Ten warming signs that climate change is unmistakeable fact

Published on Wednesday 28 July 2010 17:34

THE scientific evidence for global warming is "unmistakeable", a major study by more than 300 researchers has concluded.

The 2009 State of the Climate report, published last night, showed that air and sea temperatures were rising, while Arctic sea ice, glaciers and snow cover in the northern hemisphere were all declining.

It confirmed the past decade was the hottest on record and that the Earth has been growing progressively warmer for more than three decades.

The study drew on data from ten key climate indicators which, the scientists said, pointed to the finding that the world was warming.

It was put together by the US National Oceanic and Atmospheric Administration (NOAA), with input from more than 300 scientists from 160 research groups in 48 countries.

The UK Met Office's Hadley Centre drew up the temperature indicators used for the report.

Deke Arndt, chief of the Climate Monitoring Branch of NOAA's National Climatic Data Centre, said: "For the first time, in a single compelling comparison, the analysis brings together multiple observational records from the top of the atmosphere to the depths of the ocean.

"The records come from many institutions worldwide. They use data collected from diverse sources, including satellites, weather balloons, weather stations, ships, buoys, and field surveys. These independently produced lines of evidence all point to the same conclusion: our planet is warming."

Environmental groups will hope the report helps to quash the furore caused by leaked e-mails from the University of East Anglia's Climatic Research Unit, which sceptics claimed called into question evidence to support a warming climate.

Of ten indicators analysed in yesterday's report, seven were rising: air temperature over land, sea-surface temperature, marine air temperature, sea level, ocean heat, humidity, and tropospheric temperature in the "active-weather" layer of the atmosphere closest to the earth's surface. Three are declining: Arctic sea ice, glaciers and spring snow cover in the northern hemisphere.

Dr Peter Stott, contributor to the report and head of climate monitoring and attribution at the Hadley Centre, emphasised that long-term trends needed to be looked at, rather than year-on-year changes.

"Despite the variability caused by short-term changes, the analysis conducted for this report illustrates why we are so confident the world is warming," he said. "When we look at air temperature and other indicators of climate, we see highs and lows in the data from year to year because of natural variability.

"Understanding climate change requires looking at the longer-term record. When we follow decade-to-decade trends using different data sets and independent analyses from around the world, we see clear and unmistakable signs of a warming world."

The report shows that each of the past three decades has been warmer than that before. At the time, the 1980s was the hottest decade on record. In the 1990s, every year was warmer than the average of the previous decade, and the 2000s were warmer still.