Environmental and ecological impacts on the Arctic
Average Arctic temperatures have risen at twice the rate of the rest of the world in the past few decades, 3-4°C in the last 50 years in Alaska and northwest Canada.
Over the next 100 years, they could rise a further 3-5°Cover land and up to 7°C over the oceans.
This is already leading to the melting of the Greenland ice sheet.
The present summer sea-ice extent, present tree-line and present permafrost boundary are all projected to decrease and move further north.
Impacts on natural systems - Arctic
Vegetation shifts - Vegetation zones are predicted to shift northwards. This shift will destabilise existing food webs.
Thawing permafrost - Up to 40% of total permafrost is expected to thaw, especially in Siberia. Lakes and rivers in some areas will drain. This will impact species, particularly freshwater fish like the Arctic char.
Increasing fire and insects - Global warming will increase forest fires and insect-caused tree death, which may have an impact on old-growth forest, a valuable habitat.
Ultraviolet impacts - Increased UV will reach the Earth's surface as snow and ice are lost. It destroys phytoplankton at the base of the marine food chain.
Carbon cycle changes - The replacement of Arctic vegetation with more forests will lead to higher primary productivity and increased CO2 uptake, but increased methane emissions could counterbalance this positive impact.
Other impacts - Increased coastal erosion as thawing permafrost weakens the coast and there are more waves and storm surges as the protection of the sea ice is lost.
Impacts on animal species and society - Arctic
- Species will shift north with forests. Some species are likely to suffer major decline.
- Marine species dependant on sea ice e.g. polar bears will decline. Birds like geese will have different migration patterns.
- Land species adapted to the Arctic climate e.g. Arctic fox are at risk.
- Loss of hunting culture and decline of food security for indigenous peoples.
- Need for herd animals to change their migratioon routes.
- Enhanced agriculture and forestry.
- The Arctic will become more accessible and vulnerable to exploitation for oil, gas, fish and other resources.
Socioeconomic impacts on the continent of Africa
It is the continent which makes the least contribution to global warming but it is the most vulnerable to climate change.
Much of its population is dependant on climate-sensitive resources, such as local water and ecosystems, and has a limited ability to respond to changing climate because of poverty.
It is predicted that temperatures in Africa overall will rise by around 3°C by 2100.
Rainfall is likely to increase in the equatorial region but decrease to the north and south of that band.
Africa's vulnerability to gobal warming
Water issues - Life in Africa is regulated by access to water. Demand outstrips the supply of water for 25% of Africans, but, enough water is available in most parts of Africa. Millions have no access to safe and reliable water supplies because of poverty. Water stress could lead to wars, global migration and famine.
Food insecurity - 70% of the population are subsistence farmers and many will be unable to feed themselves if e.g water supplies dry. Increased locust plagues may threaten food supplies.
Natural resources - Poor people depend directly on wild plants and animals to support their way of life; a loss of biodiversity due to climate change will threaten them.
Health - Diseases like malaria (vector) and diarrhoea (water) could increase with climate change, overloading inadequate healthcare systems.
Development of coastal zones - 60% of Africans live in coastal zones (increasing with enironmental refugees), many of which are at risk from flooding and coastal erosion. Rising sea level will increase these threats and if the zones were flooded, much of the infrastructure of roads, bridges and buildings would be lost.
Poverty - Africa's vulnerability mainly stems from poverty. It is worsened by conflict and an unjust trading system forces many countries to sell their exports at a low price. Unpayable debt means that no money is available for the mitigation of climate impacts and the introduction of adaptive strategies.