The IPCC report synthesises the three aspects of climate change that it has already pronounced on earlier in the year, on the science, the likely impacts, and options for dealing with the problem.Some IPPC projections are:
Among the top-line conclusions are that climate change is "unequivocal", that humankind's emissions of greenhouse gases are more than 90% likely to be the main cause, and that impacts can be reduced at reasonable cost. [Snip]
...climate change may bring "abrupt and irreversible" impacts.
Such impacts could include the fast melting of glaciers and species extinctions.
"Approximately 20-30% of species assessed so far are likely to be at increased risk of extinction if increases in global average temperature exceed 1.5-2.5C (relative to the 1980-1999 average)," the summary concludes.
Other potential impacts highlighted in the text include:
* between 75m and 250m people are projected to have scarcer fresh water supplies than at present
* yields from rain-fed agriculture could be halved
* food security is likely to be further compromised in Africa
* there will be widespread impacts on coral reefs
The panel's chairman, Rajendra Pachauri, highlighted the need to deal with impacts which are coming whether or not global emissions are curbed.
Even if levels of CO2 in the atmosphere stayed where they are now, he said, research showed sea levels would rise by between 0.4 and 1.4 metres simply because sea water would continue warming up, which makes it expand.
"This is a very important finding, likely to bring major changes to coastlines and inundating low-lying areas, with a great effect in river deltas and low-lying islands," he said.
"If you add to this the melting of some of the ice bodies on Earth, this gives a picture of the kinds of issue we are likely to face." [Snip]
"If you look at the overall picture of impacts, both those occurring now and those projected for the future, they appear to be both larger and appearing earlier than we thought [in our 2001 report]," Martin Parry, co-chair of the impacts working group, told BBC News.
"Some of the changes that we previously projected for around 2020 or 2030 are occurring now, such as the Arctic melt and shifts in the locations of various species."
There are indications that projected increases in droughts are also happening earlier than expected, he said, though that was less certain.
The IPCC considered about 29,000 pieces of real-world evidence in compiling this report, as well as the projections of computer models.
These include observations showing that dry areas of the world such as the Sahel and southern Africa are receiving less rainfall, while it has increased in northern Europe and parts of the Americas.
The panel also pointed out that two different sets of actions are needed to deal with global warming. Governments need to both take actions to restrict the emissions of greenhouse actions, and simultaneously work to deal with the changes that are occurring in the climate.
- Probable temperature rise between 1.8C and 4C
- Possible temperature rise between 1.1C and 6.4C
- Sea level most likely to rise by 28-43cm
- Arctic summer sea ice disappears in second half of century
- Increase in heat waves very likely
- Increase in tropical storm intensity likely
A summary of the report is available at
here. The description of the climate changes that have already occurred is quite fascinating all by itself. For example, last September I reported on the fact that the fabled Northwest Passage from Europe to China through the arctic has opened up for the first time in recorded history.
Mimikatz at Firedoglake provides an interesting discussion of the report.
Mimikatz also points out that the contribution of the Bush administration has been to deny reality by attempting to water the report down. The Republican Party as dominated by the movement conservatives is, as usual, attempting to create its own reality. Individuals who do that are routinely described as "crazy" or "insane." The modern Republican Party is proving Paul Berman's thesis in Terror and Liberalism that there are insane organizations as well as insane people.
Even many businesses are taking global warming seriously now and beginning to work to limit their environmental impact. The demogogues currently spreading fear over "the challenge of the 21st Century - Islamic Jihadism" are very soon going to lose their audience as everyone realizes that there is a real threat to the very existence of mankuind that must be combatted.
No comments:
Post a Comment