An
eminent UK engineer is suggesting building cloud-whitening towers in the Faroe
Islands as a "technical fix" for warming across the Arctic.
Scientists
told UK MPs this week that the possibility of a major methane release triggered
by melting Arctic ice constitutes a "planetary emergency".
The
Arctic could be sea-ice free each September within a few years.
Wave
energy pioneer Stephen Salter has shown that pumping seawater sprays into the
atmosphere could cool the planet.
The
Edinburgh University academic has previously suggested whitening clouds using
specially-built ships.
At
a meeting in Westminster organised by the Arctic Methane Emergency Group
(Ameg), Prof Salter told MPs that the situation in the Arctic was so serious
that ships might take too long.
"I
don't think there's time to do ships for the Arctic now," he said.
"We'd
need a bit of land, in clean air and the right distance north... where you can
cool water flowing into the Arctic."
Favoured
locations would be the Faroes and islands in the Bering Strait, he said.
Towers
would be constructed, simplified versions of what has been planned for ships.
In
summer, seawater would be pumped up to the top using some kind of renewable
energy, and out through the nozzles that are now being developed at Edinburgh
University, which achieve incredibly fine droplet size.
In
an idea first proposed by US physicist John Latham, the fine droplets of
seawater provide nuclei around which water vapour can condense.
This
makes the average droplet size in the clouds smaller, meaning they appear
whiter and reflect more of the Sun's incoming energy back into space, cooling
the Earth.
On melting ice
The
area of Arctic Ocean covered by ice each summer has declined significantly over
the last few decades as air and sea temperatures have risen.
For
each of the last four years, the September minimum has seen about two-thirds of
the average cover for the years 1979-2000, which is used a baseline. The extent
covered at other times of the year has also been shrinking.
What
more concerns some scientists is the falling volume of ice.
Peter
Wadhams, professor of ocean physics at Cambridge University, presented an
analysis drawing on data and modelling from the PIOMAS ice volume project at
the University of Washington in Seattle.
It
suggests, he said, that Septembers could be ice-free within just a few years.
“In
2007, the water [off northern Siberia] warmed up to about 5C (41F) in summer,
and this extends down to the sea bed, melting the offshore permafrost."
Among
the issues this raises is whether the ice-free conditions will quicken release
of methane currently trapped in the sea bed, especially in the shallow waters
along the northern coast of Siberia, Canada and Alaska.
Methane
is a much more potent greenhouse gas than carbon dioxide, though it does not
last as long in the atmosphere.
Several
teams of scientists trying to measure how much methane is actually being
released have reported seeing vast bubbles coming up through the water -
although analysing how much this matters is complicated by the absence of
similar measurements from previous decades.
Nevertheless,
Prof Wadhams told MPs, the release could be expected to get stronger over time.
"With
'business-as-usual' greenhouse gas emissions, we might have warming of 9-10C in
the Arctic.
"That
will cement in place the ice-free nature of the Arctic Ocean - it will release
methane from offshore, and a lot of the methane on land as well."
This
would - in turn - exacerbate warming, across the Arctic and the rest of the
world.
Abrupt
methane releases from frozen regions may have played a major role in two
events, 55 and 251 million years ago, that extinguished much of the life then
on Earth.
Meteorologist
Lord (Julian) Hunt, who chaired the meeting of the All Party Parliamentary
Group on Climate Change, clarified that an abrupt methane release from the
current warming was not inevitable, describing that as "an issue for
scientific debate".
But
he also said that some in the scientific community had been reluctant to
discuss the possibility.
"There
is quite a lot of suppression and non-discussion of issues that are difficult,
and one of those is in fact methane," he said, recalling a reluctance on
the part of at least one senior scientists involved in the Arctic Climate
Impact Assessment to discuss the impact that a methane release might have.
Reluctant solutions
The
field of implementing technical climate fixes, or geo-engineering, is full of
controversy, and even those involved in researching the issue see it as a
last-ditch option, a lot less desirable than constraining greenhouse gas
emissions.
"Everybody
working in geo-engineering hopes it won't be needed - but we fear it will
be," said Prof Salter.
Adding
to the controversy is that some of the techniques proposed could do more harm
than good.
The
idea of putting dust particles into the stratosphere to reflect sunlight,
mimicking the cooling effect of volcanic eruptions, would in fact be disastrous
for the Arctic, said Prof Salter, with models showing it would increase
temperatures at the pole by perhaps 10C.
And
last year, the cloud-whitening idea was also criticised by scientists who
calculated that using the wrong droplet size could lead to warming - though
Prof Salter says this can be eliminated through experimentation.
He
has not so far embarked on a full costing of the land-based towers, but
suggests £200,000 as a ballpark figure.
Depending
on the size and location, Prof Salter said that in the order of 100 towers
would be needed to counteract Arctic warming.
However, no funding is currently on the table for cloud-whitening. A proposal to build a prototype ship for about £20m found no takers, and currently development work is limited to the lab.