5 ways to hack the planet

It's been a week of doom as far as the
public face of science is concerned.
On Tuesday we had Sir David
Attenborough's depressing
prognostications that the future is
going to be worse for our children
and their children (especially if we
insist on producing more children in
the first place).
Now the comments by the astronomer
royal, Martin Rees, take the
apocalyptic tone to a new level, one
which resonates with his medieval
title. With a Nostradamus-like gloom,
he intimates it may be too late to
naturally reverse the effects of
climate change - and believes that
radical geoengineering may be the
only way we can cope with the
desperate scenario. It is one which
Lord Rees does not relish:
"Geoengineering would be an utter
political nightmare", he
acknowledges, as well as stirring up
practical and ethical dilemmas we
can't begin to imagine. But that
doesn't stop us trying.
Geoengineering - planet-hacking, in
other words - is another of those
scientific ventures that pursues the
fantastical and seeks to implement it
in reality. It's a kind of steampunk
for boffins and entrepreneurs - Jules
Verne gone viral. It ranges from the
ostensibly practical, to the practically
insane - but it reminds us that we
humans have that one extraordinary
superpower which might yet get us out
of this fix: imagination itself.
So (every science statement begins
thus nowadays), what are the ideas?
1. The giant sunshade
One of Lord Rees's fellow
astronomers, the aptly named Roger
Angel, has come up with a vast
sunshade to be constructed from 16tr
glass discs, assembled in space, and
sent into orbit using electromagnetic
launchers. This has a beautiful,
obvious simplicity. Angel believes that
by blocking just 2% of the sun's rays,
global warming could be reduced to
manageable proportions. That we
could regulate the earth's
temperature, much as we do with the
blinds in a sunny conservatory. All
well and good - but issues of
maintenance and other practicalities - asteroids, for one - cast a shadow
on this mega-space umbrella.
Practicality rating: 5/10
Apocalypse rating: 3/10
Cost: 8/10
2. Iron fertilisation
This is the idea that by infusing the
ocean with iron filings, we could
stimulate phytoplankton blooms,
increasing bio-productivity and
create a green carbon sink, in the
process absorbing large amounts of
CO2. It may sound like a school lab
experiment gone crazy, but since the
1990s, this has been one of the most
favoured geoengineering techniques.
However, it completely ignores its
effect on marine life. Surely one
reason we're trying to save the planet
is to preserve the reasons why we
liked it in the first place. And
anyway, sperm whales have been
doing this naturally for millennia. A
recent Australian report estimated the
southern ocean population of whales
release enough faeces to absorb
400,000 tonnes of carbon a year.
Although no-one's proposing training
huge pods of the creatures to do our
dirty work. Yet.
Nevertheless, more localised
environmental concerns didn't stop
Russ George of Planktos dumping 100
tonnes of iron sulphate in the Pacific
last year, an act which has been
accused of violating the UN's
convention on biological diversity
and other international conventions
that forbid dumping at sea. Good old
human bureaucracy may yet stymie
the wilder excesses of geoengineering.
Meanwhile, other scientists claim that
diatoms - photosynthetic plankton -
may merely absorb the iron into their
shells and sink to the sea bed,
negating the intended effect.
Practicality rating: 8/10
Apocalypse rating: 6/10
Cost: 3/10
3. Seaweed farms
Proposals for giant seaweed farms
work on a similar principle to iron
fertilisation, and would cultivate
larger, more CO2-absorbing plant
forms than phytoplankton. They also
sound rather more directly appealing
(at least for lovers of Japanese
cuisine) in that they'd have the added
bonus of furnishing us with food as a
Practicality rating: 8/10
Apocalypse rating: 2/10
Cost: 2/10
4. Solar radiation management
Surely the most practical solutions
are the simplest. Reflecting the sun's
rays back into space could help lower
the temperature on earth. White roofs
would reflect up to 80% of the sun's
rays, compared to dark roofs, which
only reflect 20% at most, according to
the Lawrence Berkley national
laboratory in California. They also
reduce the need for air-conditioning
by making the rooms within cooler.
But a pot of whitewash isn't exactly
sexy stuff in the heady, macho world
of planet hacking. The sense of
emergency evoked by Lord Rees's
remarks will surely encourage those
with plans for a fleet of cloud-
making ships to do a similar job, or
schemes to turn great swaths of desert
lands green and soak up more of
those pesky rays.
Practicality rating: 7/10
Apocalypse rating: 4/10
Cost: 3/10
5. Artificial volcano
Perhaps the most extraordinary
project on the geoengineers' cyber
drawing board, however, is the
artificial volcano. Another version of
solar radiation management, it
would pump ash into the atmosphere,
reflecting the sun's rays back into
space. One of the idea's supporters
Samuel Thernstrom, co-director of the
Geoengineering Project in
Washington DC, declares: "There is no
argument for ignorance - we should
know more about geo-engineering."
However, anyone whose travels were
disrupted by the eruption of the
Icelandic volcano Eyjafjallajökull in
2010 would certainly have their
reservations. Would we have to call
out a futuristic Bruce Willis to sort it
all out for us? And there's a more
serious note of caution to be made
here, too. It was a natural volcanic
explosion in Indonesia in 1815 which
created "the Year without a Summer"
of 1816 . Those broody skies and
stormy nights over the Villa Diodati
on the banks of Lake Geneva inspired
Mary Shelley to write Frankenstein ;
or, the Modern Prometheus - a book
freighted with ominous warnings
about the consequences of human
beings using science to manipulate
the world to their own ends.
Practicality rating: 6/10
Apocalypse rating: 7/10
Cost: 6/10