The Impacts and Costs of Climate Change Page: 16
The following text was automatically extracted from the image on this page using optical character recognition software:
The Impacts and Costs of Climate Change
Millennium Development Goals (as agreed at the World Summit of Sustainable Development (WSSD)
Overall, the IPCC (2001) concluded that 'Projected climate change will have beneficial and adverse
effects on both environmental and socio-economic systems, but the larger the changes and rate of
change in climate, the more the adverse effects predominate'. Essentially, the severity of the adverse
impacts will be larger for greater cumulative emissions and associated changes in climate.
Major catastrophic effects
Finally, there are a number of major effects - potentially catastrophic effects or major climate
discontinuities. These would be classified as 'significant' changes in climate, and from a
precautionary principle viewpoint, these would be the effects that we would want to avoid. They
potentially include (Schellnhuber, 2004, Downing et al, 2004, Stabilisation 2005).):
* Loss of the West Antarctic ice sheet;
* Loss of the Greenland ice sheet;
* Methane outbursts, including runaway methane hydrates;
* Instability or collapse of the Amazon Forest;
* Reduced carbon sink capacity;
* Changes in the thermo-haline circulation (loss or reversal of the gulf stream, changes in Atlantic
deep water formation, changes in southern ocean upwelling/circumpolar deep water formation);
* Indian Monsoon transformation;
* Change in stability of Saharan vegetation;
* Tibetan albedo change;
* ENSO triggering;
* Climate change induced ozone hole;
* Salinity valves;
* Rearrangement of biome distributions;
* A shift in mean climate towards an El Nino like state;
* Bodele dust supply change;
Many (but importantly not all) are thought to be longer-term events (i.e. that would occur at
temperature changes >2C). The risk of these effects might warrant the consideration of a strong
precautionary approach in policy setting, based around strong sustainability principles. This would
support the setting of a precautionary threshold (e.g. such as the 2C level or another level that the
scientific evidence indicated).
Recent research indicates that in many cases the risks from climate change impacts are greater than
originally thought at the time of the Third Assessment Report 2001. The International Symposium on
the Stabilisation of Greenhouse Gases, held in February 2005, identified new impacts. For example,
the recent change in the acidity of the ocean is likely to reduce the capacity to remove CO2 from the
atmosphere and affect the entire marine food chain (Stabilisation 2005).
It has been highlighted that catastrophic effects from major changes in the climate system could
overwhelm our response strategies.
Critical temperature thresholds were proposed at the International Symposium which would trigger
major catastrophic effects. A global temperature increase of about 1.5oC over present levels
corresponds to an increase of 2.70C over Greenland. This temperature increase may be a threshold
that triggers the melting of the Greenland ice-cap. If the Greenland ice sheet melted, global average
sea levels would increase by around 7 metres- though this would take millennia (half the ice would
melt in the first 1,000 years, with all melting after 3,000 years.). A smaller rise in global temperatures
of around 1C is likely to cause extensive coral bleaching (Stabilisation 2005). With a temperature
increase of 3C, the serious risk of large scale, irreversible disruption becomes more likely and impacts
would include changes to the thermo-haline circulation, reversal of the land carbon sink and possible
AEA Technology Environment, August 2005
Here’s what’s next.
This text can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Text.
Watkiss, Paul; Downing, Tom; Handley, Claire & Butterfield, Ruth. The Impacts and Costs of Climate Change, text, September 2005; Oxford, England. (digital.library.unt.edu/ark:/67531/metadc29337/m1/27/: accessed September 21, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .