The Impacts and Costs of Climate Change
destabilisation of the Antartic ice sheets (with a temperature increase of >2C, the melting of the West
Antarctic Ice Sheet is considered a possibility, which could raise sea levels by a further 5-6 metres i.e.
0.6-1.2m per century.).
The time frame for major catastrophic events is not yet known, though it is apparent that 'tipping
points' of temperature change could trigger these major events.
The Key Impacts of Climate Change
From the review undertaken here, we have concluded that the main impacts ('major effects' as defined
in the project scope) are:
* Impacts of sea level rise, erosion, the loss of land and coastal wetlands, and need for coastal
* Effects on agriculture;
* Effects on energy use (including heating and cooling);
* Effects to human health from changes in cold related and heat related effects
* Effects to human health from the disease burden (and other secondary effects);
* Effects on water resources, water supply and water quality;
* Changes to tourism potential and destinations;
* Effects on ecosystems (loss of productivity and bio-diversity);
* Impacts from drought;
* Impacts from flooding;
* Impacts from storm damage and extreme weather (including costs to infrastructure);
* Socially contingent effects (arising from multiple stresses and leading to migration, famine, etc);
* Impacts from major events (e.g. loss of thermo-haline circulation, collapse of West-Antarctic ice
sheet, methane hydrates).
The Impacts associated with Different Stabilisation Targets
Most of the impacts literature is focused on the impacts of climate change. It is much more difficult to
find the impacts at different concentration or temperature levels, especially at a global scale, and to
combined this to provide a matrix of the benefits of different policy out-turns.
The Third Assessment Report confirms that risks of adverse impacts from climate change increase
with the magnitude of climate change. This is shown in the figure below, which highlights the
magnitude of the negative impact and the risk of this occurring in relation to increased temperature
change. The left part of the figure displays the observed temperature increase (relative to 1990) and
the range of projected temperature increase after 1990 as estimated by Working Group I of the IPCC
from the Special Report on Emissions Scenarios (SRES). The right side displays five causes for
concern regarding climate change risks evolving in the period to 2100. Risks from large-scale
discontinuities only start to become significant above a 3C temperature change. Negative impacts on
unique or threatened systems and risks from extreme climate events occur with a temperature change
as small as 1 C and these impacts and risks are projected to become significant and widespread for
changes of 2 to 3C. Above 2C temperature increase, the vast majority of market impacts are
predicted to be negative and most regions will suffer adverse affects from climate change.
AEA Technology Environment, August 2005
Watkiss, Paul; Downing, Tom; Handley, Claire & Butterfield, Ruth. The Impacts and Costs of Climate Change. Oxford, England. UNT Digital Library. http://digital.library.unt.edu/ark:/67531/metadc29337/. Accessed July 14, 2014.