Climate change far worse than thought before

Global alarm over climate change and its effects has risen manifold after the 2007 report of the

Intergovernmental Panel on

Climate Change (IPCC). Since then, many of the 2,500-odd IPCC scientists have found
climate change is progressing faster than the worst-case scenario they had predicted.

Their studies will be considered for the next IPCC report, but since that will come out only in 2013, the University of New South Wales in Sydney has just put together the main findings in the last three years. Most are by previous IPCC lead authors “familiar with the rigour and completeness required for a scientific assessment of this nature”, a university spokesperson said.
The most significant recent findings are:

* Global carbon dioxide emissions from fossil fuels in 2008 were 40 percent higher than in 1990. The recent Copenhagen Accord said warming should be contained within two degrees, but every year of delayed action increases the chances of exceeding the two-degree warming mark.

Carbon dioxide is the main greenhouse gas (GHG) warming the atmosphere.

* To keep within the two-degree limit, global GHG emissions need to peak between 2015 and 2020 and then decline rapidly. To stabilise climate, near-zero emissions of carbon dioxide and other long-lived GHG should be reached well within this century.

More specifically, the average annual per-capita emissions will have to shrink to well under one tonne carbon dioxide by 2050. This is 80-95 percent below the per-capita emissions in developed nations in 2000.

* Over the past 25 years temperatures have increased at a rate of 0.19 degree Celsius per decade. The trend has continued over the last 10 years despite a decrease in radiation from the sun.

* The studies show extreme hot temperature events have increased, extreme cold temperature events have decreased, heavy rain or snow has become heavier, while there has been increase in drought as well.

They also show that the intensity of cyclones has increased in the past three decades in line with rising tropical ocean temperatures.

* Satellites show recent global average sea level rise (3.4 mm/year over the past 15 years) to be about 80 percent above IPCC predictions. This acceleration is consistent with a doubling in contribution from melting of glaciers, ice caps, and the Greenland and West-Antarctic ice sheets.

Times of India