On Saturday, the UN Intergovernmental Panel on Climate Change (IPCC) presented its Synthesis Report of the other three volumes of the Fourth Assessment Report (AR4) released earlier this year. (Earlier post.) The consolidation of the three other elements—scientific reviews of climate trends; an assessment of the world’s ability to adapt to a warming planet; and strategies for mitigation—provides an integrated view of the scientific basis for what UN Secretary General Ban Ki-moon described as “the defining challenge of our time.”
The message contained in the Synthesis Report, said the Secretary General at the presentation event in Spain, “could not be simpler. The threat of climate change is real, and there are concrete and affordable ways to deal with it.”
The publication of the report, he noted, sets the stage for the climate change conference which begins in two weeks in Bali, Indonesia.
This conference is so very critical...it is in Bali that governments will have to provide political solutions to what are now well established scientific facts. The breakthrough needed in Bali is an agreement to launch negotiations for a comprehensive climate change deal that all nations can embrace, developed and developing alike. Scientists have now done their work, and I call on political leaders to do theirs and agree not only to launch negotiations but also to conclude them by 2009.
Global, sweeping, concerted action is needed now. There is no time to waste.—Ban Ki-moon
Presenting an overview of the Synthesis Report for policymakers, IPCC Chair Rajendra Pachauri noted again the finding of the AR4 scientists that the arming of the climate system is unequivocal, and is marked by increasing global air and ocean temperatures; rising global average sea level; and reductions in snow and ice cover.
The frequency of heavy precipitation events has increased over most areas. From 1900 to 2005, precipitation increased significantly in eastern parts of North and South America, northern Europe and northern and central Asia but declined in the Sahel, the Mediterranean, southern Africa and parts of southern Asia. Yet globally, the area affected by drought has likely increased since the 1970s.
AR4 reflects a higher level of confidence than its predecessor report (TAR) in projected patterns of warming and other regional-scale features, including changes in wind patterns, precipitation, and some aspects of extremes and sea ice.
Anthropogenic warming would lead to some impacts that are abrupt or irreversible, including the partial loss of ice sheets in ice polar land with associated major changes in coastlines and low-lying areas caused by sea-level rise. Approximately 20-30% of species assessed so far are likely to be at increased risk of extinction under the warming scenarios. Large scale and persistent changes in Meridional Overturning Circulation (MOC) will have impacts on marine ecosystem productivity, fisheries, ocean CO2 uptake and terrestrial vegetation.
|Projected sear-level rise under different GHG concentration scenarios from thermal expansion alone—i.e., not factoring in ice melt. Click to enlarge.|
One finding that Dr. Pachauri highlighted specifically in his overview to the press on Saturday was the amount of sea-level rise already locked in due solely to thermal expansion caused by the increase in global temperatures at current levels of atmospheric greenhouse gas concentrations: between 0.4 to 1.4 meters.
We have already committed the world to a sea level rise through thermal expansion alone, noted on the chart [at right]. This in itself is quite serious.—Dr. Pachauri
On the other hand, AR4 finds that there exist a wide variety of policies and instruments enabling governments to create the incentives for mitigation action. One of the most important of these is a carbon price signal.
This [carbon pricing] is an important finding. If we want action, then clearly there has to be a price attached to carbon which will move us to a low-carbon economy.—Dr. Pachauri
|Highlighted mitigation technologies and practices (top) and adaptation options/strategies (bottom) for the transport sector. Click to enlarge.|
In his presentation, Dr. Pachauri also raised four questions that he had developed “as an individual”, that he hopes the delegates in the Bali meeting will consider:
How do we define what constitutes “dangerous anthropogenic” climate change?
How do we prepare the human race to face sea level rise & a world with new geographical features?
Is the current pace and pattern of development sustainable?
What changes in lifestyles, behavior patterns and management practices are needed, and by when?
What we really need is a new ethic by which every human being realizes the importance of the challenge we are facing and starts taking action...through changes in lifestyle, through changes in behavior.—Dr. Pachauri