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September 27, 2007

FACTBOX: U.N. CLIMATE PANEL REPORT'S KEY FINDINGS

Here are key findings on climate change from a February 2, 2007 report
by the U.N. 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.

TEMPERATURE INCREASES

* It is very likely that extremes such as heat waves and heavy rains
will become more frequent.

* "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.

* 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.

SEA LEVEL RISES

* The report cites six models with core projections of sea level rises
ranging from 7.2 to 23.6 inches this century. That is a narrower and
lower band than the 3.5 to 34.6 inch 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 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.

HURRICANES

* 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.

* "There may not be an increase in number, there may be a
redistribution to more intense events -- which is what has been
observed in the Atlantic since 1970," Stott said.

Copyright Reuters 2007