UN Climate Panel Report's Key Findings
Date: 24-Sep-07
Country: INTERNATIONAL
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 allot," 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 (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 meter) sea level increase.
CHANGING OCEAN CURRENTS
* The report predicts a gradual slow-down this century in
ocean currents such as the one which carries warm water to
north-west 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.