nothing to re-
duce the build-
up of carbon
dioxide in the
and the oceans.
in the atmosphere will go unchecked. And the planet will
This leads us to another geoengineering proposal aimed
at addressing the carbon dioxide problem more directly.
The idea is to use more than a dozen supertankers at a total
cost of $25 billion to spread iron in the oceans for the purpose of fertilizing plankton. The hope is that the plankton
would remove CO via photosynthesis and eventually sink
to the bottom, where the carbon would be theoretically
sequestered. But it's a long way to the bottom of the ocean,
and there are plenty of bacteria and animals that can eat
that plankton on its way down, so it's not clear how much
of that carbon actually would get sequestered. As with any
geoengineering proposal, there is a large potential for unintended consequences.
Clearly it is much safer to solve the carbon dioxide problem by not emitting it in the first place, that is, by reducing
energy use and switching to carbon-free energy sources.
Geoengineering solutions not only have known disadvantages and unknown consequences, but even putting them
out there as options can have the effect of undermining the
commitment to change our energy system. The conundrum
is that by studying geoengineering, we could make it more
likely that we will actually need it.
So why are highly respected scientists like Tom Wigley
at the National Center for Atmospheric Research and David
Keith at the University of Calgary advocating research on
geoengineering? For one thing, they are understandably
unimpressed by the progress we humans have made to date
in addressing climate change. Combining geoengineering
with whatever carbon emissions reductions we can achieve
could buy us time and might result in less total damage to
the environment than would an approach that relies on
emissions reductions alone. Also, what if China or India
decides to pursue geoengineering? Shouldn't we understand it as best we can, so we will be prepared to develop
informed international treaties?
While the prospect of geoengineering might provide
some people with an excuse to continue business-as-usual,
perhaps the thought of another uncontrolled, planetary-scale experiment will motivate the rest of us to finally get
serious about deploying renewable energy. Because regardless of the rationales some scientists may come up with,
Plan B just doesn't look so hot. ST
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