news.yahoo.com/fc/World/Climate_ChangeMelting of Siberian peat bog could speed global warming: reportLONDON (AFP) - A huge expanse of western Siberia is going through an unprecedented thaw that could speed the rate of global warming dramatically, a British weekly said.
Scientists recently back from the Russian region say the world's largest frozen peat bog is melting into shallow lakes. It is thawing for the first time since it formed 11,000 years ago.
The area, a million square kilometres, is equivalent to the size of France and Germany and could release billions of tonnes of methane, a greenhouse gas, into the atmosphere, the New Scientist said on its website.
The discovery was made by Judith Marquand from Britain's University of Oxford and botanist Sergei Kirpotin from Russia's Tomsk State University.
Kirpotin described the situation as an "ecological landslide that is probably irreversible and is undoubtedly connected to climatic warming".
The whole western Siberian sub-Arctic region has started to thaw, he added, and this "has all happened in the last three or four years".
Climate scientists were worried by the discovery and warned future global temperature predictions may have to be revised.
"When you start messing around with these natural systems, you can end up in situations where it's unstoppable. There are no brakes you can apply," David Viner, a senior scientist at the Climatic Research Unit at Britain's University of East Anglia, told The Guardian newspaper.
"This is a big deal because you can't put the permafrost back once it's gone. The causal effect is human activity and it will ramp up temperatures even more than our emissions are doing," he told the British daily's Thursday edition.
The intergovernmental panel on climate change thought in its last major report in 2001 that global temperatures would rise between 1.4 degrees Celsius and 5.8 degrees Celsius between 1990 and 2100.
However, that only considered global warming sparked by known greenhouse gas emissions.
"These positive feedbacks with landmasses weren't known about then. They had no idea how much they would add to global warming," Viner said.
Europe's big cities feel the heat of climate change: WWF GENEVA (AFP) - Summer temperatures have risen sharply in most west European capital cities over the past 30 years, adding to evidence of the accelerating impact of climate change, the environmental group WWF said.
WWF International blamed most of the warming on pollution from power stations rather than road traffic and urged the European Union to set tougher targets for emissions of greenhouse gases, notably carbon dioxide.
Between 2000 and 2004, average temperatures in 13 of the 16 cities surveyed were at least one degree Celsius higher than during the first five years of the 1970s, the environmental organisation said.
The study covered the 15 capitals of the pre-2004 European Union as well as Warsaw in Poland.
The largest rise in average temperatures between June and late September was 2.2 degrees Celsius in Madrid, where the summer average reached about 23.7 degrees C (74 degrees Fahrenheit) during the first five years of this decade, according to the study.
London experienced a sharp rise in peak summer temperatures, which now average 22.5 degrees C there against 20.5 degrees C three decades ago.
Dublin and Copenhagen had the lowest increases of just 0.7 degrees C and 0.2 degrees C respectively.
Average temperatures across Europe over the whole of the past century rose by 0.8 degrees Celsius, according to the UN's Intergovernmental Panel on Climate Change (IPCC).
The panel of scientists also predicted four years ago that average temperatures on the continent should rise by 0.1 to 0.4 degrees Celsius every decade, while summer heatwaves would be both more intense and more frequent.
Environmentalists said the significant difference between the overall data and the WWF's more limited study on urban summers backed up evidence of an acceleration in warming in recent decades caused by pollution.
"The cities are reflecting this trend," said Imogen Zethoven of WWF. "There is a trend of increasing summer temperatures and that is due to global warming."
"There is a primary source and that is the power sector," she added.
The data was released as part of a WWF campaign to get governments to replace "dirty antiquated" power stations with cleaner alternatives to generate electricity, such as hydrolectric stations, wind farms or natural gas plants.
The WWF blames the power industry for generating 39 percent of man-made carbon dioxide emissions in Europe.
Global warming, also called the greenhouse effect, is caused by carbon gases mostly discharged by burning oil, gas and coal, that trap the sun's heat.
The WWF measurements, taken from national meteorological offices, included day and nighttime temperatures.
Dramatic collapse of Antarctic ice shelf linked to global warmingwww.livescience.com/images/050206_iceberg_a53_02.jpgClick for image
PARIS (AFP) - The collapse of a huge ice shelf in Antarctica in 2002 has no precedent in the past 11,000 years, according to a study to be published that points the finger at global warming.
Measuring some 3,250 square kilometers (1,250 sq. miles) in area and 220 metres (715 feet) thick, the Larsen B iceshelf broke away from the eastern Antarctic Peninsula in 2002, eventually disintegrating into giant icebergs.
By chance, a US-led team of geologists had gathered a rich harvest of data around the iceshelf just before the spectacular collapse, including six cores that had been drilled into marine sediment.
The cores contain the remains of plankton and algae imbedded in layers of minerals, and their radiocarbon and oxygen isotopes provide clues about ice cover and climate change over the millennia.
The researchers, reporting in Nature, the British science weekly, say that since the end of the last Ice Age, some 11,000 years ago, the iceshelf had been intact but had slowly thinned, by several dozen metres (several dozen feet).
Its coup de grace came from a recent but decades-long rise in air temperature, they say.
"The modern collapse of the LIS-B (Larsen B iceshelf) is a unique event within the Holocene," they write.
"The LIS-B eventually thinned to the point where it succumbed to the prolonged period of regional warming now affecting the entire Antarctic Peninsula region."
The Holocene is the period of relatively balmy weather that followed the last Ice Age.
The research is the latest in a series of studies to sound the alarm about the effects of climate change in Antarctica, where the bulk of the world's freshwater is locked up.
The Antarctic Peninsula, which juts northwards out of West Antarctica, is considered a warming hot-spot.
Over the past half century, temperatures in the peninsula have risen by around 2 C (3.6 F).
In recent years, the peninsula has lost ice shelves totalling more than 12,500 sq. kms (4,826 sq. miles), equivalent to four times the area of Luxembourg.
Of the 244 glaciers that drain inland ice and feed these shelves, 87 percent have fallen back since the mid-1950s, according to a British study published in April.
Global warming, also called the greenhouse effect, is caused by carbon gases mostly discharged by burning oil, gas and coal, that trap the Sun's heat.
But Earth's climate also goes through natural oscillations of warming and cooling, resulting in Ice Ages and the milder interglacial periods inbetween.
The new study does not say that man-made global warming was responsible for the Larsen B's demise.
However, it refers to a steep rise in the temperatures over the past several decades, a phenomenon that climatologists concur was unleashed by fossil fuels.