According to a study published yesterday (20 October) by the Berkley Earth Project, which included US physicists, climatologists and statisticians, the average world land temperatures climbed approximately 1 degree Celsius since the mid-1950s.
The Berkley project, funded among others by the Koch Foundation, linked to the company which Greenpeace called a 'kingpin of climate science denial,' has analysed data from 15 different sources, in some cases going back as far the 1800. That makes it the most complete historical record of land temperature ever compiled, said physicist and head of the project, Richard Muller.
"My hope is that the findings will cool the debate over global warming by addressing many of the valid concerns of the sceptics in a clear and rigorous way," said Elisabeth Muller, co-founder and executive director of the Berkley Earth project.
Much of the concerns over available and reliable data were fuelled by the so-called Climategate scandal, which started in 2009 before the Copenhagen climate conference, with the hacking of roughly 1,000 emails from a server at the University of East Anglia’s Climatic Research Unit, one of the leading centre providing data to the Intergovernmental Panel on Climate Change (IPCC).
Climate sceptics alleged that the emails revealed scientists were manipulating data and that global warming was a scientific conspiracy, while in fact they seemed to express more a genuine exchange of ideas.
The more than one billion temperature records, compiled by the Berkley Earth project's scientists, in fact agree with figures already collected by other scientists in the US and the UK and spelled out in previous studies, carried out by the US National Oceanic and Atmospheric Administration (NOAA) and the Nasa’s Goddard Institute for Space Studies and the Met Office's Hadley Centre with the University of East Anglia.
"Our biggest surprise was that the new results agreed so closely with the warming values published previously by other teams in the US and the UK," Muller said. "This confirms that these studies were done carefully and that potential biases identified by climate change sceptics did not seriously affect their conclusions."
Ahead of the Durban climate conference in December, the Berkley group decided to use alternative methodologies to find convincing arguments addressing sceptics' concerns primarily on urban heat island effect, poor weather stations quality and the risk of data selection data.
The Berkeley group surveyed about 40,000 weather stations around the world whose output has been recorded and stored in digital form.
According to the Berkley project's leading scientist, Robert Rhode, urban heat does not contribute significantly to the average land temperature rise, because urban regions amount to less than 1% of the global land area.
Still, two-thirds of the weather stations reported warming of land temperatures over the last 70 years, while only one-third of sites, the bulk of them in Europe and the United States, reported cooling temperatures.
"The large number of sites reporting cooling might help explain some of the scepticism of global warming," Rhode said, adding that it is very hard to measure weather consistently over decades and the presence of sites reporting cooling temperatures can falsify data. This is why it takes hundreds of stations to detect and measure an average warming, work that was done by the California University scientists.
Environmental migrants and refugees
While scientists try to reassert clear evidence that temperatures are rising, a British government study released yesterday (20 October) has underscored that millions of people will move from areas where they will feel vulnerable to global environmental change, greatly affecting migration trends in the next 50-60 years.
Prepared by the Foresight group, a think tank that advises the UK government, the report explores the complex relationship between human migration and changing environmental conditions and argues that the issue must become a top policy priority on national and international agendas.
The study, titled 'Migration and Global Environmental Change', warns that trying to block migration will result in increased poverty and ultimately, potentially unmanageable waves of movement.