Why climate change matters
Climate change threatens the necessities of life that we take for granted - access to food and water and political stability:
- By 2080 half the world's population could face a shortage of water because of climate change.
- By 2050 200 million people could be permanently displaced by floods, rising sea levels and draughts.
- Food and water shortages could lead to migration and instability on a scale not seen before
And that's just the human cost. At least 30% of species are expected to be at risk of extinction.
The human cost of climate change
It is clear that climate change threatens the basic elements of life for people around the world - access to water, food production, health, and use of land and the environment.
Milder winters, warmer summers ... in theory global warming sounds quite appealing. Indeed there will be some benefits from climate change in some region - higher agricultural yields and increased water availability in certain areas. However these are expected to be far outweighed by the negatives.
Scientists have warned that half the world's population could face a shortage of clean water by 2080 because of climate change.
More than one sixth of the world's population live in regions supplied by melt water from major mountain ranges (e.g. Himalayas, Andes). Contracting glaciers and melting snow will significantly reduce the water available for drinking, irrigation and hydropower.
By 2020 between 75 and 250 million people in Africa are projected to be exposed to increased water stress due to climate change. Looking further ahead, that number could increase to 600 million, with another billion under pressure in Asia.
Production from agriculture and forestry will also decline in many places including Africa and parts of Australia and New Zealand. By 2020, yields from rain-fed agriculture in some parts of Africa could be reduced by up to 50%, leaving hundreds of millions without the ability to produce or purchase sufficient food.
Increased variability in rainfall is expected to increase the risks of flooding even in areas in which the overall level of rainfall is projected to decrease. According to one estimate, by the middle of the century, 200 million people may become permanently displaced due to rising sea levels, heavier floods, and more intense droughts.
Increased mortality from floods, heat waves and droughts are expected in many parts of the world, including Europe and North America. Heat waves like that experienced in 2003 in Europe, when 35,000 people died and agricultural losses reached $15 billion, will be commonplace by the middle of the century.
The fallout could be political and economic instability which would have implications for everyone.
Mass species extinction; damage to ecosystems
Climate change may alter the world's habitats and ecosystems - all living things are included in and rely on these places. Many of these places depend on a delicate balance of rainfall, temperature, and soil type. A rapid change in climate could upset this balance and seriously endanger many living things.
Most past climate changes occurred slowly, allowing plants and animals to adapt to the new environment or move somewhere else. However, if future climate changes occur as rapidly as some scientists predict, plants and animals may not be able to react quickly enough to survive. The ocean's ecosystems also could be affected for the same reasons.
Species at risk around the world
- Scientists predict that global warming could contribute to the mass extinction of wild animals in the near future.
An overheating world is creating a big change in climatic conditions and this can harm the delicate ecosystems in which species live. Threatened species can already be found all over the world - from polar bears in Canada, sea turtles in South America, pandas in China and orang-utans in Asia to elephants in Africa and frogs in Australia.
Rising sea levels, melting ice
Understanding of some important effects driving sea level rise is still limited and therefore it is difficult to provide an upper bound on the predicted sea level rise.
Most scenarios suggest a rise of between 0.2m and 0.5m by the end of the 21st century, with a further rises expected over the following 200 years. Thermal expansion would continue for many centuries, due to the time required to transport heat into the deep ocean. The final equilibrium sea levels could be almost 4 metres higher than pre-industrial levels.
Millions more people could experience coastal flooding each year, with increasing damage from floods and storms.
The Arctic Ocean is today losing sea ice at a rate that was not expected to be reached for another 30 years. The summer sea ice is expected to disappear completely between 2013 and 2040; a state not seen on earth for more than a million years.
In 2007 the area of the Greenland Ice Sheet affected by melting was 60% greater than in 1998.
Implications for the UK and Europe
The Met Office is currently producing a detailed set of climate change projections ever showing the risks of sea level rise, droughts and floods in Britain over the next 80 years.
The predications are expected to show areas of Norfolk could be flooded by seawater by the end of the century. Temperature increases mean London could experience temperatures of up to 41 degrees C by 2080 and East Anglia could experience 60 per cent less rainfall making agriculture increasingly difficult.
The implications of climate change for the UK seem relatively mild, at least compared to the implications for Asia and Africa. However if the rest of the world is on the move, or indeed at war, the impacts of climate change will be felt in the UK as much as anywhere else.
The implications of climate change for Europe as a whole are summarised in the following chart.