Skeptics say "global warming is happening"
- 24 Oct 2011, 15:00
- Verity Payne
Last week the Berkeley Earth Surface Temperature (BEST) study released four
reports that gained a huge amount of media coverage (for a
scientific study) - particularly for work that has not yet been
peer reviewed. Media reports focused on the project's finding that
the average global temperature on land has increased by around 1°C
since the middle of the 20th century.
Michael Hanlon, science editor for the Daily Mail, and self
confessed ex-climate skeptic,
suggests that the BEST study is likely to do a lot to answer
some of the criticisms of climate skeptics, saying:
"In the end, the sceptics - the genuine
sceptics (ie not those with say a financial stake in climate change
denial) - will come round. But it will take time and more
extraordinary evidence like that produced by this latest
This was certainly the intention of the BEST study team, whose
executive director Elizabeth Muller hoped
their work would "cool the debate over global warming".
So has the BEST study persuaded any climate skeptics to change
their minds and cool the debate? We take a look at the response
from climate skeptic commentators:
We've never disputed warming
Some skeptic commentators seem to be swiftly backtracking from
previously held opinions over global warming and the 'corruption'
amongst climate scientists. Take for example James Delingpole, who
in response to the BEST study:
"Global warming is real...Professor
Muller [of the BEST team] sets up his straw man...by ascribing to
"skeptics" views that they don't actually hold. Their case, he
pretends for the sake of his wafer-thin argument, rests on the idea
that the last century's land-based temperature data sets are so
hopelessly corrupt that they have created the illusion of global
warming where none actually exists.
"It has been a truth long acknowledged
by climate sceptics, deniers and realists of every conceivable hue
that since the mid-19th century, the planet has been on a warming
This is in contrast to a post Delingpole wrote on his website
Global warming: is it even happening?" in January 2010, where
he argued that:
"the surface temperature records are
such a mess that they simply can't be trusted"
Or a 2009
blogpost from the Telegraph immediately after the leaking of
the UEA emails:
Andrew Bolt puts it, this scandal could well be "the greatest
in modern science". These alleged emails - supposedly exchanged by
some of the most prominent scientists pushing AGW theory - suggest:
'Conspiracy, collusion in exaggerating warming data'...
"The world is currently cooling."
We don't know what's caused the warming
The Global Warming Policy Foundation (GWPF)'s David Whitehouse
"the Berkeley researchers themselves say
they cannot determine why the world has warmed."
Whilst the Daily Mail, whose recent coverage of climate science
has been decidedly
questionable, ran with the
"New analysis of 1.6 billion weather
records concludes the world IS warming (but still can't say what's
In fact the BEST study's objectives have
never included determining the cause of global warming. Their aim
has been to answer some of the doubts that skeptics have about
global temperature records, including meteorological station
quality and the urban heat island effect.
Other studies (see
here for example) have investigated how human activity
influences global surface temperature and have concluded that
natural climate variations alone (including volcanic activity,
solar activity, changes to ocean and atmospheric currents) cannot
account for the warming over the last 40 years. Only when manmade
greenhouse gases are included can the observed trends be simulated
by climate models.
This has also been found to be the case for warming in
specific regions, such as at the poles
and over North
Other climate features such as
surface humidity and air
temperature have also been attributed to human activity, whilst
recent research found that man-made climate change is "having a
significant impact on physical and biological systems globally and
in some continents".
Human component of warming overstated
Whitehouse feels that the headline "missed by all" media outlets
"Scientists say human component of
global warming may be overstated."
One of the four BEST study papers investigated the correlation
between cycles in the North Atlantic and the land surface
temperature. The researchers suggest the 'Atlantic Multidecadal
Oscillation' (AMO) as an
area for further study, as it might contribute to global land
The AMO refers to changes in North Atlantic cycles. The BEST
researchers themselves point out however that these changes could
be a result of man-made global warming:
"If the long-term AMO changes have been
driven by greenhouse gases then the AMO region may serve as a
positive feedback that amplifies the effect of greenhouse gas
forcing over land. On the other hand, some of the long-term change
in the AMO could be driven by natural variability, e.g.
fluctuations in thermohaline flow. In that case the human component
of global warming may be somewhat overestimated."
Currently climate scientists
believe that warming resulting from man-made greenhouse gases
outweights the temperature influence from AMO.
The BEST report has errors
The methods of the BEST study have come in for criticism,
notably from Anthony Watts of the skeptic blog WUWT. When the BEST
work was in development,
Watts was strongly supportive of it and wrote that he was
"prepared to accept whatever result they produce, even if it proves
my premise wrong." Since the release of the reports, however, he
has criticised the BEST
Specifically Watts complains that in the BEST
paper investigating weather station quality, researchers used
60-year records not 30-year records to determine station quality.
Watts implies this might impair the BEST temperature analysis,
although it is hard to see how limiting their analysis to Watts'
30-year suggestion would significantly alter the BEST study's key
Watts has also criticised the BEST team's decision to publicly
announce their findings
before peer-review. Yet, as the BBC's Richard Black points
out, WUWT frequently features non-peer-reviewed science, yet is
now heavily criticising the BEST study for making the papers public
Overall, the BEST study has made a good media story but it
unclear how successful it will be in its stated aim of 'cooling the
global warming debate'.
Sir Brian Hoskins, Director of the Grantham Institute said:
"If and when such a study is
peer-reviewed and published, hopefully we can then focus on the
implications for the future of this warming rather than wrangling
over whether the warming is really there."
This is to be hoped for. It wil be interesting to see whether it
Modified 15.15 24/10/11 to correct typo: 19th changed to 20th