Thursday, April 05, 2007

Impacts of Climate Change

An overview of impacts of global warming outlined in a draft UN climate report due to be released in Brussels on April 6:


-- Reductions in the area suitable for agriculture, and in length of growing seasons and yield potential, are likely to lead to increased risk of hunger.

-- An increase of 5-8 percent (60-90 million hectares) of arid and semi-arid land in Africa is projected by the 2080s under various climate change scenarios.

-- Current stress on water in many areas of Africa is likely to increase, with floods and droughts.

-- Any changes in the productivity of large lakes are likely to affect local food supplies.

-- Ecosystems in Africa are likely to experience dramatic changes with some species facing possible extinctions.

-- Major delta regions with large populations, such as the Nile and Niger rivers, are threatened by sea level rises.


-- The percentage of river basin areas with severe water stress is expected to increase from 19 percent to 34-36 percent by the 2070s.

-- Millions of people are likely to live in watersheds with shortages in western Europe.

-- Under scenarios of a fast rise in global temperatures, an extra 2.5 million people a year will be affected by coastal flooding by the 2080s.

-- By the 2070s, hydropower potential for Europe is expected to decline overall by 6 percent, ranging from a 20-50 percent decrease in the Mediterranean region to a 15-30 percent increase in Northern and Eastern Europe.

-- A large percentage of European flora could become vulnerable, endangered, critically endangered or extinct under a range of scenarios.

-- By 2050, crops are expected to show a northward expansion. In northern Europe, wheat yields may gain by 8 to 25 percent by 2050. But in the south, yields may range from a fall of 8 percent to a gain of 22 percent by 2050.

-- Forested area is likely to increase in the north and decrease in the south, with a redistribution of species. Forest fire risk is virtually certain to increase greatly in southern Europe.

-- Small alpine glaciers will disappear, while larger glaciers will suffer a volume reduction of between 30 to 70 percent by 2050.

-- Tourism to the Mediterranean might fall in summer and increase in spring and autumn.

-- A rapid shutdown of the Gulf Stream bringing warm waters northwards across the Atlantic to Europe -- viewed as a low probability -- could have severe impacts such as cutting crop production, more cold-related deaths, and a shift in populations south.


-- Population growth, rising property values and continued investment increase the vulnerability of coastal regions. Any rise in destructiveness of coastal storms is very likely to bring "dramatic increases" in losses from severe weather and storm surges.

-- Sea level rises and tidal surges and flooding have the "potential to severely affect transportation and infrastructure along the Gulf, Atlantic and northern coasts."

-- Severe heatwaves are likely to worsen over parts of the United States and Canada.

-- Ozone related deaths are projected to increase by 4.5 percent from the 1990s to the 2050s.

-- Projected warming in the western mountains is likely to cause large decreases in snowpack, earlier snowmelt, more winter rains by mid-century.

-- Climate change is likely to increase forest production. But by the second half of the century, the dominant impacts will be disruptions from pests and fires. Forest areas burnt each summer in Canada could rise by between 74 and 118 percent by 2100 compared to now.

-- Vulnerability to climate change is likely to be concentrated in specific groups and regions, such as indigenous peoples and the poor and elderly in cities.


-- Glaciers in the tropical Andes are very likely to disappear over the next 15 years, reducing water availability and hydropower generation in Bolivia, Peru, Colombia and Ecuador.

-- Any decline in rainfall in semi-arid regions of Argentina, Brazil and Chile is likely to lead to severe water shortages.

-- By the 2020s, between 7 and 77 million people are likely to suffer from a lack of adequate water supplies.

-- A rise in sea level, weather and climatic variability are very likely to have impacts on low-lying areas, buildings and tourism, mangroves, coral reefs and the location of fish stocks off Peru and Chile.

-- Temperature increases of 2 Celsius (3.6 Fahrenheit) and decreases in soil water would turn eastern parts of Amazonia to savannah from tropical forest. In turn, that could threaten many species.

-- The frequency and intensity of hurricanes in the Caribbean might increase.

-- Rice yields are expected to fall after 2020, but soybean yields in south eastern parts of South America may increase.


-- The extent of annually averaged Arctic sea-ice is projected to contract by between 22 to 33 percent by 2100. In Antarctica, projections range from a slight increase to an almost complete loss of summer sea ice.

-- There will be "important reductions" in the thickness and extent of Arctic glaciers and ice caps, and the Greenland ice sheet this century. Losses from glaciers on the Antarctic peninsula will continue, along with a thinning in part of the West Antarctic ice sheet. The melt will raise sea levels.

-- Northern hemisphere permafrost is projected to decrease by 20-35 percent by 2050.

-- In one scenario of rapid change, 10 percent of Arctic tundra will be replaced by forest by 2100 and 15-25 percent of polar desert will be replaced by tundra.

-- In both polar regions, climate change will mean decreases in habitat for migratory birds and mammals, with "major implications" for predators such as seals and polar bears.

-- Reductions in lake and river ice cover are expected in both polar regions. Warming will affect distribution of fish stocks.

-- In Siberia and North America, there may be an increase in agriculture and forestry as the limits for both shift northwards by several hundred km (miles) by 2050. Major forest fires and outbreaks of tree-killing insect pests are likely to increase.

-- Warming will cut the number of human deaths in winter from cold. But more pests and diseases in wildlife, such as tick-borne encephalitis, could affect humans.

-- More frequent and severe floods, erosion, droughts, and destruction of permafrost "threaten community, public health, and industrial infrastructure and water supply".

-- "The resilience of indigenous populations is being severely challenged," because of climate changes, along with economic and social shifts.


-- "Sea level rise and increased sea water temperature are projected to accelerate beach erosion, and cause degradation of natural coastal defences such as mangroves and coral reefs".

-- That could curb tourism. Studies in some islands indicate that up to 80 percent of tourists would be unwilling to return for the same price if corals and beaches were damaged.

-- Ports, as well as roads and international airports which are also often by the coast, are likely to be at risk from rising seas.

-- Reductions in rainfall would have a big impact in cutting the size of underground freshwater stocks in islands such as Tarawa Atoll, Kiribati. Some small islands states are investing in desalination to offset projected water shortages.

-- Rising temperatures and decreasing water availability is likely to increase diarrhoea and other infectious diseases in some small island states.

-- Without measures to adapt to change, agriculture economic losses are likely to reach between 2 and 18 percent of 2002 gross domestic product by 2050 for both higher islands such as Fiji and low-lying islands such as Kiribati.

-- New microbes, fungi, plants and animals are already causing changes to wildlife on sub-Antarctic islands.

-- Costs of adapting to change may be high, and options limited.


-- Many ecosystems are likely to be altered by 2020. Among the most vulnerable are the Great Barrier Reef, south-western Australia, Kakadu wetlands, rainforests and mountain areas.

-- Water security problems are very likely to increase by 2030 in southern and eastern Australia, and parts of eastern New Zealand away from major rivers. In Australia, there could be a 10-25 percent reduction in river flow in the Murray-Darling basin by 2050.

-- Development of coastal regions could lead to property coming under threat from rising sea levels. By 2050 there is likely to be loss of high-value land, faster road deterioration and degraded beaches.

-- In southeast Australia, the frequency of of days when bush fires threaten is likely to rise by between 4 and 25 percent by 2020.

-- Increased temperatures and demographic changes are likely to increase peak energy demand in summer which could lead to black-outs.

-- Farm production is likely to decline over much of southern and eastern Australia and parts of eastern New Zealand due to increased drought and fire. If enough water is available, longer growing seasons and less risk of frost are likely to aid farming in much of New Zealand and parts of southern Australia.

-- In south and west New Zealand, growth rates of economically important plantation crops are likely to increase.

-- The elderly will be at risk from heatwaves, with an extra 3,200-5,200 deaths on average per year by 2050.

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