Climate Change 2007

The Intergovernmental Panel on Climate Change 4th assesment is coming out shortly, but they have already released their summary report for policymakers which can be viewed here: http://www.ipcc.ch/SPM6avr07.pdf

Here are a few highlights from this document:

Current knowledge about observed impacts of climatechange on the natural and human environment:

Observational evidence from all continents and most oceans shows that many natural systems are being affected by regional climate changes, particularly temperature increases.

Other effects of regional climate changes on natural and human environments are emerging, although many are difficult to discern due to adaptation and non-climatic drivers.

Current knowledge about future impacts:

More specific information is now available across a wide range of systems and sectors concerning the nature of future impacts, including for some fields not covered in previous assessments.

More specific information is now available across the regions of the world concerning the nature of future impacts, including for some places not covered in previous assessments.

Magnitudes of impact can now be estimated more systematically for a range of possible increases in global average temperature.

Current knowledge about responding to climate change

Some adaptation is occurring now, to observed and projected future climate change, but on a limited basis.

Adaptation will be necessary to address impacts resulting from the warming which is already unavoidable due to past emissions..

A wide array of adaptation options is available, but more extensive adaptation than is currently occurring is required to reduce vulnerability to future climate change.

There are barriers, limits and costs, but these are not fully understood.
Vulnerability to climate change can be exacerbated by the presence of other stresses.

Future vulnerability depends not only on climate change but also on development pathway.

Many impacts can be avoided, reduced or delayed by mitigation.

A portfolio of adaptation and mitigation measures can diminish the risks associated with climate change.

Impacts of climate change will vary regionally but, aggregated and discounted to the present, they are very likely to impose net annual costs which will increase over time as global temperatures increase.