Global warming is no longer a theory. Since the 1970s, the world has warmed by about 0.15 °C per decade, and 1998 was the warmest year on record. The evidence is mounting. Globally 1998 was the hottest year ever recorded and 7 out of the 10 hottest years ever recorded have fallen in the last decade.
In the UK we have seen 4 out of 5 of the hottest years ever recorded over a 330-year period in the last 10 years. These are startling statistics. This warming is due, at least in part, to the increasing concentrations of greenhouse gases in the atmosphere.
The world is now warmer than at any time since the last Ice Age Temperatures have risen faster in the last hundred years than ever before. This is called global warming. As a consequence, you may have heard people making all sorts of guesses about how high the seas will rise.
The earth must be able to return energy into space at the same rate at which it absorbs energy in order not to overheat.The energy being returned to space is in the form of infra-red radiation and does not pass directly through the atmosphere.
|Global warming is caused by a blanket of 'greenhouse gases' building up around the earth trapping heat from the sun. The earth is kept warm and able to support life by the solar energy from the sun. This energy arrives in the form of short wave radiation most of which passes through the atmosphere to warm the earth's surface.
Lots of processes that influence the climate occur as the energy is transported through the atmosphere, it is absorbed by water vapour, carbon dioxide, methane, nitrous oxide and other natural 'greenhouse gases'. These gases act like a blanket around the earth.
|Above the atmosphere, the stratosphere and mesosphere are cooling faster than anybody thought. The heat trapped by the greenhouse gases in the lower troposhere causes the cooling. This is called radioative cooling and may be the "miner's canary" - the latest and largest sign that things are wrong. The cooling also creates more ice particles encouraging further ozone depletion.
Human activity is adding to these greenhouse gases. During the last hundred years vast stores of coal, oil and gas have been burnt that took millions of years to form. We have burnt fossil fuels faster than ever before releasing lots of carbon dioxide. Methane and nitrous oxide are emitted from other sources such as keeping cattle and growing rice fields.
Each year the world pumps about 31,000 million tonnes of carbon and about 250 million tonnes of methane into the atmosphere. Vegetation and oceans absorb approximately half the carbon and 4/5ths of the methane produced, the remainder contribute to climate change and global warming.
|The main greenhouses gases are :
- Carbon dioxide mainly from burning fossil fuels.
- Chlorofluorocarbons (CFCs) used for propellants, foam plastics, refrigerants and solvents
- Nitrous oxides mainly from fossil fuels, industries, households, cement manufacture and burning rainforests
- Methane from cattle ranching, coal mines and paddy fields
|Worldwide emissions of CO2 from burning fossil fuels grew by 1.2% in 1997compared to 2.8% in 1996. Half comes from the top five emitters.
Have a look at Beginner's Guide to the UN Framework Convention and its Kyoto Protocol at http://www.unep.ch/iuc/submenu/begin/beginner.htm
Since 1988, international forecasts of the threat posed by global warming have been revised downward a number of times, from 0.8C/decade in 1988 to 0.2C/decade in 1995, resulting in a sea level rise of 5-35 cm instead of 20 - 150 cm.
|Industrialised regions such as Europe, North America and Japan have been responsible for most of the increase in greenhouse gases by the energy used to create and maintain the wealth and standard of living. More people are demanding better food, cleaner water, more electricity, more consumer goods increasing the demand for even more energy use. Developing countries want economic growth, the ability to expand their industries and their people aspire to a quality of life comparable with developed nations.
|Health Effects of Climate Change The WHO and World Resources Institute consider that as many as 700,000 lives could be saved annually by accepting a 15% reduction in the greenhouse gases from 1990 level. Otherwise deaths will come from new infectious diseases on top of increases in malaria and cholera
People are realising that the consequences of what was happening would affect the world long before the seas started to rise. The mixture of possible events is called climate change.
Climate changes could have enormous consequences such as:
There are many arguments about climate change. This is not surprising as there are many vested interests in the debate.
- food shortages as crops fail as a result of shorter wet winters and long dry summers
- violent storms and more hurricanes
- new pests and diseases
- melting of icecaps
- flooding of low lying areas as sea levels rise
- extinction of many plants and animals as conditions change.
|The UK has gathered together the first set of indicators that are influenced by climate. These indicators cover climate such as temperature and rainfall but also include environmental and economic pointers such as risk of flooding, egg-laying dates of birds, abundance of butterflies and effects on the Scottish skiing industry.
|March temperatures have become warmer in recent years This is reflected in consistently earlier laying by both Robins and Chaffinches. Years with particularly warm March temperatures occurred in 1957, 1959, 1961, 1981 and 1990, often with correspondingly early laying by both species. Check out Indicators of Climate Change in the UK by visiting http://www.nbu.ac.uk/iccuk/
Findings from Britain's Hadley Centre for Climate Change were presented to 170 countries at the Fourth UN Conference of Parties in Buenos Aires. They showed that parts of the Amazon will be desert by 2050, threatening the world with an unstoppable greenhouse effect. The computer at the Hadley Centre shows the earth is heating up fast, with 1988 already the hottest year since records began.
Among the findings are :
For more, check out: http://www.met-office.gov.uk/sec5/
- Land temperatures will go up 6C by the end of the next century
- The number of people on the coast subject to flooding will rise from 5 million now to 100 million by 2050
- Another 30 million people will be hungry in 50 years because of drought in Africa
- An extra 170 million people will live in countries with extreme water shortages
These new calculations make far better estimates for ocean currents. El Nino and latterly La Ninya have been stronger and longer than any previous Pacific climate changes.
The Dept of Environment's Climate Change Impacts Review Group in 1996 believed that the most probable change in the UK would be about 0.2 C per decade, but slightly slower in the north and west. Very warm seasons would become more frequent, while rainfall will increase - 5% in the 2020 and 10% by 2050s. Summer rain will decline in the south and east, and increase in the north and west. Wind will increase and gales increase by 30% by 2050.
The principle impacts will be:
- Soil in the south become more droughty
- Wildlife migrate north
- Arable areas likely to move north
- Forest species increase in north, but beech in the south may die out
- Higher wind speeds will affect the design industry
- Increased claims for insurers
- Increasing incidence of infectious diseases and heat induced deaths.
For More Information:
The Intergovernmental Panel on Climate Change (IPCC) was established under the United Nations General Assembly (UNEP). They assess the evidence and present their finding to a series of UN Conferences under the UN Convention on Climate Change.
|Micheal Meacher when the UK Environment Minister said at Buenos Aires. "Combating climate change is the greatest challenge of human history".
Visit http://www.unfccc.de/ for International Law and Climate Change
A great student research page for Global Warming http://www.globalwarming.org/brief/student.htm