http://www.american.edu/sis/news/20150218-3Q-Nicholson-Climate-Engineering.cfm

Climate Engineering – Three Questions for Simon Nicholson

February 18, 2015

A panel convened by the National Research Council of the U.S. National
Academy of Sciences recently released a report that called for further
study of "climate engineering" -- efforts to re-engineer the planet’s
climate to battle global warming. We asked Assistant Professor Simon
Nicholson, an expert on geoengineering and a founder of the Forum for
Climate Engineering Assessment, for some insights:

Q: Climate engineering was once considered a fringe idea. Why is it
gaining currency now?

A: It’s quite true that climate engineering was an idea that used to
be confined to the darkest fringes of the conversation about responses
to climate change. That has changed in the last handful of years for
three main reasons:
• First, a small but vocal cohort of climate scientists has become
disillusioned enough with the lack of political and social progress on
climate change that they are pushing hard for serious consideration of
ideas that in the past would have been seen as outlandish.
• Second, modeling studies have confirmed that the leading climate
engineering proposal -- reflecting some amount of incoming sunlight by
deploying sulfate particles high in the earth’s atmosphere -- would
likely indeed have a cooling effect, though the positive and negative
side effects attached to such an action are still being puzzled
through.
• And third, studies and other activities like the recent reports from
the National Academy of Sciences (NAS) make it clear that there are
people within major governments giving thought to climate engineering.
There are no guarantees that climate engineering proposals will ever
advance from the drawing board stage. These are still speculative,
unproven technological suggestions, and none are any kind of
substitute for the hard yet critical work of reducing greenhouse gas
emissions and adapting to the impacts of a changing climate. At the
same time, it can now be said that consideration of climate
engineering is not going away, and will only grow louder and more
insistent as the climatic condition worsens.

Q: What concepts did the expert panel propose to study and test?

A: The NAS panel decided to release two separate reports on climate
engineering, and in doing so they reinforced categories that most
people use when looking at climate engineering options. The first
report is titled, “Climate Intervention: Carbon Dioxide Removal and
Reliable Sequestration.” It examines the state of scientific knowledge
around so-called carbon dioxide removal (CDR) proposals -- basically,
imagined technologies that would draw large amounts of CO2 down from
the atmosphere and hold it in long-term storage.

The second (and much thicker) report is titled, “Climate Intervention:
Reflecting Sunlight to Cool Earth.” It looks at the state of
scientific knowledge, this time around solar radiation management
(SRM) proposals. These are technologies that might, someday, be
developed and deployed to reflect some amount of incoming sunlight
back into space before it can warm the earth’s atmosphere, as a way to
lower regional or global average atmospheric temperatures.

In common with prior reports conducted by other bodies, the NAS
documents suggest that CDR proposals are probably the less risky of
the two approaches, but given current understandings and technologies
would be incredibly costly and difficult to deploy at any useful
scale, and work over such long timeframes that they don’t offer any
kind of near-term help in combatting climate change. Some SRM
proposals, on the other hand, most notably the injection of sulfates
into the stratosphere, would likely be relatively cheap and could set
to work tackling one major aspect of climate change, atmospheric
temperature increase, almost immediately. SRM, though, is a much
riskier undertaking.

The reports ended up calling for modest research agendas to advance
the physical science of both CDR and SRM. Interestingly, the reports
made clear that the knowledge gap on the physical science side is
dwarfed by our lack of collective understanding of the social and
political implication of climate engineering. There is, in other
words, a huge amount of work that needs to be done on governance,
public engagement, and civil society outreach. These are the major
areas in which my SIS-based group, the Forum for Climate Engineering
Assessment, are engaged.

Q: What could be the side effects and dangers of climate engineering?

A: We still have a great deal to learn about the potential upsides and
downsides of climate engineering. At the rollout event for the NAS
reports, a couple of the speakers characterized CDR technological
options as largely free from risk. This is not true. Drawing down CO2
from the atmosphere is a good thing on its face, but the prevailing
proposals would have enormous implications for landuse patterns, would
require the development of huge new industrial infrastructures to
transport and store CO2, and would require extraordinary new
arrangements to enable international cooperation.

Leading SRM proposals like the injection of sulfates into the
stratosphere pose their own sets of conundrums. I break the risks down
into three categories: material (what if, as some models suggest,
cooling the atmosphere shuts off the monsoon rains in India?);
political (who gets to decide how SRM technologies are used, and how
would conflicts be adjudicated?); and existential (what does all of
this mean for our collective capacities to respond to climate change
and for the sorts of future technological and social pathways we
privilege?).

The Forum for Climate Engineering Assessment works to build a more
robust, inclusive, and informed climate engineering assessment. Its
next event, co-sponsored with Resources for the Future, will be held
on February 24: “What’s Next for Climate Engineering?” Follow the
Forum on Twitter at @CEAssessment.

Follow Simon Nicholson on Twitter @simonnicholson4. For media
requests, please call J. Paul Johnson at 202-885-5943.

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