,
25 tweets,
8 min read
Read on Twitter
1/25 @HoneggerM, there are alot of assertions in your tweets, so I will try to take them seriatum. @ciel_tweets @lilifuhr @Davzoul
2/25 First, if I understand correctly, you argue that its unfair to ask whether Carbon Dioxide Removal (CDR) actually reduces carbon emissions because it "is not intended to" do so...
3/25 While I share your assessment--at least for most technological forms of CDR--it is rare to hear a geoengineering proponent (or researcher, if you prefer) acknowledge the fact.
4/25 But it's a critical point since the primary rationale offered for CDR--the most widely discussed and most heavily relied on form of geoengineering--is to reduce atmospheric CO2; not, as you suggest to "limit suffering" caused by climate change.
5/25 Indeed, most research, including your own useful report, bit.ly/2KWJNHX, suggests that most forms of technological CDR are more likely to negatively impact SDGs than to benefit them...
6/25 Conservation and restoration of ecosystems and agricultural soils are exceptions to this rule that @ciel_tweets and others critical of CDR risks have indicated an interest in exploring, while acknowledging that even these forms of natural CDR must be undertaken carefully.
7/25 With those limited exceptions, however, most forms of CDR would do nothing to "limit suffering". If, as you seem to suggest, CDR is not intended to reduce emissions, then who benefits from CDR aside from fossil interests and those who want to perpetuate a fossil economy?
8/25 I also share your assessment that Solar Radiation Modification (SRM) has neither the intent nor the effect of reducing the GHG emissions that drive climate change.
9/25 Even though dramatically reducing GHG emissions is the most direct, permanent and least risk route to addressing climate change, you assert that SRM should be measured instead by whether it "limits suffering"...
10/25 For the reasons we discuss at length in #FueltotheFire, bit.ly/2TNtceq, we believe whether and how rapidly a technology or policy choice reduces those emissions is the most valid way of assessing climate solutions.
11/25 And, to be clear, adaptation is not a solution to climate change. It is a necessary response. Adaptation will absolutely be needed to limit human suffering, though many of the most effective forms of adaptation will also reduce new emissions in the process.
12/25 I find your equating of SRM with adaptation particularly notable because some geoengineering proponents have taken pains to distinguish geoengineering from other forms of technological adaptation...
13/25...promoted by the fossil fuel industry, reut.rs/2Fn5Ibj climate denialists and their allies. (See, among too many, bit.ly/2FjNEPg and bit.ly/2HtJ3vY.2
14/25 But even applying your own metric of "limiting suffering" without reducing emissions, our reading of the balance of evidence is that most forms of SRMs are as or more likely to compound or at best shift human suffering than to reduce it.
15/25 My reading of your 2018 report, bit.ly/2Fbltkb, is that it reached the same conclusion with respect to both SRM and Cloud Engineering, and with respect to large-scale surface albedo modification (at least outside the Arctic). Perhaps I misinterpreted.
16/25 Neither your reference to 1/2 SRM, nor the Irvine paper that argues 1/2 SRM is somehow safer, changes that analysis from my perspective.
17/25 To the contrary, that paper reinforces the limitation and risks of SRM as part of any climate response. @Ccolose analyzes those risks far better than I could. ( ).
18/25 As @Ccolose notes, the Irvine paper looks at only a single category of SRM risk: precipitation impact. It does not address in details the impacts on ozone layer or acidification.
19/25 Even with respect to precipitation impacts, moreover, the supplemental material for Irvine's paper buries the real lede for the story: that at anything about 1/2 SRM, the impacts on precipitation rise rapidly and dramatically.
20/25 Thus, at best their paper stands for the proposition that, ignoring other categories of harmful impacts, the impact of SRM on precipitation will be manageable if you limit SRM to offset only a portion of temperature rise.
21/25 To justify even that conclusion, however, Irvine et al have to apply an idealized version of SRM that could not exist in reality. As @Ccolose, @MichaelEMann and others have noted, you can't simply dial down the sun.
22/25 The idealized, perfectly distributed and perfectly controlled aerosol layer posited by Irvine et al. bears little relation to the uneven injection and dissipation of aerosols under any SRM technique that I have seen described in the literature. .
23/25 So, in response and in conclusion, Yes, CIEL believes the first best metric of a climate solution is: does it solve climate change. In our view, neither SRM nor technological CDR will achieve that.
24/25 The next best metric of an climate response, is will it limit harmful climate impacts to communities and ecosystems. The most appropriate forms of adaptation will do just that. Technological forms of CDR, or CCS reliant forms of CDR like BECCS, almost certainly won't.
25/25 Nor, in our view, will SRM. @ciel_tweets believes the surest, safest and most effective response to climate change is also the most readily deployable: moving the world rapidly and completely away from fossil fuels.
