Global Climate Change

The Intergovernmental Panel on Climate Change (IPCC) was set up in 1988 to asses’ information on climate change and its impact. It's Third Assessment Report predicts global temperature rises by the end of the century of between 1.4C and 5.8C. Although the issue of the changing climate is very complex and some changes are uncertain, temperature rises are expected to affect countries throughout the World and have a knock on effect with precipitation and sea level rises.

Scientists have argued about whether temperature rises are due to human activities or due to natural changes in our environment. The IPCC announced in 2001 that 'most of the warming observed over the last 50 years is likely to be attributable to human activities'.

This was a more forceful statement than in 1996 when the Second Assessment Report stated that there was a 'discernible human influence on the climate' which was the first time they had concluded such a link. Many experts believe the faster the climate changes, the greater the risk will be.

Scientists in the UK are playing a major role in predictions for our future climate. The UK 's most recent climate scenarios (published by UKCIP) details projections for the UK 's climates which fit in with the IPCC's view of world changes.

Key points - projections for climate change globally:

• By the second half of the 21st century, wintertime precipitation in the northern mid to high latitudes and Antarctica will rise
• By the same time, Australasia, Central America and southern Africa is likely to see decreases in winter precipitation
• In the tropics, it's thought some land areas will see more rainfall and others will see less
• It is thought the West Antarctic ice sheet is unlikely to collapse this century. If it does fall apart, sea level rises would be enormous
• Global average temperatures are predicted to rise by between 1.4C and 5.8C by 2100
• Maximum and minimum temperatures are expected to rise
• More hot days over land areas and fewer cold days and frost
• More intense precipitation events

  Key Points

  • Global temperatures have risen by over 0.7C in the last 300 years - climate change is therefore already taking place. 0.5C of this warming occurred during the 20th century. Most of the warming was from 1910 to 1940 and from 1976 onwards
  • Four out of five of the warmest years ever recorded were in the 1990's
  • The 1990's was the warmest decade of the last millennium with 1998 being the warmest year globally since records began in 1861
  • 1999 was the warmest year on record in the UK
  • January-June 2002 was the warmest start to a year in the northern hemisphere
  • The total number of cold days (where the average temperature was under 0C) has fallen from between 15 and 20 per year prior to the twentieth century, to around 10 per year in recent years
  • 1995 saw the most hot days in 225 years of daily measurements - 26 days above 20C
  • Sea levels are rising globally, arctic sea ice is thinning and rainfall is becoming heavier in some parts of the World. Average global sea levels have increased by between 0.1 and 0.2 metres over the last 100 years
  • Snow cover in the Northern Hemisphere has declined since the late 1960's by around 10%
  • Mountain glaciers in non polar regions have retreated significantly during the 20th century
  • There is evidence of more precipitation in large parts of the World - an increase of 0.5-1% per decade in many mid and high level areas of the northern hemisphere
  • In the same area of the World there has been a 2-4% increase in the frequency of heavy rainfall events
  • In Asia and Africa there has been an increased frequency and intensity of droughts in the last few decades