"We are seeing substantial global warming" declares new scientific work from an independent group of researchers called the Berkeley Earth Surface Temperature Study. The research team is at least partially funded by the Koch Brothers who fund several climate denial groups. The team was setup to identify flaws in the climate science of global average temperature trends, but has confirmed the analysis undertaken by NASA, NOAA and the Hadley Climate Centre in the UK that about 1 degree Celsius of global warming has occurred since 1950.
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The study also subtantially eliminated arguments that heat island effects, temperature station quality, and the risk of data selection bias had more than a very modest or marginal impact on the trend for increasing global average temperatures.
In a related study published this week - Effects of Urban Surfaces and White Roofs on Global and Regional Climate - Stanford University researchers have quantified the contribution of the heat islands on a global basis for the first time, showing that the contribution to global warming from urban heat islands is very modest compared with what greenhouse gas emissions contribute. The study also ran a simulation for the geoengineering solution of painting roofs white in urban areas to enhance local cooling. The cooling effect does work, but it also marginally increases warming on a global scale. Professor Jacobson advised it was better to Install solar panels to combat Global Warming rather than paint roofs white.
Four research papers have been released for public discussion by the Berkeley Earth team with a view for them all to be submitted for peer review and eventually published. The research team was lead by Professor Richard Muller, a physicist at the University of California at Berkeley and included Saul Perlmutter who was recently announced as a winner of the 2011 Nobel Prize in Physics (for his work in cosmology). Muller criticised the global temperature trend during 2004 in an article in Technology Review, alledging that the "hockey stick" of global temperatures was broken.
"Our biggest surprise was that the new results agreed so closely with the warming values published previously by other teams in the U.S. and the U.K.,” Muller said. “This confirms that these studies were done carefully and that potential biases identified by climate change skeptics did not seriously affect their conclusions."
The study ruled out of contention the urban heat island effect and poor station quality in terms of bias in the results by NASA, NOAA and the Hadley Centre. Robert Rohde, lead scientist for Berkeley Earth, noted that "the Berkeley Earth analysis is the first study to address the issue of data selection bias, by using nearly all of the available data, which includes about 5 times as many station locations as were reviewed by prior groups."
On the urban heat island effect the BEST study reported "The urban heat island effect is locally large and real, but does not contribute significantly to the average land temperature rise. That’s because the urban regions of the Earth amount to less than 1% of the land area".
On temperature sites the BEST study detailed "About 1/3 of temperature sites around the world reported global cooling over the past 70 years (including much of the United States and northern Europe). But 2/3 of the sites show warming. Individual temperature histories reported from a single location are frequently noisy and/or unreliable, and it is always necessary to compare and combine many records to understand the true pattern of global warming."
"The large number of sites reporting cooling might help explain some of the skepticism of global warming,” Rohde commented. “Global warming is too slow for humans to feel directly, and if your local weather man tells you that temperatures are the same or cooler than they were a hundred years ago it is easy to believe him."
The research looked in some depth into the allegations by Anthny Watts that temperature results were skewed in the US due to "poor" station data. The research identified that these stations showed the same pattern of global warming as stations ranked “OK”. "Absolute temperatures of poor stations may be higher and less accurate, but the overall global warming trend is the same, and the Berkeley Earth analysis concludes that there is not any undue bias from including poor stations in
The website explains in depth the methodology of the research and also publishes full datasets which required combining data from different sites and formats and building from scratch a statistical analysis of the data.
While the research identifies that the same degree of global warming is ocurring as other well known analyses, it hasn't made an independent assessment of how much of the observed warming is due to human actions according to Richard Muller.
Scientists from Australian and the UK have commented on the release of these papers. Several commented that the papers need to undergo the peer review process. “I think it would be very unwise to comment until the peer review process has completed. If we have learned anything over the last couple of years it is surely that ensuring the rigour of the science is paramount - however good the "scoop" might seem." said Professor Chris Rapley, Professor of Climate Science at UCL
Professor Neville Nicholls from the School of Geography and Environmental Science at Monash University, Melbourne said "Only those most desperate to dismiss global warming have tried to blame urbanization for the observed warming. But I guess it is always good to have yet another group confirm decades of work by climate scientists. Perhaps this will finally put to rest the furphy that the warming is caused by urbanization. I won't hold my breath though. I guess those spreading misinformation about warming will just move on to another one of their furphies."
Professor Dave Griggs, CEO of ClimateWorks Australia and Director of the Monash Sustainability Institute, Melbourne said that: "The paper confirms previous work that the observed warming of the Earth since the beginning of the 20th Century cannot be attributed to the urban heat island (UHI) effect."
"This comes as no surprise to climate scientists who take great care to take account of this effect in their work. It also confirms findings from other studies using very different methods. For example, looking at temperature trends on windy days and calm days also show no difference contrary to what you would expect from the urban heat island as the heat would build up more on calm days. So, hopefully this paper will help to put this urban (heat island) myth to bed." said Dave Griggs.
Professor Simon Tett, Head of Global Change Research Institute School of Geosciences at the University of Edinburgh, said:
"Earlier analysis, including that from the [Hadley] Climatic Research Unit, using a restricted set of temperature records, to avoid urban warming, show large scale warming. Comparison of that data with climate models leads to the conclusion that anthropogenic drivers are responsible for the late 20th century warming. The BEST study, assuming its results are similar after peer review, would not change that view."
Bob Ward, Policy and Communications Director, Grantham Institute for Climate Change and the Environment at the London School of Economics (LSE), said:
"This new study confirms what we already knew. The warming of the land areas of the Earth since the 19th century cannot be explained by the impact of cities growing to engulf rural weather stations. So-called 'sceptics' should now drop their thoroughly discredited claims that the increase in global average temperature could be attributed to the impact of growing cities, which create an urban heat island effect. This claim was always dubious as oceans also show the same level of warming as land areas."
"The warming of the Earth is unequivocal and, as every major scientific organisation in the world has pointed out, the overwhelming evidence indicates that this warming is being driven by the unarguable increase in greenhouse gas concentrations in the atmosphere."
"More broadly this study also proves once again how false it was for 'sceptics' to allege that the e-mails hacked from the University of East Anglia proved that the Climatic Research Unit's land temperature record had been doctored. Several independent inquiries, and now this study, have shown that allegation to be entirely untrue. It is now time for an apology from all those, including US Presidential hopeful Rick Perry, who have made false claims that the evidence for global warming has been faked by climate scientists." concluded Bob Ward.
- Berkeley Earth Summary of Findings, 20 October, 2011 - Cooling the Warming Debate -
Berkeley Earth Releases Global Land Warming Analysis (PDF)
- Australian Science Media Centre, 21 October 2011 - RAPID REACTION: New data on climate change from the Berkeley Earth Surface Temperature (BEST) project – experts respond
- Image - Decadal Land-Surface Average Temperature from Berkeley Earth