The net benefits of climate change till 2080 - Matt Ridley

My Spectator cover story on the net benefits of climate
change.

I will post rebuttals to the articles that criticised this piece
below.

Climate change has done more good than harm so far and is likely
to continue doing so for most of this century. This is not some
barmy, right-wing fantasy; it is the consensus of expert opinion.
Yet almost nobody seems to know this. Whenever I make the point in
public, I am told by those who are paid to insult anybody who
departs from climate alarm that I have got it embarrassingly wrong,
don’t know what I am talking about, must be referring to Britain
only, rather than the world as a whole, and so forth.

At first, I thought this was just their usual bluster. But then
I realised that they are genuinely unaware. Good news is no news,
which is why the mainstream media largely ignores all studies
showing net benefits of climate change. And academics have not
exactly been keen to push such analysis forward. So here follows,
for possibly the first time in history, an entire article in the
national press on the net benefits of climate change.

There are many likely effects of climate change: positive and
negative, economic and ecological, humanitarian and financial. And
if you aggregate them all, the overall effect is positive today
— and likely to stay positive until around 2080. That was the
conclusion of Professor Richard Tol of Sussex University after he reviewed 14 different studies of the effects
of future climate trends.

To be precise, Prof Tol calculated that climate change would be
beneficial up to 2.2˚C of warming from 2009 (when he wrote his
paper). This means approximately 3˚C from pre-industrial levels,
since about 0.8˚C of warming has happened in the last 150 years.
The latest estimates of climate sensitivity suggest that such
temperatures may not be reached till the end of the century
— if at all. The Intergovernmental Panel on Climate Change,
whose reports define the consensis, is sticking to older
assumptions, however, which would mean net benefits till about
2080. Either way, it’s a long way off.

Now Prof Tol has a new paper, published as a chapter in a new book, called How Much have
Global Problems Cost the World?, which is edited by Bjorn
Lomborg, director of the Copenhagen Consensus Centre, and was
reviewed by a group of leading economists. In this paper he casts
his gaze backwards to the last century. He concludes that climate
change did indeed raise human and planetary welfare during the 20th
century.

You can choose not to believe the studies Prof Tol has collated.
Or you can say the net benefit is small (which it is), you can
argue that the benefits have accrued more to rich countries than
poor countries (which is true) or you can emphasise that after 2080
climate change would probably do net harm to the world (which may
also be true). You can even say you do not trust the models
involved (though they have proved more reliable than the
temperature models). But what you cannot do is deny that this is
the current consensus. If you wish to accept the consensus on
temperature models, then you should accept the consensus on
economic benefit.

Overall, Prof Tol finds that climate change in the past century
improved human welfare. By how much? He calculates by 1.4 per cent
of global economic output, rising to 1.5 per cent by 2025. For some
people, this means the difference between survival and
starvation.

It will still be 1.2 per cent around 2050 and will not turn
negative until around 2080. In short, my children will be very old
before global warming stops benefiting the world. Note that if the
world continues to grow at 3 per cent a year, then the average
person will be about nine times as rich in 2080 as she is today. So
low-lying Bangladesh will be able to afford the same kind of flood
defences that the Dutch have today.

The chief benefits of global warming include: fewer winter
deaths; lower energy costs; better agricultural yields; probably
fewer droughts; maybe richer biodiversity. It is a little-known
fact that winter deaths exceed summer deaths — not just in
countries like Britain but also those with very warm summers,
including Greece. Both Britain and Greece see mortality rates rise
by 18 per cent each winter. Especially cold winters cause a rise in
heart failures far greater than the rise in deaths during
heatwaves.

Cold, not the heat, is the biggest killer. For the last decade,
Brits have been dying from the cold at the average rate of 29,000
excess deaths each winter. Compare this to the heatwave ten years
ago, which claimed 15,000 lives in France and just 2,000 in
Britain. In the ten years since, there has been no summer death
spike at all. Excess winter deaths hit the poor harder than the
rich for the obvious reason: they cannot afford heating. And it is
not just those at risk who benefit from moderate warming. Global
warming has so far cut heating bills more than it has raised
cooling bills. If it resumes after its current 17-year hiatus, and
if the energy efficiency of our homes improves, then at some point
the cost of cooling probably will exceed the cost of heating
— probably from about 2035, Prof Tol estimates.

The greatest benefit from climate change comes not from
temperature change but from carbon dioxide itself. It is not
pollution, but the raw material from which plants make
carbohydrates and thence proteins and fats. As it is an extremely
rare trace gas in the air — less than 0.04 per cent of the air
on average — plants struggle to absorb enough of it. On a
windless, sunny day, a field of corn can suck half the carbon
dioxide out of the air. Commercial greenhouse operators therefore
pump carbon dioxide into their greenhouses to raise plant growth
rates.

The increase in average carbon dioxide levels over the past
century, from 0.03 per cent to 0.04 per cent of the air, has had a
measurable impact on plant growth rates. It is responsible for a
startling change in the amount of greenery on the planet. As Dr
Ranga Myneni of Boston University has documented, using three decades of satellite
data, 31 per cent of the global vegetated area of the planet has
become greener and just 3 per cent has become less green. This
translates into a 14 per cent increase in productivity of
ecosystems and has been observed in all vegetation types.

Dr Randall Donohue and colleagues of the CSIRO Land and Water
department in Australia also analysed satellite data and found greening to
be clearly attributable in part to the carbon dioxide fertilisation
effect. Greening is especially pronounced in dry areas like the
Sahel region of Africa, where satellites show a big increase in
green vegetation since the 1970s.

It is often argued that global warming will hurt the world’s
poorest hardest. What is seldom heard is that the decline of
famines in the Sahel in recent years is partly due to more rainfall
caused by moderate warming and partly due to more carbon dioxide
itself: more greenery for goats to eat means more greenery
left over for gazelles, so entire ecosystems have benefited.

Even polar bears are thriving so far, though this is mainly
because of the cessation of hunting. None the less, it’s worth
noting that the three years with the lowest polar bear cub survival
in the western Hudson Bay (1974, 1984 and 1992) were the years when the sea ice was too thick
for ringed seals to appear in good numbers in spring. Bears need
broken ice.

Well yes, you may argue, but what about all the weather
disasters caused by climate change? Entirely mythical — so
far. The latest IPCC report is admirably frank about this,
reporting ‘no significant observed trends in global tropical
cyclone frequency over the past century … lack of evidence and thus
low confidence regarding the sign of trend in the magnitude and/or
frequency offloads on a global scale … low confidence in observed
trends in small-scale severe weather phenomena such as hail and
thunderstorms’.

In fact, the death rate from droughts, floods and storms has dropped by 98 per cent since the 1920s,
according to a careful study by the independent scholar Indur
Goklany. Not because weather has become less dangerous but because
people have gained better protection as they got richer: witness
the remarkable success of cyclone warnings in India last week.
That’s the thing about climate change — we will probably
pocket the benefits and mitigate at least some of the harm by
adapting. For example, experts now agree that malaria will continue
its rapid worldwide decline whatever the climate does.

Yet cherry-picking the bad news remains rife. A remarkable
example of this was the IPCC’s last report in 2007, which said that
global warming would cause ‘hundreds of millions of people [to be]
exposed to increased water stress’ under four different scenarios
of future warming. It cited a study, which had also counted numbers
of people at reduced risk of water stress — and in each case that
number was higher. The IPCC simply omitted the positive
numbers.

Why does this matter? Even if climate change does produce
slightly more welfare for the next 70 years, why take the risk that
it will do great harm thereafter? There is one obvious reason:
climate policy is already doing harm. Building wind turbines,
growing biofuels and substituting wood for coal in power stations
— all policies designed explicitly to fight climate change
— have had negligible effects on carbon dioxide emissions. But
they have driven people into fuel poverty, made industries
uncompetitive, driven up food prices, accelerated the destruction
of forests, killed rare birds of prey, and divided communities. To
name just some of the effects. Mr Goklany estimates that globally nearly 200,000 people
are dying every year, because we are turning 5 per cent of the
world’s grain crop into motor fuel instead of food: that pushes
people into malnutrition and death. In this country, 65 people a
day are dying because they cannot afford to heat their homes
properly, according to Christine Liddell of the University of
Ulster, yet the government is planning to double the cost of
electricity to consumers by 2030.

As Bjorn Lomborg has pointed out, the European Union will pay £165
billion for its current climate policies each and every year for
the next 87 years. Britain’s climate policies — subsidising
windmills, wood-burners, anaerobic digesters, electric vehicles and
all the rest — is due to cost us £1.8 trillion over the course of
this century. In exchange for that Brobdingnagian sum, we hope to
lower the air temperature by about 0.005˚C — which will be
undetectable by normal thermometers. The accepted consensus among
economists is that every £100 spent fighting climate change brings
£3 of benefit.

So we are doing real harm now to impede a change that will
produce net benefits for 70 years. That’s like having radiotherapy
because you are feeling too well. I just don’t share the certainty
of so many in the green establishment that it’s worth it. It may
be, but it may not.

Disclosure: by virtue of owning shares and
land, I have some degree of interests in all almost all forms of
energy generation: coal, wood, oil and gas, wind (reluctantly),
nuclear, even biofuels, demand for which drives up wheat prices. I
could probably make more money out of enthusiastically endorsing
green energy than opposing it. So the argument presented here is
not special pleading, just honest curiosity.

My response to Duncan Geere’s article in the New Statesman:

Four of Geere’s paragraphs in turn begin with “He’s right…” so
I am glad that Geere confirms that I am right about all my main
points. if you read my article you will find that each of Geere’s
assertions about the eventual harm of climate change are also in my
piece. For example, I say: “Even if climate change does produce
slightly more welfare for the next 70 years, why take the risk that
it will do great harm thereafter?”. I do not ignore sea level rise:
and anyway it is taken into account in all of the studies collated
by Tol.

Geere’s main point, that the graph of benefits starts declining
at 1C above (today’s) is very misleading. What this means is that
the benefit during one year is slightly smaller than the benefit
during the year before, not that there has been net harm during
that year. Geere seems to have misunderstood Tol’s graph.

My points about fewer droughts and richer biodiversity are
grounded in the peer reviewed literature. Many models and data sets
agree that rainfall is likely to increase as temperature rises,
while the evidence for global greening as a result of carbon
dioxide emissions (and rainfall increases) is now strong. Greater
yields means more land sparing as well.

The main point I was trying to make is that very few people know
that climate change has benefits at all, let alone net benefits
today; even fewer know that it is likely to have net benefits in
the future for about 70 years. This fact, which Mr Geere confirms,
is worth discussing. Judging by the incredulous reaction to my
article in some quarters, this was indeed news to many people.

I note Mr Geere has nothing to say about the harm being done by
climate policies to the very poorest people in the world. A
peer-reviewed estimate is that 200,000 people are dying every year
because of the effect of biofuels on food prices. Western elites
may feel comfortable about this, but I do not, and I think a
serious debate about whether some current policies (as opposed to
others) do more harm than good even in the long run is worth
having.

Barry Brill’s comment on my article, posted at Bishop Hill:

The 1°C rise mentioned by Mr Gere has its base in 2009. As the
IPCC says that global surface temperatures have increased by 0.85°C
since the pre-industrial era, this point of maximum benefit is
about equal to the 2°C target set by all UNFCCC conferences since
Copenhagen.

At the rate of warming recorded in the recent AR5WG1 SPM
(0.12°C/decade since 1951) it will be well after 2100 before even
this level of diminishing benefit is reached. The IPCC says that
the historic rate won’t increase unless the TCR is above about
1.5°C – which seems unlikely in view of recent studies.

The series of published economic studies relied upon by
Professor Tol are based on the IPCC’s earlier assessment reports,
which were blithely unaware of the “hiatus”. Allowance needs to be
made for at least three new factors:

(1) The hiatus has already set the timetable back by about 17
years;
(2) The models assumed a Best Estimate for ECS of 3.0°C. The
consensus behind that figure has now evaporated;
(3) We now know that natural variation (or the Davy Jones
hypothesis) regularly offsets the effects of AGW.

All these factors suggest that Matt Ridley’s timing is extremely
conservative. Any warming occurring in the 21st century is likely
to be a great boon to planet Earth and its inhabitants.

My response to Bob Ward’s article on the LSE website:

This week Bob Ward twice repeated in published form a claim that
he surely knows to be misleading. It concerns the number of people
who die in winter versus summer. Both Bjorn Lomborg in the Times
and I in the Spectator have cited studies showing that there are
more excess deaths in winter than summer in most countries. Mr Ward
does not dispute this. But he cites a Health Protection Agency
report which argues that by 2050 winter deaths in the UK will
probably fall less than summer deaths will rise, and argues that
this means that climate change will then be doing more harm than
good in this one respect at least.

Yet the very source he uses states that the increase in summer
deaths reflects “the increasing size of the population in most
UK regions during the 21st century.” (p41) It goes on to show
that if you hold population constant, projected climate change will
increase heat deaths by 3,336, but reduce cold deaths
by 10,766.

Anybody can make a mistake. But surely it was impossible to miss
the HPA’s explanation? Yet in the last ten days Mr Ward simply
repeated the error twice, in an article on the Grantham Institute’s
website attacking me and in a letter to the Times this week
attacking Lomborg.

He says the average temperature increase expected is “much lower
than the top of the range of projections” from the IPCC. Well,
indeed – that’s the very meaning of the word average, that it’s
less than the extreme. And he says that the IPCC’s “high” emissions
scenario suggests sea level “could” be higher than the average
projection. Indeed. I was careful to say in my article that I was
talking about central estimates, not high-end projections. Either
Mr Ward is simply unable to grasp this point or he was being
deliberately mendacious in implying that the extreme scenarios are
likely to happen.

On the effect of carbon dioxide on global vegetation indices,
one of the main ways in which carbon dioxide emissions are
benefiting the planet, Mr Ward is entirely silent. He simply
ignores the data I cite showing a net global greening in all types
of ecosystem over the past 30 years as measured by satellites. Yet
he implies that carbon dioxide fertilisation is a myth. Has he not
read the Donohue paper or examined the Myneni data? It’s easily
viewed on the internet.

I am happy to debate the benefits of climate change with
anybody, and I stressed in my original article that there is no
certainty about the future. I have never said we need to do nothing
to head off the damaging effects of climate change towards the end
of the 21st century. But I do think the fact, an under-reported
one, that climate change has had net benefits so far should be
discussed alongside the fact that many climate policies are doing
real harm to people and ecosystems. Terms of abuse are not
helpful.