As governments, scientists and individuals grapple with how to tackle a looming climate crisis, new research from UC San Diego released Thursday explores a possible mode of response that seems borderline science fiction.
Their idea involves a massively funded program to deploy direct air- capture systems that remove carbon dioxide directly from the ambient air and sequester it safely underground.
The findings reveal a program could reverse the rise in global temperature well before 2100, but only with immediate and sustained investments from governments and firms to scale up the new technology.
Despite the enormous undertaking explored in the study, the research also reveals the need for governments to simultaneously adopt policies for deep cuts in CO2 emissions. The scale of the effort needed just to achieve the Paris Agreement goals of holding average global temperature rise below 2 degrees Celsius is massive, the researchers said.
The study, published in Nature Communications, assesses how crisis- level government funding on direct air capture — on par with government spending on wars or pandemics — would lead to deployment of a fleet of DAC plants that would collectively remove CO2 from the atmosphere.
"DAC is substantially more expensive than many conventional mitigation measures, but costs could fall as firms gain experience with the technology," said first-author Ryan Hanna, assistant research scientist at UCSD. "If that happens, politicians could turn to the technology in response to public pressure if conventional mitigation proves politically or economically difficult."
Co-author David Victor, professor of industrial innovation at UCSD's School of Global Policy and Strategy, said atmospheric CO2 concentrations are so high, meeting climate goals requires not just preventing new emissions, but also finding ways to remove historical emissions already in the atmosphere.
"Current pledges to cut global emissions put us on track for about 3 degrees C of warming," Victor said. "This reality calls for research and action around the politics of emergency response. In times of crisis, such as war or pandemics, many barriers to policy expenditure and implementation are eclipsed by the need to mobilize aggressively."
Even with a massive program, the globe would see temperature rise of 2.4-2.5 degrees C by the year 2100 without further cuts in global emissions below current trajectories.
The authors estimate the financial resources possibly available for emergency deployment of direct air capture could exceed $1 trillion per year based on previous spending the U.S. has made in times of crisis.
The authors built a bottom-up deployment model that constructs, operates and retires successive vintages of DAC scrubbers -- given available funds and the rates at which direct-air capture technologies might improve with time. They link the technological and economic modeling to climate models that calculate the effects of these deployments on atmospheric CO2 concentration level and global mean surface temperature.
With massive financial resources committed to DAC, the study finds the ability of the DAC industry to scale up is the main factor limiting CO2 removal from the atmosphere. The authors point to the ongoing pandemic as an analog: even though the FDA has authorized use of coronavirus vaccines, there is still a huge logistical challenge to scaling up production, transporting and distributing the new therapies quickly and efficiently.
Conventional mitigation is still needed, even with wartime spending combating climate change.
Regardless, they note that the long-term vision for combating climate requires taking negative emissions seriously.
