperature of the North Atlantic in the early fall," Emanuel told Discovery News. The warmer the water at that time of the year, the rowdier the hurricane season appears to be. "It's an astoundingly good correlation."

In other words, ever since the air got cleaner over the North Atlantic, hurricanes have been playing catch up with global warming.

Elsewhere in the world, however, the aerosols are still holding sway, said Schmidt. While the West has been reducing aerosols, India and China have been increasing their emissions. In the Indian Ocean the cooling effects of aerosols has been recently tied to powerful Indian Monsoons.

Thursday, May 04, 2006

As hurricanes loom, many in Florida Keys flee

KEY WEST, Fla., May 3 (Reuters) - Spiraling living costs, lingering trauma from past evacuations and fear that one day million-dollar homes could be reduced to rubble or again flooded are driving people out of the vulnerable Florida Keys as another hurricane season looms.

While most of Florida experiences one of the country's fastest population growths, the number of people living in the low-lying 110-mile (180-km) island chain at the southern tip of the peninsula is slowly dwindling.

In the last two years, residents have been ordered to evacuate six times up a narrow, mangrove-fringed 126-mile (200-km) road, the Overseas Highway, linking the Florida Keys to the mainland.

When Hurricane Wilma swept by on Oct. 24, it flooded about 3,700 of 15,000 homes in Key West with a foot or more of water and destroyed 1,000 cars. Most residents were stunned.

"We're seeing adjustment disorders, post-traumatic stress," said Betsy Langan, assistant director of Womankind Inc., a health services provider. "Because of the hurricanes, people are exhibiting sleeplessness, difficulties in concentration and are feeling hopeless and overwhelmed."

On top of that, property values have soared beyond the reach of most working families. Home insurance rates are sky-rocketing. And salaries can't keep pace.

"You pay $400,000 for a trailer that's going to be junk soon. It's incredible," said Jose Cuevas, a moving company manager who commutes to work in Sugarloaf Key from Miami each day -- a 300-mile (490-km) round trip.

The moving-out business is booming. "Clients are worried about insurance. One said, 'They only want rich folks,'" Cuevas said. "They don't want to go, but they have to."

A palm-fringed paradise that boasts the only living coral reef in the continental United States, the Florida Keys is the sort of island paradise that many dream about. But much of it is hemmed in by turquoise waters and the island at the end of the chain, Key West, is densely populated and usually crowded with tourists.

Home prices in the entire Florida Keys average $846,000, and in Key West, the main city, $935,000, according to Coldwell Banker Schmitt Real Estate.

The head-turning price of real estate, and limited land for development, also is putting a squeeze on renters as apartments and mom-and-pop motels are converted into condominiums and sold off as second and third homes to wealthy retirees.

"We're gun-shy about going through another hurricane. We gave up on buying a home here in Key West," said Dorothy McCoy, a daycare provider who with her painter husband Denis recently left the Keys.

Keys homeowners are also socked with Florida's highest insurance premiums. Citizens Property Insurance, the state-run insurer of last resort, proposed a base windstorm rate of $20.91 per $1,000 of insured home value for this year.

Furious Keys officials threatened to sue the state, and a grass-roots organization, Fair Insurance Rates in Monroe, or FIRM, met with Gov. Jeb Bush, brother of U.S. President George W. Bush, in April to seek support.

Florida insurance regulators rejected the rate filing on Monday and Insurance Commissioner Kevin McCarty froze Keys' windstorm rates at the 2005 level of $20.58 per $1,000, still the state's highest and two to three times as high as the rates in other hurricane-hit counties.

Key West resident David Lane and his wife Pam recently listed their historic 2,000-square-foot (186-sq-m) home at $1.5 million and plan to head to Asheville, North Carolina. Their windstorm insurance premium: $12,700.

"If a really bad storm hit here, a big part of the value of our house is the land. What would the land be worth?" David Lane said.

"I don't want to feel like I'm turning into an old weenie. We really love Key West, but evacuating is hard. It just gets tedious."

Many residents feel the same way, and the result is a slow exodus from paradise.

The population of Monroe County -- the entire Florida Keys -- dropped 2.16 percent to 76,329 in the year to July 2005. In the last five years, the county's population has shrunk 4.1 percent at a time when most areas in Florida are growing rapidly, according to a U.S. Census report in March.

"These are people who've lived here 20 to 25 years," said John Strong, owner of Pak Mail, a packing and crating franchise. "They're going to Arizona, North Carolina and Central America, seeking no hurricanes."

The problem is acute for teachers, nurses and police officers. An increasing number of Monroe County sheriff's employees commute from Miami. Sheriff Rick Roth is adding 18 bunks at a detention center which could be used by the commuters in an emergency.

A recent Monroe County School District poll found that 7 percent of families with school-aged children planned to leave when the school year ends in May.

"We can't get nurses, we can't get doctors," said John Dolan-Heitlinger, an advocate for affordable housing for working professionals.

On Big Pine Key, resident Pam Henry said she is struggling to pay $16,000 a year in property taxes and home insurance, and is moving to central Florida.

"The hurricanes put the icing on the cake," Henry said.

Federal study finds accord on warming

(May 3, 2006 New York Times) A scientific study commissioned by the Bush administration concluded yesterday that the lower atmosphere was indeed growing warmer and that there was "clear evidence of human influences on the climate system."

The finding eliminates a significant area of uncertainty in the debate over global warming, one that the administration has long cited as a rationale for proceeding cautiously on what it says would be costly limits on emissions of heat-trapping gases.

But White House officials noted that this was just the first of 21 assessments planned by the federal Climate Change Science Program, which was created by the administration in 2002 to address what it called unresolved questions. The officials said that while the new finding was important, the administration's policy remained focused on studying the remaining questions and using voluntary means to slow the growth in emissions of heat-trapping gases like carbon dioxide.

The focus of the new federal study was conflicting records of atmospheric temperature trends.

For more than a decade, scientists using different methods had come up with differing rates of warming at Earth's surface and in the midsection of the atmosphere, called the troposphere. These disparities had been cited by a small group of scientists, and by the administration and its allies, to question a growing consensus among climatologists that warming from heat-trapping gases could dangerously heat Earth.

The new study found that "there is no longer a discrepancy in the rate of global average temperature increase for the surface compared with higher levels in the atmosphere," in the words of a news release issued by the Commerce Department and approved by the White House. The report was published yesterday online at

The report's authors all agreed that their review of the data showed that the atmosphere was, in fact, warming in ways that generally meshed with computer simulations. The study said that the only factor that could explain the measured warming of Earth's average temperature over the last 50 years was the buildup heat-trapping gases, which are mainly emitted by burning coal and oil.

All other industrial powers except Australia have accepted mandatory restrictions on such gases under the Kyoto Protocol, but efforts to extend and expand that treaty face hurdles.

The Intergovernmental Panel on Climate Change, a United Nations body that conducts an exhaustive periodic review of causes and impacts of warming, has just finished reviewing drafts of its next assessment, to be published next year.

Scientists involved in that effort, while refusing to comment on specific findings, said that research since the last assessment, in 2001, had generated much greater certainty that humans are the main force behind recent warming, and that much more warming is in store unless emissions are curtailed.

Michele St. Martin, a spokeswoman for the White House Council on Environmental Quality, said, "We welcome today's report" and added that it showed that President Bush's decision to focus nearly $2 billion a year on climate monitoring and research was "working."

Thomas Karl, the director of the National Climatic Data Center in the Commerce Department and the lead editor of the report, said it was not simply a review of existing work but also, by forcing scientists with differing views to meet repeatedly, resulted in breakthroughs.

"The evidence continues to support a substantial human impact on global temperature increases," Dr. Karl said.

John R. Christy, an author of the new report whose analysis of satellite temperature records long showed little warming above Earth's surface, said he endorsed the conclusion that "part of what has happened over the last 50 years has clearly been caused by humans."

But Dr. Christy, who teaches at the University of Alabama, Huntsville, said the report also noted that computer simulations of the climate system, while good at replicating the globally averaged temperature changes, still strayed in projecting details, particularly in the tropics.

This implied that the models remained laden with uncertainties when used to study future trends, he said.

Dr. Christy also said that even given what the models projected, it would be impossible to slow warming noticeably in the coming decades. Countries would be wise to seek ways to adapt to warming, he added, even as they seek new sources of energy that do not emit heat-trapping gases.

Global warming fastest in 20,000 years, and it is mankind's fault

(From the UK's Independent Online) Global warming is made worse by man-made pollution and the scale of the problem is unprecedented in at least 20,000 years, according to a draft report by the world's leading climate scientists.

The leaked assessment by the group of international experts says there is now overwhelming evidence to show that the Earth's climate is undergoing dramatic transformation because of human activity.

A draft copy of the report by a working group of the Intergovernmental Panel on Climate Change (IPCC) states that concentrations of carbon dioxide, methane and other greenhouse gases are at the highest for at least 650,000 years.

It predicts that global average temperatures this century will rise by between 2C and 4.5C as a result of the doubling of carbon dioxide levels caused by man-made emissions.

These temperatures could increase by a further 1.5C as a result of "positive feedbacks" in the climate resulting from the melting of sea ice, thawing permafrost and the acidification of the oceans.

The draft report will become the fourth assessment by the IPCC since it was established in 1988 and was meant to be confidential until the final version is ready for publication next year.

However, a copy of the report has been made available by a US government committee and can be found on the internet by anyone who makes an e-mail request for a password to access the area on its website.

The US Climate Change Science Programme, which yesterday released its own report saying climate change was being affected by man-made pollution, said it wanted as many experts and stakeholders as possible to comment on the draft IPCC report.

The IPCC's chairman, Rajendra Pachauri, however, did not learn of the decision to, in effect, publish the report until it was posted online, according to the journal Nature. The IPCC assessment is written by scores of scientists - who can draw on the expertise of hundreds more researchers - to produce the most definitive and authoritative assessment of climate change and its impacts.

Global warming sceptics will get little comfort from the confident language in the draft report, which dismisses suggestions that climate change is an entirely natural rather than man-made phenomenon.

"There is widespread evidence of anthropogenic warming of the climate system in temperature observations taken at the surface, in the free atmosphere and in the oceans," it says.

"It is very likely that greenhouse gas forcing has been the dominant cause of the observed global warming over the past 50 years.

"And it is likely that greenhouse gases alone would have caused more warming than has been observed during this period, with some warming offset by cooling from natural and other anthropogenic factors." Since its last report in 2001, the IPCC's working group says it has amassed convincing evidence showing that climate change is already happening.It also finds that climate change is set to continue for decades and perhaps centuries to come even if man-made emissions can be curbed.

"2005 and 1998 were the warmest two years on record. Five of the six warmest years have occurred in the past five years (2001-2005)," the report says.

Satellite data since 1978 shows that the Arctic sea ice has shrunk by about 2.7 per cent each decade, with even larger losses of about 7.4 per cent during the warmer summer months.

"The smallest extent of summer sea ice was observed in 2005. Average Arctic temperatures have been rising since the 1960s and 2005 was the warmest Arctic year," the draft IPCC report says.

"An increasing body of evidence suggests a discernible human influence on other aspects of climate, including sea ice, heat waves and other extremes, circulation, storm tracks and precipitation," it says.

Melting glaciers and polar ice sheets could cause sea levels to rise by up to 43cm by 2100, and the rise for the next two centuries is predicted to be nearly double that figure.

Man-made emissions of greenhouse gases have probably already caused the increase in sea levels observed over the past century, says the report.

"Anthropogenic forcing, resulting from thermal expansion from ocean warming and glacier and ice sheet melt, is likely the largest contributor to sea level rise during the latter half of the 20th century," the report says.

"Anthropogenic forcing has likely contributed to recent decreases in Arctic sea ice extent. There is evidence of a decreasing trend in global snow cover and widespread retreat of glaciers consistent with warming and evidence that this melting has also contributed to sea-level rise," it adds.

Evidence of climate change

* Arctic sea ice has shrunk by 2.7 per cent per decade since 1978 and by 7.4 per cent each decade during the summer months.

* Five of the six warmest years have occurred in the past five years, with 2005 and 1998 being the two warmest years on record.

* Global average sea levels rose at a rate of about 2mm a year between 1961-2003, and by an average of more than 3mm a year between 1993-2003.

* Mountain glaciers and polar land ice have in general melted faster than they have formed over the past 40 years.

* Permafrost temperatures have increased on average and the area covered by seasonally frozen ground has decreased by about 7 per cent over the past 50 years.

Friday, April 07, 2006

Global warming: an ethical issue?

OAKLAND (from Al Gore brought corporate executives and environmentally minded investors roaring to their feet Thursday with multimedia images of an overheating planet and a call for Americans to reclaim their "moral authority" by tackling global warming.

"This is really not a political issue, it is disguised as a political issue," Gore said. "It is a moral issue, it is an ethical issue. If we allow this to happen, we will destroy the habitability of the planet. We can't do that, and I am confident we won't do that."

As a U.S. senator, Gore gave global warming talks 15 years ago in Washington that relied almost entirely on scientists' best guesses and computer models.

Now bolstered by real climate changes, he has gone Hollywood, with movies of collapsing ice shelves, then-and-now shots of vanishing glaciers and lakes, telegenic photos of dwindling wildlife species plus floods, tornadoes and, of course, hurricanes.

"We have been blind to the fact that the human species is now having a crushing impact on the ecological system of the planet," Gore said.

After Katrina, Rita and Wilma in 2005, federal hurricane scientists used the Greek alphabet in naming tropical storms.

"This is the first foretaste of a cup that will be offered to us again and again and again until we regain our moral authority," Gore told members of Ceres, an organization of companies, investors and environmentalists pressing for greener behavior by corporations.

Gore's message is much the same as it was in the early 1990s, but his talk in Oakland comes at a political tipping point in the debate not about global warming, but what to do about it.

Twenty-two states and the District of Columbia now insist on some percentage of renewables for their energy. Washington state and Oregon are considering a carbon tax. California and a coalition of eight Northeast states are setting mandatory caps on greenhouse gases and moving toward carbon markets. Oakland and 217 other U.S. cities with a total population of more than 40 million have endorsed the Kyoto treaty's limits on greenhouse gases.

More than 40 U.S. corporations in the Fortune 500 say they favor mandatory federal regulation of greenhouse gases, and many executives say they now see such emissions limits as inevitable within five to 10 years.

In Congress, the number of bills dealing with climate change has rocketed from seven in 1997 to more than 100 this year, said Truman Semans of the Pew Center on Global Climate Change.

"It shows what politicians believe it's important to have a record on, and they believe it's important to have a record on climate change," he said Thursday.

New Mexico's U.S. senators, Pete Domenici and Jeff Bingaman, who led the Senate last summer in passing a resolution favoring some form of regulation on greenhouse gases, on Tuesday held the first hearings in Congress on creating a mandatory cap on greenhouse emissions and setting up a carbon market to drive less carbon-intensive technologies.

At those hearings, trade associations for the electric-power and mining industries opposed the new rules as potentially disastrous for the U.S. economy. But executives of General Electric, Wal-Mart, Duke Energy, Exelon and other companies urged the senators to move ahead.

If a carbon market were in place that could place a price on the right to release greenhouse gases, then technologies to curb those emissions would rise in value, and the corporate risks of those emissions could be quantified by financial markets, said Kaj Jensen of Bank of America.

"It's inevitable," Jensen told Ceres members. "The only real question we think is when we will have a market in place."

Many of the answers - increased energy efficiency, conservation, expanded use of alternative fuels - already are in hand, Gore argued.

"We already have everything we need to get started on solving this crisis. We can solve it," he said. The nation overcame slavery, gave women the right to vote, defeated global fascism on two fronts simultaneously and put a man on the moon, he said. "We can do this if we set our minds to this."

Wednesday, March 29, 2006

The New Hot Zone

April 3, 2006 issue of Newsweek magazine - In the din and clamor of issues competing for public attention, there's an inner circle of causes that virtually define good citizenship. Who would argue that a mind isn't a terrible thing to waste? The quasi-official gatekeeper to this pantheon is the Ad Council, which deploys more than $1 billion in donated media time and space each year for a few dozen carefully vetted, slickly produced messages. Last week a new issue got the Ad Council's blessing, a potential catastrophe that could make college dropouts the least of our worries: global warming.

The council's two new TV spots were released on the same day as the premiere of a lavishly produced documentary, "The Great Warming," and in the same month as two major books on the subject: "The Weather Makers" by Australian biologist Tim Flannery and "Field Notes From a Catastrophe" by journalist Elizabeth Kolbert. May will also see the release of "An Inconvenient Truth," a film and book about Al Gore's one-man crusade against warming. Both the Ad Council campaign and the Gore film are linked to Web sites (, that emphasize citizen action to reduce production of greenhouse gases a departure from how the issue is usually framed, in terms of contentious political decisions about gas mileage and international treaties. "There's a moment when we move from fear to action, and I think we're there on global warming," says Fred Krupp, president of Environmental Defense, the Ad Council's partner on the campaign. Implicitly, this approach also removes the taint of partisan politics from an issue on which the Bush administration has been widely criticized. Which is not to say that the ads pull their punches. In one, a man stands in the path of a speeding train, symbolizing the threat of global warming. When he realizes the danger is decades away, he steps safely off the track, revealing a young girl standing behind him.

But what's significant is that the issue now has the high-minded imprimatur of the Ad Council, which gave the world Smokey Bear. This has not escaped the notice of people on the other side of this issue, such as James M. Taylor, the spokesperson for climate issues at the Heartland Institute, a conservative Chicago-based think tank. The Ad Council is supposed to be nonpartisan, Taylor wrote in an e-mail, but "global warming alarmism is markedly controversial ... This Ad Council campaign amounts to nothing more than an end run around a skeptical Congress, a skeptical president and a sharply split scientific community." Like the groups promoting "intelligent design" as an alternative to evolution, Taylor's outfit is fighting to convince the public that there's even a debate going on. But in a statement earlier this month he actually went further, asserting, preposterously, that the only remaining scientific debate is over how much "marginal" harm or benefit global warming will bring to humanity.

Taylor's evidence for a split in scientific opinion is a petition circulated by the eminent physicist Frederick Seitz and signed by some 17,000 scientists in various fields, calling on the United States to reject any limits on carbon emissions. It was attached to a study by four scientists, none of them climatologists, which called global warming "an invalidated hypothesis." But the paper and the petition date from 1998, and climate science has come a long way since then, says Dan Lashof, a researcher at the Natural Resources Defense Council. The paper makes much of a chart showing that atmospheric temperatures measured by satellites appeared to decline from 1979 to 1997. Then, after the paper was written, they began to climb. The climatologist who did the original satellite study, John R. Christy of the University of Alabama, who is personally skeptical of the need to control carbon dioxide, told NEWSWEEK in an e-mail that "[s]ince the El Nino of 1997-98, our satellite trend has been positive." That doesn't prove anything by itself, but it calls into question the fairness of using decade-old data to make a political point in 2006.

To be fair, neither side has a monopoly on hot air in this debate. While the Gore film is affecting and low-key as it follows him on his travels, "The Great Warming" shows exactly what's wrong with turning complex issues over to Hollywood: it's manipulative (it travels to Peru to report on the death of two boys from cholera contracted during a flood, implying a causal connection that serious scientists invariably warn against) and muddled in its use of scientific terms. But both the Kolbert and Flannery books are sober, detailed and alarming without being alarmist. Kolbert is better at evoking melting glaciers and dying butterflies, while Flannery is especially clear on the global science. Perhaps the most significant two words in his book, though, are "Paul Anderson." Anderson, chairman and CEO of Duke Energy Corp., one of the nation's largest utilities, wrote the foreword.

Which is the sort of straw in the wind that gives hope to Richard C. J. Somerville, a distinguished climatologist at Scripps Institution of Oceanography. "I'm an optimist," he says. "I think people now realize climate change is important. What they don't know yet is that something can be done about it."

Sunday, March 26, 2006

How much future sea level rise?

Lots of press has been devoted to four papers in this week's Science, on the topic of ice sheets and sea level.

We've already discussed the new evidence that Greenland's glaciers are speeding up. What is new this week is an effort to evaluate the impact of future warming on Greenland by looking at what happened to it last time it got very warm -- namely during the Last InterGlacial (LIG) period, about 125,000 years ago. The same group of authors looked at this in two ways, using NCAR's Community Climate System model (CCSM) coupled to a state-of-the-art 3-D ice sheet model.

First, in a paper by Otto-Bliesner et al. they ran simulations for the Last Interglacial, and took a look at what happened to the ice sheets. They find that most of the icefields in Arctic Canada and Iceland disappear, and that the Greenland ice sheet is reduced to a steep ice dome in central and northern Greenland. These results are in very good agreement with the available ice core and other paleoclimate data evidence, which indeed show that the Canadian ice sheets disappeared during the LIG, and strongly suggest that much of southern Greenland was deglaciated.

Second, in a paper by Overpeck et al., they examine the implications for past and future sea level rise. The results show that the Greenland and other Arctic ice sheets probably did not contribute more than 3.4 m to the LIG sea level rise. However, data from coral reefs exposed above sea level today, and other evidence, point to an LIG sea level at least 4 m and possibly as much as 6 m greater than today. This suggests that the balance came from the Antarctic ice sheet. This is turn implies a strong sensitivity of the Antarctic ice sheet to sea level rise and climate warming -- an idea that goes back to John Mercer (1976) but that had until recently fallen out of favor in much of the glaciology community.

Projecting forward in time, the implication is that our future will also see 4-6 m of sea level rise, and that -- given the recent evidence for accelerated flow of both Greenland and Antarctic glaciers -- this may occur much faster than we expect. In the model simulations, Greenland may already be warmer in 2100 than it was at the height of the LIG. The rate of sea level rise associated with the warming into the last interglacial was probably greater than 10 mm/yr* while current sea level rise is roughly 3 mm/yr. To the extent that the LIG is a good analog for our future, sea level rise is therefore rather likely to accelerate.

Also in this week's Science are two articles that further strengthen the case that ice sheets are quite sensitive to warming climate. A paper by Gran Ekstrm et al. shows that the increased speed of Greenland glaciers occurs in distinct lurches (observed as micro "ice-quakes") that are strongly seasonal, with the greatest number occuring in late summer. This provides evidence that meltwater plays an important role in the acceleration of Greenland's glaciers. Essentially, the idea is that surface melting that occurs in the summer can make its way quickly down to the glacier bed, lubricating the bed and allowing the glaciers to slide more rapidly. The "ice quakes" occur because the rough bedrock surface causes the glaciers to stick; they only accelerate when enough hydraulic pressure has built up to help float the glacier over the bumps. This is strong evidence that climate, not merely "internal ice sheet dynamics", has contributed to the recent increases in Greenland's glaciers. Indeed, a doubling of the rate of quakes has occurred over the past five years, just as the aerial extent of surface melting has increased.

Finally, in a very nice bit of work Velicogna and Wahr use data from the "Gravity Recovery and Climate Experiment" (GRACE) satellites to show that the Antarctic ice sheet has been losing mass at a rate of 150 +/- 80 km3 each year since 2002. That's equivalent to about 0.4 mm of sea level rise each year. This is about twice other recent estimates, while IPCC 2001 actually gives negative 0.1 mm/yr. What is especially nice about Velicogna and Wahr's study is that by using gravity measurements they have measured mass changes directly, avoiding the problem of virtually all previous measurements of ice sheet mass change, which usually measure either input (snowfall) or loss (calving, melting, or thinning of the ice), but not both at once.

What does all this news mean in practice? Reading the editorials in Science, and quotations from various researchers in newspaper articles, one might be under the impression that we should now expect "catastrophic sea-level rise" (as Science's Richard Kerr writes). Of course, what is catastrophic to the eye of a geologist may be an event taking thousands of years. In the Otto-Bliesner et al. simulations, it takes 2000-3000 years for Greenland to melt back to its LIG minimum size. And while we don't advocate sticking with the typical politician's time frame of 4 or 5 years, the new results do not require us to revise projections of sea level rise over the next century or so. This is because even with Arctic temperature continuing to rise rapidly, there will still be significant delay before the process of ice sheet melting and thinning is complete. There is uncertainty in this delay time, but this is already taken into account in IPCC uncertainty estimates. It is also important to remember that the data showing accelerating mass loss in Antarctica and rapid glacier flow in Greenland only reflect a very few years of measurements -- the GRACE satellite has only been in operation since 2002, so it provides only a snapshot of Antarctic mass changes. We don't really know whether these observations reflect the long term trend.

On the other hand, none of the new evidence points in the direction of smaller rates of sea level rise in the future, and probably nudge us closer to the upper end of the IPCC predictions. Those who have already been ignoring or naysaying those predictions now have even less of a leg to stand on. Coastal managers, real estate developers, and insurance companies, at the least, would be wise to continue to take such predictions seriously.** As Don Kennedy and Brooks Hanson write in the lead Editorial, "accelerated glacial melting and larger changes in sea level should be looked at as probable events, not as hypothetical possibilities." (source: RealClimate)

Potential for another record hurricane season

The formation of tropical storm Epsilon far out in the Atlantic in late December, 2005 (lingering into early January, 2006) is a fitting bookend to the busiest hurricane season ever recorded.

This season, which began June 1, started out as the busiest on record, with 4 named storms by July 5.

It soon got worse.

Hurricanes Katrina and Rita were the most devastating highlights. Katrina has been called the most destructive U.S. storm ever.

Epsilon, No. 26 for those keeping track, is destined to head northeast and die over open water. But it is a rare storm, forming in the final moments of the season, which officially ends Nov. 30. The rarity only adds to what was by all accounts an unusual year.

The season included 26 named storms, the most ever. Of those, 13 became hurricanes; again, the most ever. Seven major hurricanes formed, being Category 3 or stronger. Four of those major hurricanes made landfall in the United States -- another record.

And finally, 2005 saw an unprecedented three storms reach Category 5 status.

More to come

And now the bad news: This year was part of a natural active cycle that began in 1995 and is expected to continue. Even worse, storm intensity may be increasing due to global warming, some scientists believe. And warmer seas may also be fueling more of the major hurricanes.

"Arguably, it was the most devastating hurricane season the country has experienced in modern times, said Conrad C. Lautenbacher, Jr., the administrator of NOAA, the parent organization to the National Weather Service and the National Hurricane Center. I'd like to foretell that next year will be calmer, but I can't. Historical trends say the atmosphere patterns and water temperatures are likely to force another active season upon us.

Long term conditions such as warmer-than-average sea-surface temperatures and low wind shear in the upper atmosphere are among the factors expected to fuel activity in coming years, forecasters say.

"Evidence of this active cycle was demonstrated this year as the Atlantic Basin produced the equivalent of more than two entire hurricane seasons over the course of one," David L. Johnson, director of the National Weather Service. "Because we are in an active hurricane era, it's important to recognize that with a greater number of hurricanes comes increasing odds of one striking land."

So busy ...

(2005) was so busy the Hurricane Center ran out of names and had to switch to the Greek alphabet for the first time. A handful of letters are not used in the regular list of 21 names.

Hurricane Wilma, which exhausted the standard list of 21 names, set its own record. It was briefly the strongest hurricane ever recorded.

Tropical Storm Alpha and Hurricane Beta hit the Dominican Republic and Nicaragua, respectively. Tropical Storm Gamma brought deadly flooding to parts of Central America. Tropical Storm Delta largely stayed over open water then moved across the Canary Islands off the northwest coast of Africa. (source: Live Science)

2005 vies for the hottest year on record

Global average surface temperatures pushed 2005 into a virtual tie with 1998 as the hottest year on record.[1] For people living in the Northern Hemisphere most of the world's population, 2005 was the hottest year on record since 1880, the earliest year for which reliable instrumental records were available worldwide.

The year 2005 exceeded previous global annual average temperatures despite having weak El Nino conditions at the beginning of the year and normal conditions for the rest of the year. (El Nino is a period of warmer-than-average sea surface temperatures in the east-central Pacific Ocean that influences weather conditions across much of the globe.) In contrast, the record-breaking temperatures of 1998 were boosted by a particularly strong El Nino.

The record heat of 2005 is part of a longer-term warming trend exacerbated by the rise of heat-trapping gases in our atmosphere that is due primarily to our burning fossil fuels and clearing forests. Nineteen of the hottest 20 years on record have occurred since 1980.

The record surface temperatures of the past 20 years reinforce other indications that global warming is under way. For example, the observed rise in average surface temperatures has been accompanied by warming of the atmosphere and oceans, and increased melting of ice and snow. These observations, summarized briefly below, paint a consistent picture of widespread and significant changes in global climate over the past several decades.

Evidence of Twentieth Century Global Warming

Warming of the Troposphere

The latest report on U.S. emissions found that 2004 marked the highest annual total of heat-trapping gases released since record keeping began in 1990

A 2005 re-analysis of satellite observations of temperature trends in the troposphere, the layer of atmosphere extending about five miles up from Earth's surface uncovered errors in previous studies. The updated studies show that air temperatures have increased in the past 20 years or so, consistent with the fundamental understanding that increases in surface temperatures are accompanied by increases in air temperatures above the surface. The new results are also consistent with recent increases in tropospheric water vapor, which would be expected when rising temperatures accelerate ocean evaporation.

By comparing several sets of data from satellites and weather balloons, these new atmospheric analyses account for drifts in satellite orbits and changes in instrumentation over the measurement period. While the corrected results represent only one of several pieces of global warming evidence, they are important in part because the earlier flawed analysis has often been cited.

Melting of Snow and Ice

Further evidence of widespread warming comes from observations of seasonal snow and frozen ground coverage.

The extent and duration of frozen ground have declined in most locations. Snow cover in the Northern Hemisphere has declined about five percent over the past 30 years, particularly in late winter and spring, and the freezing altitude has risen in every major mountain chain. Alpine and polar glaciers have retreated since 1961, and the amount of ice melting in Greenland has increased since 1979. Over the past 25 years, the average annual Arctic sea ice area has decreased by almost five percent and summer sea ice area has decreased by almost 15 percent. The collapse of the Larsen Ice Shelf off the Antarctic Peninsula appears to have no precedent in the last 11,000 years. (source: Union of Concerned Scientists).

Latest research confirms spike in severe hurricanes

While the question of what role, if any, humans have had in all this is still a matter of intense debate, most scientists agree that stronger storms are likely to be the norm in future hurricane seasons.

The study is detailed in the March 17 issue of the journal Science.

In the 1970s, the average number of intense Category 4 and 5 hurricanes occurring globally was about 10 per year. Since 1990, that number has nearly doubled, averaging about 18 a year.

Category 4 hurricanes have sustained winds from 131 to 155 mph. Category 5 systems, such as Hurricane Katrina at its peak, feature winds of 156 mph or more. Last year, Wilma packed wind speeds of 175 mph and set a record as the strongest hurricane in terms of barometric pressure.

While some scientists believe this trend is just part of natural ocean and atmospheric cycles, others argue that rising sea surface temperatures as a side effect of global warming is the primary culprit.

According to this scenario, warming temperatures heat up the surface of the oceans, increasing evaporation and putting more water vapor into the atmosphere. This in turn provides added fuel for storms as they travel over open oceans.

The researchers used statistical models and techniques from a field of mathematics called information theory to determine factors contributing to hurricane strength from 1970 to 2004 in six of the world's ocean basins, including the North Atlantic, Pacific and Indian oceans.

They looked at four factors that are known to affect hurricane intensity:

* Humidity in the troposphere, the part of the atmosphere stretching from surface of the Earth to about 6 miles up.
* Wind shear that can throttle storm formation.
* Rising sea-surface temperatures.
* Large-scale air circulation patterns known as "zonal stretching deformations".

Of these factors, only rising sea surface temperatures was found to influence hurricane intensity in a statistically significant way over a long-term basis. The other factors affected hurricane activity on short time scales only.

"We found no long-term trend in things like wind shear," said study team member Judith Curry of the Georgia Institute of Technology. "There's a lot of year to year variability but there's no global trend. In any given year, it's different for each ocean."

Answering critics
The new study potentially addresses one major criticism leveled by scientists skeptical of any strong link between sea surface temperatures and hurricane strength, said Kerry Emanuel, a climatologist at the Massachusetts Institute of Technology who was not involved in the study.

Last year, Emanuel published a study correlating the documented increase in hurricane duration and intensity in the Atlantic and Pacific oceans since the 1970s to rises in sea surface temperatures over the same time period.

"We were criticized by the seasonal forecasters for not including the other environmental factors, like wind shear, in our analysis," Emanuel said in an email. "[We didn't do so] because on time scales longer than 2-3 years, these do not seem to matter very much. This paper more or less proves this point."

Kevin Trenberth, the head of climate analysis at the National Center for Atmospheric Research (NCAR), believes the new study's main finding is accurate but thinks the effects of some of the environmental factors on hurricane intensity might have been underestimated.

"The reason is they're covering a period from 1970 to 2004. 1979 is the year when satellites were introduced into the [NCEP/NCAR] Reanalysis. The quality of the analysis prior to 1979 is simply nowhere near as good," said Trenberth, who also was not involved in the study.

The NCEP/NCAR Reanalysis is the database the researchers drew upon for information about the effects of troposphere humidity, wind shear and zonal stretching deformation on hurricane intensity; sea surface temperature data came from a different database.

Curry acknowledged that reanalysis data prior to 1979 is of slightly lower quality than more recent data but believes this doesn't substantially change the study's main finding. Trenberth agreed: "I suspect they may well have gotten the right answer anyway," he told LiveScience.

These cycles definitely do influence hurricane intensity, but they can't be the whole story, Curry said.

While scientists expect stronger hurricanes based on natural cycles alone, the researchers suspect other contributing factors, since current hurricanes are even stronger than natural cycles predict.

"We're not even at the peak of current cycle, we're only halfway up and already we're seeing activity in the North Atlantic that's 50 percent worse than what we saw during the last peak in 1950," Curry said.

Some scientists still think it's too premature to make any definitive links between sea surface temperatures and hurricane intensity.

"We simply don't have enough data yet," said Thomas Huntington in of the U.S. Geological Survey. "Category 5 hurricanes don't come around very often, so you need the benefit of a much longer time series to look back and say 'Yup, there has been an increase.'"

Huntington is the author of a recent review of more than 100 peer-reviewed studies showing that although many aspects of the global water cycle — including precipitation, evaporation and sea surface temperatures — have increased or risen, the trend cannot be consistently correlated with increases in the frequency or intensity of storms or floods over the past century. Huntington's study was announced this week and is published in the current issue of the Journal of Hydrology.

Whatever the underlying cause, most scientists agree that people will need to brace themselves for stronger hurricanes and typhoons in the coming years and decades.

However, most regions around the world will not experience more storms. The only exception to this is the North Atlantic, where hurricanes have become both more numerous and longer-lasting in recent years, especially since 1995. The reasons for this regional disparity are still unclear.

The team's findings are controversial because they draw a connection between stronger hurricanes and rising sea surface temperatures — a phenomenon that has itself already been linked to human-induced global warming.

The study by Curry and her colleagues therefore raises the frightening possibility that humans have inadvertently boosted the destructive power of one of Nature's most devastating and feared storms.

"If humans are increasing sea surface temperatures and if you buy this link between increases rising sea surface temperatures and increases in hurricane intensity, that's the conclusion you come to," Curry said.

Tuesday, January 03, 2006

California floods, while Texas burns

Posted by Picasa Dry conditions and gusty winds are fanning fast-moving grassland fires in southern Oklahoma and northern Texas in the first part of 2006. Several ranching and farm communities have been devastated by the blazes, some of which were as large as 40,000 acres according to local news reports. This image of the south-central United States on January 2, 2005, shows several fires in Oklahoma (north) and Texas (south). The image and fire detections (marked in red) were captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite. Just south of the border between the two states, a thin, brown burn scar marks the location of the small town of Ringgold, Texas, which, according to news reports, was almost completely destroyed by a grassland fire on January 1, 2005.

NASA image created by Jesse Allen, Earth Observatory, using data obtained courtesy of the MODIS Rapid Response team.

Tropical Storm "Zeta"

Posted by Picasa December 30, 2005, saw an unexpected addition to the year’s weather events: Tropical Storm Zeta. The Moderate Resolution Imaging Spectroradiometer (MODIS) flying onboard the Aqua satellite captured this image several days later on January 2, 2006, at 16:05 UTC (roughly 2:05 p.m. local time). At that time, Zeta had sustained winds of around 82 kilometers per hour (52 miles per hour), a steady strength the storm has now maintained for several days without relenting, waxing, or waning.

After the previous record-holding storm season of 1933, which saw 21 named storms, weather forecasters established a convention of using just 21 letters of the alphabet (the last letter being W) to begin the names of Atlantic tropical storms. After Hurricane Wilma in October 2005, forecasters turned to the Greek alphabet. Zeta is the sixth letter of that alphabet, and this is the 27th named storm of 2005. One month after 2005’s record-breaking storm season officially ended, this storm appeared roughly 1,600 kilometers (1,000 miles) to the southwest of the Azores Islands.

Saturday, November 26, 2005

Old bubbles back global warming theory

 Posted by Picasa There is more carbon dioxide in the atmosphere today than at any point during the last 650,000 years, says a new study that let scientists peer back in time at greenhouse gases that can help fuel global warming.

By analyzing tiny air bubbles preserved in Antarctic ice for millennia, a team of European researchers shows how people are dramatically influencing the buildup of these gases.

The research promises to spur "dramatically improved understanding" of climate change, said geosciences specialist Edward Brook of Oregon State University.

The study, by the European Project for Ice Coring in Antarctica, will be published today in the journal Science.

Scientists now directly measure levels of carbon dioxide and other greenhouse gases, which accumulate in the atmosphere as a result of fuel-burning and other processes. Those gases help trap solar heat, like the greenhouses for which they are named, resulting in a gradual warming of the planet.

Those measurements are disturbing:

# The levels of carbon dioxide have climbed from 280 parts per million two centuries ago to 380 p.p.m. today.

# The Earth's average temperature, meanwhile, increased by about 1 degree Fahrenheit in recent decades, a relatively rapid rise.

Many climate specialists warn that continued warming could have severe impacts, such as rising sea levels and changing rainfall patterns.

Skeptics sometimes dismiss the rise in greenhouse gases as part of a naturally fluctuating cycle. The new study provides ever-more definitive evidence countering that view.

Deep Antarctic ice encases tiny air bubbles formed when snowflakes fell over hundreds of thousands of years.

Extracting the air allows a direct measurement of the atmosphere at past points in time, to find the naturally fluctuating range.

A previous ice-core sample had traced greenhouse gases back about 440,000 years. This new sample, from East Antarctica, goes 210,000 years further back in time.

Today's still rising level of carbon dioxide already is 27% higher than its peak during all those millennia, said lead researcher Thomas Stocker of the University of Bern in Switzerland."We are out of that natural range today," he said.

Moreover, that rise is occurring at a speed that "is over a factor of a hundred faster than anything we are seeing in the natural cycles," Stocker added. "It puts the present changes in context."

The team found similar results for methane, another greenhouse gas.

Researchers also compared the gas levels with the Antarctic temperature over that time period, covering eight cycles of alternating glacial or ice ages and warm periods.

They found a stable pattern: Lower levels of gases during cold periods and higher levels during warm periods.

The bottom line: "There's no natural condition that we know about in a really long time where the greenhouse gas levels were anywhere near what they are now. And these studies tell us that there's a strong relationship between temperature and greenhouse gases," said Oregon State's Brook. The article can be found at (Associated Press, as reported in the Detroit Free Press)

Rise in gases unmatched by a history in ancient ice

 Posted by Picasa (New York Times) Shafts of ancient ice pulled from Antarctica's frozen depths show that for at least 650,000 years three important heat-trapping greenhouse gases never reached recent atmospheric levels caused by human activities, scientists are reporting today.

The measured gases were carbon dioxide, methane and nitrous oxide. Concentrations have risen over the last several centuries at a pace far beyond that seen before humans began intensively clearing forests and burning coal, oil and other fossil fuels.

The sampling and analysis were done by the European Program for Ice Coring in Antarctica, and the results are being published today in the journal Science.

The evidence was found in air bubbles trapped in successively older ice samples extracted from a nearly two-mile-deep hole drilled in a remote spot in East Antarctica called Dome C.

Experts familiar with the findings who were not involved with the research said the samples provided a vital long-term view of variations in the atmosphere and Antarctic climate. They say the data will help test and improve computer models used to forecast how accumulating greenhouse emissions will affect the climate.

Some climate experts not involved in the research said the findings also confirmed that the buildup of carbon dioxide and other heat-trapping smokestack and tailpipe emissions was taking the atmosphere into uncharted territory.

The longest previous record of carbon dioxide fluctuations, compiled from ice cores collected at the Russian research station at Vostok, in East Antarctica, goes back slightly more than 400,000 years.

"They've now pushed back two-thirds of a million years and found that nature did not get as far as humans have," said Richard B. Alley, a geosciences professor at Pennsylvania State University who is an expert on ice cores. "We're changing the world really hugely - way past where it's been for a long time."

James White, a geology professor at the University of Colorado, Boulder, not involved with the study, said that although the ice-age evidence showed that levels of carbon dioxide and the other greenhouse gases rose and fell in response to warming and cooling, the gases could clearly take the lead as well.

"CO2 and climate are like two people handcuffed to each other," he said. "Where one goes, the other must follow. Leadership may change, or they may march in step, but they are never far from each other. Our current CO2 levels appear to be far out of balance with climate when viewed through these results, reinforcing the idea that we have significant modern warming to go."

The new data from the ice cores also provides the first detailed portrait of conditions during ice-age cycles that occurred more than 400,000 years ago - a point in Earth's two-million-year history of cold periods and warm intervals after which some unknown influence lengthened ice ages and shortened and amplified the warm periods.

Both before and after that transition, the ice record shows, there was always a tight relationship between amounts of the greenhouse gases and air temperature.

While the overall climate pattern has been set by rhythmic variations in Earth's orientation to the Sun, the records show that carbon dioxide and methane consistently made the interglacial climate warmer than it would otherwise have been, said Thomas Stocker, one of the researchers and a physicist at the University of Bern in Switzerland.

Last year, the same cores provided new evidence that the current warm period, the Holocene, which began about 12,000 years ago, is similar to the longer warm periods that were typical before 400,000 years ago, and could last at least another 16,000 years.

The European team is analyzing deeper, older sections of the Dome C ice cores, and the researchers said they might be able to take the climate record back 800,000 years, possibly providing information about yet another early warm interval similar to the Holocene.

The new long-term record is essentially creating a subset of climate science, letting scientists compare different warm periods. They can then sort out influences, including greenhouse gases, said Gavin A. Schmidt, a climate modeler at the Goddard Institute for Space Studies in Manhattan.

Monday, November 21, 2005

Wilma's rage suggests new category may be needed for extreme hurricanes

 Posted by Picasa (LiveScience) In a season that has included three Category 5 hurricanes for the first time on record in the Atlantic Basin, scientists are beginning to wonder if their rating system is adequate, LiveScience has learned.

On the Saffir-Simpson hurricane scale, there is no Category 6. But Hurricane Wilma this week brushed up against where a 6 would be if the scale were logically extrapolated to include another category.

And hurricanes are getting stronger, apparently fueled by global warming. Researchers expect that trend to continue.

Kerry Emanuel, a climatologist at the Massachusetts Institute of Technology, calls the Saffir-Simpson scale irrational, in part because it deals only with wind. "I think the whole category system needs serious rethinking," Emanuel told LiveScience.

But in a telephone interview, the 88-year-old co-creator of the scale, Herbert Saffir, defended it as simple and useful for the public.

"As simple as it is, I like the scale," Saffir said today. "I don't like to see it too complex."The history of the scale

In 1967, the United Nations commissioned Saffir, a Florida consultant engineer, to study low-cost housing in regions of the world that were prone to tropical cyclones and hurricanes.

Saffir realized there was no way to describe the effects of a hurricane, so he developed his own five-category scale. Later, Robert Simpson, then director of the National Hurricane Center, modified Saffir's work, adding measurements for flooding and storm surge.

The result was the Saffir-Simpson Hurricane Rating scale. A Category 1 storm begins at 74 mph and a Category 5 at 156 mph. On average, there is about a 20 mph increment in wind speed between the categories.

An extrapolation suggests that if a Category 6 were there, it would be in the range of 176-196 mph. Hurricane Wilma, which had maximum recorded wind speeds of 175 mph, would have been on the verge of breaking into this hypothetical new category.

The scale didn't include a Category 6 for two reasons.

First, it was designed to measure the amount of damage inflicted by a hurricane's winds, and beyond 156 mph, the damage begins to look about the same, according to Simpson.

"When you get up into winds in excess of 155 mph you have enough damage," Simpson said in a 1999 interview with the National Weather Log, a publication of the National Oceanic and Atmospheric Administration.

"If that extreme wind sustains itself for as much as six seconds on a building it's going to cause rupturing damages that are serious no matter how well it's engineered. So I think that it's immaterial what will happen with winds stronger than 156 miles per hour. That's the reason why we didn't try to go any higher than that," Simpson said.

Another reason is that Category 5 hurricanes are relatively rare, or at least they used to be.

"In general, I didn't expect that there would be too many hurricanes that went [above] 155 miles per hour for sustained winds," Saffir said. "The limit seems to be about 175 miles per hour and I don't know of anything that goes much over that."

Some scientists predict, however, that the intensity of hurricanes and their maximum wind speeds may be increasing and that Category 4 and 5 storms will become more common in the years to come.

Behind the beast

Ocean and atmospheric temperatures work together to determine the maximum wind speed attainable. This value is known as the "maximum potential hurricane intensity" and is calculated using a formula developed in 1998 by Emanuel, the MIT climatologist.

Based on ocean and atmospheric conditions on Earth nowadays, the estimated maximum potential for hurricanes is about 190 mph.

This upper limit is not absolute, however. It can change as a result of changes in climate. Scientists predict that as global warming continues, the maximum potential hurricane intensity will go up. They disagree, however, on what the increase will be.

Emanuel and other scientists have predicted that wind speeds—including maximum wind speeds—should increase about 5 percent for every 1 degree Celsius increase in tropical ocean temperatures.

Chris Landsea, a meteorologist at the National Hurricane Center, disagrees.

Landsea believes that even in the worst-case global warming scenarios, where global temperatures ratchet up by an additional 1-6 degrees Celsius, there would be about a 5 percent change, total, by the end of the 21st Century. That means that hurricane-force winds are unlikely to exceed 200 mph, Landsea said.

The fastest "regular" wind that's widely agreed upon was 231 mph, recorded at Mount Washington, New Hampshire, on April 12, 1934. During a May 1999 tornado in Oklahoma, researchers clocked the wind at 318 mph.

Time for a new scale?

Some scientists believe that the Saffir-Simpson scale is too simplistic and that it should either be extended or replaced.

"A rational scale would have equal increments of either the wind speed squared or the wind speed cubed," Emanuel said today. "There's nothing like that [with the Saffir-Simpson scale], it's all over the place. I think it will ultimately be revised."

Other critics have pointed out that the Saffir-Simpson scale doesn't take into account a hurricane's size or the amount of rainfall.

The rains associated with some hurricanes can lead to flooding that causes just as much or more death and damage than wind.

A hurricane's size can also make a large difference in the amount of damage it inflicts. Hurricane Katrina, which was a Category 5 storm before weakening prior to landfall, caused much more damage than Camille—another Category 5 hurricane that struck in 1969. Katrina was a much larger. Katrina's hurricane-force winds extended 105 miles from its center while Camille's only extended 60 miles out.

Emanuel says a new hurricane rating system will need to have at least three numbers, describing not only wind speed, but also rainfall and storm size.

"It will also be continuous, so you can have a category 4.6 or 4.7, and it will be open-ended, so that the categories just keep going up," Emanuel said.

Saffir says: Keep it simple

Adding too many variables into a rating system would make it too complex, Saffir said. Part of the reason that the Saffir-Simpson scale has lasted so long is because it is easy for the public to grasp.

"Every hurricane is different," Saffir said today, "so you really couldn't categorize every type of hurricane as far as size and extent. As far as rainfall goes, we already have a scale for rainfall; it's measured in inches and I think that's really all that's needed."

But some critics argue that the simplicity of the scale often comes at the price of accuracy.

A new hurricane rating system might indeed become too complex for the public to easily understand, but in a way, the public doesn't have to understand it, Emanuel said.

"If you just think about it, the public's not directly involved in the decision to evacuate based on weather forecasts. In the case of Katrina, the mayor of New Orleans said, 'Get out.' It's important that the mayor and his associates or emergency managers understand the three numbers, but it's not so important that the public does."

Thursday, November 17, 2005

Rising sea levels threaten New Jersey

(Reuters) Rising sea levels caused by global warming could shrink New Jersey by up to 3 percent in the next 100 years, U.S. scientists warned on Wednesday.

The Princeton University researchers also projected that as much as 9 percent of the state's low-lying land could be hit by periodic coastal flooding in a trend that would devastate property, disrupt wildlife, erode beaches, and salinate drinking water in populated areas.

"Sea level rise is a significant and growing threat to New Jersey," Princeton professors Matthew Cooper, Michael Beevers and Michael Oppenheimer wrote in the report titled "Future Sea Level Rise and the New Jersey Coast."

Coastal development, which has surged in recent years, is increasingly susceptible to inundation by rising sea waters, the erosion of beaches and low-lying areas, and storm-induced flooding, the report said.

New Jersey's coastal counties, which contain about 60 percent of the state's 8.6 million people, are vulnerable to rising sea levels because of a flat coastal plain, a gently sloping shoreline and barrier islands, beaches and salt marshes.

The combination can produce extensive shoreline changes with relatively small rises in sea level, the report said.

New Jersey authorities have responded to the threat by taking steps such as reinforcing flood-prone structures and building up dunes, but those efforts are likely to fail, it said.

The best response to rising sea levels is to restrict development in vulnerable coastal areas, the researchers concluded.

The authors called for a reduction in greenhouse gas emissions, which many scientists believe lead to global warming, as the most effective way of reducing the rate of sea-level rise.

Cutting emissions would have a limited effect on sea levels over the next 50 years, but it could slow the rate by 2100 and beyond, the report said.

Worldwide, sea levels are expected to rise between 0.09 and 0.88 meter (0.29 and 2.88 feet) between 1990 and 2100, the report said, citing figures from the Intergovernmental Panel on Climate Change.

In New Jersey, the rise is projected at an overall 0.71 meter (2.3 feet) over the period. Posted by Picasa

Wednesday, November 02, 2005

14.5 degree temperature rise by the year 2300?

(Science Daily and Lawrence Livermore Laboratory) If humans continue to use fossil fuels in a business as usual manner for the next several centuries, the polar ice caps will be depleted, ocean sea levels will rise by seven meters and median air temperatures will soar 14.5 degrees warmer than current day.

Lawrence Livermore modeled carbon emissions and climate change from pre-industrial levels (1870) through 2300. This animation shows how the present (year 2000) global mean surface temperature change of 0.8�C increases to 7.8�C by 2300. Land areas warm more than the oceans. Arctic and Antarctic regions warm more than the tropics. Note the extreme warming of more than 20�C over the Arctic by 2300. (Animation: Michael Wickett)

These are the stunning results of climate and carbon cycle model simulations conducted by scientists at the Lawrence Livermore National Laboratory. By using a coupled climate and carbon cycle model to look at global climate and carbon cycle changes, the scientists found that the earth would warm by 8 degrees Celsius (14.5 degrees Fahrenheit) if humans use the entire planet's available fossil fuels by the year 2300.

The jump in temperature would have alarming consequences for the polar ice caps and the ocean, said lead author Govindasamy Bala of the Laboratory's Energy and Environment Directorate.

In the polar regions alone, the temperature would spike more than 20 degrees Celsius, forcing the land in the region to change from ice and tundra to boreal forests. "The temperature estimate is actually conservative because the model didn't take into consideration changing land use such as deforestation and build out of cities into outlying wilderness areas," Bala said.

Today's level of atmospheric carbon dioxide is 380 parts per million (ppm). By the year 2300, the model predicts that amount would nearly quadruple to 1,423 ppm.

In the simulations, soil and living biomass are net carbon sinks, which would extract a significant amount of carbon dioxide that otherwise, would be remaining in the atmosphere from the burning of fossil fuels. However, the real scenario might be a bit different.

"The land ecosystem would not take up as much carbon dioxide as the model assumes," Bala said. "In fact in the model, it takes up much more carbon than it would in the real world because the model did not have nitrogen/nutrient limitations to uptake. We also didn't take into account land use changes, such as the clearing of forests."

The model shows that ocean uptake of CO2 begins to decrease in the 22nd and 23rd centuries due to the warming of the ocean surface that drives CO2 fluctuations out of the ocean. It takes longer for the ocean to absorb CO2 than biomass and soil.

By the year 2300, about 38 percent and 17 percent of the carbon dioxide released from the burning of all fossil fuels are taken up by land and the ocean, respectively. The remaining 45 percent stays in the atmosphere.

Whether carbon dioxide is released in the atmosphere or the ocean, eventually about 80 percent of the carbon dioxide will end up in the ocean in a form that will make the ocean more acidic. While the carbon dioxide is in the atmosphere, it could produce adverse climate change. When it enters the ocean, the acidification could be harmful to marine life.

The models predict quite a drastic change not only in the temperature of the oceans but also in its acidity content, that would become especially harmful for marine organisms with shells and skeletal material made out of calcium carbonate.

Calcium carbonate organisms, such as coral, serve as climate-stabilizers. When the organisms die, their carbonate shells and skeletons settle to the ocean floor, where some dissolve and some are buried in sediments. These deposits help regulate the chemistry of the ocean and the amount of carbon dioxide in the atmosphere. However, earlier Livermore research found that unrestrained release of fossil-fuel carbon dioxide to the atmosphere could threaten extinction for these climate-stabilizing marine organisms.

"The doubled-CO2 climate that scientists have warned about for decades is beginning to look like a goal we might attain if we work hard to limit CO2 emissions, rather than the terrible outcome that might occur if we do nothing," said Ken Caldeira, of the Department of Global Ecology at the Carnegie Institution and one of the other authors.

Bala said the most drastic changes during the 300-year period would be during the 22nd century in which precipitation change, an increase in atmospheric precipitable water and a decrease in sea ice size are the largest when emissions rates are the highest. During the model runs, sea ice cover disappears almost completely in the northern hemisphere by the year 2150 during northern hemisphere summers.

"We took a very holistic view," Bala said. "What if we burn everything? It will be a wake up call in climate change."

As for the global warming skeptics, Bala said the proof is already evident. "Even if people don't believe in it today, the evidence will be there in 20 years," he said. "These are long-term problems."

He pointed to the 2003 European heat wave, and the 2005 Atlantic hurricane season as examples of extreme climate change. "We definitely know we are going to warm over the next 300 years," he said. "In reality, we may be worse off than we predict."

Other Livermore authors include Arthur Mirin and Michael Wickett, and Christine Delire of ISE-M at the Universit� Montepellier II. The research appears in the Nov. 1 issue of the American Meteorological Society's Journal of Climate.

Global warming cause of more intense hurricanes?

(NBC News) In recorded history, two storms as powerful as Hurricanes Rita and Katrina have never hit the United States in one season. A coincidence, perhaps, but scientists say ocean temperature could be big factor.

"If you think of a hurricane like a car," explains NASA's Dr. David Adamec, "there are a lot of parts that keep it going, but the sea surface temperature and the heat that is provided by the ocean, that is the gasoline that fuels it."

In the Gulf of Mexico, there is a lot of fuel right now. To measure sea temperature, researchers use buoys that transmit readings directly, as well as remote sensing satellites. Those readings have found record temperatures in the gulf and Atlantic Ocean this year.

"The sun was having an easy time reaching the sea surface and just warmed up the water," says Adamec, "and just made it ripe for a lot of strong intense hurricanes this year."

The big question is will the trend continue in future years?

Scientists say one season, even like this one, cannot indicate anything about climate change. But those same measurements show that in the past 50 years the oceans have gotten one degree warmer. That may not sound like much, but the experts say it is a lot of energy.

Indeed, recent studies show that, worldwide, the number of Category 4 and 5 hurricanes has doubled with that one degree change and that�s a source of worry.

"At the moment we've only warmed up one," says Dr. Stephen Schnieder, a climatologist at Stanford's Institute for International Studies. "What happens when we warm up three or five degrees - which is projected in the next several decades to the end of the century?�

It's global warming that many experts say results partly from humans releasing greenhouse gases - possibly creating even more violent storms in the future.

New study warns of total loss of arctic tundra

(New York Times) If emissions of heat-trapping gases continue to accumulate in the atmosphere at the current rate, there may be many centuries of warming and a near-total loss of Arctic tundra, according to a new climate study.

Over all, the world would experience profound transformations, some potentially beneficial but many disruptive, and all at a pace rarely seen in nature, said the authors of the study, being published today in The Journal of Climate.

"The question is no longer whether we will need to address this problem, but when we will need to address the problem," said Kenneth Caldeira, an author of the study and a climate expert at the Carnegie Institution's Department of Global Ecology, based at Stanford University.

"We can either address it now, before we severely and irreversibly damage our climate, or we can wait until irreversible damage manifests itself strongly," Dr. Caldeira said. "If all we do is try to adapt, things will get worse and worse."

The paper's lead author, Bala Govindasamy of the Energy Department's Lawrence Livermore National Laboratory, said it might take 20 or 30 years before the scope of the human-caused changes becomes evident, but from then on there is likely to be no debate.

The researchers ran a computer model that simulates both the climate system and the flow of heat-trapping carbon into the air in the form of carbon dioxide, then back into soils and the ocean.

Most simulations of the potential human impact on climate have been confined to studying the next 100 years or so, but in this case the scientists started the calculations in 1870 and let the computers churn away through 2300.

The authors stressed that the uncertainties were high over such a time span, and said the study was intended to illustrate broad consequences rather than project specific ones.

They programmed the model to run as if the atmospheric concentration of carbon dioxide rose about 0.45 percent a year through 2300. That is slightly less than the current rate, about 0.5 percent.

In the simulation, the concentration of carbon dioxide doubles from pre-industrial levels in 2070, triples in 2120, and quadruples in 2160.

The results are sobering, Dr. Caldeira and other climate experts said, because the computer model used in this study tends to produce less warming from a greenhouse-gas buildup than many of the other climate simulations being run by other research teams.

It also presumes that plants and the ocean will continue to sop up carbon dioxide in the future, limiting the amount retained in the atmosphere. Many other independently developed models calculate that at some point, chemical and biological shifts caused by warming would reverse that flow and cause even more greenhouse gases to flood into the atmosphere.

Consistent with many other studies, the model showed that the Arctic would see the most warming, with average annual temperatures in many parts of Arctic Russia and northern North America rising more than 25 degrees Fahrenheit around 2100.

Antarctica would follow suit later, with temperatures there rising sharply around 2200.

The impact on vegetation and landscapes would transform large areas of the earth.

In the simulation, at least one ecosystem, the scrubby Arctic tundra largely vanishes as climate zones shift hundreds of miles north. Tundra would decline from about 8 percent of the world's land area to 1.8 percent.

Alaska, in the model, loses almost all of its evergreen boreal forests and becomes a largely temperate state.

But vast stretches of land that were once locked beneath permanent ice cover would open up. The area locked beneath ice would diminish to 4.8 percent of the planet's total land area, from 13.3 percent.

Several climate scientists not associated with the study said its main benefit was akin to the murky visions of possible futures experienced by Ebenezer Scrooge in "A Christmas Carol."

"It's a cautionary tale," said Gerald A. Meehl, a climate modeler at the National Center for Atmospheric Research in Boulder, Colo., who has conducted similar studies.

"The message is not to give up because the changes appear overwhelming, but instead the message should be the longer we wait to do something, the worse the consequences."

Sunday, October 23, 2005

Climate model predicts dramatic changes over the next 100 years

WEST LAFAYETTE, Ind. � The most comprehensive climate model to date of the continental United States predicts more extreme temperatures throughout the country and more extreme precipitation along the Gulf Coast, in the Pacific Northwest and east of the Mississippi.

The climate model, run on supercomputers at Purdue University, takes into account a large number of factors that have been incompletely incorporated in past studies, such as the effects of snow reflecting solar energy back into space and of high mountain ranges blocking weather fronts from traveling across them, said Noah S. Diffenbaugh, the team's lead scientist. Diffenbaugh said a better understanding of these factors � coupled with a more powerful computer system on which to run the analysis � allowed the team to generate a far more coherent image of what weather we can expect to encounter in the continental United States for the next century. Those expectations, he said, paint a very different climate picture for most parts of the country.

"This is the most detailed projection of climate change that we have for the U.S.," said Diffenbaugh, an assistant professor of earth and atmospheric sciences in Purdue's College of Science and a member of the Purdue Climate Change Research Center. "And the changes our model predicts are large enough to substantially disrupt our economy and infrastructure."

The research team also includes Diffenbaugh's Purdue colleague Robert J. Trapp, as well as Jeremy S. Pal and Filippo Giorgi of the Abdus Salam International Centre for Theoretical Physics in Trieste, Italy. Their paper appears in today's (Monday, Oct. 17) online edition of the journal Proceedings of the National Academy of Sciences.

Climate models are sophisticated computer codes that attempt to incorporate as many details about the complex workings of our environment as possible. Hundreds of dynamic processes, such as ocean currents, cloud formations, vegetation cover and - of particular import - the increase in atmospheric greenhouse gases, are programmed into the computers, which then attempt to discern the net effects on square-shaped plots of land that represent small pieces of the Earth's surface. The smaller these squares are, the better the resolution the model can provide.

"Just as a digital camera that creates images with more pixels can result in a better photograph, we want to make those squares as small as possible," Diffenbaugh said. "We'd also like to incorporate as much of the climate system as we can so the analysis will be realistic."

Despite the number-crunching power of the linked computers used for these simulations, a model must factor in so many changing variables that a full analysis can require months of nonstop computational effort. Diffenbaugh's team required five months to run their model on a cluster of Sun computers at the Rosen Center for Advanced Computing on Purdue's campus.

"The results were worth it, though, because this model allows us to project changes in climate with unprecedented resolution," Diffenbaugh said.

Until now, the fastest computers have been used to resolve squares 50 kilometers to a side, which can return a reasonably accurate but rather grainy "photograph" of climate change.

"We can now analyze areas that are only 25 kilometers to a side, which, for example, allows us to discern more clearly where California's central valley stops and the Sierra Nevada mountain range begins."

With their improvements over previous models, the team has been able to make several observations about the change in climate over the next century, particularly for the late century when greenhouse gas accumulation could have greater effect than, say, a decade from now.

"These projections are not necessarily about specific weather events," Diffenbaugh said. "But they do give us a good idea about what kind of weather to expect over the long run in a particular part of the country."

Some of these expectations include:

- The desert Southwest will experience more heat waves of greater intensity, combined with less summer precipitation. Water is already at a premium in the four-corners states and southern Nevada and, as years pass, even less water will be available for the region's burgeoning populations, with extreme hot events increasing in frequency by as much as 500 percent.

- The Gulf Coast will be hotter and will receive its precipitation in greater volumes over shorter time periods. "The region actually will get more rainfall than it does now, but it will not be steady," Diffenbaugh said. "We project more dry spells punctuated by heavier rainfalls. We need to perform further analyses to understand how much of this is related to tropical cyclone activity."

- In the northeastern United States � roughly the region east of Illinois and north of Kentucky � summers will be longer and hotter. "Imagine the weather during the hottest two weeks of the year," Diffenbaugh said. "The area could experience temperatures in that range lasting for periods of up to two months by century's end."

- Similarly, the continental United States will experience an overall warming trend: Temperatures now experienced during the coldest two weeks of the year will be a past memory, and winter's length will diminish as well, according to the model.

The model, Diffenbaugh said, assumes that greenhouse gases will attain a concentration more than twice their current levels, but he said he is confident that the model's performance gives as accurate a picture of the future as we can hope for at the moment.

"We checked our model's performance by analyzing the period from 1961 to 1985 for which, of course, we do not need a prediction," Diffenbaugh said. "The model performed admirably, which tells us we've got a good understanding of how to represent the physical world in terms of computer code. It's certainly not perfect, but we'll need a computer at least 100 times as powerful as the cluster we used to really improve the accuracy. We would like to have access to such computing power in the future."

Diffenbaugh emphasized that, while the model was in no way designed to return an alarmist image of our climate's future, the picture it painted should be considered.

"The more detail we look at with these models, the more dramatic the climate's response is," he said. "Critics have complained that climate models lack sufficient spatial detail to be trusted. In terms of looking at the whole contiguous United States, we've quadrupled the spatial detail and, as a result, it appears that climate change is going to be even more dramatic than we previously thought. Of course, we can never be completely certain of the future, but it's clear that as we consider more and more detail, the picture of future climate change becomes more and more severe."

Commenting on the study, Stanford University's Stephen H. Schneider said the results confirm scientists' suspicions about the future of climate change.

"This study is the latest and most detailed simulation of climatic change in the United States," said Schneider, who is Stanford's Melvin and Joan Lane Professor for Interdisciplinary Environmental Studies. "Critics have asserted that the coarse resolution of previous studies made their sometimes dire predictions suspect, but this new result with a very high resolution grid over the United States shows potential climatic impacts at least as significant as previous results with lower resolution model. As the authors wisely note, such potential impacts certainly should not be glibly dismissed."

This research was funded in part by a grant from the National Science Foundation.