The glacier, north of Puerto Eden, Chile has retreated several miles in the last 20 years, leaving exposed rock.

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Climate change is happening. There is overwhelming consensus among the world’s leading climatologists that global warming is being caused mainly by carbon dioxide and other ‘greenhouse gases’ emitted by human activities, chiefly the combustion of fossil fuels and deforestation. These gases remain in the atmosphere for many decades and trap heat from the sun in the same way as the glass of a greenhouse.

The latest science report, from the UN Intergovernmental Panel on Climate Change (IPCC), published on 2 February 2007, represents the most authoritative and up-to-date global scientific consensus on climate change. It concludes that the warming of the global climate system is “unequivocal” and is accelerating.

The global average temperature has risen by 0.76°C over the past 100 years, with Europe warming faster than the average, by around 1°C. The 15 hottest years on record have all occurred during the last 20 years, 11 of them since 1995. The second half of the 20th century was the warmest period in the northern hemisphere for at least 1,300 years. The rate of sea level rise has almost doubled from 18 cm per century between 1961 and 2003 to 31 cm per century in 1993-2003.

The report points to a greater than 90% probability that increases in man-made emissions of greenhouse gases have caused most of the temperature increase seen since the middle of the 20th century. The current atmospheric concentrations of carbon dioxide and methane, another greenhouse gas, are the highest for at least 650,000 years.

The results of the IPCC wor­ing group indicate that temperatures and sea levels will rise further this century. The global average temperature is projected to increase by between 1.1 and 6.4°C. Its best estimate, assuming no further action is taken to reduce emissions, is a temperature rise of between 1.8 and 4.0°C and a further rise in sea level of between 18 and 59 mm. However, the projec tions of sea level rise may be underestimated as they do not include the full effects of changes in ice flows.

What impact is climate change expected to have?

The warming of the global climate system is already evident in the increases in average air and ocean temperatures, widespread melting of snow and ice and rising sea levels. The impacts of climate change are expected to become progressively severe as temperatures rise. There is strong scientific evidence that the risks of irreversible and possibly catastrophic changes would greatly increase if global warming exceeded 2°C above the pre-industrial temperature. The EU’s position is therefore that the objective of global action must be to keep the temperature rise within this 2°C limit.

The impacts of climate change are generally forecast to include the following:

Extreme weather events - storms, floods, droughts and heat waves - will become more frequent, causing human suffering and economic damage. It is likely that tropical typhoons and hurricanes will become more intense, with larger peak wind speeds and more heavy rain.

Changes in rainfall patterns will put pressure on water resources in many regions, which will in turn affect both drinking water supplies and irrigation. Increases in the amount of precipitation are very likely in high latitudes and the tropics whereas decreases are likely in most sub-tropical regions.

Warm seasons will become dryer in the interior of most mid-latitude continents, increasing the frequency of droughts and land degradation.

Geographical shifts in the occurrence of different species and/or the extinction of species will occur. Cold weather mammals like polar bears could be especially threatened.

Projections show that by 2080 cold winters could disappear almost entirely and hot summers, droughts and incidents of heavy rain or hail could become much more frequent.

What about impacts in Europe?

According to the new IPCC projections, the temperature in Europe may climb by a further 4 - 7 °C this century as emissions of greenhouse gases continue building up.

A 2004 report by the European Environment Agency identified a broad range of current and future impacts of climate change in Europe, including the following:

Almost two out of every three catastrophic events since 1980 have been directly attributable to floods, storms, droughts or heat waves. The average number of such weather and climate related disasters per year doubled over the 1990s compared with the previous decade.

Economic losses from such events have more than doubled over the past 20 years to around €8.5 billion annually. This is due to several reasons, including the greater frequency of such events but also socio-economic factors such as increased household wealth, more urbanisation and more costly infrastructure in vulnerable areas.

The annual number of floods in Europe and the numbers of people affected by them are rising. Climate change is likely to increase the frequency of flooding, particularly of flash floods, which pose the greatest danger to people.

Glaciers in eight of Europe’s nine glacial regions are in retreat, and are at their lowest levels for 5,000 years.

Climate change over the past three decades has caused decreases in populations of plant species in various parts of Europe, including mountain regions. Some plants are likely to become extinct as other factors, such as fragmentation of habitats, limit the ability of plant species to adapt to climate change.

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