VILLAGEApril/May 
M
ICHAEL Mann is one of the world’s
leading climate scientists. He is
director of the Earth Systems
Science Centre in Penn State University and
has been a lead IPCC author since . His
‘hockey stick graph’ became the defining
symbol of man-made climate change – and
made him a special target of the fossil-fuel
lobby. He is author of ‘The Hockey Stick and
the Climate Wars’, an insider’s account of the
murky world of climate denialism. Mann was
implicated in the so-called ‘Climategate’
hacking affair in , but was exonerated
of all alleged wrongdoing by several inde-
pendent investigations.
JG: Mike, you’re best known for your work
on the Hockey Stick. Can you tell us about it,
why it’s so important, and why it gets you
into so much trouble?
MM: The Hockey Stick is this graph my
colleagues and I published a decade and a
half ago depicting how temperatures, spe-
cifically over the northern hemisphere, have
changed over the past , years. We used
information from tree rings, ice cores and
coral records, what we call climate proxy
data. We know the globe has warmed by
about one degree centigrade over the past
century but the question of how unusual is
that warming requires us to go back in time.
The record shows relatively warm condi-
tions around , years ago, a steady, slow
cooling trend into the s – and then an
abrupt warming over the past century. The
shape of that curve is like a hockey stick…
what it indicates is that the recent warm-
ing really is unprecedented as far back as
we can go. This curve became iconic in the
climate-change debate – it became a potent
symbol in the larger debate over human-
caused climate change, and it thus became an
object of attack by those looking to discredit
the case for concern over climate change.
Climate deniers felt if they could ‘take down’
the hockey stick, then somehow the case for
concern over human-caused climate change
would collapse. Of course, that’s silly because
there’s so much other evidence.
JG: Why do you think climate science has
become such a red-hot focus of controversy?
In other scientific areas, the controversies
are in the (peer-reviewed) journals. Why is
this one on the street?
MM: The fact is that any time you see the
findings of science come into conflict with
powerful vested interests, they’ve done
their best to try to discredit the science
and the scientists. Take tobacco, industry
documents actually contained the phrase
“doubt is our product”. They manufacture
doubt when it comes to scientific findings
that pose some potential threat (to their
profits). Fossil-fuel interests are pouring in
tens of millions of dollars here in the US to
discredit the science of climate change, and
to discredit arguments for renewables and
clean energy. The Koch brothers for instance
are funding both.
JG: If the more serious projections com-
ing from climate science (up to  degrees
C warming by mid-century) are borne out,
there’s no future for anybody. Is it not a
puzzle that the so-called deniers somehow
believe that the impacts won’t affect them?
MM: Denial takes many forms. Those
who are orchestrating the disinformation
campaign at the top, one might imagine
are fairly cynical – it’s quite clear that the
fossil-fuel companies know their product
is damaging the planet. There may also
be some cognitive dissonance. Aside from
sociopathic and psychopathic individuals,
most people don’t want to believe they’re
doing something fundamentally wrong or
evil: they may want to believe those indi-
viduals who claim that it’s not going to be
as bad as the scientists are saying. In other
cases it’s almost ideological, it’s no longer a
matter of logically looking at the scientific
evidence, they see (opposition to) climate
change as just another part of their cultural
and ideological identity, like their stance on
gun control or healthcare. In the US, belief in
climate change is about as good a predictor
Mann enough
His ‘hockey stick graph’ became the defining
symbol of man-made climate change – and
made him a special target of the fossil-fuel
lobby. John Gibbons interviews Michael Mann
Michael Mann
ENVIRONMENT
INTERVIEW
Michael
Mann;
Hockey
Stick
graph