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eu No. 63 | APRIL 2010
9
SPECIAL REPORT
CLIM
A
T
E
INTERVIEW
Earth’s climate is influenced by
variations in the energy radiated
by the solar corona – as clearly
visible here during an eclipse – as
well as Earth’s position in relation
to its star. While these parameters
vary over vast expanses of time,
they are insufficient to explain the
sharp rise in temperatures recorded
since the industrial revolution.
© ESO
2009, in the US scientific journal PNAS (Pro-
ceedings of the National Academy of Sciences).
I have explained how it is not for me, as IPCC
Vice-Chair, to define this danger threshold.
What I can say, on the other hand, is that if the
ministers who met 13 years ago to set the
threshold of 2°C and 450 ppm were to meet
again today to consider the same criteria as
before, they would very probably set the dan-
ger threshold at 1.5°C and 350 ppm.
What would be the consequences of such
a change in the ‘danger threshold’?
For the moment, the IPCC is not answering
this question as the most ‘virtuous’ scenario
that it has evaluated in terms of emissions gen-
erates a temperature rise of between 2°C and
2.4°C. So we are forced to extrapolate to have
an idea of the emissions that would enable us
to remain below 1.5°C! I believe this shortcom-
ing will be corrected in the next report – but
clearly it will mean rendering all the reduction
targets even more constraining.
Have politicians listened more attentively
to the IPCC since its last report?
There has been a major positive change –
and this does not contradict what I have just
said – as the 2°C target was adopted recently
at the G8 and then at the G20. This is very
important, despite the reservations I have
expressed regarding this value, because until
then there had not been any figure adopted
internationally, and that is the worst possible
situation! The United Nations Framework
Agreement on Climate Change, adopted in
1992 just before the Rio summit, simply stated
that greenhouse gas concentrations must be
stabilised “at a level that prevents any danger-
ous anthropic disturbance in the climate sys-
tem”. So for 17 years we were without any
internationally recognised quantified objective.
The adoption of a figure constitutes enormous
progress as a whole series of figures stem from
that one, principally the emission reduction
targets.
So the IPCC’s work is therefore slowly being
translated into political decisions?
Except for the fact that the readings of our
estimations are often… selective. We said that
for a temperature rise of between 2°C and 4°C
– and not, please note, below 2°C! – and given
the scientific uncertainties, global emissions
should reach their peak “between 2000 and
2015”. For some this has already been reduced
to “in 2015” and I condemn the fact that just
a few weeks ago, for the European Council,
this had been transformed inexplicably into
“before 2020”! This is perhaps because the Euro-
pean ‘climate package’ was drawn up with 2020
as the horizon, but the physics of climate change
has nothing to do with a political agenda.
Let me give you another example. The
recent G8, when it adopted the 2°C target,
translated this as “a 50 % reduction in global
emissions” but without giving a reference year,
which suggests that we are referring to present
emissions. But in its report the IPCC said
that global emissions should be cut by 50 % to
85 % compared with the 1990 levels. Since
then emissions have increased by around 40 %!
To sum up, independently of any considera-
tion of our ability to achieve these targets,
the targets currently envisaged at international
level fall short of what would be needed to
protect populations and ecosystems.
What remains to be done in reducing
emissions?
We have done a lot – but it remains terribly
little compared with the immensity of the prob-
lem. Take the Kyoto Protocol: the aim was to
reduce emissions by 5 % in 22 years for the
developed countries (between 1990 and 2012)
and this target will probably only just be met
at best. But what we now need to do in these
same countries is reduce emissions by between
80 % and 95 % in 40 years, which would per-
mit a reduction of between 50 % and 85 % for
the planet as a whole. And by the end of the
century emissions should be zero. This sup-
poses a fundamental review of the way we
consume, of the way we produce – not just
energy but all goods, of the way we travel,
and of the way we live and work… A genuine
revolution!
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