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The Berkley Earth Surface Temperature (BEST) project was
launched and chaired by Professor Richard
Muller, a physicist at the University of California at
Berkeley. It aims to address
criticisms raised by climate skeptics about how existing
records of the Earth's average surface temperature have been
compiled. Team members include physicist Robert Rohde,
Curry, and other physicists and statisticians.
Research from the
BEST group, released in October 2011, addressed concerns raised by
skeptics about records of surface temperatures, including the urban
heat island effect and poor weather station siting. These issues
were not found to have a significant effect on the global land
surface temperature record.
What does the latest BEST research show?
This latest research from the BEST team confirms that the
Earth's average land temperature has risen by roughly 0.9 degrees
Celsius since the 1950s, and by 1.5 degrees Celsius over the last
250 years. This is in line with existing records, which put average
global land temperature rise over the last 50 years at 0.81 - 0.93
The study also uses a simple model to work out whether the
change in global land temperature fits best with changes in
atmospheric carbon dioxide levels, volcanic activity or solar
activity - and find the best fit with a combination of change in
atmospheric carbon dioxide and volcanic activity:
The contribution of solar activity, it concludes, must be
notes this doesn't prove that carbon dioxide is
responsible for warming, but adds:
"To be considered seriously, any
alternative explanation must match the data at least as well as
does carbon dioxide."
How do the latest BEST results differ from previous
The BEST temperature reconstruction of global land temperature
records differs from other records - produced by the NOAA National
Climatic Data Center (NCDC),
the NASA Goddard Institute for Space Studies (GISS), and a
collaboration between the UK Met Office Hadley Centre and the
Climatic Research Unit at the University of East Anglia (HadCRUT)
- because it uses many more station records.
The BEST team also use a different
statistical method to calculate the average land
temperature record from the methods used by NOAA, GISS and HadCRUT.
The team boasts that its approach is simple,
pointing out that it doesn't rely on complicated climate
The attribution of much of the last 50 years' warming to human
activity is in line with
a variety of sophisticated approaches to calculate the
and human causes of global warming. The studies agree that
human activity is the dominant cause of warming over the last
century, and particularly over the last 50 years.
Is the BEST research peer reviewed?
This new research is not yet peer reviewed. The BEST team
"Some people think that peer review
consists of submitting a paper to a journal and waiting for the
anonymous comments of referees. Traditional peer review is much
broader than that and much more open. In science, when you have a
new result, your first step is to present it to your colleagues
[...] Such traditional and open peer review has many advantages. It
usually results in better papers in the archival journals, because
the papers are widely examined prior to publication. It does have a
disadvantage, however, that journalists can also pick up preprints
and report on them before the traditional peer-review process is
When the BEST team last released papers they were also
non-peer-reviewed preprints. Those papers have since been submitted
to peer-reviewed journals. Only one out of those four, however,
appears to have been accepted for publication so far, according to
The peer review process allows independent qualified experts to
scrutinise scientific methods, results and interpretations before
they are made public. It provides a kind of stamp of approval for
new research, in that it shows that the research is considered
valid, significant and original by experts in the field. So the
fact that any BEST research has attracted so much media attention
before even being peer reviewed is a little worrying - the research
could turn out to be good, but could also turn out to be flawed or
How much does the BEST study matter?
Beyond the media the new results have had a
mixed reception. Climate scientist William Connolley is
"[The BEST team has] done none of the
attribution work you'd expect, in order to talk about attribution.
And what they say [...] appears absurdly naive."
Climate scientist Ken Caldeira
"The basic scientific results have been
established for a long time now, so I do not see the results of
Muller et al as being scientifically important. However,
their result may be politically important. It shows that even
people who suspect climate scientists of being charlatans, when
they take a hard look at the data, see that the climate scientists
have been right all along."
BEST member Curry
describes its temperature record as "the best land surface
temperature data set that we currently have", but
declined to be a co-author on the latest paper, since she
disagrees with its interpretation attributing the temperature rise
to atmospheric carbon dioxide.
The climate skeptic community meanwhile, is largely
dismissive of the new findings, and has been keen to point
out that Muller was
never truly a skeptic.