Berkeley Earth

The Berkeley Earth Surface Temperature (BEST) project is an effort to resolve criticism of the current records of the Earth's surface temperatures by preparing an open database and analysis of these temperatures and temperature trends, to be available online, with all calculations, methods and results also to be freely available online. BEST's stated aim is a "transparent approach, based on data analysis." "Our results will include not only our best estimate for the global temperature change, but estimates of the uncertainties in the record."

BEST founder Richard A. Muller told The Guardian "...we are bringing the spirit of science back to a subject that has become too argumentative and too contentious," "...we are an independent, non-political, non-partisan group. We will gather the data, do the analysis, present the results and make all of it available. There will be no spin, whatever we find. We are doing this because it is the most important project in the world today. Nothing else comes close."

The BEST project is funded by unrestricted educational grants totalling (as of March 2011) about $635,000. Large donors include Lawrence Berkeley National Laboratory, the Charles G. Koch Foundation, the Fund for Innovative Climate and Energy Research (FICER), and the William K. Bowes, Jr. Foundation. The donors have no control over how BEST conducts the research or what they publish.

The team's preliminary findings, data sets and programs were made available to the public in October 2011. The study addressed scientific concerns raised by skeptics including urban heat island effect, poor station quality, and the risk of data selection bias. The Berkeley Earth group concluded that the warming trend is real, that over the past 50 years the land surface warmed by 0.911 °C, and their results mirrors those obtained from earlier studies carried out by the U.S. National Oceanic and Atmospheric Administration (NOAA), the Hadley Centre, NASA's Goddard Institute for Space Studies (GISS) Surface Temperature Analysis, and the Climatic Research Unit (CRU) at the University of East Anglia. The study also found that The urban heat island effect and poor station quality did not bias the results obtained from these earlier studies.

Scientific team

Berkeley Earth team members include:

• Richard A. Muller, founder and Scientific Director. Professor of Physics, UCB and Senior Scientist, Lawrence Berkeley National Laboratory (LBNL). Muller is a member of the JASON Defense Advisory Group who has been critical of other climate temperature studies before this project.
• Robert Rohde, lead scientist. Ph.D. in physics, University of California, Berkeley (UCB). Rohde's scientific interests include earth sciences, climatology, and scientific graphics. Rohde is the founder of Global Warming Art.
• David Brillinger, statistical scientist. Professor of Statistics at UCB. A contributor to the theory of time series analysis.
• Judith Curry, climatologist and Chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology.
• Robert Jacobsen, Professor of Physics at UCB and an expert in analyses of large data sets.
• Saul Perlmutter, Nobel Prize-winning astrophysicist at Lawrence Berkeley National Laboratory and Professor of Physics at UCB.
• Arthur H. Rosenfeld, Professor of Physics at UCB and former California Energy Commissioner. Research he directed at Lawrence Berkeley National Laboratory led to the development of compact fluorescent lamps.
• Charlotte Wickham, Statistical Scientist.
• Jonathan Wurtele, Professor of Physics at UCB and Senior Scientist, LBNL
• Elizabeth Muller, founder and Executive Director

Initial results

After completing the analysis of the full land temperature data set, consisting of more than 1.6 billion temperature measurements dating back to the 1800s from 15 sources around the world, and originated from more than 39,000 temperature stations worldwide, the group submitted four papers for peer-review and publication in scientific journals. The Berkeley Earth study did not assess temperature changes in the oceans, nor tried to assess how much of the observed warming is due to human action. The Berkeley Earth team also released the preliminary findings to the public on October 20, 2011 in order to promote additional scrutiny. The data sets and programs used to analyze the information, and the papers undergoing peer review were also made available to the public.

The Berkeley Earth study addressed scientific concerns raised by skeptics including urban heat island effect, poor station quality, and the risk of data selection bias. The team's initial conclusions are the following:

• The urban heat island effect and poor station quality did not bias the results obtained from earlier studies carried out by the U.S. National Oceanic and Atmospheric Administration (NOAA), the Hadley Centre and NASA's GISS Surface Temperature Analysis. The team found that the urban heat island effect is locally large and real, but does not contribute significantly to the average land temperature rise, as the planet's urban regions amount to less than 1% of the land area. The study also found that while stations considered "poor" might be less accurate, they recorded the same average warming trend.
• Global temperatures closely matched previous studies from NASA GISS, NOAA and the Hadley Centre, that have found global warming trends. The Berkely Earth group estimates that over the past 50 years the land surface warmed by 0.911°C, just 2% less than NOAA’s estimate. The team scientific director stated that "...this confirms that these studies were done carefully and that potential biases identified by climate change sceptics did not seriously affect their conclusions."
• 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 Atlantic multidecadal oscillation (AMO) has played a larger role than previously thought. The El Niño-Southern Oscillation (ENSO) is generally thought to be the main reason for inter-annual warming or cooling, but the Berkeley Earth team's analysis found that the global temperature correlates more closely with the state of the Atlantic Multidecadal Oscillation index, which is a measure of sea surface temperature in the north Atlantic.

The BEST analysis uses a new methodology and was tested against much of the same data as NOAA and NASA. The group uses an algorithm that attaches an automatic weighting to every data point, according to its consistency with comparable readings. The team claims this approach allows the inclusion of outlandish readings without distorting the result and standard statistical techniques were used to remove outliers. The methodology also avoids traditional procedures that require long, continuous data segments, thus accommodating for short sequences, such as those provided by temporary weather stations. This innovation allowed the group to compile an earlier record than its predecessors, starting from 1800, but with a high degree of uncertainty because at the time there were only two weather stations in America, just a few in Europe and one in Asia.

Reactions

When the study team was announced, blogger Anthony Watts, who popularized several of the issues addressed by the Berkeley Earth group study, stated

“I’m prepared to accept whatever result they produce, even if it proves my premise wrong. The method isn’t the madness that we’ve seen from NOAA, NCDC, GISS, and CRU. That lack of strings attached to funding, plus the broad mix of people involved especially those who have previous experience in handling large data sets gives me greater confidence in the result being closer to a bona fide ground truth than anything we’ve seen yet."

After the initial result were released, Watts spoke to the New York Times, which wrote: "Mr. Watts ... contended that the study’s methodology was flawed because it examined data over a 60-year period instead of the 30-year-one that was the basis for his research and some other peer-reviewed studies. He also noted that the report had not yet been peer-reviewed and cited spelling errors as proof of sloppiness." Steven Mosher, a co-author of a book critical of climate scientists, did not give his seal of approval, saying that the study still lacked transparency. He said: “I’m not happy until the code is released and released in a language that people can use freely.” The code and dataset are available from the BEST Dataset web page. Stephen McIntyre, editor of Climate Audit, a blog devoted to the analysis and discussion of climate data, said that "the team deserves credit for going back to the primary data and doing the work" and even though he have not had an opportunity to read the papers in detail, he is questioning the analyses of urban heating and weather station quality.

James Hansen, a leading climate scientist and head of NASA Goddard Institute for Space Studies commented that he had not read the research papers but was glad Muller was looking at the issue. He said "It should help inform those who have honest scepticism about global warming." Phil Jones the director of the Climatic Research Unit (CRU) at the University of East Anglia (UEA), said: "I look forward to reading the finalised paper once it has been reviewed and published. These initial findings are very encouraging and echo our own results and our conclusion that the impact of urban heat islands on the overall global temperature is minimal." Michael Mann, director of the Earth System Science Center at Pennsylvania State University, commented that "...they get the same result that everyone else has gotten," and "that said, I think it's at least useful to see that even a critic like Muller, when he takes an honest look, finds that climate science is robust." Peter Thorne, from the Cooperative Institute for Climate and Satellites in North Carolina and chair of the International Surface Temperature Initiative, said: "This takes a very distinct approach to the problem and comes up with the same answer, and that builds confidence that pre-existing estimates are in the right ballpark. There is very substantial value in having multiple groups looking at the same problem in different ways." Scientists writing at the RealClimate.org noted that it was unsurprising that BEST's results matched previous results so well. "Any of various simple statistical analyses of the freely available data ...show... that it was very very unlikely that the results would change," they wrote.

See also

• Anthony Watts (blogger)
• Global warming controversy
• Instrumental temperature record
• Urban heat island

External links

• Berkeley Earth Surface Temperature (BEST) home page
• Papers submitted for review (as of October 2011):

1. Berkeley Earth Temperature Averaging Process
2. Influence of Urban Heating on the Global Temperature Land Average
3. Earth Atmospheric Land Surface Temperature and Station Quality in the United States
4. Decadal Variations in the Global Atmospheric Land Temperatures