About David Keith and Buffering the Sun: Climate Engineering

by Erin O’Donnell


1.      Current carbon emissions

         a.      2011: 38.2 billion tons of CO2 emitted, 3% increase previous year

         b.      Likely to go up as China and India burn more coal and drive more cars

         c.      Average daily level of CO2 in atmosphere over 400 parts per million

         d.      Been 2 million years since earth seen that level

         e.      **Even if stop right now, most of heat-trapping gases linger for decades or centuries

                   i.       40% of peak concentration of CO2 remain for 1000 years

         f.       By 2100, 2-5 degree rise (best), 4-11 degree rise (worst)

         g.      Some problems: Rising sea levels, increased storm severity and droughts, melting glaciers and permafrost


2.      Solar geoengineering = SGE (or SRM)

         a.      Strategies to “adjust planet’s thermostat”

         b.      Deflect sunlight away from earth

                   i.       Massive space shields

                   ii.      Extra-bright, low-altitude clouds over oceans

                            (1)    Created by spraying water into clouds from ships

                   iii.     Modify a fleet of jets to spray sulfates into stratosphere (main proposal) Scott pictures

                            (1)    Description of the process (first 2 paragraphs)

                            (2)    We know this will work as studied volcanic eruptions which do similar things

                            (3)    Mt Pinatubo 1991 eruptions shot 10 million tons of sulfur into air and reduced global temps by 1 degree


3.      Keith a proponent of solar geoengineering=SGE

         a.      Ways to counter rising global temps by reduce amount of sunlight reaches Earth

         b.      It might someday save the planet

         c.      Keith rejects automatic discomfort about manipulating the planet and has more nuanced view

                   i.       “I think there are lots of things that are scary about this prospect, but I just don’t see how finding a potentially life-saving technology that helps to reduce climate risk a lot is awful”

         d.      Keith overall view: SGE is likely to help

                   i.       “It is by no means clear what the right answer is, or how much, if any, geoengineering we should use,” he says, “but the balance of evidence from the climate models used to date suggests that doing a little bit would reduce climate risks.”

                   ii.      Note degrees of degrees of geo-engineering

                            (1)    This makes it sound less scary

         e.      Need Plan B: Take control of climate’s future

                   i.       Because

                            (1)    Skeptics question GW real

                            (2)    Efforts to cut GHG stalled

4.      *Important for case for GE

         a.      Already committed to warming in future whatever we do about our emissions

         b.      Cutting emissions won’t help with global warming to which already committed

         c.      Hence quick-acting, geo-engineering strategies seem attractive


5.      Assessing the two geo-engineering strategies

         a.      CDR, “carbon dioxide removal” or capturing carbon

                   i.       Because of massive scale of CO2 problem, this will be slow and expensive

                   ii.      Local risks but no chance of harming entire planet

                            (1)    Seeding oceans with iron could affect a whole lot of the planet!

         b.      SRM “solar radiation management” or limiting the amount of sunlight that reaches earth

                   i.       Solar geoengineering works quickly

                   ii.      Low cost

                            (1)    A few billion dollars a year

                            (2)    A fraction of cost of reducing GHG emissions (25% reduction by 2050 costs 1% GDP or $1 trillion)

                            (3)    Costs so low this will not be a factor


6.      Will GE undermine efforts to cut carbon emissions?

         a.      Keith himself argues that

                   i.       People already compare costs of climate damages to costs of cutting emissions

                   ii.      Thinks we need to spend much more to cut emissions

                   iii.     But argues if we reduce risk of climate damages some by SGE, then should be able to put a little less money into cutting emissions, saving some of the trillions in costs for future GHG cutting efforts


7.      Risks of spraying sulfates

         a.      Sulfate aerosols could damage ozone layers

         b.      Might disrupt weather patterns, especially precipitation patterns and lead to widespread droughts

         c.      Sunlight-blocking would reduce amount of solar power electricity

         d.      If not done gradually, could create drastic climate changes

8.      Big problem of SRM/SGE is ignores CO2 buildup

         a.      Doesn’t address danger of CO2 buildup

                   i.       So will have to do more and more of SRM to counter more CO2? And keep doing it forever?

         b.      Ignores other problems CO2 build up causes besides warming, namely ocean acidification (harms coral reefs and other marine life)

9.      But we must weigh risks of SGE versus risks of not doing it

         a.      Note there are “risks of not doing it”

         b.      If have a technology and refuse to use it, that itself coud expose you to other risks

         c.      It is not just risky to use it


10.    Political issues

         a.      Nothing approaching a social consensus that it’s worth making a serious effort to solve the problem

                   i.       No consensus to try to geo-engineer

                   ii.      Also no consensus to address global warming at all (even to move to green energy)

11.    Governance challenges

         a.      SRM requires collective global decision making

         b.      Diverse nations (and groups within nations) need to agree on joint course of action

                   i.       Not been able to when addressing GHG emissions

                            (1)    But that’s because that is expensive and significantly affects economies

                            (2)    SRM is cheap so likely to be a lot easier

                            (3)    But what if there are holdouts (countries who say no), maybe because they think they are benefitting from GW?

         c.      Because SGE is cheap, a single nation or group of island nations threatened by rising seas could act unilaterally

                   i.       Keith: it would be easy to stop them (from flying airplanes and putting sulfur in atmosphere unilaterally)

         d.      Keith worries that because SGE provides a significant way to reduce climate risk at very low cost it will be hard to stop people from rushing to it

                   i.       He does not want to see this happen fast w/o careful analysis


12.    One argument for why research should proceed

         a.      To prepare for emergencies

                   i.       Like unilateral action by rogue nation

         b.      It’s scary, but better to be informed.


13.    Keith trying to do small-scale field-testing

         a.      Send a helium balloon with small amount of sulfur and water into stratosphere to see how affects ozone

                   i.       Been shown that sulfur and water vapor react with atmospheric chlorine and change it so it damages ozone

         b.      Won’t affect climate any more than a single commercial airline flight

14.    Are field tests first step down a slippery slope toward full-scale SGE?

         a.      Keith will not do study w/o public assent: “Not w/o some formal government approval and public funding”

15.    Keith called for government oversight of GE research

         a.      Self-reg not sufficient to manage risks

         b.      For a non-binding set of international norms issued by scientific bodies, to manage risk, and openness

         c.      Wants international moratorium on large-scale deployment

16.    Keith has a company that is building an industrial-scale plant to capture CO2 from air and use it commercially

Questions about David Keith and Buffering the Sun: Climate Engineering


1.      Would the problem of global warming be solved for future people if we cut greenhouse gas (GHG) emissions to zero today? Why not?

2.      How does the above fact strengthen the case for solar geo-engineering (= SGE) (as against spending our money on reducing CO2 emissions)?

3.      Describe what is involved in SGE. What is the evidence that it will work?

4.      Identify the two main geoengineering strategies and then contrast them in terms of speed of effectiveness and cost

5.      Explain why some see a tension between GE and cutting carbon emissions.

6.      What are some of the major risks/problems with spraying sulfates in stratosphere as a way to address global warming? Are there risks associated with not using GE?

7.      Describe some of the “governance challenges” involved in SGE. Do think these are serious? How might these challenges be addressed?