Reflective, a San Francisco-based research group, has issued a thorough roadmap for the experiments, studies, and infrastructure that would need to be put into place before making informed decisions on dimming the sun through solar geoengineering. Released today, the report lays out a coordinated approach meant to resolve decades of scientific doubt surrounding the field.
Decades of Scientific Uncertainty
For 50 years, researchers have studied ways to cool the planet by spraying reflective particles into the upper atmosphere, imitating the chill brought on by volcanic eruptions. Despite hundreds of studies on stratospheric aerosol injection (SAI), the field still lacks clear answers about its effectiveness and side effects. No organized effort has yet been put in place to resolve those unknowns.
Reflective’s Mission
A group that backs studies into solar geoengineering calls its road map a means of directing scientific work while also pushing private donors and public offices to support projects judged most important.
Dakota Gruener, cofounder and chief executive of the organization, said its mission is to supply the world with the data and tools needed for making informed decisions about sunlight reflection at a pace that still counts. She added that her sense is that the world may have to make very consequential decisions on timelines far shorter than the organization’s research system is ready for.
The hope is the exercise will “responsibly accelerate research,” says Gruener.
Reflective grew into a major force in solar geoengineering research after Gruener brought the nonprofit on board late last year. It has taken in over $20 million from a number of well-known charities and individuals, and has put about $4 million toward several dozen research groups. The organization has also carried out its own work, such as building an open-source solar geoengineering simulator and setting up an online hub for collaborative research.
The Cost of Knowing
The report estimates that completing all the work in the road map in a coordinated fashion would take about a decade and cost around $370 million. Without coordination, the same work would take roughly 20 years and cost nearly $1.4 billion.
The new guide draws upon an earlier Reflective initiative. This year, the group put out its SAI Uncertainties database, which lays out a lengthy roster of scientific uncertainties and engineering hurdles that must be resolved before any small-scale solar geoengineering attempt can proceed.
Among the largest uncertainties are which gas or particles would work best and how they would behave after being let loose in the dry stratosphere. It remains unclear whether they would spread out so as to maximize reflectivity, or instead gather together and swiftly drop back down into the troposphere, the lowest layer of Earth’s atmosphere.
Three Research Phases
Reflective’s plan starts with what it calls “foundational knowledge,” which covers more computer modeling and hands-on testing aimed at revealing how climate change might affect specific areas, living systems, and natural events, such as ocean currents, ice masses, and farm harvests.
The report further points out that there is a requirement to start building more observational instruments during this period, so as to better understand the natural state of the stratosphere. This knowledge would then give us a stronger basis for judging any impacts from the eventual release of materials.
The initial phase is expected to run for two to three years, with a price tag ranging from $30 million to $75 million, even though some of the analytical and observational tasks will carry over into later stages.
Four modified aircraft would release a total of 10 metric tons of sulfur dioxide into the stratosphere, with each of four deployments spaced across two seasons. The entire research phase could last between four and eight years and carry a price tag of $70 million to $150 million, according to the report. That work could cut uncertainty about the “cooling efficacy” of solar geoengineering — the cooling produced per ton of sulfur released — by roughly one quarter.
During the next round of tests, the volume of sulfur dioxide released would rise sharply, reaching 25,000 tons spread across a single season, carried out at least once and potentially twice. That phase of study, which also covers other related work, is projected to span four to 11 years and cost between $270 million and $1.1 billion.
The Controversy Over Outdoor Tests
Reflective doesn’t promote deploying this kind of solar geoengineering, but Gruener notes that the report argues for carrying out outdoor tests. Such trials would put progressively greater quantities of sulfur dioxide (or substances that would turn into it) into the stratosphere so researchers can watch how they behave.
That is a controversial standpoint.
Academics began signing an open letter back in 2002, asking for a stop to outdoor experiments and pushing for what they call an “international non-use agreement.” They say that a technology with this much power could never be managed in a fair way across the whole world. Several of those who signed the letter say no amount of additional research could settle one of the largest questions tied to using solar geoengineering: Who gets to carry it out.
Aarti Gupta, a professor of global environmental governance at Wageningen University in the Netherlands who is also the co-initiator of the non-use initiative, said in a recent on-stage interview with MIT Technology Review that “the first-order questions, from my perspective, are not technical.”
The central issue concerns who controls a planetary-scale technology such as stratospheric aerosol injection. The questions of who builds it, who puts it into use, and for what purpose are deeply important. What goals does it serve, and whose goals are they? These queries are extremely foundational, since this kind of technology will create both beneficiaries and those left behind.
“Who would control a planet-altering technology like stratospheric aerosol injection? Who would develop it, and who would deploy it, and to what end?”
What Critics Argue
The plan outlines how to answer nearly all of the technical questions raised in Reflective’s original database. Still, opponents say it fails to settle the governance issues.
The signatories of the non-use letter, including Gupta, claim that the initial questions are not technical in nature. Their argument is that further research will not resolve who controls a planet-altering technology, who develops it, or for what purposes.
Reflective doesn’t push for the use of this form of solar geoengineering, and Gruener concedes as much. The group says its job is to offer information and instruments to help people decide, not to argue for putting it into service.
The Road Ahead
A timeline that could span a decade or more is what the road map sets forth, provided funding and coordination hold steady. Just the opening stage would require two to three years and tens of millions of dollars.
Four to eight years is the time frame for the second phase, which uses the altered aircraft and smaller releases. The third phase, with its much larger releases, would require four to 11 years.
Scientists are still weighing whether solar geoengineering could serve as an answer to climate change, and the new report arrives amid that ongoing inquiry. The questions on the table remain considerable: which gas or particles would prove most effective, how they might act in the dry stratosphere, and just how much cooling per ton of sulfur released the planet would see.
That document is meant to address those questions. It is still unknown if funding will be secured, or if the answers provided will be sufficient to resolve the political disputes.
Reflective has set forth a course of action. Whether any others choose to take it up remains to be seen.
Source: technologyreview.com
Get the Notebook.
The day's best stories and every fresh verdict, in plain English, in your inbox by seven. One email a day, no more.