Below is a regional breakdown of the main impacts of climate change by continent in a business-as-usual scenario. Additional resources are provided with specific country-by country breakdowns.
By 2020, 75 – 250 million people will face severe food and water shortages. More famines will force farmers to become environmental refugees.
Towards the end of the century, sea-levels will rise above low-lying coastal areas with large populations, destroying hundreds of thousands of homes and businesses. The cost of adaptation will be at least 10% of Gross Domestic Product (GDP). Coral reefs and fisheries will be unsustainable, reducing income from tourism and exports.
Australia and New Zealand
Lower rainfall will intensify water shortages in the South and East of Australia and in the North and East of New Zealand. Food production in major export areas will be reduced, with flow-on effects for the rest of the world.
Extinctions and biodiversity loss will be significant, devastating some ecologically rich sites like the Great Barrier Reef, alpine areas and Kakadu wetlands.
Rapid and under-regulated coastal developments and population growth along the East coast of Australia and from Northland to the Bay of Plenty in New Zealand will put millions of buildings at risk from sea-level rises.
Higher risk of flash floods, more frequent coastal flooding and increased erosion from sea-level rises will affect some areas of Europe. The Mediterranean food basin will have longer and more frequent droughts and heat waves, making large parts of southern Europe uninhabitable by 2100.
The majority of organisms and ecosystems will have difficulty adapting to climate change, so up to 60% of species will become extinct, and most others will move north 2100.
Melting glaciers and mountain snow will reduce tourism and create water shortages in summer, which will reduce food production.
In Latin America, the main impacts will be deforestation due to a drier climate. The Amazon rainforest may dry out and start to be consumed by forest fires, releasing more carbon dioxide into the atmosphere and causing mass extinctions.
Melting glaciers will cause water shortages, higher ocean temperatures will kill coral reefs and move fish stocks further south.
In North America, water shortages will be more severe, as warming reduces winter snows. Fortunately for the US, food production may actually increase as cold climate areas warm, however some crops will no longer be able to grow.
Heat waves will become more frequent and severe, threatening human health, and expensive coastal developments will be lost to rising sea levels.
Sea level rises and ocean acidification will lead to erosion and coral bleaching, both of which will affect local environmental resources like fisheries, and reduce the value of small islands for tourism.
Flooding, extreme storms, erosion and other coastal hazards will increase due to sea level rises, threatening vital infrastructure and facilities that support island communities.
By 2050, climate change will cause water shortages to the point that water supplies fail to meet demand during low-rainfall periods. Food production will be drastically cut as a result.
Water shortages threaten more than a billion people in Asia, because of melting Himalayan glaciers, rapid population growth and rising living standards.
Coastal areas, especially in heavily populated mega-delta regions in South-East Asia, will be at greatest risk due to increased flooding due to higher sea levels.
Extreme weather events like tropical storms will rise in frequency, destroying infrastructure, homes and crops in highly populated areas.
This summary was adapted from the Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007, ‘Impacts, Adaptations and Vulnerability’, M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson (eds) Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, http://www.ipcc.ch/publications_and_data/publications_ipcc_fourth_assessment_report_wg2_report_impacts_adaptation_and_vulnerability.htm