David Keith Profile picture
Born at 319 ppm & worked climate since 351. Now focused on solar geoengineering. Teaches @Harvard. Founded Carbon Engineering. Nature Needs Half!
Shashank Profile picture Eric Carroll 💉💉😷 Profile picture 2 added to My Authors
5 Apr
1/13 Johnathan Foley @GlobalEcoGuy says "Solar Geoengineering: Ineffective, Risky, and Unnecessary".

Well, 2 out of 3 ain't bad. But, before we get to which 2, let's consider his arguments. globalecoguy.org/solar-geoengin…
2/13 Foley opens with a common ad hominem attack, claiming that folks who argue for SG research do so because they are "unwilling to accept" that the tools to cut emissions are at hand so they want to "counteract climate change *instead of* addressing its underlying causes"
3/13 This attack works by emphasizing the (false) idea that SG is an alternative to rapid decarbonization. It's goal is to make SG research advocates look like defenders of the status quo or even oil companies dupes.
Read 15 tweets
19 Mar
1/5 How to improve models used for solar geoengineering?

New @AGU_Eos paper by the steering committee of the Geoengineering Modeling Consortium (GMRC) What's GMRC? We are a science community consortia anchored at NCAR

eos.org/science-update…
2/5 GMRC aims to identify weaknesses in geophysical models used for solar geoengineering and then develop collaborative efforts to improve the models.

Our next event (May 5th) is on the NAS report that will be released Thursday
cgd.ucar.edu/projects/gmrc/
3/5 PiG in the GCM? An example, of one of model improvements I happen to be working on. Aerosols or aerosol precursors would most plausibly be released into the stratosphere by aircraft. Observations show that stratospheric plumes are coherent for >10 days.
Read 6 tweets
15 Mar
1/13 Is solar geoengineering like nuclear weapons?

In critiquing the SCoPEx experiment Ray Pierrehumbert @ClimateBook compared our work to helping North Korea get nuclear weapons.

So, time for thread #2 debunking solar geoengineering's BS mountain

2/13 This is not personal. Ray, you are an amazing scholar & human. In the early '90s helped me on meridional energy transport. We have enjoyed dinners talking about shared love of the northern wilds. I am jealous of your musical ability, and wish to count you a friend.
3/13 But, Ray, do you truly think our experiment is as bad as if we were helping a crazed dictator get nuclear weapons?

Nuclear weapons threaten to burn us alive without warning. They are machines of death:

Read 14 tweets
12 Mar
1/7 Geoengineering droughts?

Thread #1 debunking solar geoengineering's BS mountain

Search geoengineering & drought, you get's ~0.5 million google hits and 1,696 news articles in Nexis starting with a 1991 Newsweek article.

Must be some facts underneath?
2/7 The '91 Newsweek article reported that US National Academy has endorsed research on solar geoengineering. It mentioned drought as a climate risk and geoengineering as an uncertain and potentially risky way to ameliorate such risks. Other '90s articles have a similar take.
3/7 Yet, most recent articles with "drought & geoengineering" describe drought as a risk of geoengineering rather than climate risk that geoengineering might ameliorate.

This shift must be the result of new science. Right?

Wrong.
Read 10 tweets
11 Feb
1/n A $100m carbon removal @xprize cool! But folks who care about climate should ask some hard questions.

Virgin Earth Challenge $25m prize launched in '07 by @richardbranson. Original prize terms were nonsensical: required a $ bn business to win so the $25m would be meaningless
2/n the Virgin (VEC) prize revamped the terms to say winners had to have pathway to giga scale commercial #CDR, but terms remained deeply ambiguous.

On the plus side, VEC helped us raise funds and attention when I was working to found @CarbonEngineer in '09.
3/n On minus side, the VEC prize diverted resources inside @CarbonEngineer, @Climeworks and other competitors.

@richardbranson and team waited until total funding in space was >> $25 m so impact would have been small, then they punted. Result? Not much.
Read 10 tweets
25 Oct 19
1/3 Cheap intermittent solar power can make carbon-neutral hydrocarbons: high-energy fuels that are easy to store and use. My 12 min talk at Royal Society #CodexTalks describes a low-risk fast path to industrial-scale solar-fuels
2/3 Background: Carbon-Neutral Hydrocarbons keith.seas.harvard.edu/publications/c…. Recent work on renewable hydrogen nature.com/articles/s4156…. H2 will win in some markets, but it has many disadvantages as a fuel. The big $$$ is getting to H2, once there, why not go to hydrocarbons with DAC?
3/3 I am *so* proud of @CarbonEngineering, but..

This is NOT about one company. It’s about an energy pathway that could grow to >10% of global primary energy before mid-century, allowing intermittent solar energy to energize heavy transport and other hard-to-decarbonize sectors.
Read 4 tweets