https://earther.gizmodo.com/turns-out-a-wild-geoengineering-plan-to-refreeze-arctic-1840270787
[links in online article]
Turns Out a Wild Geoengineering Plan to Refreeze Arctic Sea Ice Isn't
the Best Idea
Brian Kahn
Dec. 6, 2019
As the world spins closer to climate catastrophe, fringe ideas are
inching toward the mainstream. Geoengineering is among the topics that
were once verboten but are now finding traction. And that includes some
pretty out-there ideas, including ones focused on saving polar ice by
pumping massive amounts of seawater onto the surface of ice, where it
will refreeze quicker and strengthen all icepack against melting.
The refreezing idea has been proposed for both poles and would be
massively expensive. But a new study shows that, in the Arctic, saving
sea ice would do little to slow the climate crisis elsewhere. And it
would unleash shocking and unintended consequences in the Arctic itself.
The paper, published in Earth’s Futures on Thursday, takes its
inspiration from a previous study that first raised the prospect of an
Arctic geoengineering project. That study outlined a proposal to install
wind turbines across the Arctic that would power pumps to draw water to
the surface of the remaining sea ice, where it would refreeze more
quickly than from the bottom-up. Sounds a little bit (OK, a lot) radical
to be sure, but the rapidly warming Arctic needs all the help it can
get. Old sea ice that used to hold the icepack together is all but gone,
and we could see an ice-free Arctic as early as the next decade if
carbon pollution isn’t slowed soon.
But while the previous research showed it was technologically feasible
to do the wind turbine thing, it didn’t look too hard at what the
climate ramifications would be. The new paper picks up at that point
because, as Lorenzo Zampieri, the new study’s lead author and PhD
student at Germany’s Alfred Wegener Institute, told Earther, “this
geoengineering idea had never been tested with a climate model and, in
our opinion, this was a necessary step to contextualize this approach.”
The scientists used an advanced climate model to explore what the scheme
would actually do to the Arctic. They modeled a number of scenarios,
including one idealized scenario in which seawater was pumped over the
entirety of the sea ice. That model found that ice would grow up to 65
meters (213 feet) thick over the rest of the century, a huge change from
the average historical thickness of 1.8 meters (6 feet).
They dialed things back to a bit more “realistic” scenario that aimed
for an average thickness of around 2 meters (a little over 6 feet) and
moderately spaced out wind mills and pumps. The good news: It would
indeed help refreeze.
But the less good news is that the process would radically alter the
climate in the Arctic while doing very little to fix the global climate
overall. Healthy, reflective ice that lasts through the summer would
restore the late summer Arctic climate to some semblance of its former self.
Pumping throughout the winter, however, would result in an unintended
warming for parts of the Arctic in the latter half of the century.
That’s because as the ice freezes, it releases energy in the form of
heat. Layer that on top of the warmth from global warming, and you have
a recipe for a very confusing Arctic winter.
Oh, and speaking of that global warming: While saving Arctic sea ice is
great for polar bears and the people who live there, it does just about
jack shit for the climate globally. The mid-latitudes, where most humans
live, would see just a few hundredths of a degree of cooling as a
result. That’s nice and all, but it ain’t gonna do much to save the
coral, stop wildfires from burning out of control, or keep people from
dying.
This type of modeling will be crucial in the coming decade to understand
the options we have on the table. Other forms of geoengineering, like
blocking sunlight or undertaking massive reforestation projects to suck
carbon out of the air, are also gaining steam as the climate we so rely
on keeps unraveling. There’s a seductiveness to thinking we can just
implement a few techno fixes to buy time while the world gets its act
together drawing down emissions, but the reality is they will almost
surely come with tradeoffs and gnarly surprises of their own.
“I would like to point out that, according to our findings, this
approach could only buy some decades to the Arctic sea ice, while a
permanent solution can only be achieved by reducing the excess of
greenhouse gasses in the atmosphere and cooling the climate,” Zampieri said.
That’s right. The best thing we could do for the climate and future
generations is the one the world has so far failed at. It might not be
as sexy as building huge wind turbines in the Arctic, but it damn well
gives us a better chance at survival.
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