Planetary Ruin

Europeans are overwhelmingly convinced that human activity is contributing to global warming, and a majority would be prepared to accept restrictions on their lifestyle to combat it, according to a poll for the Financial Times.

Research carried out this month by Harris Interactive in Germany, France, the UK, Italy and Spain found that 86 per cent of people believed humans were contributing to climate change, and 45 per cent thought it would be a threat to them and their families within their lifetimes.

More than two-thirds – 68 per cent – said they would either strongly or somewhat support restrictions on their behaviour and purchases in order to reduce the threat.

Climate change has been rising up the political agenda in Europe. The recent British government report by Sir Nicholas Stern, former chief economist of the World Bank, argued that the economic costs of global warming could be far greater than the costs of acting to limit it.

The poll also found Europeans were more willing to accept curbs on their lifestyles in principle than to endorse specific additional burdens.

Less than half – 43 per cent – either strongly or somewhat supported a charge on airline passengers to pay for environmental damage, while 36 per cent opposed it, either strongly or somewhat. Support was weakest in Italy and Spain, possibly because of fears about the effect on their tourist industries.

Only a minority were prepared to make significant financial sacrifices to eliminate the threat of global warming. A quarter said they would pay one week’s wages or more – roughly the 2 per cent of national income figure that Sir Nicholas Stern suggested rich countries might need to pay – but a third said they would not pay anything at all.

However, concerns about climate change and energy security have not translated into majority support for investment in new nuclear power stations.

Only 12 per cent of Europeans polled were strongly in favour of investment in new nuclear capacity, while a further 18 per cent were somewhat in favour – a total of 30 per cent. Almost as many – 29 per cent – strongly opposed new nuclear construction, with a further 17 per cent somewhat opposed.

There is also a remarkably deep gender divide, with a balance of men in favour of new nuclear building in France, Italy and the UK, but a majority of women opposed everywhere except the UK, where there is a large number neither for nor against.

Public opinion need not stand in the way of nuclear development. France is pressing ahead with a new reactor, which will go into construction next year, even though the poll shows just 29 per cent of the population supports it. But in Spain and Germany, where some in the industry hope government policy can be turned away from its official anti-nuclear stance, the high level of public opposition will provide a significant obstacle to a U-turn: 53 per cent of Germans and 62 per cent of Spaniards are against new nuclear building.

The answer, Europeans think, is renewables: 85 per cent believe their governments should spend more on renewable energy, while only a handful believe they should spend less. In France and Spain, more than 90 per cent backed more investment in renewables. The potential problem is the cost of that renewable energy.

Ahead of a summit of the leaders of the European Union and Russia at the end of this week, the poll also found widespread mistrust of Russia as an energy supplier. Only 21 per cent of Europeans believed Russia would be a reliable source of oil and gas in the future, while 35 thought it would not be.

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Arctic sea ice has melted back farther this year than in 25 years of satellite monitoring, marking the fourth consecutive summer with “a stunning reduction” in the polar pack north of Alaska, Asia and Europe, according to scientists at the National Snow and Ice Data Center and NASA.

Combined with record or near record declines since 2002, the ice appears to be slipping into a long-term meltdown that may be slowly accelerating as the summer sun pumps more and more heat into the green-dark surface of the sea.

If the sea ice continues to shrink at the same rate, the summertime Arctic could be completely ice-free well before the end of this century, the scientists said.

While many factors contribute to the ice loss — warm water creeping north from the Bering Sea and Atlantic Ocean, changes in air circulation, thinning floes that don’t rebound in winter — overall warming across the Arctic appears to be a growing influence.

“The sea ice cover seems to be rapidly changing and the best explanation for this is rising temperatures,” said climate researcher Mark Serezze, a senior scientist at the snow and ice center. “My view is it’s getting increasingly difficult to argue against the notion that what we’re seeing is a greenhouse gas effect taking hold.”

Shrinking ice may be the most dramatic consequence of widespread climate change in the Arctic that includes melting glaciers and disintegrating permafrost. The loss of ice could disrupt Native subsistence life, expose coastal communities to devastating storms and erosion, and threaten the existence of marine mammals like polar bears. Until recent years, the ice melted in summer then rebounded during the long, dark Arctic winter. But during the past four seasons, something has changed.

The refreezing of ice during the 2004-05 winter season produced the smallest recovery ever measured by satellites, with nine of the past 10 months setting new records for low ice cover, the scientists said.

During the five days centered on Sept. 21 — the general period when sea ice reaches an annual minimum and starts refreezing — the ice pack covered only 2.05 million acres. That left hundreds of miles of mostly open water off northwest Alaska and Far Eastern Russia and appeared to beat the previous record of open Arctic water set in 2002. The pack also is smaller than previous low-ice periods of the 1930s and 1940s, the scientists said in their release.

Comparing the average extent of September coverage since 1979 to last week’s observations, it’s as though an area the size of Texas had melted away.

“Considering the record low amounts of sea ice this year leading up to the month of September, 2005 will almost certainly surpass 2002 as the lowest amount of ice cover in more than a century,” said Julienne Stroeve, a scientist at the data center, in a statement.

The trend has been moving faster. Between 1979 and 2001, sea ice cover retreated 6.5 percent per decade. By this summer, the rate had leapt to about 8 percent.

“That means, come autumn and winter, it’s harder to grow sea ice back in again,” Serreze said. “It’s not that you had one really low year. It’s four in a row now. At least part of what we’re seeing is a greenhouse gas signal, and it’s starting to kick in.”

The results are consistent with predictions made last year by the Arctic Climate Impact Assessment and match what scientists would expect from more water soaking up ever more solar heat instead of white ice and snow reflecting it back, several Alaska researchers said.

“Basically, you’re dimming down the Arctic,” said ice researcher Hajo Eicken, an associate professor of geophysics at the University of Alaska Fairbanks Geophysical Institute. “If you remove that ice, then you start heating the water by as much as a factor of 10 or more. And, as a result, you expect that the ice doesn’t fully recover and it just keeps inching back.”

“You don’t have to be a rocket scientist to interpret this picture,” said Lawson Brigham, Alaska office director for the U.S. Arctic Research Commission in Anchorage and a former captain of a U.S. Coast Guard icebreaker. “With the sunlight for 24 hours in the summer and all that dark (ocean) area, it’s just like you painted your house a dark color. It’s going to warm it even more.”

One mystery in the situation is that researchers don’t have a good way to measure the total volume of ice in the Arctic, what Serreze called the “Holy Grail” of sea ice science. But a clear harbinger of thinning ice occurred this season, when a record nine ships reached the North Pole, including the first vessel that was not specifically an icebreaker, said Brigham, who in 1994 captained the first U.S. icebreaker across the pole from the Bering to the Atlantic.

This summer, the passage along the Arctic coast of Russia between Europe and the Bering Strait remained ice free between Aug. 15 and Sept. 28, the scientists said. The Northwest Passage through Canada, the fabled route of Arctic lore, opened up except for one 60-mile-long stretch.

Though shrinking ice might sound like an immediate boon to transportation, actual conditions could become more complex and difficult, Eicken said. Ice floes can blow into open areas fast, making navigation especially treacherous.

“You can’t say, you can just take a whole bunch of barges up there and you’ll never see sea ice,” he said. “That ice may move a heck of a lot faster than it would have before, and it may be present throughout the summer.”

Still, of the 61 ships to ever visit the North Pole, 17 traveled there in the past two years, Brigham said. Two of the seven ships ever to cross the ice pack from ocean to ocean made the transit in 2005.

“The numbers aren’t huge, but I think that one can correlate the retreating sea ice and changing ice conditions with the increasing number of ships,” Brigham said. “So, here at the beginning of the century, I would say you can, if you’ve got the right kind of boat, routinely go to the North Pole. Pretty amazing, huh?”

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Warming temperatures over the past half-century have been slowly drying out the Kenai Peninsula, transforming wetlands into forests and shrinking ponds, according to a study that analyzed vegetation change at more than 1,100 locations.

 

The loss of wetlands could reduce bird nesting habitat, and the expansion of woody growth into wet areas could increase the danger from wildfires, said biologist Eric Klein, lead author of a paper published this August in the Canadian Journal of Forest Research.

“You’re getting rid of these natural breaks,” Klein said. “It becomes quicker and easier for wildfires to spread.”

The study found that wooded areas in the Kenai National Wildlife Refuge had grown dramatically since 1950, expanding from 57 percent to 73 percent of the land. Wetlands shrank, from covering about 5 percent to less than 1 percent.

Many lakes lost volume too, especially small, isolated “kettle lakes” that have existed since the ice age ended 8,000 to 12,000 years ago. “It seems like that there is an environmental shift taking place,” said Klein, who conducted the research for his master’s degree in environmental science at Alaska Pacific University. “This is just one more piece of the puzzle.”

Global air temperature has risen at least 1 degree Fahrenheit over the past century, but some areas of the Arctic have warmed much faster. Many scientists believe that increases in human-produced greenhouse gases have helped drive the warming, in addition to complex natural cycles.

Whatever the causes, the impacts have been accelerating. Every decade has brought spring green-up about 2.3 days sooner and pulled the ranges of animals and plants about four miles farther north. Recent scientific papers have documented the invasion of shrubs into North Slope tundra, while spruce forests in the Interior have declined because of summer droughts. Last year’s Arctic Climate Impact Assessment cited forest fires and the Kenai’s beetle epidemic as further evidence of climate in motion.

On the Kenai, average air temperatures have risen about 1.2 degrees Fahrenheit over the past 30 years, allowing dwarf birch, blueberries and black spruce to colonize bogs that existed intact since glaciers retreated up to 12,000 years ago, according to co-author Ed Berg, an ecologist with the U.S. Fish and Wildlife Service.

“When you dig down into the peat, you don’t see any stems or shrubs,” Berg said in a statement about the research. “Had they grown there in the past, they would have been preserved.”

Klein, now a staff biologist for an Anchorage environmental engineering firm, launched the study in 2003 with help from Berg in the field and help with the analysis from APU biology professor Roman Dial. The three scientists completed “Wetland drying and succession across the Kenai Peninsula Lowlands” last fall.

Using aerial photographs taken in 1950, Klein examined 1,113 locations chosen at random across about 546,000 acres in three broad areas of the Kenai wildlife refuge. At the time, more than half were forested, with 31 percent open land, 5 percent swampy and 7 percent ponds or small lakes.

When Klein located the same spots on photos taken in 1996, he discovered that a remarkable shift had taken place. Forest had grown, while open land and lakes had shrunk. The area covered by swamps and bogs had almost disappeared. Burned and unburned areas changed about the same.

Klein also visited 84 sites in the field with Berg and several technicians, spending much of the summer of 2003 thrashing through Kenai backcountry, examining firsthand how the land had changed. “The bugs were horrible,” he said. “There were some places where you could only write if you had a head net on, and that was after you covered yourself in Deet.”

Klein documented many lakes and ponds with expanding aprons of vegetation, with new bushes and trees lurking at the fringes. One pond off Swan Lake Road was especially dramatic, completely swallowed by successive bands of invading plants.

On the 1950 aerial photo, it had stretched 100 feet across. “When we got to the site, and there was no water left at all,” Klein said, “you could see these very distinct bands (of vegetation), almost like a bull’s-eye on a dart board, extending from the center out.”

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Scientists here on Monday painted a gloomy picture of the effects of global warming on the Arctic, warning of melting ocean ice, rising oceans, thawed permafrost, and forests susceptible to bugs and fire.

“A lot of the stories you read make it sound like there’s uncertainty,” said Jonathan Overpeck, a professor of geosciences at the University of Arizona. “There’s not uncertainty.”

The questions scientists continue to address, he said after his presentation at the Alaska Forum on the Environment, are how much of the warming is caused by humans and how drastic the long-term effects will be.

Deborah Williams, a conference organizer and former director of the Alaska Conservation Foundation, said Alaska is ground zero for observing the effects of global warming because so many natural phenomena are tied to ice and the repercussions of it melting.

“We are the Paul Revere of global warming,” she said.

Overpeck reviewed NASA studies showing how Arctic ice has shrunk in size and depth. Climate models 25 years ago predicted a shrinking ice pack.

“What we didn’t predict is that it would be so dramatic,” Overpeck said.

Scientists predict the summertime Arctic could be ice-free before the end of the century, opening up northern sea routes but threatening the existence of polar bears, a marine mammal that depends on sea ice to live.

Other scientists listed the effects of warming on fish, forests and tundra.

James Overland, a research scientist with the National Oceanic and Atmospheric Administration for more than 30 years, said the loss of sea ice has meant some marine life has thrived and some has been hurt.

“The marine ecosystem is shifting north dramatically,” he said.

Pollock are thriving in warmer water. Pink salmon are being found in great numbers farther north, “an incredible indicator of warming,” he said. Crab and other bottom-dwellers who depend on ice overhead for part of the year are suffering.

Glenn Juday, professor of forest ecology at the University of Alaska Fairbanks, said tree growth has decreased at Interior Alaska sites that were promising for commercial harvest. Studies of temperatures at Talkeetna and Fairbanks indicate daily lows are not as low as they used to be. The warming lowers the water available to white spruce, black spruce and birch, Juday said.

“The warmer it is, the less the trees grow,” Juday said. Warming also makes them more susceptible to fire and insects.

Vladimir Romanovsky, an associate professor of geophysics at UAF, reviewed effects of warming on permafrost, or ground continuously frozen for two years. Areas of thick permafrost in the far north remain stable but have warmed over 20 years one-half to 2 degrees at a depth of 20 meters, Romanovsky said.

Matthew Sturm of Cold Regions Research and Engineering Laboratory studied shrubs in Arctic tundra by comparing 50-year-old photographs taken along the Chandalar River for the National Petroleum Reserve-Alaska with photos taken recently.

“They all pretty much tell the same story,” he said.

Shrubs have thrived in the greater warmth and in turn accelerate warming. Like open water in the ocean, shrubs darken what otherwise would be a mostly white, reflective snow-covered environment, Sturm said.

If warming trends continue, Overpeck said, the globe eventually will get a nasty message from the Arctic: a rise in sea levels. Higher oceans will flow into low-lying parts of the world such as New Orleans, making recovery in that hurricane-ravaged city moot.

“It’s hard to imagine why we’re wanting to rebuild if we’re going to allow global warming,” Overpeck said.

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Climatologists around the world may agree that burning fossil fuels is a significant contributor to global warming, but U.S. Rep. Don Young isn’t buying it.

“I am a little bit concerned when everything that is wrong is our fault, that the human factor creates all the damages on this globe,” the Alaska Republican said during a debate on the U.S. House floor Thursday. “That is pure nonsense.”

U.S. Rep. David Obey, D-Wis., suggested Young sounded like one of the “charter members of the Flat Earth Society.”

Young was working to kill a statement in an appropriations bill that says Congress agrees that people are contributing to global warming and that carbon emissions should be limited.

Young said we need “a good study” and a debate among scientists. That launched U.S. Rep. John Olver, D-Mass., a former chemistry professor with a doctorate from the Massachusetts Institute of Technology, on a mini lecture to explain the rapid accumulation of carbon dioxide in the atmosphere in the last 40 years. Sounding a bit like the late Carl Sagan, Olver spoke of the carbon dioxide record gathered from ice samples two miles deep in the Antarctic ice. The ice holds pockets of air trapped as long as 400,000 years ago.

“Suddenly, within the last 40 years, concentration of carbon dioxide in our atmosphere has smashed through the 400,000-year maximum of 280 parts per million to a 380 parts per million level and continues to rise,” Olver said.

Another former educator, U.S. Rep. Wayne Gilchrist, R-Maryland, then continued the lesson, explaining how tiny increases in the carbon dioxide level in the atmosphere could have big consequences on earth.

Young allowed that the earth may be warming in some areas, but “I just read a report, in fact, that Greenland is cooling.”

NASA issued a statement in February that began: “The loss of ice from Greenland doubled between 1996 and 2005, as its glaciers flowed faster into the ocean in response to a generally warmer climate, according to a NASA/University of Kansas study.”

The study was published in the journal Science.

Young also told his colleagues that alarmists are too quick to blame America for the carbon emissions.

“It is always the fault of the Americans,” Young complained during the debate. “It is never the fault of the bigger countries that burn as many barrels of oil as we are doing today — not per capita, but as many barrels of oil. It is never their fault.”

It was unclear what other big oil-consuming countries he was referring to.

According to the U.S. Energy Information Administration, the United States burned 20.6 million barrels of oil a day last year. The second biggest consumer, China, burned just under 7 million.

Young’s steadfastness irked U.S. Rep. Norm Dicks, D-Wash., who thought Young, of all congressmen, should care, since Alaska is warming faster than the rest of the country.

“While Alaska melts away, their congressman will be down here in D.C.,” Dicks said, “and everybody will be wondering, ‘what ever happened to Alaska?’ ”

Among other signs of global warming, Dicks said: “The polar bears are dying because there is not enough ice.”

Young said Dicks didn’t know what he was talking about.

“If you look at any of the studies that are taking place now, the polar bear pack is very healthy and, in fact, increasing. This is science from the Fish and Wildlife people. Read that. They will tell you we are increasing the numbers, not decreasing,” Young said.

Rosa Meehan, supervisor of marine mammal management for the U.S. Fish and Wildlife Service in Alaska, said she doesn’t have any such data.

“Up until five years ago we assumed the population was stable, and we’re questioning that now,” she said.

The agency is considering whether to list the polar bear as “threatened” under the Endangered Species Act.

Alaska’s southern Beaufort Sea polar bears are changing their behaviors, she said. They are spending more time on the coast in the fall because the sea ice they usually hunt seals from is retreating, she said.

A team of polar bear researchers from the U.S. Geological Survey just returned from the Arctic, but their data hasn’t been analyzed yet, USGS biologist Geoffrey York said.

Meredith Kenny, Young’s spokeswoman, said her boss isn’t entirely skeptical about climate change.

“He doesn’t doubt something is happening, but it’s not as drastic as they make it out,” she said.

As for any misstatements Young may have made, she said, “He might have been caught up in the moment, in the debate.”

In any event, Young prevailed Thursday and the statement on climate change was removed from the bill. He had challenged it as inappropriate for a spending bill and won on technical grounds.

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Global talks to widen a fight against climate change reached gridlock on their final day on Friday after scant progress overnight to encourage rich nations to help Africa.

The two weeks of talks of some 190 countries were meant to set out next steps to work out a stronger pact beyond 2012 to rein in emissions mainly from burning fossil fuels in power plants, factories and cars widely blamed for heating the planet.

After overnight talks, some 70 ministers agreed to encourage rich nations to fund emissions cuts in Africa, but remained deadlocked on the broader extension of the U.N.’s Kyoto Protocol for fighting warming beyond 2012.

“It’s not a very strong statement that encourages (rich) countries — who are willing to do so — to consider initiatives including financial support,” said Janos Pasztor, the U.N. climate body’s coordinator of such funding, said of the overnight deal.

“Some will do it and some won’t.”

Under Kyoto rich states have contributed over $5 billion to clean energy projects in developing countries over 2 years. The money has largely bypassed Africa, and the new initiative is meant to cut investor risk by funding startup costs.

But talks had ground to a halt on setting out steps to extend the Kyoto Protocol, which some developed countries want linked to a review of the pact — too slow for some African countries.

A new proposal for the review, reached on Friday, could break the deadlock, said the Executive Director of the U.N.’s climate change body, Yvo de Boer, on Friday.

“I hope it can be approved quite rapidly,” he said.

Environmentalists said the talks, likely to last into Saturday, had to take tougher steps and set firm deadlines for agreements.

The Kyoto Protocol is supposed to be a tiny, first step towards solving climate change — the planet’s top problem alongside conflict and poverty, U.N. Secretary-General Kofi Annan told the Nairobi conference this week.

DELAY

In a proposal seen irrelevant by some delegates, Russia seeks a decision on allowing developing countries, which have no targets at present, to volunteer to cut their emissions.

“The Russian proposal seemed to be quite stuck last night. There do seem to be some openings again,” said de Boer.

Meanwhile Belarus wants to join the club of industrialized countries which already face targets — but under such lax terms it could dump its surplus emissions rights and swamp an emerging carbon market, said Steve Sawyer of Greenpeace.

Besides debating how to cut further the greenhouses gases blamed for global warming, the conference had meant to turn the spotlight on how to adapt to climate changes — floods, droughts, desertification and rising sea levels.

But the meeting has delayed until next year a decision on who should run funds to help poor countries adapt to climate change.

“Rich countries should have achieved more at this conference and made more firm commitments to combat climate injustice,” said Sharon Looremeta of environmental group Practical Action.

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An international team of scientists reported Thursday that rising temperatures are steadily transforming the Arctic — warming millions of square miles of permafrost, promoting lush greenery on previously arid tundras and steadily shrinking the annual sea ice.

Yet the researchers also found new patterns of cooling ocean currents and prevailing winds that suggested the Arctic, long considered a bellwether of global warming, may be reverting in some ways to more normal conditions not seen since the 1970s.

Taken together, these findings may be evidence, the researchers said, of the region struggling to keep its balance, as rising temperatures slowly overturn the long-established order of seasonal variations.

“This is a region that is fighting back,” said lead author Jacqueline Richter-Menge, a civil engineer at the Cold Regions Research and Engineering Laboratory in Hanover, N.H. “There are things that showed signs of going back to norms, trying to right themselves under very dire circumstances.”

For a year, 20 researchers in seven countries reviewed the condition of the atmosphere, ocean, sea ice and land at the top of the world. They summarized their findings in the “State of The Arctic,” a report released Thursday by the National Oceanic & Atmospheric Administration.

On average, global temperatures have been steadily warming for decades — 2005 was the warmest year since record-keeping began in 1880 — but the polar region appears to be warming twice as fast as the rest of the world. Local weather variations at Earth’s upper latitudes create a seesaw of annual hot spots and cold sinks above the Arctic Circle that, combined with incomplete data records, can easily disguise longer regional climate trends.

By pulling together data from many countries and scientific sources, the researchers sought to determine more conclusively how the climate throughout the Arctic behaved from 2000 through winter 2006.

“Arctic temperatures were above their average — at least 1 degree centigrade above average over the entire Arctic over the entire year. This is a unique situation,” said co-author James Overland at NOAA’s Pacific Marine Environmental Laboratory in Seattle.

The study reports an increase in northward movement of warmer water through the Bering Strait in 2001 to 2004. This may have contributed to a continuing reduction of sea ice.

Last year, the Arctic sea ice set record lows every month except May, the researchers reported, continuing a trend that started in 2000. The permanent ice cap has been thinning as well. Summer melting began earlier every year of the study and was more extensive.

Glaciers everywhere receded. For the past five years, rivers flowing into the Arctic Ocean have been 3 percent to 9 percent higher than average with fresh melt water, stream gauges showed. That, in turn, has made the seawater less salty, affecting ocean currents.

Permafrost throughout the Alaska Arctic steadily warmed, records documented. Last year, soil temperatures in the interior of Alaska were among the warmest of the past 70 years, the researchers reported.

In response, vegetation in the tundras increased by 10 percent over the past 20 years, satellite measurements showed.

Shrubs rooted more readily above the Arctic Circle in Alaska and Siberia. The new ground cover provided shelter for some creatures while making it harder for others, such as reindeer and caribou herds, to move through their grazing grounds.

The study was designed to assess the overall impact of climate change in the Arctic and will be updated annually. It was compiled by researchers from the United States, Canada France, Germany, Poland, Norway, Sweden and Russia, she said.

In addition, 2007 has been designated the International Year of the Arctic, with intense scientific study of the region planned.

There have been many changes over the Arctic land areas, said Vladimir E. Romanovsky, a professor at the geophysical institute of the University of Alaska. These include changes in vegetation, river discharge into the Arctic Ocean, glaciers and permafrost.

The tundra is becoming greener with the growth of more shrubs, he said. This development is causing problems in some areas as herds of reindeer migrate.

At the same time, there is some decrease in the greening of the northern forest areas, probably due to drought. The glaciers are continuing to shrink and river discharge into the Arctic Ocean is rising, Romanovsky said.

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The global warming controversy is an ongoing dispute about the effects of humans on global climate and about what policies should be implemented to avoid possible undesirable effects of climate change.

The current scientific consensus on climate change is that recent warming indicates a fairly stable long-term trend, that the trend is largely human-caused, and that serious damage may result at some future date if steps are not taken to halt the trend. Mainstream scientific organizations worldwide (American Geophysical Union, Joint Science Academies, Intergovernmental Panel on Climate Change, American Meteorological Society, and American Association for the Advancement of Science (AAAS)) concur with the assessment that “most of the observed warming over the last 50 years is likely to have been due to the [human caused] increase in greenhouse gas concentrations”[1]. However, there is also a small but vocal number of scientists in climate and climate-related fields that disagree with the consensus view.

There is considerable opposition from parts of the political and business communities both to the conclusion that humans are causing climate change, and to the need to take action to reduce human effects on climate. Chiefly, opposition arises because of claims that these actions would cause enormous expense and disruption to the current geopolitical and economic situation, with no obvious recognizable short-term benefits.

This is a public and political debate. While the climate projections involved in the discussion are constrained by basic physical principles (though they depend on assumptions about emissions), political and economic effects of both global warming and mitigation are more difficult to quantify. As an example, in asking whether the costs of reducing fossil fuel dependency compare with the costs of not taking action, one is confronted by the fact that it is difficult to anticipate social or technological changes that affect such costs.

This article is about that controversy. The description and scientific explanation of global warming is spread over several other articles: