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Evidence


There is overwhelming scientific consensus that human activity is the primary force driving climate change. The UN’s Intergovernmental Panel on Climate Change (IPCC), made up of more than 1200 scientists from more than 130 countries have agreed that man-made greenhouse gas emissions have, with more than 90% certainty, caused most of the overall increase in global average temperatures since the mid 20th century. Their work was peer reviewed by around 2500 climate experts.

This represents the most authoritative evidence we have about climate change. Since the IPCC’s 2007 report, new studies confirm that the climate is continuing to change, that there is more evidence of change in natural systems, and that the consequences of continued change are likely to be more serious than laid out in the IPCC report.

How our climate is changing


The following illustrate just some of the evidence of climate change. Other facts can be found on the Met Office Publications website.

  • Levels of carbon dioxide (CO2) in the atmosphere have risen by 40% since the industrial revolution, a figure higher than for at least the last 800,000 years
  • 8 of the warmest 10 years on record in the UK have all been since 1990
  • Global sea levels have already risen by 10 centimeters during the last 50 years
  • Most glaciers in temperate regions of the world are in retreat, as are those along the Antarctic Peninsula and in parts of Greenland.
  • In the Arctic, temperatures have risen by up to twice the global average since the mid-1970s, leading to some thawing in permafrost and a decline in late summer Arctic sea ice of about 10% per decade since 1979.
  • Northern Hemisphere snow cover has dropped by 5% since the late 1980s.

Future predictions


Even if we stabilised greenhouse gases at year 2000 levels, we would already be locked into a warming of a further 0.6 degrees C by 2100 because of the time lag between emissions and temperature rise - giving and overall increase of 1.4 degrees C.


The IPCC sets out predictions for emissions paths:

  • Low path: temperatures predicted to increase by 1.2  - 2.9 degrees C above 1990 levels by the end of the century
  • A higher path: where temperatures increase 1.8 – 4 degrees C.

As well as rising temperatures, predictions suggest rising sea levels, more frequent temperature extremes, changing rainfall patterns, and increased prevalence of extreme events, such as droughts, floods, fires and hurricanes. 


A 2 degree target


We want to see an agreement which takes action to limit global temperature increases to no more than 2 degrees Celsius, beyond which the risks of dangerous climate change become much greater.


Climate models show that above 2°C, the impacts and associated costs rise sharply, as food production declines, water stress increases markedly, sea level rises and species loss accelerates.


Graph1


Related Links

Met office warming brochure (PDF 1.04MB)



4 degrees

Ed and David Miliband and the Government’s Chief Scientist today launch a map of the impacts of a global 4degree C (7F) rise in temperatures.

Forest Fire

The research for this study used the daily climate output directly from an ensemble of versions of the HadCM3 climate model 2.5° × 3.75° latitude-longitude resolution [Gordon et al., 2000; Collins et al., 2001].

Crops

The agricultural impacts on the map were generated from work from a variety of sources. These include the Intergovernmental Panel on Climate Change Working Group 2 report, Impacts, adaptation and vulnerability, 2007.

Water Availability

The impacts for the availability of water were generated from work from a variety of sources. These include the Intergovernmental Panel on Climate Change Working Group 2 report, Impacts, adaptation and vulnerability, 2007.

Sea level rise

The headlines on sea level rise were generated from work from a variety of sources. These include the Intergovernmental Panel on Climate Change Working Group 2 report.

Marine

For more information about the latest research on the affects of acidification of the ocean, see: Vulnerability of national economies to the impacts of climate change on fisheries. Fish and Fisheries 10 (2), 173-196.

Drought

The research on the changes in drought events was conducted at the Met Office Hadley Centre by Dr Eleanor Burke.

Permafrost

For more information about the source of the headline on permafrost, see: Lawrence, D. M., and A. G. Slater (2005).

Tropical cyclones

Research into the effect of climate change on tropical cyclone activity is inconclusive. Some research suggests that as temperatures increase, tropical cyclones could become more intense, if not more frequent, but not all research supports this.

Extreme temperature

The research on the changes in extreme temperatures was conducted at the Met Office Hadley Centre by Dr Robin Clark.

Health

The subject of health covers a wide variety of issues from heat stress and the relationship between temperature and mortality, to changes in the extend of vector-borne diseases, to the health implications of water scarcity and flooding.