An extensive analysis of the abstracts or summaries of
scientific papers published over the past 20 years shows that even though
public perception tends to be that climate scientists disagree over the fundamental
cause of climate change, they all agree that humans are to blame.
To help put a stop to the squabbling, two dozen scientists
and citizen-scientists from three continents - including Sarah Green, professor
and chair of chemistry at Michigan Technological University in Houghton, Mich.—
analysed the abstracts of nearly 12 000 peer-reviewed scientific papers on
climate change published between 1991 and 2011. They also surveyed the authors
of those papers, to find out how well the analysis agreed with the authors’ own
views on how their papers presented the cause of climate change.
Scientists all seem
They found that more than 97% of the scientists who
expressed any opinion in their papers about the primary cause of global climate
change believed that human activity was the cause. Approximately the same
percentage of authors who responded to the survey said that their papers
endorsed anthropogenic (human-caused) climate change. Nine of the scientists
who analysed the abstracts- including Green- reported their findings in the
journal Environmental Research Letters,
published by the Institute of Physics.
Green says she got involved because she was curious about
the apparent disconnect between the general public’s lack of concern about
climate change and what she calls “the clear scientific evidence that humans
are changing the planet's atmosphere.” That led her to SkepticalScience.com, a
web site that tracks and addresses common myths about climate change. She has
since contributed several articles.
John Cook, who maintains the web site, is a climate
communications fellow for the Global Change Institute at the University of
Queensland in Australia. He found that
one dominant myth about climate change is the idea that scientists disagree
about the cause.
Rating of abstracts
To investigate how much disagreement there really is in the
peer-reviewed scientific literature, Cook set up an on-line system that enabled
a group of SkepticalScience.com authors to rate nearly 12 000 abstracts from
the Web of Science database (1991-2011) on whether they report human activities
as the main contributors to climate change.
“John cleverly set up the rating process so it felt like a
game to me,” says Green. “After I rated five abstracts, another five would
quickly appear, and counters showed how many each person had done, making it
like a contest.”
The abstract raters were a combination of professional and
citizen-scientists from Australia, Canada, the UK, Finland, the US and Germany.
The group was organised through the sceptical science web site.
“I read and rated 4,146 abstracts for this study, over about
four months in winter/spring 2012,” Green explains. “This is the first time
I’ve published a paper where all the research was accomplished sitting on my
Green adds, “I found it fascinating to see the array of
implications of climate change identified in the abstracts—beyond the usual
ones we hear about. They examined
everything from production of tea in Sri Lanka, the stripes on salamanders, child
undernutrition, frequency of lightning strikes, distribution of prickly pear
cactus (and pine trees, kelp beds, wild boars, penguins, arctic fishes, canine
leishmaniasis, and many, many others), mitochondrial electron transport
activity in clams, copper uptake by minnows, lake effect snowfall, the
rotational speed of the Earth and the prevalence of naked foxes in Iceland.”
Green also found a large number of papers addressing
mitigation of climate change through alternative energy and other ways to limit
“It is critical to raise public awareness of the scientific
consensus on climate change, so the public can make policy decisions based on
factual evidence,” she says. “Typically, the general public thinks that only
around 50 percent of climate scientists agree that humans are causing global
warming. This research has shown that the reality is 97 percent.”