Peter
I’m sorry you’re frustrated. I don’t think your interpretation is entirely fair. It would be ridiculous to claim that solar geoengineering is “necessary”. I did not make that claim here and I believe I’ve been consistent on this over years in writing and speaking. I don’t believe I said anything to contradict that view in this interview. It’s true I did not specifically say in this interview that this was not true. But note that this interview this was tightly edited and omitted many things I often say about governance and about context including mitigation and carbon removal. For a longer unedited video that does mention carbon removal see: https://www.technologyreview.com/video/609398/the-growing-case-for-geoengineering/ I have been clear consistently that solar geoengineering has substantial risks, that it is, at best, a partial supplement to emissions reductions. Here’s how I see the trade-off between emissions reductions, carbon removal, and solar geoengineering. Emissions reductions are necessary if we want a stable climate. If we try to continue emissions and offset them with increasing solar geoengineering the world will walk further and further away from the current climate with higher and higher risks. One could, in principle get a stable climate, by continuing emissions and offsetting them with carbon removal. But I fail to see why it would make economic or environmental sense to have massive carbon removal (with its attendant costs and environmental impacts) while we still have massive emissions. If there is truly a low impact way to do carbon removal that is significantly cheaper than emissions reductions, then I would change my view on this. (Yes, I know you believe you can do carbon removal at some low number like 30 or $50 a ton. I truly hope you’re correct. I simply haven’t seen the evidence yet.) While emissions are high I don’t believe there is a meaningful distinction between emissions mitigation and carbon removal. The climate can’t tell the difference between a ton not emitted in a ton emitted and recaptured. So, while emissions are high, I think we should only put significant effort into large-scale deployment of carbon removal if it is cheaper than other methods of reducing emissions, or if it has lower environmental impacts and roughly the same cost. Once emissions get down towards zero carbon removal provides a unique ability to reduce concentrations. Once emissions get to zero carbon removal can do something that can’t be done by emissions mitigation or solar geoengineering. That’s part of the reason I’m very proud to have worked on carbon removal from my early work on BECCS (early papers, first PhD of the topic) to my work at Carbon Engineering). I would therefore like to see serious effort to developing carbon removal even if it is not now cheaper or otherwise better than emissions reduction. And serious development will entail limited deployment. It makes sense to do this during the time emissions are high to buy the option for net negative emissions once emissions get towards zero. Finally, solar geoengineering may provide a way to substantially reduce climate risks during a carbon concentration peak. A peak defined by continued positive emissions on the front and by carbon removal on the far side. Finally, note that, contrary to your assertion, solar geoengineering does in fact provide some significant reduction in carbon concentrations <ure.com/articles/nclimate3376.epdf?author_access_token=LJ7xrnEo6oZoRNRYgu7btNRgN0jAjWel9jnR3ZoTv0NZqUjovChb9EdabCEcR6GuvZkepQXaPwfxVdn3_EQ1onk9bPWOsX7ETCUW7OvjKbM7syCkanNFs4sG07XAXjcx>. Peter, I think were roughly on the same side. I think the work you’re doing is terrific. Yours, David N.B., I am not subscribed to this list so please email me or post on twitter if you want to continue the conversation. On Sunday, 19 November 2017 11:34:14 UTC-5, Peter Eisenberger wrote: > > David Keith was on TV and did what I have expressed concern about > generally about the advocacy for SRM > He accepted the framework that we will fail to address the carbon > emissions reduction targets , failed to mention the CDR > option he himself helped pioneer and then pushed off concerns expressed > about doing SRM by saying doing nothing > also has risks ( not even mentioning that acidification of the ocean will > continue for sure and the continuing buildup of co2 etc ) . But most > importantly he supported the choice as being between doing nothing or doing > SRM which as a previous comment pointed out will be embraced by those who > want to do nothing that doing this will enable us to avoid the adverse > impacts of climate change and thus is acceptable as a response to climate > change threat > > My general point has been and continues to be that if us scientists allow > our advocacy for a particular approach to determine what we say and not > discipline ourselves with > a overall coherent approach we will become (are) part of the problem and > not part of the solution > > (Now I know that media can distort messages but I also know that it is > possible upfront to tell them the distortions one will not accept ) > > Sent from my iPhone > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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