Research into global warming presented online this week from the Proceedings of the National Academy of Sciences by researchers at the University of Wisconsin-Madison and the University of Wyoming, predicts that many of our current climate zones will be gone by the year, 2100.

"Driven by worldwide greenhouse gas emissions, the climate modeling study uses average summer and winter temperatures and precipitation levels to map the differences between climate zones today and in the year 2100 and anticipates large climate changes worldwide."

Montreal's transit corporation is switching to biodiesel fuel and buying hybrid buses in an attempt to green its fleet and cut carbon emissions.

All Société de transport de Montréal (STM) buses will run on biodiesel fuel by 2008, and the transition should be fairly inexpensive, said president Claude Trudel.

Bus engines can run on biodiesel fuel without requiring any modifications, and the cost of a fill-up should be the same. The STM even stands to save money on maintenance, because biodiesel is "a cleanser, so it will keep your engines and your cylinders cleaner," said spokesman Luc Tremblay.

The Bush administration ran a systematic campaign to play down the dangers of climate change, demanding hundreds of politically motivated changes to scientific reports and muzzling a pre-eminent expert on global warming, Congress was told yesterday.

The testimony to the house committee on oversight and government reform painted the administration as determined to maintain its line on climate change even when it clashed with the findings of scientific experts. James Hansen, who heads the Goddard Institute for Space Science in New York, said in prepared testimony: "The effect of the filtering of climate change science during the current administration has been to make the reality of climate change less certain than the facts indicate, and to reduce concern about the relation of climate change to human-made greenhouse gas emissions."

Arctic sea ice that has been dwindling for several decades may have reached a tipping point that could trigger a cascade of climate change reaching into Earth's temperate regions, says a new University of Colorado at Boulder study.

Mark Serreze, a senior research scientist at CU-Boulder's National Snow and Ice Data Center who led the study synthesizing results from recent research, said the Arctic sea-ice extent trend has been negative in every month since 1979, when concerted satellite record keeping efforts began. The team attributed the loss of ice, about 38,000 square miles annually as measured each September, to rising concentrations of greenhouse gases and strong natural variability in Arctic sea ice.

Al Gore, a Democratic favorite for the presidency despite pronouncements that he's not running, spoke out on his signature issue Wednesday, warning of a "true planetary emergency" if Congress fails to act on global warming.

In a return he described as emotional, Gore testified before House panels that it is not too late to deal with climate change "and we have everything we need to get started." By turns folksy and prescriptive, he urged the Democratic-controlled Congress to adopt an immediate freeze on greenhouse gases blamed for global warming.

Scores of heavy-hitting, deep pocket investors called the US government to reduce American-produced global warming gases by up to 90%, under 1990 levels by 2050, on Monday.

"Wall Street investment house Merrill Lynch and Calpers, the largest U.S. public pension fund, were among those saying such rules could ensure development of technology to cut emissions from tailpipes, smokestacks, coal mines, and farms."

The investors group also suggests cap-and-trade systems should be initiated to reduce emissions wherever they can.

"U.S. Rep Edward Markey, chair of the U.S. House committee on global warming, said in a statement Monday the United States, as the world's biggest emitter, "must lead the way," with a cap and trade system, to stabilize global emissions."

Colorado's distinctive lodgepole pine trees are under attack from a beetle infestation described by scientists as a "perfect storm" which could destroy 90% of the western American state's pine forests.

The bark beetle outbreak was responsible for the death of 4.8m lodgepole pines in Colorado last year, up from 1m in 2005. The infestation has spread across 1,000 square miles of forest - nearly half the total in the state. Forty three per cent of the state's lodgepole pines have died as a result of the infestation. But it is not limited to Colorado: the beetles have munched their way through the western US and Canada, affecting 36,000 square miles of forest.

At the mouth of the Yangtze River, an hour by ferry from Shanghai, a new kind of Chinese city will rise from the mudflats and wetlands.

In three years, the island's black-faced spoonbills and other rare birds will share this migratory stop with 25,000 humans, the initial inhabitants of what developers call the world's first "eco-city."

If Dongtan Eco-City opens on schedule, it will become a carbon-neutral urban showcase at about the same moment scientists foresee China surpassing the United States as the globe's leading emitter of greenhouse gases.

A moderate rise in global temperature could put 20 to 30 percent of species at risk of extinction and endanger billions of people worldwide with food and water shortages, a draft U.N. report warns.

According to Reuters, the draft report, which will be released April 6 in Brussels, outlines the major impacts expected from global climate change, such as rising sea levels, that could inundate low-lying Pacific islands and changes in the environment that could drastically alter biological diversity.

The report also states that the most severe consequences of global warming, such as water shortages and species extinction, can be mitigated through cuts in greenhouse gases, Reuters reported.