Recent op-ed by Simon Nicholson and Mike MacCracken.
Technology to the Planet's Rescue? It's time to explore whether
geoengineering can reverse Antarctic ice loss.
http://www.usnews.com/opinion/articles/2014/06/06/could-geoengineering-reverse-antarctic-ice-loss-and-global-warming?int=a41f09
Research from NASA released on May 12 suggests that a large section of the
West Antarctic ice sheet is now on a path, perhaps irrevocably, to
collapse. The result could be billions of tons of ice poured into the
Southern Ocean each year. This could lead, over the span of coming decades
and centuries, to as much as 10 feet of global sea level rise, attributable
to this event alone.
Sea level rise of this magnitude, even spread over a long timescale, will
be extremely disruptive and likely dangerous for human societies, with the
worst and highest costs falling on those who are least able to bear them.
What can be done? The first choice would be an immediate halt to all global
greenhouse gas emissions, which would help to slow sea level rise
generally. Given the difficulty and seeming impracticality of that, it
bears asking, could some sort of large-scale technological intervention in
the region help to slow the calving away of the ice? While the shape of the
underlying ocean bottom that no longer will hold back the ice stream is a
critical contributor to the vulnerability of the ice sheet, there are,
conceptually, a number of ways by which human intervention could reduce
regional Antarctic warming, perhaps with the potential to slow the movement
and loss of ice.
One possible option would be to increase the reflectivity of clouds over
the Southern Ocean during the sunlit season, thus reducing ocean heat
uptake. Models suggest that, in areas that are fairly clean, injection of
finely misted salt water, targeted regionally, could increase the amount of
solar radiation reflected back into space.
Another way to possibly bring about a localized cooling effect might be to
inject reflective microbubbles into the frigid Antarctic waters,
brightening the surface in the way that ship wakes brighten the waters, but
doing so more efficiently.
Two other interventions could, potentially, encourage more rapid radiation
of absorbed heat to space. One way to release heat trapped in the oceans
could be to use icebreaking ships to open up selected areas of the ocean
during the winter, allowing heat otherwise contained beneath the sea ice to
escape to the atmosphere. Another option that has been proposed would be to
use cloud-seeding techniques to thin out the high-altitude, winter layer of
cirrus clouds, allowing heat radiated from the ocean’s surface to more
readily pass into space.
Now, such ideas are highly speculative, at best. In fact, it’s easy to
write them off as the stuff of science fiction. They are, though, among the
kinds of climate geoengineering proposals that have been suggested as
bottom-of-the-barrel approaches to limiting the increasingly severe impacts
of climate change, perhaps, in the best case scenario, buying time for the
growth in global emissions of carbon dioxide to be stopped and then
reversed. Such geoengineering approaches are not a long-term solution and
have limited potential, but they may be able to temporarily limit some of
the worst impacts of climate change while actions are taken that cut
through political and societal dithering around seriously addressing the
increasing risks of climate change.
On the same day that that the world learned of the potential for runaway
Antarctic ice melt, Sen. Marco Rubio, R-Fla., spoke for many conservative
politicians when he declared, “I don't agree with the notion that some are
putting out there, including scientists, that somehow, there are actions we
can take today that would actually have an impact on what’s happening in
our climate.” The day then closed with the announcement that the U.S.
Senate, because of political wrangling over the Keystone XL pipeline,
appears unable to pass a straightforward energy efficiency bill that has
bipartisan sponsorship.
While these kinds of political and social intransigence seem to be making
climate geoengineering technologies increasingly attractive, such
approaches are not a long-term panacea, and they are, for good reason,
controversial.
For one thing, it is unclear whether the kinds of ideas proposed above are
technically feasible at the kind of scale that would make a difference in
and around Antarctica. Nor is it clear that creating a solar shield could
bring about a rapid and sufficient enough cooling of the ocean waters to
slow the warming of the Antarctic ice streams that are so concerning to
NASA scientists.
At the same time, there are thorny governance and justice issues presented
by any geoengineering scheme. Who gets to control the technology and decide
how and to what ends it is used? What if the talk of a technological
response to Antarctic ice melt distracts attention from the greenhouse gas
reduction
