Man Made Volcanoes May Cool Earth
August 30, 2009
Here now is the latest episode of Pinky
and the Brain and how to save the planet.
THE
Royal Society is backing research into simulated volcanic eruptions, spraying
millions of tons of dust into the air, in an attempt to stave off climate
change.
The society will this week call
for a global programme of studies into geo-engineering — the manipulation of
the Earth’s climate to counteract global warming — as the world struggles to
cut greenhouse gas emissions.
It will suggest in a report that
pouring sulphur-based particles into the upper atmosphere could be one of the
few options available to humanity to keep the world cool.
The intervention by the Royal
Society comes amid tension ahead of the United Nations-sponsored climate talks
in
Ken Caldeira, an earth scientist
at
“If I had a dollar for
geo-engineering research I would put 90 cents of it into stratospheric aerosols
and 10 cents into everything else,” said Caldeira.
The interest in so-called
aerosols is linked to the eruption of Mount Pinatubo in the
The Royal Society is
Brian Launder, a professor at
The world’s population generates
the equivalent of 50 billion tons of CO2 a year, a figure which is projected to
reach 60-70 billion tons by 2030 on current trends.
Scientists warn that the planet
could warm by 5C by 2100 and say emissions must fall to 20 billion tons a year
by 2050 if a disaster is to be averted.
However, many researchers and
policymakers regard this target as impossible.
The Royal Society report is
expected to draw partly on research by Tim Lenton, professor of earth sciences
at the
“We estimate that 1.5-5m tons of
sulphate particles could be released [artificially] into the stratosphere each
year on a recurring basis,” said Lenton.
“This is quite a small amount,
which makes it potentially economically viable, but it could reduce global
temperature rise by up to 2C.”
The study investigates several
other proposals for geo-engineering, dividing them into two broad approaches.
One approach involves reducing the sunlight reaching the Earth’s surface — a
premise that lies behind both aerosol release and the construction of mirrors
in space.
Lenton regards the latter idea as
“science fiction”, pointing out that any space sunshade would need a surface
area of 1.8m square miles to be effective.
Another suggestion for cutting
the light reaching the Earth is cloud-whitening, where salt water is sprayed
into the air from thousands of ships, producing brighter clouds.
However, the Met Office has
attacked this idea in its submission to the Royal Society, warning that it
could cut rainfall in areas such as the Amazon and
Vicky Pope, head of climate
change advice at the Met Office, said: “If humanity starts messing with the
world’s cloud systems it is bound to have major side effects, some of which
will be dangerous.”
The other main approach to
geo-engineering is to try to accelerate the rate at which CO2 is removed from
the air by plants and ocean plankton, or through chemicals.
This is the basis of ideas such
as ocean fertilisation, where nutrients such as iron are added to water to
promote plankton growth. Plankton absorb CO2 as they
grow and carry it down to the seabed when they die.
Such techniques would have
relatively few adverse side effects but the disadvantage, the report will say,
is that they would take far too long to make significant cuts in atmospheric
CO2.
The same criticism applies to the
idea of using giant artificial filters driven by nuclear power that chemically
strip CO2 from the air.
John Shepherd, professor of earth
system science at the National Oceanography Centre in
Met Office research has suggested
that if techniques such as sulphate aerosols were to be suddenly discontinued
the Earth could experience a disastrous warming surge.