Global Warming

Carbon Footprint

2008-03-25T06:49:00.007-07:00

The Planet Is Heating Up—and Fast

Global warming is the increase in the average temperature of the Earth's near-surface air and oceans since the mid-twentieth century and its projected continuation.

Global warming is causing a set of changes to the Earth's climate, or long-term weather patterns, that varies from place to place. As the Earth spins each day, the new heat swirls with it, picking up moisture over the oceans, rising here, settling there. It's changing the rhythms of climate that all living things have come to rely upon.

The climate is changing at an unnerving pace. Glaciers are retreating, ice shelves are fracturing, sea level is rising, permafrost is melting. What role do humans play?

The global average air temperature near the Earth's surface rose 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the hundred years ending in 2005. The Intergovernmental Panel on Climate Change (IPCC) concludes "most of the observed increase in globally averaged temperatures since the mid-twentieth century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations" via the greenhouse effect. Natural phenomena such as solar variation combined with volcanoes probably had a small warming effect from pre-industrial times to 1950 and a small cooling effect from 1950 onward. These basic conclusions have been endorsed by at least thirty scientific societies and academies of science, including all of the national academies of science of the major industrialized countries. While individual scientists have voiced disagreement with some findings of the IPCC, the overwhelming majority of scientists working on climate change agree with the IPCC's main conclusions.

Climate model projections summarized by the IPCC indicate that average global surface temperature will likely rise a further 1.1 to 6.4 °C (2.0 to 11.5 °F) during the twenty-first century. The range of values results from the use of differing scenarios of future greenhouse gas emissions as well as models with differing climate sensitivity. Although most studies focus on the period up to 2100, warming and sea level rise are expected to continue for more than a thousand years even if greenhouse gas levels are stabilized. The delay in reaching equilibrium is a result of the large heat capacity of the oceans.

Increasing global temperature will cause sea level to rise, and is expected to increase the intensity of extreme weather events and to change the amount and pattern of precipitation. Other effects of global warming include changes in agricultural yields, trade routes, glacier retreat, species extinctions and increases in the ranges of disease vectors.

Glaciers are melting, sea levels are rising, cloud forests are drying, and wildlife is scrambling to keep pace. It's becoming clear that humans have caused most of the past century's warming by releasing heat-trapping gases as we power our modern lives. Called greenhouse gases, their levels are higher now than in the last 650,000 years.

Remaining scientific uncertainties include the amount of warming expected in the future, and how warming and related changes will vary from region to region around the globe. Most national governments have signed and ratified the Kyoto Protocol aimed at reducing greenhouse gas emissions, but there is ongoing political and public debate worldwide regarding what, if any, action should be taken to reduce or reverse future warming or to adapt to its expected consequences.

What will we do to slow this warming? How will we cope with the changes we've already set into motion? While we struggle to figure it all out, the face of the Earth as we know it—coasts, forests, farms and snow-capped mountains—hangs in the balance.

Huge Antarctic Ice Sheet on Verge of Collapse

2008-03-25T06:49:00.005-07:00

Ice shelf succumbs to warming

A vast ice shelf hanging on by a thin strip looks to be the next chunk to break off from the Antarctic Peninsula, the latest sign of global warming's impact on Earth's southernmost continent.

Scientists are shocked by the rapid change of events.

A large chunk of an Antarctic ice shelf has disintegrated over the last month, with scientists saying it's further evidence of the warming effect of human greenhouse gas emissions.

Satellite images show a 160-square mile area of the 5000-sq.m. Wilkins Ice Shelf in the south-west Antarctic below South America has broken up and a much larger area is at risk of falling away, according to the National Snow and Ice Data Center at the University of Colorado.

Lead scientist at the Center, Ted Scambos, told Reuters that half the entire shelf could disappear within a few years after being a permanent fixture for hundreds of years. The way it is shattering is consistent with previous ice shelf losses that subsequent studies have put down to global warming, he said.

The dramatic collapse of the Larsen B Ice Shelf in Antarctica over just a month in 2002 helped raise awareness of climate change around the world and the British Antarctic Survey has since said human greenhouse emissions are responsible.

The collapse of the Wilkins Ice Shelf comes toward the end of the Southern Hemisphere summer and follows record ice-melt of the Arctic ice cap last Northern summer. Scientists have been surprised by the rate of polar thawing and say that global warming is occurring fastest in polar regions.

A separate study has concluded that soot particles falling on polar and mountain ice cover around the world may explain higher rates of ice thaw and overall global warming in recent years than had been predicted. Another study concluded that the high polar melt rates were due to a combination of factors, including natural events, not just the effects of human greenhouse gas emissions.

Why are thousands of bats dying ?

2008-03-25T06:48:00.015-07:00

Mysterious ‘white nose syndrome’ spreading at alarming rate

Bats are dying from mysterious causes. Some biologists claim pesticides are to blame but others think the bats are the latest casualty of global warming

Bats in New York, Vermont and Massachusetts are mysteriously dying off by the thousands, often with a white ring of fungus around their noses, and scientists in hazmat suits are crawling into dank caves to find out why.

"White nose syndrome," as the killer has been dubbed, is spreading at an alarming rate, with researchers calling it the gravest threat in memory to bats in the U.S.

The affected bats are mostly little brown bats (Myotis lucifugus), among the most common North American bats. Other affected bats include the endangered Indiana bat (Myotis Sodalis), the northern long-eared bat (Myotis septentrionalis) and the eastern pipistrelle (Perimyotis subflavus). The bats live year round in the general area of study and usually hibernate each winter in the same caves.

A significant loss of bats is chilling in itself to wildlife experts. But —like the mysterious mass die-offs around the country of bees that pollinate all sorts of vital fruits and vegetables — the bat deaths could have economic implications. Bats feed on insects that can damage dozens of crops, including wheat and apples.

"Without large populations of bats, there would certainly be an impact on agriculture," said Barbara French of Bat Conservation International of Austin, Texas.

White nose syndrome has afflicted at least four species of hibernating bats, spreading from a cluster of four caves near Albany last winter to more than a dozen caverns up to 130 miles away.

The die-offs could be caused by bacteria or a virus. Or the bats could be reacting to some toxin or other environmental factor. Whatever it is, afflicted bats are burning through their winter stores of fat before hibernation ends in the spring, and appear to be starving.

Bats are Dying Video