About climate change: Global effects
Climate change is one of the most serious environmental threats facing the world today. Its impacts will be felt across the world, as sea level rise threatens the existence of some small island states and puts millions of people at risk. Temperature increases, drought and flooding will affect people's health and way of life, and cause the irreversible loss of many species of plants and animals.
Key impacts
However effective policies are to reduce emissions of greenhouse gases, the world will now experience a significant degree of climate change. This is likely to have far-reaching effects on all aspects of the world's environment, economy and society including:
Rising sea levels
Sea level is expected to rise by between 20 and 60 cm by the end of the century because of thermal expansion of the oceans as temperatures rise and because of melting of land ice. This will threaten the existence of some small island states and put millions of people at risk.
Flooding in poor countries
The poorest countries are likely to be the most vulnerable to the effects of climate change. 60% of the additional 80 million people projected to be at risk of flooding are expected to be in Southern Asia (Pakistan, India, Sri Lanka, Bangladesh and Myanmar) and 20% in South East Asia (from Thailand to Vietnam, including Indonesia and the Philippines).
Food shortage and disease
Africa is expected to experience significant reductions in cereal yields, as are the Middle East and India. And an additional 290 million people could be exposed to malaria by the 2080s, with China and Central Asia likely to see the largest increase in risk.
Severe water shortages
In some areas, water resources for drinking and irrigation will be affected by reduced rainfall or as ground water in coastal zones suffers from salination as sea levels rise. People's lives may be put at risk from an increased frequency of droughts and flooding. An additional three billion people could suffer increased water stress by 2080. Northern Africa, the Middle East and the Indian subcontinent will be the worst affected.
Loss of tropical forests
By the 2070s, large parts of northern Brazil and central southern Africa could lose their tropical forests because of reduced rainfall and increased temperatures. If this happens, global vegetation which currently absorbs carbon dioxide at the rate of some 2-3 gigatonnes of carbon (GtC) per year will become a carbon source generating about 2 GtC per year by the 2070s and further adding to carbon dioxide build up in the atmosphere. (Current global man-made emissions are about 6-7 GtC per year). This will make climate change even more severe.
Further information
Page last modified: 12 March 2007
Page published: 01 December, 2005