NYT, By Shaila Dewan, May 3

Like a true belle, this city flounces into bloom when the weather turns, its redbuds, azaleas and forsythia emerging like so much lace on a bodice.

But in recent years, plants that thrive in even warmer weather have begun crashing the ball. At the Habersham Gardens nursery, where well-heeled homeowners choose their spring seedlings, a spiky-leafed, sultry coastal oleander has been thriving in a giant urn.

“We never expected it to come back every year,” said Cheryl Aldrich, the assistant manager, guiding a visitor on a tour of plants that would once have needed coddling to survive here: eucalyptus, angel trumpets, the Froot Loop-hued Miss Huff lantana. “We’ve been able to overwinter plants you didn’t have a prayer with before.”

Forget the jokes about beachfront property. If global warming has any upside, it would seem to be for gardeners, who make up three-quarters of the population and spend $34 billion a year, according to the National Gardening Association. Many experts agree that climate change, which by some estimates has already nudged up large swaths of the country by one or more plant-hardiness zones, has meant a longer growing season and a more robust selection. There are palm trees in Knoxville and subtropical camellias in Pennsylvania.

But horticulturists warn that it is shortsighted to view this as good news. Warmer temperatures help pests as well as plants, and studies have shown that weeds and invasive species receive a greater boost from higher levels of carbon dioxide, a heat-trapping gas, than desirable plants do. Poison ivy becomes more toxic, ragweed dumps more pollen, and kudzu, the fast-growing vine that has swallowed whole woodlands in the South, is creeping northward.

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Earth in 2100 could be up to 2.7 degrees F. hotter than previously predicted, studies say.

Christian Science Monitor, By Peter N. Spotts, May 3

When it comes to global warming, nature's help is limited.

While the continents and oceans have absorbed much of the carbon dioxide that humanity has pumped into the atmosphere so far, they won't be able to keep up with the expected rise in greenhouse-gas emissions over the next several decades. Indeed, some recent studies suggest that current scientific estimates about natural absorption are too optimistic: Earth's climate by century's end could be on average up to 1.5 degrees C (2.7 degrees F.) hotter than current "business as usual" projections suggest.

What this implies is that policy and technological measures to cope with climate change will become even more important. This week, scientists and government negotiators are wrestling over those measures in a key international meeting in Bangkok, Thailand. They will lay out their recommendations in a summary statement slated for release Friday.

"We've been getting a free ride from forests and oceans," says Robert Jackson, a Duke University ecologist who heads the southeastern division of the US Department of Energy's National Institute for Climate Change Research. But "I'm not confident – especially as our fossil-fuel emissions continue to grow – that we can rely on natural systems to bail us out of this."

To be sure, few if any in the climate-policy community advocate a hands-off, let-nature-do-it-all approach. But the use of natural "sinks" – oceans, plants, and soil that can hold carbon – is said to appear in the report researchers and politicians are haggling over this week.

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A new analysis shows that well before the century's end, it could be ice-free for part of the year.

Christian Science Monitor, By Gregory M. Lamb, May 3

Hundreds of scientists and government officials from around the world are meeting in Bangkok, preparing to issue a May 4 report on what steps should be taken to combat global warming. But a new study released May 1 showed that one of the group's predictions on climate change, made in an earlier February report, may already be too conservative.

The Intergovernmental Panel on Climate Change (IPPC) had said that Arctic sea ice was shrinking by as much as 5.4 percent per decade. At that rate, it could disappear entirely toward the end of this century.

But new analysis from scientists at the National Center for Atmospheric Research and the National Snow and Ice Data Center (NSIDC), both in Boulder, Colo., shows that the rate from 1953 to 2006 was more like 7.8 percent per decade. The earlier IPCC models suggested that about half the polar melting was due to global warming. The NSIDC study says greenhouse gases may play an even more significant role.

"Because of this disparity, the shrinking of summertime ice is about 30 years ahead of the [IPCC] climate model projections,'' said Ted Scambos, an NSIDC scientist, in an article by the Bloomberg news service.

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FEATURE-Bhutan to pay for others' climate sins
04 May 2007 01:01:23 GMT

By Simon Denyer

THIMPU, Bhutan, May 4 (Reuters) - High in the Himalayas, the isolated mountain kingdom of Bhutan has done more to protect its environment than almost any other country.

Forests cover nearly three quarters of its land, and help to absorb the greenhouse gases others emit. Its strict conservation policies help to guard one of the world's top 10 biodiversity hotspots, often to the chagrin of its own farmers. Yet Bhutan could pay a high price for the sins of others -- global warming is a major threat to its fragile ecosystem and the livelihoods of its people.

"Our farmers are paying a high price for our strict conservation policies," Agriculture Minister Sangay Ngedup told Reuters in an interview. "We are sacrificing a lot, but the world is not making a positive contribution to us."

"The effect of climate change and global warming is going to cause havoc to our ecosystem here."

The most dramatic threat is posed by what scientists call Glacial Lake Outburst Floods. As the Himalaya's glaciers recede, these lakes are forming and filling with melt water all along the mountain range, dammed by the rocks of glacial moraine.

In 1994, one of those lakes burst its banks in Bhutan, and unleashed a torrent of floodwater which claimed 17 lives in the central Punakha valley, sweeping away homes, bridges and crops.

Some of Bhutan's glaciers are believed to be retreating at 20 to 30 metres a year. And as that glacial melt accelerates, 24 of Bhutan's 2,674 glacial lakes are in danger of bursting.

Some studies predict the wall separating two lakes in central Bhutan could burst as early as 2010, unleashing 53 million cubic metres of water, twice the volume of the 1994 outburst.

"You get what is almost a mountain tsunami, which can wipe out anything in its path," said Nicholas Rosellini, resident representative of the United Nations Development Programme.

more

New York Times, By ANDREW C. REVKIN, May 16

While much of the world has warmed in a pattern that scientists have linked with near certainty to human activities, the frigid interior of Antarctica has resisted the trend.

Now, a new satellite analysis shows that at least once in the last several years, masses of unusually warm air pushed to within 310 miles of the South Pole and remained long enough to melt surface snow across a California-size expanse.

The warm spell, which occurred over one week in 2005, was detected by scientists from the Jet Propulsion Laboratory of NASA and the University of Colorado, Boulder.

Balmy air, with a temperature of up to 41 degrees in some places, persisted across three broad swathes of West Antarctica long enough to leave a distinctive signature of melting, a layer of ice in the snow that cloaks the vast ice sheets of the frozen continent...

[...]

Dr. Steffen said if such conditions intensified or persisted for a long time, the melting could conceivably produce streams of water that could, as has been measured in Greenland, percolate down to bedrock and allow the thick ice sheets coating the continent to slide a bit faster toward the sea.

National Geographic, Tim Appenzeller, June 2007

Even in better times, the Chacaltaya ski area was no competition for Aspen. Set in a bleak valley high in the Andes mountains of Bolivia, it offered a half-mile (one kilometer) swoop downhill, a precarious ride back up on a rope tow, and coca-leaf tea for altitude headaches. At 17,250 feet (5,260 meters), after all, Chacaltaya was the highest ski area in the world. "It gave us a lot of glory," says Walter Laguna, the president of Bolivia's mountain club. "We organized South American championships—with Chile, with Argentina, with Colombia."

The glory days are over. Skiing at this improbable spot depended on a small glacier that made a passable ski run when Bolivia's wet season dusted it with snow. The glacier was already shrinking when the ski area opened in 1939. But in the past decade, it's gone into a death spiral.

By last year all that remained were three patches of gritty ice, the largest just a couple of hundred yards (200 meters) across. The rope tow traversed boulder fields. Laguna insists that skiing will go on. Perhaps the club can make artificial snow, he says; perhaps it can haul in slabs of ice to mend the glacier. But in the long run, he knows, Chacaltaya is history. "The process is irreversible. Global warming will continue."

From the high mountains to the vast polar ice sheets, the world is losing its ice faster than anyone thought possible. Even scientists who had monitored Chacaltaya since 1991 thought it would hold out for a few more years. It's no surprise that glaciers are melting as emissions from cars and industry warm the climate. But lately, the ice loss has outstripped the upward creep of global temperatures.

Scientists are finding that glaciers and ice sheets are surprisingly touchy. Instead of melting steadily, like an ice cube on a summer day, they are prone to feedbacks, when melting begets more melting and the ice shrinks precipitously. At Chacaltaya, for instance, the shrinking glacier exposed dark rocks, which sped up its demise by soaking up heat from the sun. Other feedbacks are shriveling bigger mountain glaciers ahead of schedule and sending polar ice sheets slipping into the ocean.

Most glaciers in the Alps could be gone by the end of the century, Glacier National Park's namesake ice by 2030. The small glaciers sprinkled through the Andes and Himalaya have a few more decades at best. And the prognosis for the massive ice sheets covering Greenland and Antarctica? No one knows, if only because the turn for the worse has been so sudden. Eric Rignot, a scientist at NASA's Jet Propulsion Laboratory who has measured a doubling in ice loss from Greenland over the past decade, says: "We see things today that five years ago would have seemed completely impossible, extravagant, exaggerated."

The fate of many mountain glaciers is already sealed. To keep skiing alive in Bolivia, Walter Laguna will need to find a bigger, higher ice field. And the millions of people in countries like Bolivia, Peru, and India who now depend on meltwater from mountain glaciers for irrigation, drinking, and hydropower could be left high and dry. Meanwhile, if global warming continues unabated, the coasts could drown. If vulnerable parts of the ice that blankets Greenland and Antarctica succumb, rising seas could flood hundreds of thousands of square miles—much of Florida, Bangladesh, the Netherlands—and displace tens of millions of people.

The temperature threshold for drastic sea-level rise is near, but many scientists think we still have time to stop short of it, by sharply cutting back consumption of climate-warming coal, oil, and gas. Few doubt, however, that another 50 years of business as usual will take us beyond a point of no return.

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Also: Life at the edge and the images.