The Impacts and Costs of Climate Change

The Impacts and Costs of Climate Change
A review of the impacts of temperature change on human systems formed an important outcome from
the International Symposium on the Stabilisation of Greenhouse Gases, held in February 2005.
Appendix 1 of this report presents literature review tables of human system impacts and the tables
were published as an outcome of the Stabilisation 2005 event. The impacts have been grouped
according to the degree of temperature change relative to pre-industrial levels and some key examples
are highlighted below. The magnitude of the impact depends on the population scenario used for each
model output and the temperature change, thus the examples below illustrate the severity of the impact
but are sometimes not directly comparable.
Impacts on human systems from 1C temperature increase relative to pre-industrial levels:
* Globally 615-1660 millions at risk from water stress for scenario A2 (Parry 2004)
* Arnell predicts 240 millions at risk from water stress for scenario IS92a S750 (Arnell 2002)
Impacts on human systems between 1C and 2C temperature increase relative to pre-industrial levels:
* Risk of death due to flooding increased 4.64 fold in Central and South America for S550
(McMichael et al 2004)
* Globally 1620-1973 millions at risk from water stress for scenario A2 (Parry 04)
Impacts between 2 and 3C temperature increase relative to pre-industrial levels:
* Food production threatened in Southern Africa, S Asia and parts of Russia (ECF 2004)
* Globally 2.3-3.0 billions at risk from water stress for scenario IS92a S750 (Parry 2001)
Impacts at or above 3C temperature increase relative to pre-industrial levels:
* Globally 3.1-3.5 billions at risk from water stress for scenario IS92a, unmitigated emissions
(Parry 2001)
* Entire regions out of production, 80-125 millions at risk from hunger (Hare 2003, Parry 2001)
* Wheat yield decline of up to 34% in Indian subcontinent (ECF 2004)
Ecosystems
A literature review of the impacts of temperature change on ecosystems was a key conference
outcome from the recent International Symposium on the Stabilisation of Greenhouse Gases
(Stabilisation 2005). A summary table on ecosystem impacts, published on the web-site of this Defra
sponsored event, is provided in Appendix 2 of this report. In this section the ecosystem impact has
been grouped according to the scale temperature change for an increase of 1C through to 3C or
above.
Some of the significant potential impacts of temperature change of 1 C relative to pre-industrial levels
are listed below:
* 82% of global coral reefs are likely to be bleached (Hoegh-Guldberg 1999)
* 10% global ecosystems transformed (Leemans and Eickhout 2003)
* Only 53% of wooded tundra remains stable and ecosystems variously lose between 2 to 47% of
their extent (Leemans and Eickhout 2003)
* Increased ecosystem disturbance by pests and disease
Impacts between 1 and 2oC temperature increase relative to pre-industrial levels:
* 97% of global coral reefs are likely to be bleached (Hoegh-Guldberg 1999) and reefs become
extinct in the Indian ocean (Sheppard 2003)
* Total loss of artic summer ice and whole ecosystem stressed (ACIA 2004)
* 16% global ecosystems transformed (Leemans and Eickhout 2003)

* 50% loss of salmonid fish in USA (Keleher & Rahel 1996)
Impacts between 2 and 3C temperature increase relative to pre-industrial levels:
* 15-37% of species extinct globally for 2.50C increase (Thomas 2004)
* Large impacts on the Tibetan plateau (Ni 2000)

AEA Technology Environment, August 2005

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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 December 26, 2014.