Water vapor is known to be Earth's most abundant greenhouse gas, but the extent of its contribution to global warming has been debated.

Scientists say global warming is causing glaciers in the Andes Mountains to shrink at a faster pace than ever. In Ecuador, the pace of glacier melt threatens hydroelectric power plants and water systems that rely on water from the glaciers.

Gov. Schwarzenegger signs a pact with heads of other states and provinces to cut greenhouse emissions. 'We have got to do something worldwide here,' he says.

Scientists now suspect that the earth's greatest mass extinction wasn't caused by an asteroid strike or any other single cataclysmic event.

Under his plan, the U.S. government will steer the country on a course to reduce emissions to their 1990 levels by 2020 and cut them by a further 80 percent by 2050.

If the rising level of carbon dioxide in the earth's atmosphere is a slowly ticking time bomb, some scientists say, the CO2 building in seawater is a depth charge about to explode.

In a short video addressed to the Summit's attendees, President-elect Obama emphasized his enthusiasm for the Poznan Conference and promised that his administration would mark a "new chapter in American leadership on climate change

Andrew Dessler and colleagues from Texas A&M University in College Stationconfirmed that the heat-amplifying effect of water vapor is potent enough to double the climate warming caused by increased levels of carbon dioxide in the atmosphere.

Half the world's population could face a shortage of clean water by 2080 because of climate change, experts warned Tuesday.

A pretty good, albeit not complete, summary of many of the counter 'arguments' Have a look and see.