There’s a broad consensus that we  must avoid

letting atmospheric CO2 levels exceed 450 ppm

(parts per million), because 450ppm will heat the

planet to a dangerous 2 Celsius above

pre-industrial levels.


Over the past couple years, there’s been a

broadening consensus that we won’t hold the ppm

to 450. Why? Simply because we aren’t cutting our

consumption of forests and fossil fuels by

anywhere near enough to do that job.



“In the jargon used to count the steady

accumulation of carbon dioxide in the Earth’s

thin layer of atmosphere, he said it was

‘improbable’ that levels could now be restricted

to 650 parts per million (ppm).”



The Guardian (UK)

Tuesday December 9 2008


Too late? Why scientists say we should expect the worst


At a high-level academic conference on global

warming at Exeter University this summer, climate

scientist Kevin Anderson stood before his expert

audience and contemplated a strange feeling. He

wanted to be wrong. Many of those in the room who

knew what he was about to say felt the same. His

conclusions had already caused a stir in

scientific and political circles. Even committed

green campaigners said the implications left them



Anderson, an expert at the Tyndall Centre for

Climate Change Research at Manchester University,

was about to send the gloomiest dispatch yet from

the frontline of the war against climate change.

Despite the political rhetoric, the scientific

warnings, the media headlines and the corporate

promises, he would say, carbon emissions were

soaring way out of control – far above even the

bleak scenarios considered by last year’s report

from the Intergovernmental Panel on Climate

Change (IPCC) and the Stern review. The battle

against dangerous climate change had been lost,

and the world needed to prepare for things to get

very, very bad.


“As an academic I wanted to be told that it was a

very good piece of work and that the conclusions

were sound,” Anderson said. “But as a human being

I desperately wanted someone to point out a

mistake, and to tell me we had got it completely



Nobody did. The cream of the UK climate science

community sat in stunned silence as Anderson

pointed out that carbon emissions since 2000 have

risen much faster than anyone thought possible,

driven mainly by the coal-fuelled economic boom

in the developing world. So much extra pollution

is being pumped out, he said, that most of the

climate targets debated by politicians and

campaigners are fanciful at best, and

“dangerously misguided” at worst.


In the jargon used to count the steady

accumulation of carbon dioxide in the Earth’s

thin layer of atmosphere, he said it was

“improbable” that levels could now be restricted

to 650 parts per million (ppm).


The CO2 level is currently over 380ppm, up from

280ppm at the time of the industrial revolution,

and it rises by more than 2ppm each year. The

government’s official position is that the world

should aim to cap this rise at 450ppm.


The science is fuzzy, but experts say that could

offer an even-money chance of limiting the

eventual temperature rise above pre-industrial

times to 2C, which the EU defines as dangerous.

(We have had 0.7C of that already and an

estimated extra 0.5C is guaranteed because of

emissions to date.)


The graphs on the large screens behind Anderson’s

head at Exeter told a different story. Line after

line, representing the fumes that belch from

chimneys, exhausts and jet engines, that should

have bent in a rapid curve towards the ground,

were heading for the ceiling instead.


At 650ppm, the same fuzzy science says the world

would face a catastrophic 4C average rise. And

even that bleak future, Anderson said, could only

be achieved if rich countries adopted “draconian

emission reductions within a decade”. Only an

unprecedented “planned economic recession” might

be enough. The current financial woes would not

come close.


Lost cause


Anderson is not the only expert to voice concerns

that current targets are hopelessly optimistic.

Many scientists, politicians and campaigners

privately admit that 2C is a lost cause. Ask for

projections around the dinner table after a few

bottles of wine and more vote for 650ppm than

450ppm as the more likely outcome.


Bob Watson, chief scientist at the Environment

Department and a former head of the IPCC, warned

this year that the world needed to prepare for a

4C rise, which would wipe out hundreds of

species, bring extreme food and water shortages

in vulnerable countries and cause floods that

would displace hundreds of millions of people.

Warming would be much more severe towards the

poles, which could accelerate melting of the

Greenland and West Antarctic ice sheets.


Watson said: “We must alert everybody that at the

moment we’re at the very top end of the worst

case [emissions] scenario. I think we should be

striving for 450 [ppm] but I think we should be

prepared that 550 [ppm] is a more likely

outcome.” Hitting the 450ppm target, he said,

would be “unbelievably difficult”.


A report for the Australian government this

autumn suggested that the 450ppm goal is so

ambitious that it could wreck attempts to agree a

new global deal on global warming at Copenhagen

next year. The report, from economist Ross

Garnaut and dubbed the Australian Stern review,

says nations must accept that a greater amount of

warming is inevitable, or risk a failure to agree

that “would haunt humanity until the end of time”.


It says developed nations including Britain, the

US and Australia, would have to slash carbon

dioxide emissions by 5% each year over the next

decade to hit the 450ppm target. Britain’s

Climate Change Act 2008, the most ambitious

legislation of its kind in the world, calls for

reductions of about 3% each year to 2050.


Garnaut, a professorial fellow in economics at

Melbourne University, said: “Achieving the

objective of 450ppm would require tighter

constraints on emissions than now seem likely in

the period to 2020 … The only alternative would

be to impose even tighter constraints on

developing countries from 2013, and that does not

appear to be realistic at this time.”


The report adds: “The awful arithmetic means that

exclusively focusing on a 450ppm outcome, at this

moment, could end up providing another reason for

not reaching an international agreement to reduce

emissions. In the meantime, the cost of excessive

focus on an unlikely goal could consign to

history any opportunity to lock in an agreement

for stabilising at 550ppm – a more modest, but

still difficult, international outcome. An

effective agreement around 550ppm would be vastly

superior to continuation of business as usual.”


Henry Derwent, former head of the UK’s

international climate negotiating team and now

president of the International Emissions Trading

Association, said a new climate treaty was

unlikely to include a stabilisation goal – either

450ppm or 550ppm.


“You’ve got to avoid talking and thinking in

those terms because otherwise the politics

reaches a dead end,” he said. Many small island

states are predicted to be swamped by rising seas

with global warming triggered by carbon levels as

low as 400ppm. “It’s really difficult for

countries to sign up to something that loses them

half their territory. It’s not going to work.”


A new agreement in Copenhagen should concentrate

instead on shorter term targets, such as firm

emission reductions by 2020, he said.


Worst time


The escalating scale of human emissions could not

have come at a worst time, as scientists have

discovered that the Earth’s forests and oceans

could be losing their ability to soak up carbon

pollution. Most climate projections assume that

about half of all carbon emissions are reabsorbed

in these natural sinks.


Computer models predict that this effect will

weaken as the world warms, and a string of recent

studies suggests this is happening already.


The Southern Ocean’s ability to absorb carbon

dioxide has weakened by about 15% a decade since

1981, while in the North Atlantic, scientists at

the University of East Anglia also found a

dramatic decline in the CO2 sink between the

mid-1990s and mid-2000s.


A separate study published this year showed the

ability of forests to soak up anthropogenic

carbon dioxide – that caused by human activity –

was weakening, because the changing length of the

seasons alters the time when trees switch from

being a sink of carbon to a source.


Soils could also be giving up their carbon

stores: evidence emerged in 2005 that a vast

expanse of western Siberia was undergoing an

unprecedented thaw.


The region, the largest frozen peat bog in the

world, had begun to melt for the first time since

it formed 11,000 years ago. Scientists believe

the bog could begin to release billions of tonnes

of methane locked up in the soils, a greenhouse

gas 20 times more potent than carbon dioxide. The

World Meteorological Organisation recently

reported the largest annual rise of methane

levels in the atmosphere for a decade.


Some experts argue that the grave nature of

recent studies, combined with the unexpected boom

in carbon emissions, demands an urgent

reassessment of the situation. In an article

published this month in the journal Climatic

Change, Peter Sheehan, an economist at Victoria

University, Australia, says the scale of recent

emissions means the carbon cuts suggested by the

IPCC to stabilise levels in the atmosphere

“cannot be taken as a reliable guide for

immediate policy determination”. The cuts, he

says, will need to be bigger and in more places.


Earlier this year, Jim Hansen, senior climate

scientist with Nasa, published a paper that said

the world’s carbon targets needed to be urgently

revised because of the risk of feedbacks in the

climate system. He used reconstructions of the

Earth’s past climate to show that a target of

350ppm, significantly below where we are today,

is needed to “preserve a planet similar to that

on which civilisation developed and to which life

on Earth is adapted”. Hansen has suggested a

joint review by Britain’s Royal Society and the

US National Academy of Sciences of all research

findings since the IPCC report.


Rajendra Pachauri, who chairs the IPCC, argues

that suggestions the IPCC report is out of date

is “not a valid position at all”.


He said: “What the IPCC produces is not based on

two years of literature, but 30 or 40 years of

literature. We’re not dealing with short-term

weather changes, we’re talking about major

changes in our climate system. I refuse to accept

that a few papers are in any way going to

influence the long-term projections the IPCC has

come up with.”


At Defra, Watson said: “Even without the new

information there was enough to make most policy

makers think that urgent action was absolutely

essential. The new information only strengthens

that and pushes it even harder. It was already

very urgent to start with. It’s now become very,

very urgent.” © Guardian News and Media Limited 2008



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