Climate change
The rate of climate change expected over the next 100 years is unprecedented in human history. The average temperature of the earth's surface has risen by 0.6 degrees Centigrade since the late 1800s. It is expected to increase by another 1.4 to 5.8 degrees C by the year 2100. This may only seem a small rise, but it is enough to have enormous impacts all over the world.
The main reason for the increase is our burning of increasing quantities of oil, gas, and coal, and the cutting down of forests. These activities have increased the amount of 'greenhouse gases' in the atmosphere, (carbon dioxide, methane, and nitrous oxide). These gases occur naturally and help keep the world warm, but in increasing quantities they are pushing up the global temperature and altering the climate. The 1990s appear to have been the warmest decade of the last Millennium.
What will happen?
Scientists have already documented many changes caused by climate change. For example trees flower earlier in spring, insects emerge faster and birds lay eggs sooner. But there are many other more worrying impacts that are already starting to be felt, or are likely to occur:
Extreme weather events
Events such as severe storms, floods, and droughts are occurring more often. Worldwide, the rain, is often more intense. Heat waves are becoming more extreme. There is increased variability in temperature and rainfall.
Rising sea levels
The average sea level rose by 10 to 20 cm during the 20th century, and an additional increase of 9 to 88 cm is expected by the year 2100. (Higher temperatures cause ocean volume to expand, and melting glaciers and ice caps add more water.) The sea could overflow the heavily populated coastlines of countries such as Bangladesh and cause the disappearance of some nations entirely (such as the island state of the Maldives).
Spreading disease
The range of diseases such as malaria may expand, as more countries develop a hotter climate.
Falling agricultural yields
Yields of crops are expected to drop in most tropical and sub-tropical regions as temperatures increase and there is reduced annual rainfall.
Extinctions
Numerous plant and animal species, already weakened by pollution and loss of habitat, are not expected to survive the next 100 years.
Climate change and poverty
The industrialised countries of North America and Western Europe, along with a few other states, such as Japan, are responsible for the vast bulk of past and current greenhouse-gas emissions. Yet those who will suffer most from climate change will be poor people in the developing world. For example, millions of poor people live in dangerous places such as on floodplains or in shantytowns on exposed hillsides around cities, but often there is nowhere safer for them to go. The poor have the most limited capability for coping with storms, floods, droughts, disease outbreaks, and with disruptions to food and water supplies. The poorer nations of the world have done almost nothing to cause global warming yet are most exposed to its effects.
What is being done?
In 1994 most countries joined an international treaty - the United Nations Framework Convention on Climate Change - to begin to consider what can be done to reduce global warming and to cope with whatever temperature increases are inevitable. The Kyoto Protocol, drawn up in 1997, is an addition to the treaty, which has more powerful measures. It sets legally binding targets and timetables for cutting the greenhouse-gas emissions of industrialized countries. It became law in February 2005. However, not all countries are signed up to it [include map of countries that are signed up].
What more can be done?
There are several measures that can be taken to help slow the rate of global warming. Some climate change is now inevitable because of past and current emissions which will continue to affect the earth's natural systems for hundreds of years. We need to take action now before the situation gets even worse.
Reduce emissions Use fossil fuels more efficiently and make use of improved more energy-efficient technology. Switch to natural gas as it causes less carbon dioxide emissions than coal or oil.
Use renewable energy Solar energy and wind-generated electricity are increasingly being used, but the current contribution of these methods to world supplies is still less than 2 per cent.
Expand forests Trees take carbon dioxide out of the atmosphere, releasing oxygen and storing carbon in a safe and useful way. Planting more trees, instead of cutting them down, will have a beneficial effect on global warming.
Change consumer demand We need to demand consumer products that cut emissions. Increased demand will increase innovation and technological progress. If customers become interested in combating global warming and are willing to buy products that cut emissions, they are more likely to be invented.
Reuse and Recycle We need to cut down the amount we consume, and reuse and recycle as much as possible to reduce the need to make new products.
Click here to find out how you can take action to combat climate change.