James Lovelock was on his finest doom-mongering form when he spoke at the
House of Commons last week. Humanity, he told MPs, would be lucky if just
20% of us survived imminent climatic disaster.
“We have passed the point of no return,” he insisted. “We have reached a point
where civilisation itself is threatened and we have no one to blame but our
own ignorance and greed.”
Buried among the gloom, however, was an unexpected message. If humanity has
any hope at all, said Lovelock, it lies in the use of radical technologies
to deal with the greenhouse gases that are altering our climate.
Lovelock is already renowned for supporting nuclear power as a way of cutting
carbon emissions, but he is now proposing something even more radical: a
global programme to pollute the stratosphere with sulphur compounds. These,
he suggested, would enable it to reflect more sunlight back into space — and
so cool the world.
“We could fit sulphur dispensers on to the world’s airliners so that they
could mitigate the world’s carbon emissions as they go,” he said.
Twenty years ago this suggestion would have sounded mad.
The great environmental battles then were to rein back sulphate pollutants
which were damned as the cause of acid rain — and Lovelock’s own Gaia
theory, which suggests that the Earth behaves like a living system, was one
of the philosophical underpinnings for green activists.
What, then, is he doing suggesting a scheme that would effectively reengineer
the behav-iour of the Earth itself? Could Lovelock be right that such ideas
really do offer a new and practical way of dealing with climate change?
An increasing number of climate researchers share Lovelock’s vision. Last
November hundreds of them met at a conference organised by the Carnegie
Institution and Nasa, America’s space agency, to work out which of them held
the most promise.
Their ideas were far-ranging and perhaps farfetched. One scientist proposed
launching a swarm of reflective spacecraft to hover between the sun and the
Earth, blocking out some sunlight.
Another suggested a fleet of large yachts which would spray seawater into the
air, creating extra clouds to reflect sunlight back into space.
Underlying them all, however, was a single idea: that if humanity has the
collective power to heat up the planet, albeit inadvertently, then perhaps
it might also find a way of cooling it down.
“Geo-engineering, as we call it, remains a last resort but it could save the
world,” said Roger Angel, professor of astronomy at Arizona University, who
suggested the reflective spaceships.
“The ideal solution is for humanity to cut its carbon emissions and stop
heating the world in the first place. But if we get to the point where the
world is warming by, say, 2C then we should consider these other measures,
however extreme they may seem.”
Angel, whose research is supported by Nasa, has proposed launching a cloud of
tens of thousands of spacecraft, each about 2ft-3ft across, to the inner
Lagrange point.
This is a point between the Earth and the sun where gravitational forces
cancel out, allowing such satellites to maintain a constant position.
“This would cut out just under 2% of the solar radiation reaching Earth for a
few trillion dollars — less than 0.5% of the world’s GDP,” he said.
“If Greenland starts to melt then the damage from rising sea levels will be
far greater than that. Such projects could be a very good investment.”
It is a view shared by Paul Crutzen, former professor of ocean science at the
Scripps Institution of Oceanography, California, whose life’s work has been
fighting pollution. Now he wants to reverse that to tackle the far bigger
threat from climate change.
Back in 1995 Crutzen won the Nobel prize for research into the workings of the
ozone layer, the part of the atmosphere that screens out deadly ultraviolet
radiation.
It was his work that helped to prompt governments to block the use of
chlorofluorocarbons and other pollutants, including sulphates, that were
attacking the ozone layer.
However, in 1991 a massive volcanic eruption from Mount Pinatubo in the
Philippines saw about 10m tons of sulphur being ejected into the
stratosphere.
Over the next two years global temperatures fell by about 0.6C — comparable
with the 0.7C rise attributed to greenhouse gases.
Crutzen now believes that humanity could save itself from climate change by
replicating the effects of such an eruption. He suggests launching hundreds
of rockets laden with burning sulphur into the stratosphere.
Crutzen realises the ironies involved in such a programme. Sulphur is not only
the cause of acid rain, but also attacks the ozone layer that he has spent
his career protecting.
“We want to clean up the environment because pollution is unhealthy,” he said
recently, “but this pollution also cools the Earth by reflecting solar
radiation into space.”
Perhaps the simplest idea for cutting the amount of sunlight reaching the
Earth comes from Stephen Salter, professor of engineering design at
Edinburgh
University. Salter, a renowned marine engineer, has drawn up designs for a
fleet of yachts that would pump fine particles of sea water into the air.
These would create clouds that would then reflect the sun’s rays back into
space.
“Our calculations suggest that increasing the amount of light reflected by
just 3% would be enough to counteract the global warming caused by
greenhouse gases,” he said.
“Worldwide about 1,000 vessels would be needed to spray about five tons of
water a second into the air. We could station them off Greenland in the
northern hemisphere’s summer and then float them down to Antarctica for its
hot season.”
The beauty of Salter’s boats is that they would be powered entirely by wind
but with conventional sails replaced by Flettner rotors — vertical
cylinders that rotate as the wind passes over them.
“It might seem a farfetched solution, but when the planet is in such a dire
situation we have to examine every option,” Salter said.
However good such schemes might be at slowing down climate change, they would
not prevent the other great threat posed by greenhouse gases: the
acidification of the oceans.
About half of the 29 billion tons of carbon dioxide released by human activity
each year becomes absorbed by sea water. This saves the Earth from warming
even faster, but it is making the seas increasingly acid and threatens to
wipe out many forms of marine life.
A number of geoscientists are proposing systems that can strip the surplus CO2
out of the air, which would ease ocean acidification.
Professor Klaus Lackner of the Earth Institute at Columbia University has
designed a 100ft tall artificial “tree” that could strip 90,000 tons of CO2
from the air each year — equivalent to the output of 20,000 cars.
Lackner believes that planting forests of such devices around the world
could halt the surge in levels. CO2 Lackner’s “trees” would work by passing
air through filters containing sodium hydroxide. This would react with CO2
to create a solution of sodium carbonate that could be piped away.
Eventually the CO2 collected would be stored away for ever, perhaps in vast
reservoirs under the seabed.
Such massive engineering programmes raise all kinds of problems. How would
they be constructed and powered without generating more carbon dioxide? How
much land would the artificial forests take up?
Other researchers are seeking more natural solutions.
Most of these focus on exploiting the tiny marine algae that fill the upper
layers of the world’s oceans. For aeons these have been part of nature’s way
of reprocessing CO2. When they photosynthesise, die and fall to the seabed
they remove billions of tons of carbon dioxide from the seas each year.
In the past few decades, however, humanity’s outpour-ings of CO2 have swamped
this system. The algae can no longer keep up.
Craig Venter, the maverick American scientist who helped to crack the human
genome, believes that there could be ways to accelerate the rate at which
such plankton absorb CO2 In a recent ocean expedition he collected thousands
of new species. Their genomes are undergoing analysis to identify those with
a high ability to collect carbon.
Venter envisages creating vast colonies of bacteria and other microbes that
are able to scrub the atmosphere of greenhouse gases such as carbon dioxide
and methane and perhaps even convert the pollutants to ethanol, which can be
used as a fuel.
“Microbes are responsible for the creation and maintenance of the Earth’s
atmosphere,” he said. “It is important to understand the role and function
of these organisms to ensure the survival of the planet and human life on
it. It’s clear we’ve only begun to scratch the surface of understanding the
microbial world.”
What stands out most about such ideas is not so much their practicality as the
fact that most of them originate in America, where politicians and the
public remain strongly resistant to cutting their carbon emissions.
Europe, by contrast, has taken the line that the best way to deal with climate
change is by trying to slash the greenhouse gas emissions that cause it.
Critics of the geo-engineering approach believe that it is driven largely by
American politics rather than by pure science.
“Schemes like reflective satellites or airliners pouring out sulphates sound
interesting, but in reality they are just ludicrous,” said David Lee,
professor of atmospheric chemistry at Man-chester Metropolitan University.
“The Americans are desperate to find technological fixes because they hate the
idea of cutting back on their high-carbon lifestyles. We should listen to
all new ideas, but in the long run cutting carbon remains the best answer.”
H-ow about we stop trying to play god. The changes in climate "if any" are unavoidable. And please dont mention global warming, because it's not real, do your own research and you will see that its a big lie
roy, bakersville, georgia
Everybody talks about trying to reflect the sunrays back from the Earth's surface. Has anyone thought about trying to focus the sunrays into a small spot that could beside cooling the Earth also act as an absorber to produce the energy? More like solar collectors but with much higher energy flux. This could be perhaps done by emitting some kind of special electromagnetic waves towards the sun. These EM waves having the shape of a cone would have to be able to increase the refractory index inside this cone (or slow the speed of fotons down) up to the value that would provide total reflection at the boundary for a given vertex angle. The fotons could be then "collected" from the "envelope" of such a cone. If this device was mounted on every roof, I believe everyone would get a cheap source of energy and help to cool the Earth down. This principle could be adopted also in big power plants in Sahara for example. What do you think about it?
Radim Velecky, Brno, Czech Republic
I f eveyone who has a home could add reflective roofing to their roof then I wonder how much heat could be reflected back into space? This would also keep our homes cooler in the summer months effectivly reducing energy consumption. Think of large cities and how many roofs you see when flying over in an airliner. It is little things like this that may buy us some time with climate change. As it is now, roofs are made up of dark color,light absorbing material. I think I'll write my term paper on this.
Joe Casper, Arcadia, California,
I read this fascinating interview with the CEO of Duke Energy, Jim Rogers, http://www.grist.org/news/maindish/2007/04/04/rogers/).
What is Duke doing in terms of its own operations to help solve the climate crisis?
I've always viewed energy efficiency as the fifth fuel. We think that the most environmentally benign plant you can build is the one you don't build. Job one is getting our customers to implement a broad array of efficiency measures, and give them more control over their bills, which will dampen the growth in demand. Job two is trying to use our distribution system more efficiently. We lose a lot of energy just in the transmission cables, so we're working to reduce what we call "line loss." Third, we're trying to increase how much we use our nuclear units. Fourth, we've contracted up to 100 megawatts of wind [power] in Indiana, and are exploring investment in other renewable energy areas such as biomass.
Takashi Kimiwada, London/Tokyo, UK/Japan
As a Brit who has a relatively high-carbon lifestyle I can’t easily point fingers at the Americans. More so when we have office blocks with all their lights on at night and shop-doors left wide open with those hot-air curtains, both habits commented on in your pages and elsewhere in the media.
However to get back to the "re-engineering the Earth angle". I don’t how serious Roger Angel is about the idea of launching all those spaceships but like many brainstorming ideas it can spark off more practical low-tech solutions.
How about spreading out long strips of aluminium cooking foil across the Sahara Desert to reflect some of the Sun’s heat back into space. If global warming should stop then it would be relatively simple to roll up all the foil until it is needed again. Another option is to place a fleet flying saucer shaped helium filled balloons in the stratosphere above the flight paths – paint the upper halves of the balloons white or silver to reflect heat back into space.
David Bennett, Amersham, UK
I think the best way to cut emissions is to cut the use of CO2 producing fuels. I do feel however that exploration of the use of microbes is a good start in the right direction. We need to have a well laid out plan. One that addresses immediate control and a long range plan for an eventual cure.
Doug Childress, Orange, Texas