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.
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. 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. Carbon Dioxide production by Sector
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.
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.
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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. |
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
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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. |
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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.
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
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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. |
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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.
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:
- 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.
There are many arguments
about climate change. This is not surprising as there are many vested interests
in the debate. |
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/ |
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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 :
- 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
For more, check
out: http://www.met-office.gov.uk/sec5/
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.
UK Affects
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.
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UN response
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.
For More Information:
Visit http://www.unfccc.de/
for International Law and Climate Change
A great student reaearch page for Global Warming http://www.globalwarming.org/brief/student.htm
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Micheal Meacher
the UK Environment Minister said at Buenos Aires. "Combating climate change
is the greatest challenge of human history". |
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