|
Stark Warning Over
Climate Change
© Richard
Black, Environment
Correspondent, BBC News 2007
Climate report
conclusions
Rising concentrations
of greenhouse gases may have more serious impacts
than previously believed, a major scientific report
has said.
The report, published
by the UK government, says there is only a small
chance of greenhouse gas emissions being kept below
"dangerous" levels.
It fears the Greenland
ice sheet is likely to melt, leading sea levels to
rise by 7m (23ft) over 1,000 years.
The poorest countries
will be most vulnerable to these effects, it
adds.
The report Avoiding
Dangerous Climate Change, collates evidence
presented by scientists at a conference hosted by
the UK Meteorological Office in February
2005.
 The
conference set two principal objectives: to ask
what level of greenhouse gases in the atmosphere
is too much, and what the options are for
avoiding such a level.
It's the
irreversibility that I think brings it home to
people.
In the report's
foreword, UK Prime Minister Tony Blair writes
that "it is now plain that the emission of
greenhouse gases... is causing global warming at
a rate that is unsustainable."
Environment
Secretary Margaret Beckett said the report's
conclusions would be a shock to many
people.
"The thing that is
perhaps not so familiar to members of the
public... is this notion that we could come to a
tipping point where change could be
irreversible," she told BBC Radio 4's Today
programme.
"We're not talking
about it happening over five minutes, of course,
maybe over a thousand years, but it's the
irreversibility that I think brings it home to
people."
Vulnerable
ecosystems
The report sets out the
effects of various levels of temperature
increase.
The European Union (EU)
has adopted a target of preventing a rise in global
average temperature of more than two degrees
Celsius.
But that, according to
the report, might be too high, with two degrees
perhaps enough to trigger melting of the Greenland
ice sheet.
This would have a major
impact on sea levels globally, though it would take
up to 1000 years to see the full predicted rise of
7m.
Above two degrees, says
the report, the risks increase "very
substantially", with "potentially large numbers of
extinctions" and "major increases in hunger and
water shortage risks... particularly in developing
countries".
The report asked
scientists to calculate which greenhouse gas
concentrations in the atmosphere would be enough to
cause these "dangerous" temperature
increases.
Currently, the
atmosphere contains about 380 parts per million
(ppm) of carbon dioxide, the principal greenhouse
gas of concern, compared to levels before the
industrial revolution of about
275ppm.
To have a good chance
of achieving the EU's two-degree target, levels
should be stabilised at 450ppm or below, the report
concludes.
But, speaking on Today,
the UK government's chief scientific adviser, Sir
David King, said that was unlikely to
happen.
"We're going to be at
400 ppm in 10 years' time, I predict that without
any delight in saying it," he said.
"But no country is
going to turn off a power station which is
providing much-desired
energy for its population to tackle this problem -
we have to accept that.
"To aim for 450 (ppm)
would, I am afraid, seem
unfeasible."
But Myles Allen, a
lecturer on atmospheric physics at Oxford
University, said assessing a "safe level" of carbon
dioxide in the atmosphere was "a bit like asking a
doctor what's a safe number of cigarettes to smoke
per day".
"There isn't one, but
at the same time people do smoke and live until
they're 90," he told Today.
On the other question
asked at the 2005 conference - what are the options
for avoiding dangerous concentrations of greenhouse
gases in the atmosphere? - the report says that
technological options to reduce emissions do
exist.
It concludes that the
biggest obstacles to the take up of technologies
such as renewable sources of energy and "clean
coal" lie in vested interests, cultural barriers to
change and simple lack of awareness.
|
