Climate change can be halted, UN concludes
By Michael McCarthy, Environment Editor
Published: 05 May 2007
Global warming is solvable, United Nations climate change experts
said yesterday, in a landmark judgement running counter to increasing
pessimism about the most serious threat facing the world.
The greenhouse gases, such as carbon dioxide, whose emissions growth
is causing the atmosphere to warm, can be brought under control, said
the economists of the UN's Intergovernmental Panel on Climate Change
(IPCC) - but only if governments act decisively.
Existing and emergent technologies, ranging from renewable energy and
nuclear power to carbon capture and storage, will be adequate to make
the reductions in emissions essential if the world is to avoid
catastrophic rises in global temperature, they asserted in a new
study. And this can be done at comparatively low cost - provided the
right incentives are put in place.
The key incentive, they stressed, is a mechanism no one had heard of
20 years ago - the price of carbon, as determined by markets such as
that of the European Union's Emissions Trading Scheme. If it is high
enough, moving to a low-carbon economy will be a cost-effective
measure around the world, and thus likely to happen much faster.
The economists' verdict, issued yesterday in Bangkok, Thailand, comes
in the final part of the IPCC's Fourth Assessment Report, or AR4. The
first two parts, issued in February and April, dealt with the science
of climate change and its impact.
Both painted dire pictures of what is likely to happen if emissions
of CO2 and other greenhouse gases continue unabated - world
temperatures soaring by up to 6C over the coming century, with
potentially catastrophic effects for mankind. These forecasts have
contributed to a growing feeling of pessimism among senior scientists
and politicians involved with climate change.
The continuing refusal of the Bush administration to get to grips
with the issue, the realisation that the developing countries will
produce emissions at gigantic levels, and the recognition that
climate change is proceeding faster than expected, are leading some
observers to take a dark view of the future.
Yet by contrast, the third part of the IPCC's 2007 assessment, which
deals with controlling climate change and emissions (in the jargon,
"mitigation") is more positive.
"This report shows we can save the climate - but only if governments
act," said Roger Higman, campaigns co-ordinator at Friends of the
Earth. "The technologies needed ... are already available. The costs
of action are far lower than the price we'll pay if we continue to
The report focuses on the feasibility of making the enormous cuts in
emissions necessary to stabilise greenhouse gas concentrations in the
atmosphere at a level where the temperature rise would be halted, and
says, it can be done.
It claims renewable energy, which provides 18 per cent of the world's
electricity, could provide 35 per cent by 2030, and nuclear power, on
a 16 per cent share, could provide 18 per cent by the same date.
However, it notes of nuclear: "Safety, weapons proliferation and
waste remain as constraints".
It proposes that biofuels could play a significant part in reducing
transport emissions, and the biggest gains might come from energy
efficiency. Exotic fixes, such as putting objects in space to shield
us from sunlight, are dismissed as "speculative".
On the fashionable idea of carbon offsetting - paying a firm to plant
trees to compensate for the CO2 emitted on your plane journey - the
report does not utter a word. What it does insist on is the necessity
of having a high price for carbon, to make the introduction of low-
carbon alternatives for energy generation and transport cost
effective around the world.
The price is, in effect, the cost, in a market such as that formed by
the EU Emissions Trading Scheme, of a "carbon credit", a notional
tonne of carbon that companies will need to buy when they want to
emit more CO2 than their government will allow.
The more governments squeeze companies' CO2 allowances, the higher
the price is likely to go, so in effect the price level is in the
hands of governments. When the second period of the EU trading scheme
begins in 2008, it is thought that carbon will trade at about $25 a
The core of the report is the calculation of how much CO2 can be cost-
effectively reduced at a given level for the price. If the price were
at $20 a tonne by 2030, the report says, emissions could be cost-
effectively cut back by up to 17 billion tonnes of greenhouse gases
per year. If it were to rise to nearly $100 a tonne by the same date,
the cut could be as much as 31 billion tonnes, which would be the 50
per cent reduction the world needs to avoid disaster.
The price of doing all this varies with the rate of the world's
economic growth, but it reckons it could be done for less than 1 per
cent of global GDP, a figure similar to that given by the British
economist Sir Nicholas Stern in his report last year.
What the report recommends
The report acknowledges that changes in lifestyle "can contribute to
climate change mitigation across all sectors".
* ENERGY SUPPLY
Renewable energy: "Can have a 30-35 per cent share of the total
electricity supply in 2030 at carbon prices of up to £50 per tonne."
Nuclear power: "Can have an 18 per cent share of the total
electricity supply in 2030 at carbon prices of up to £50 per tonne -
but safety, weapons proliferation and waste remain as constraints.
"Carbon capture and storage: "CCS in underground geological
formations has the potential to make an important contribution to
mitigation by 2030."
* ROAD TRANSPORT
Biofuels are projected to grow to 3 per cent of total transport
energy demand in 2030. "This could increase to about 5-10 per cent
depending on future oil and carbon prices, improvements in vehicle
efficiency and the success of technologies to utilise cellulose
The report says: "Medium-term mitigation potential for CO2 emissions
can come from improved fuel efficiency. However, such improvements
are expected to only partially offset the growth of emissions."
* ENERGY EFFICIENCY
The report is enthusiastic. "Energy efficiency options for new and
existing buildings could reduce CO2 emissions," it says.
There are too many plants with high emissions, the report says. "Full
use of available mitigation options is not being made."
* FARMING AND FORESTRY
Careful farming can help maintain the carbon stored in the soil, and
also keep down emissions of other greenhouse gases.
* HIGH-TECH FIXES
"Geo-engineering options, such as ocean fertilisation to remove CO2
from the atmosphere, or blocking sunlight by bringing material into
the upper atmosphere, remain unproven," the report says.
* LONG-TERM MITIGATION
Stablisation of greenhouse gas concentrations at a range of levels
can be achieved, the report says, and this can be done "by deployment
of ... technologies that are currently available and those that are
expected." But it adds: "This assumes that appropriate and effective
incentives are in place."