I like Austin Vernon’s idea for scaling CO2 direct air capture to 40 billion tons per year, i.e. matching our current annual CO2 emissions, using (extreme versions of) well-understood industrial processes.
The proposed solution may not be the cheapest out there. Other ideas like ocean seeding or olivine weathering might be less expensive. But most of the science is understood, and it can scale quickly. I’d guess 100,000 workers could build enough sites to capture our 40 billion tons goal in a decade. The capital expenditure rate would be between $1 trillion and $5 trillion yearly, or 1% to 5% of global GDP. That cost and deployment speed take doomer scenarios off the table. Say something scary like melting permafrost threatens runaway warming. You can target the area with a few years of sulfur cooling while a tiny portion of the global economy builds carbon capture devices. It is nothing like a wartime mobilization.
The most disruptive aspect would be energy usage. We’d need to ramp output up at double-digit rates because each ton of CO2 requires 2-3 MWh of energy for removal. Thankfully low-grade heat is easy to come by. There is enough energy near coal mines in Wyoming or natural gas fields in SW Pennsylvania at less than $5/MWh. Other places might use solar, hydro, or geothermal steam if they lack fossil fuel reserves. The key is to put the facilities at the energy sources instead of trying to move the energy. Cheap energy makes the operating costs <1% of global GDP. Many clean energy proponents have fretted about how to keep fossil fuel reserves in the ground. Burning them to run carbon capture equipment kills two birds with one stone!
The takeaway is that we could completely turn around the carbon dioxide problem within a few years with a similar spending rate as rich world COVID relief. There won’t be a scenario where we’ve waited too long to act.
I am admittedly perhaps biased to want moonshots like Vernon’s idea to work, and for society at large to be able to coordinate and act on the required scale, after seeing these depressing charts from Assessing the costs of historical inaction on climate change:
I like Austin Vernon’s idea for scaling CO2 direct air capture to 40 billion tons per year, i.e. matching our current annual CO2 emissions, using (extreme versions of) well-understood industrial processes.
I am admittedly perhaps biased to want moonshots like Vernon’s idea to work, and for society at large to be able to coordinate and act on the required scale, after seeing these depressing charts from Assessing the costs of historical inaction on climate change: