Met Office reconfirms human activity to blame for climate change

Friday, 05 March 2010

A review of the latest research on climate change by the British Meteorological Office has reconfirmed that human activity is the most likely cause of the rapid changes in our planet's climate.

The Met Office said its review used "sophisticated 'detection and attribution' methods" to review scientific developments since the publication of the UN Intergovernmental Panel on Climate Change report in 2007.

Phenomena like changes in rainfall patterns and shrinking Arctic ice bear the "fingerprint of human activity", the Met Office said in a statement on its website.

The Met Office did not say it was certain that human activity was to blame, but it said it was "very likely to be the cause" rather than natural variations in the Earth's climate cycles.

Peter Stott, Head of Climate Monitoring and Attribution at the Met Office, said, "Recent advances in observational data and the way it is analysed give us a better insight into the climate system than ever before.

"This has allowed us to identify changes in our climate and disentangle natural variability from the results.

"The science reveals a consistent picture of global change that clearly bears the fingerprint of man-made greenhouse gas emissions.

"This shows the evidence of climate change has gone beyond temperature increases - it is now visible across our climate system and all regions of the planet.

"Our climate is changing now and it's very likely human activity is to blame."

The Met Office listed seven changes in the Earth's climate that have been observed:

Temperature increase - global temperatures have increased by about 0.75 °C over the past century and 2000-2009 was the warmest decade on record. Human influence has been detected on every continent.

Changes in rainfall patterns - wetter regions of the world (mid to high latitudes in the northern hemisphere and tropical regions) are generally getting increasing rainfall, and drier regions less rainfall.

Humidity - surface and satellite observations show moisture in the atmosphere has increased over the last 20-30 years. This increases the amount of water that can fall in extreme rainfall, posing flooding risks.

Warming oceans - temperature increases have been observed over the last 50 years in the Atlantic, Pacific and Indian Ocean basins. These cannot be attributed to changes in solar activity, volcanic eruptions or variations in ocean currents, such as El Niño.

Salinity - the Atlantic Ocean is becoming saltier in sub-tropical latitudes. This is because of increasing ocean evaporation due to increased temperatures. In the long-term, ocean regions at higher latitudes are expected to become less salty due to melting of glaciers, ice sheets and increased rainfall.

Sea-ice - summer minimum of Arctic sea-ice is declining at a rate of 600,000 km_ per decade, an area approximately the size of Madagascar. While there has been variation from year to year, a long-term trend has been observed that can only be explained by human influences.

Antarctic - there has been a small increase in Antarctic sea ice extent since the satellite record began in 1978. This small change is consistent with the combined effects of greenhouse gas increases and reductions in the ozone layer which cause increases in some regions, such as the Ross Sea, and decreases in others, such as the Amundsen-Bellingshausen Sea.