Thanks Nature. How about applauding those who are trying to find out whether or
not CDR is magical thinking, since reaching climate goals without CDR is now
most certainly a fanciful notion (IPCC: 2013, 2014, 1.5degC report)?Greg
From: Andrew Lockley <[email protected]>
To: geoengineering <[email protected]>
Sent: Tuesday, February 27, 2018 2:17 PM
Subject: [geo] Why current negative-emissions strategies remain ‘magical
thinking’
https://www.nature.com/ articles/d41586-018-02184-x
EDITORIAL 21 FEBRUARY 2018
Why current negative-emissions strategies remain ‘magical thinking’
Work on how rocks draw carbon from the air shows the scale of the challenge.
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PDF versionSpreading basalt rock on farmland has been suggested as a way to
soak up carbon pollution from the atmosphere.Credit: Hartmut
Schmidt/imageBROKER/AlamyDecarbonization of the world’s economy would bring
colossal disruption of the status quo. It’s a desire to avoid that change —
political, financial and otherwise — that drives many of the climate sceptics.
Still, as this journal has noted numerous times, it’s clear that many
policymakers who argue that emissions must be curbed, and fast, don’t seem to
appreciate the scale of what’s required.According to the Intergovernmental
Panel on Climate Change (IPCC), carbon emissions must peak in the next couple
of decades and then fall steeply for the world to avoid a 2 °C rise. A peak in
emissions seems possible given that the annual rise in carbon pollution stalled
between 2014 and 2016, but it’s the projected decline that gives climate
scientists nightmares.The 2015 Paris agreement gave politicians an answer:
negative emissions. Technology to reduce the amount of carbon already in the
atmosphere will buy society valuable time. The agreement went as far as arguing
that incorporating one such technology — bioenergy with carbon capture and
storage (BECCS) — could even see the global temperature increase kept to 1.5
°C.What would negative emissions look like? A Perspective this week in Nature
Plants offers another glimpse, and it’s not pretty (D. J. Beerling et al.
Nature Plantshttp://dx.doi.org/10. 1038/s41477-018-0108-y; 2018). The review
focuses on the idea of enhanced weathering, which aims to exploit how many
rocks react with carbon dioxide and water to form alkaline solutions that, over
time, find their way into the sea. It’s one of a number of proposed
negative-emissions technologies.In theory, enhanced weathering could lock up
significant amounts of atmospheric carbon in the deep ocean. But the effort
required is astounding. The article estimates that grinding up 10–50 tonnes of
basalt rock and applying it to each of some 70 million hectares — an area about
the size of Texas — of US agricultural land every year would soak up 13% of the
annual global emissions from agriculture. That still leaves an awful lot of
carbon up there, even after all the quarrying, grinding, transporting and
spreading.It’s not hard to see why many climate scientists have dismissed the
near-impossible scale of required negative emissions as “magical thinking”. Or
why the European Academies’ Science Advisory Council said in a report this
month: “Negative emission technologies may have a useful role to play but, on
the basis of current information, not at the levels required to compensate for
inadequate mitigation measures.”The IPCC is now working on a report on
strategies to keep warming to under 1.5 °C, which is due to be published later
this year. By necessity, those strategies will lean heavily on negative
emissions. Scientists must continue to spell out to policymakers the harsh
reality of what this would involve, and in the strongest possible terms.Nature
554, 404 (2018)doi: 10.1038/d41586-018-02184-x--
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