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Global Warming


The Science Library has a comprehensive and up-to-date Environment Collection. This covers all environmental issues, and includes reports, pamphlets and journals as well as books.
One topic at the heart of many of the debates on the environment is global warming.

What is Global Warming?

Since the last ice age ended 10,000 years ago, our climate has been relatively stable. However, the global average temperature has risen by 0.6 in the last 100 years, whilst the ten warmest years since records begun (in 1860) have all occurred since 1990, five since 1997, and its been 221 months (as of Jan. 2004) since the world recorded a colder-than-normal month (according to the US National Climatic Data Centre see their website below).

Other scientists dispute these figures, but the weight of opinion in the scientific community is that global warming is real and a serious threat. The evidence is mounting almost daily. Both the Arctic Sea ice cap and Greenland's ice mass are shrinking, even faster than predicted. Other evidence includes the discovery of breeding colonies of stinkbugs in London. The small insect - Nezara viridula or southern green stinkbug - is native to far warmer climes in North America, South America and Africa, and these have never before been known to breed in Britain ( IOL June 19 2004 ).

Apart from the increase in sea levels, causing the flooding of large areas of land, another consequence of global warming is the disruption of the circulation of warm and cold water in the oceans. This could have disastrous repercussions, not only to climate, but also to life in the oceans.

What is the cause?

It is not easy to determine how much of this is due to natural causes and what can be attributed to human activities. However, a new and authoritative report concludes that the evidence for human contribution to climate change is overwhelming (> 90%). It was announced on 2 February 2007, in Paris, that Working Group I of the Intergovernmental Panel on Climate Change (IPCC) had adopted the Summary for Policymakers of the first volume of Climate Change 2007, also known as the Fourth Assessment Report (AR4).Climate Change 2007: The Physical Science Basis, assesses the current scientific knowledge of the natural and human drivers of climate change, observed changes in climate, the ability of science to attribute changes to different causes, and projections for future climate change. The report was produced by some 600 authors from 40 countries. Over 620 expert reviewers and a large number of government reviewers also participated. Representatives from 113 governments reviewed and revised before accepting the underlying report.

Climate changes caused by human activities, most importantly the burning of fossil fuels (coal, oil, and natural gas) and deforestation, are superimposed on, and to some extent masked by, natural climate fluctuations. Early work on climate change detection examined changes in the globally averaged surface temperature of the Earth over the last century. Most studies of this type concluded that the observed increase of roughly 0.5 (about 1) was larger than would be expected as a result of natural climate variability alone (see the IEA Greenhouse website at the link below).

So-called greenhouse gases trap the Sun's radiation in much the same way that glass windows trap heat inside a home or a greenhouse. The most powerful of those gases is carbon dioxide (through burning oil, gas and coal), which comes primarily from burning fossil fuel, while other gases include methane, sulphur dioxide and ozone. These gases remain in the upper atmosphere, trapping the Sun's heat and driving up the temperature of the Earth's land and sea.

What can be done?

In the wake of the IPCC Report, President Chirac has called for the UN Environment Programme (UNEP) to be turned into a a powerful UN environmental agency to reinforce international control over the planet. This is among a number of new initiatives that are being proposed in the aftermath of the Report. At present the principle international measures to combat global warming are contained in the Kyoto Protocol - the international treaty on climate change - which came into force in February 2005 following its acceptance by Russia. The protocol was established in 1997, based on principles set out in a framework agreement signed in 1992. The United Nations treaty, already backed by 126 countries, needed the support of Russia (which accounts for 17 %, of greenhouse gas emissions by developed nations) before it could come into force it needed to be ratified by developed nations that account for at least 55% of global greenhouse emissions. Only the U.S. and Australia have yet to sign (the U.S., whose share of emissions is 36 %, pulled out in 2001). [for further information see the link to The Environmental Literacy Council below]

The target is to reduce emissions of six key greenhouse gases to an average of 5.2% below 1990 levels by 2012. In fact the UN says industrialised countries are now well off target for the end of the decade and predicts emissions 10% above 1990 levels by 2010. Only four EU countries are on track to meet their own targets.

The European Union hopes to derive 12 percent of its total energy consumption -- and 22 percent of its electricity usage -- from renewable sources by 2010. But only four countries -- Denmark, Finland, Germany and Spain -- are on course to meet the targets. Environmentalists want the EU to be more ambitious by setting a target to supply 25 percent of its energy demands from renewable sources by 2020. A new treaty is likely some time in the near future as Australia and the USA begin to review their policies on climate change.

In a recent report, The World Wide Fund for Nature (WWF) and European Biomass Industry Association (AEBIOM) state that harnessing biomass sources could power 100 million homes, providing 15 percent of the industrialised world's energy needs by 2020 compared with just one percent now. This would reduce emissions of the greenhouse gas carbon dioxide by about 1,000 million tonnes a year. ( AFP Online 27/05/04). Other methods of reducing CO2 emissions include promoting more and better public transport and making cars that use alternative fuels like Bio-diesel, Ethanol, Liquefied Petroleum Gas (LPG), Liquefied Natural Gas (LNG), Compressed Natural Gas (CNG), and Hybrid and Electric Vehicles. These are now increasingly coming onto the market.

Computing Climate Change

The BBC are helping in an experiment to predict climate changes into the future using computer models. Given the great range of factors involved, and the enormous data required, this requires huge computer power. To obtain this a technique known as distributed computing is being used to harness the power of thousands of PCs around the world. Find out more, visit: BBC climate change experiment

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