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— December - January
- until a few months ago - govern-
ment targets for cutting greenhouse gases
had the virtue of being wrong. They were the
wrong targets, by the wrong dates, and they
bore no relationship to the stated aim of pre-
venting more than two degrees of global warm-
ing. But they used a methodology which even
their sternest critics (myself included) believed
could be improved until it delivered the right
results: the cuts merely needed to be raised
and accelerated. Three papers released ear-
lier this year changed all that. The first one,
published in the Proceedings of the National
Academy of Sciences in February, set the scene.
It showed that the climate change we cause
today “is largely irreversible for , years
after emissions stop”. Around % of the car-
bon dioxide produced by humans this century
will remain in the atmosphere until at least the
year *. Moreover, thanks to the peculiar
ways in which the oceans absorb heat from the
atmosphere, global average temperatures are
likely to “remain approximately constant …
until the end of the millennium despite zero
further emissions”.
In other words, governments’ hopes about
the trajectory of temperature change are ill-
founded. Most, including those of govern-
ments in the UK and Ireland, are working on
the assumption that we can overshoot the
desired targets for temperature and atmos-
pheric concentrations of CO, then watch them
settle back later. What this paper shows is that
wherever temperatures peak, that is more or
less where they will stay. There is no going
back.
The other two papers were published by
Nature in April. While governments and the
United Nations set targets for cuts by a certain
date, these papers measured something quite
different: the total volume of carbon dioxide
we can produce and still stand a good chance
10% ‘10
We need a radical new approach to cutting greenhouse gases,
and it might have arrived.
g e o r g e m o n b i o t
PHOTOS: GETTY IMAGES
Monbiot
PHOTOS: GETTY IMAGES
of avoiding more than two degrees of warming.
One paper, by a team led by Myles Allen, shows
that preventing more than two degrees means
producing a maximum of half a trillion tonnes
of carbon ( billion tonnes of carbon diox-
ide) between now and - and probably
much less. The other paper, written by a team
led by Malte Meinshausen, proposes that pro-
ducing billion tonnes of CO between
and would deliver a % chance
of exceeding two degrees of warming. Writing
elsewhere, the two teams gave us an idea of
what this means. At current rates of use, we
will burn the ration that Allen set aside for the
next years in four decades. Meinshausen’s
carbon budget between now and will
have been exhausted before .
There’s another way of expressing these
limits. The World Energy Council (WEC)
publishes figures for global reserves of fos-
sil fuels. A reserve means the minerals that
have been identified, quantified and are cost-
effective to exploit; in other words those that
are more or less ready to be extracted. (The
total amount of a mineral found in the earth’s
crust is called the resource). The WEC says
that billion tonnes of coal, , bil-
lion cubic metres of natural gas and bil-
lion tonnes of crude oil are good to go. We
know roughly how much carbon a tonne of
coal, a cubic metre of gas and a barrel of oil
contain. You can see the calculations and ref-
erences on www.monbiot.com: the result sug-
gests that official reserves of coal, gas and oil
amount to billion tonnes of carbon. The
molecular weight of carbon dioxide is .
times that of carbon. This means that current
reserves of fossil fuel, even when we ignore
unconventional sources such as tar sands and
oil shale, would produce billion tonnes
of carbon dioxide if they were burnt. In other
words, if we don’t want to exceed two degrees
of global warming, we can burn, according to
Allen’s paper, a maximum of % of current
fossil fuel reserves by . Meinshausen
says we’ve already used one third of his
budget since , which suggests
that we can afford to burn only % of cur-
rent reserves between now and . If you
counted unconventional sources (the carbon
content is much harder to calculate), the pro-
portion would be even smaller.
There are some obvious conclusions from
these three papers. The trajectory of cuts is
more important than the final destination.
An % cut by , for example, could
produce very different outcomes. If most of
the cut were made towards the beginning of
the period, the total emissions entering the
atmosphere would be much smaller than if
most of the cut were made at the end of the
period. The measure that counts is the peak
atmospheric concentration. This must be as
low as possible and come as soon as possible,
which means making most of the reductions
right now. Ensuring that we don’t exceed the
cumulative emissions discussed in the Nature
papers means setting an absolute limit to the
amount of fossil fuel we can burn, which, as
my rough sums show, is likely to be much
smaller than the reserves already identified.
It means a global moratorium on prospect-
ing and developing new fields. None of this
is currently on the table. The targets and
methodology being used by governments and
the United Nations - which will form the basis
for their negotiations at Copenhagen - are not
even wrong; they are irrelevant. Unless there
is a radical change of plan between now and
December, world leaders will not only be dis-
cussing the alignment of deckchairs on the
Titanic, but hotly disputing whose deckchairs
they really are and who has the responsi-
bility for moving them. Fascinating as this
argument may be, it does nothing to alter the
course of the liner.
But someone, at least, does have a radical
new plan. Last month the team that made the
film The Age of Stupid launched the :
campaign: which aims for a % cut in green-
house gas emissions in the UK and Ireland
during . This seems to be roughly the
trajectory needed to deliver a good chance of
averting two degrees of warming. By encour-
aging people and businesses and institutions
to sign up, the campaign hopes to shame gov-
ernments into adopting this as national tar-
gets. This would give them the moral leverage
to demand immediate sharp cuts from other
nations, based on current science rather than
political convenience. I don’t agree with eve-
rything the campaign proposes. It allows busi-
nesses to claim reductions in carbon intensity
as if they were real cuts: in other words they
can measure their reductions relative to turn-
over rather than in absolute terms. There’s an
uncomfortable precedent for this: cutting car-
bon intensity was George Bush’s proposal for
tackling climate change. As economic growth
is the major cause of rising emissions, this
looks like a cop-out. The cuts will not be inde-
pendently audited, which might undermine
their credibility with the government. But
these are quibbles. : is the best shot we
have left. It might not be enough, it might
not work; but at least it’s relevant. I take the
pledge. Will you?
This article first appeared in the Guardian in September.
See also www.monbiot.com which includes footnotes to
this article. Visit www.1010.ie
“If we don’t want
to exceed two
degrees of global
warming, we can
burn, according
to Allen’s paper, a
maximum of 60%
of current fossil
fuel reserves by
2050”
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