They
sound like ideas from a Jules Verne novel, but giant engineering schemes
designed to alter the climate offer the cheapest way of avoiding catastrophic
global warming, according to a growing number of scientists and green-minded
entrepreneurs.
Most
of the schemes have been dismissed as impossibly expensive or impractical, such
as the proposal to create a space sunshade by using rockets to deploy millions
of mirrors in the stratosphere.
One
relatively cheap solution, however, is gaining favour among many different
groups and is endorsed today by an independent study that compares the costs
and benefits of all the main ideas. A wind-powered fleet of 1,900 ships would
criss-cross the oceans, sucking up sea water and spraying it from the top of
tall funnels to create vast white clouds.
These
clouds would reflect a tiny proportion, between 1 and 2 per cent, of the
sunlight that would otherwise warm the ocean. This would be enough to cancel
out the greenhouse effect caused by carbon dioxide emissions. The ships would
be unmanned and directed by satellite to locations with the best conditions for
increasing cloud cover. They would mainly operate in the Pacific, far enough
from land to avoid interfering with rainfall.
The
idea has been circulating for a decade but until now has merely been one of
many climate engineering pipedreams. A study commissioned by the Copenhagen
Consensus Centre, a think-tank that advises governments on how to
spend aid money, found that the fleet would cost $9 billion (£5.3 billion) to
test and launch within 25 years. This is a fraction of the $250 billion that
the world’s leading nations are considering spending each year to cut CO2
emissions.
The
Royal Society is expected to announce next month that cloud-forming ships are
one of the most promising ideas.
The
The
eruption of
Many
scientists have proposed different methods of injecting particles, or aerosols,
into the atmosphere, including using squadrons of air tankers, possibly based
in the
The
study concluded that the scheme would cost $230 billion and would be much
harder to control than cloud-producing ships, which could be switched off if
shown to have adverse effects. The study dismissed the space sunshade idea
after calculating that the costs of launching the mirrors would be $395
trillion.
“The
space sunshade is really just science fiction but cloud whitening ships deserve
serious scrutiny,” said Bjorn Lomborg, director of the think-tank. He argues
that, although global warming is a huge problem, there might be better ways of
addressing it then simply cutting CO2 emissions. “We need to have a debate
about all of the options, not just the politically correct one of reducing
CO2,” he said.
He
is hosting a conference in
Rival
teams of British and American scientists are seeking funding for sea trials of
prototype cloud-forming ships. The Carnegie Institute has donated several
hundred thousand dollars to the