UN Climate Panel Report's Findings
Here are findings on climate change from a February 2007 report by the UN Intergovernmental Panel on Climate Change, which groups 2,500 researchers from more than 130 nations.
EVIDENCE OF HUMAN CAUSES
* "Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic (human) greenhouse gas concentrations," it says. The IPCC says "very likely" means at least a 90-percent probability.
* "The level of confidence that humans are causing global warming has increased a lot," report author Peter Stott said.
* It is very likely that extremes such as heatwaves and heavy rains will become more frequent.
* The report does not include possible warming from methane, a potent greenhouse gas, escaping from melting permafrost.
* Warming is expected to be greatest over land and at high northern latitudes, and least over the Southern Ocean and North Atlantic.
* "For the first time we have a best estimate of what we can achieve if we keep emissions levels lower," said report chair Susan Solomon.
SEA LEVEL RISES
* The report cites six models with core projections of sea level rises ranging from 7.2 to 23.6 inches (18 to 59 cm) this century. That is a narrower and lower band than the 3.5 to 34.6 inch (9 to 88 cm) gain forecast in 2001.
* If the Greenland ice sheet melts proportionally to the temperature increases, then sea levels would rise by up to 31.6 inches (79 cm) this century.
* Some models show an ice-free Arctic in summer by 2100, meaning that sea ice floating in the water disappears, but not ice resting on Greenland.
* If the Greenland ice sheet melted completely, that would lead to a 23.1-foot (7-metre) sea level increase.
CHANGING OCEAN CURRENTS
* The report predicts a gradual slowdown this century in ocean currents such as the one that carries warm water to northwest Europe.
* "It's very unlikely there will be an abrupt breakdown in ocean currents in the 21st century," said Jurgen Willebrand, the report's author with special expertise in ocean effects.
* The report says it is "more likely than not" that a trend of increasing intense tropical cyclones and hurricanes has a human cause.
* It predicts such tropical cyclones will become more intense in the future.