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Global warming will probably be a net benefit for several decades

Update: I have added a reply to a critic of the article

I have an article in the Times on the implications of a new
estimate of climate sensitivity:

There is little doubt that the damage being done by
climate-change policies currently exceeds the damage being done by
climate change, and will for several decades yet. Hunger,
rainforest destruction, excess cold-weather deaths and reduced
economic growth are all exacerbated by the rush to biomass and
wind. These dwarf any possible effects of worse weather, for which
there is still no actual evidence anyway: recent droughts, floods
and storms are within historic variability.

The harm done by policy falls disproportionately on the poor.
Climate worriers claim that at some point this will reverse and the
disease will become worse than the cure. An acceleration in
temperature rise, they say, is overdue. The snag is, the best
science now says otherwise. Whereas the politicians, activists and
businessmen who make the most noise about — and money from — this
issue are sticking to their guns, key scientists are backing away
from predictions of rapid warming.

Yesterday saw the publication of a paper in a prestigious journal, Nature
, from a high-profile international team led by
Oxford scientists. The contributors include 14 lead authors of the
forthcoming Intergovernmental Panel on Climate Change scientific
report; two are lead authors of the crucial chapter 10: professors
Myles Allen and Gabriele Hegerl.

So this study is about as authoritative as you can get. It uses
the most robust method, of analysing the Earth’s heat budget over
the past hundred years or so, to estimate a “transient climate
response” — the amount of warming that, with rising emissions, the
world is likely to experience by the time carbon dioxide levels
have doubled since pre-industrial times.

The most likely estimate is 1.3C. Even if we reach doubled
carbon dioxide in just 50 years, we can expect the world to be
about two-thirds of a degree warmer than it is now, maybe a bit
more if other greenhouse gases increase too. That is to say, up
until my teenage children reach retirement age, they will have
experienced further warming at about the same rate as I have
experienced since I was at school.

At this rate, it will be the last decades of this century before
global warming does net harm. As the economist Bjørn Lomborg
recently summarised the economic consensus: “Economic models show
that the overall impact of a moderate warming (1-2C) will be
beneficial [so] global warming is a net benefit now and will likely
stay so till about 2070.”

Now contrast the new result with the Met Office’s flagship
climate model, the one that ministers and their advisers place most
faith in. Called HadGEM2-ES, it expects a transient climate
response of 2.5C, or almost double the best estimate that the
Oxford team has just published. Indeed, the latter’s study
concludes that it is more than 95 per cent certain that the
response is below 2C, considerably short of the Met Office model’s

Why trust the new results rather than the Met Office model? The
new study not only uses the most robust method, but joins several
other observationally based studies from the past year that also
find lower climate sensitivity than complex climate models

Notice that this new understanding is consistent with what we
have actually experienced: about 0.1C per decade over the past 50
years. The most remarkable thing about the recent milestone of 0.04
per cent carbon dioxide in the atmosphere (400 parts per million)
is that it comes after 15 years of no net warming at all.

The new paper also fits the known physics of the greenhouse
effect, which predicts a warming of 1.1C for a doubling of carbon
dioxide. Only unverified assumptions by modellers about the added
effects of water vapour and clouds have allowed politicians and
activists to claim that a much higher number fits the laws of
physics. Only now-disproven claims about how much the sulphur
pollution in the air was masking the warming enabled them to
reconcile their claims with the actual data.

It is true that the “transient climate response” is not the end
of the story and that the gradual warming of the oceans means that
there would be more warming in the pipeline even if we stopped
increasing carbon dioxide levels after doubling them. But given the
advance of nuclear and solar technology, there is now a good chance
we will have decarbonised the economy before any net harm has been

In an insightful new book, The Age of Global
, Rupert Darwall makes the point that “in believing
scientists and politicians can solve the problems of a far distant
future, the tangible needs of the present are neglected”. The
strong possibility that climate change will be slow and harmless
must be taken seriously before we damage more lives, landscapes and
livelihoods in its name.


For further detailed commentary on the Otto et al study, see Nic Lewis’s essay here


Update: Here is a response I wrote to Myles Allen in reply to
his critique of the above article:

Dear Professor Allen,

In your polemical Guardian article on Tuesday you produce no
counter-arguments to my Times article. For example, you ask: “Is
Ridley right that there is no actual evidence of harm as long as
droughts, floods and storms are within historic variability?” You
then do not answer that question. Well, am I right or not?

You then say:

Where Ridley may well be right is that if you are confident that
citizens of 2065 will be rich enough and smart enough to cope with
whatever we bequeath to them; or if you really don’t care about
unborn generations anyway (what have unborn generations ever done
for me?); or if, like Bjorn Lomborg, you discount future damages to
give very little weight to anything that happens after 2065; or if
you firmly believe that the “second coming” will occur before 2065
anyway – then there probably isn’t much point in trying to reduce
carbon dioxide emissions. These are perfectly coherent ethical
positions: they don’t happen to be positions that I subscribe to,
but if that is what Ridley thinks, so be it.

This is manifestly dishonest. To find out what I think, try
reading my article rather than making up fantastic and absurd
stories and then saying “if that is what Ridley thinks…”. Where did
I mention anything remotely like a “second coming”? Where did I
imply that I “don’t care about unborn generations”, when I made the
exact opposite point? Why did you choose to distort my argument
that the citizens of 2060 will be able to cope with mild climate
change into a quite different point — “cope with whatever we
bequeath them”? And why did you choose to ignore the point I
clearly made that climate policy is doing more economic and
ecological harm to the poor today than climate change itself, and
will do so for several more decades?

Not only do I care very much about my children and potential
grandchildren, which is why I do not want to burden them with
biomass power stations and wind turbines that drive up energy
costs, spoil landscapes and exacerbate rainforest destruction. But
I also care about poor people alive today, whom you do not mention.
Climate change policies are killing nearly 200,000 people a year by
subsidizing bio-energy and driving up food prices.[1] Fuel poverty
is being driven up by subsidies for wind energy — this may not
trouble Oxford professors, but it is a real issue for many people.
Hard-pressed south-east Northumberland, where I live, has just lost
500 jobs at an aluminium plant because (in the words of Civitas)
“the smelter’s long-term viability is critically undermined by the
government’s energy policies”.

Although you describe the climate debate as acrimonious, you
will find no ad hominem attacks on you or distortions of your
position in my Times article. For anybody, let alone a scientist
purporting to speak with scientific authority, to write an article
as vicious and misleading as this is frankly despicable. It
exemplifies the sort of innuendo journalism that the Leveson report
rightly criticised. Until this week I had considerable respect for
you, having followed some of your work and disagreed only with the
political interpretations you put on it. Now you have lost my

Yours sincerely,

Matt Ridley


By Matt Ridley | Tagged:  rational-optimist  the-times