The increasing concentration of greenhouse gases is mainly a result of human activity. The burning of fossil fuels has added large amounts of carbon dioxide to the atmosphere, some of which is absorbed by vegetation and ocean water. However, the large-scale removal of vegetation increases the carbon dioxide content in the atmosphere and new plants may not be able to exchange or store as much carbon as the old ones. Methane is added to the atmosphere by deforestation, decomposition of waste and also rice and cattle production. CFC’s, though small in number have a warming effect per molecule 10 000 times greater than carbon dioxide and stays in the atmosphere for up to 1000 years, compared with just 12 years for carbon dioxide. This greater concentration is attributed to humans and significantly contributes to global warming. The responsibility for these emissions lies mainly with the industrialised world, as since 1800 they have been responsible for more than 80% of carbon dioxide emissions. However, a country such as the USA contains only 4% of the world population and emits just under 25% of all greenhouse gases. This is equal to the total emissions from all LEDC’s which contain 80% of the world population.
The impact of global warming will be widespread and not just affect those countries that contribute to it greatest. Already the impact can be seen in Britain where the winters over the past few years have been milder and with less snow. It is also predicted that there will be a climate divide in Britain, as well as the existing economic divide, where the north will become more wet and prone to flooding while the south will become drier with frequent droughts. It is anticipated that the area around London will have a climate similar to that of Bordeaux with an overall UK average temperature increase from 9°C to 10.6°C in 2050. This prediction is welcomed by those in the tourist and leisure industries yet to most farmers it will mean increased soil erosion and reduced crop yields through drought. However Britain will not escape the effects of rising sea levels and areas particularly on the south east coast are likely to see increased levels of flooding with present sea defences being unable to cope. It would destroy salt marshes and wetlands with a loss of wildlife.
Most scientists are in agreement that sea level has risen 10-20 cms in the past 100 years as a result of global temperatures increasing. This temperature increase causes glaciers and ice caps to melt and leads to warmer oceans. As the oceans warm they expand and scientists predict that if the planet continues to warm at its current rate then millions of inhabitants of coastal land could be forced to move as the land floods. Bangladesh is a country at great risk from this as 70% of the country is less than 1m asl.
There are also problems caused by the increasing temperature alone. The Sahara could move across the Mediterranean to southern Spain and Sicily and Alpine ski resorts would be forced to close, as there is a lack of snow. The Mediterranean tourist industry would also be hit as the rising sea level causes beaches to disappear. In the USA the Wheatbelt may move north and this is potentially a good thing as there may be more areas able to farm.
Governments are taking the problem very seriously and are uniting in a global effort to lower carbon dioxide emissions. In 1997, following the 1992 Rio Earth Summit, the Kyoto Conference aimed to set strict guidelines on emissions. The Kyoto Protocol was signed by 84 nations and though America signed it, the US Senate did not ratify it. Since George W. Bush has come to power he has declared that America will not follow the regulations and will not move to cut emissions. At the moment the UK is looking to exceed its target for reducing emissions and in doing so will be able to trade ‘carbon credits’ with other countries which could be worth as much as £100m. However the reduction in emissions of 12.5% is though by environmentalists to be too small and that the target should be nearer 60%. The effects of CFC’s are well known and the use of them in manufacturing is decreasing and may eventually be banned. New environmentally friendly fuels have been developed and now cars can be run on gas.
However, it has never been proved that greenhouse gases are the main cause of global warming though scientists have yet to discover if anything else is to blame. In the meantime, governments work on the basis that they are to blame and if global warming is to be slowed down then more policies on greenhouse gas emissions need to be introduced.
