Whereas Hunt agrees that such research is lacking, he said that the team needs real measurements in order to see if the tethered balloon design is viable. "If not now, then when would you start?" he asks. "This year, next year? Or maybe wait until a large block of ice falls off of Greenland? My choice is to have all the tools carefully thought through, so that we don't have to rush into anything."
To avoid dangerous climate change, some scientists estimate that global CO2 emissions must be cut by at least 80 percent by the end of the century. Geoengineering will not help achieve that long-term target, but the cooling effects of large sulfate clouds are nearly instantaneous, making geoengineering potentially valuable in the event of acute climate crises such as the melting of Arctic sea ice, which could further accelerate global warming over the decades.
The researchers made it clear in Tuesday's press conference that they do not advocate using geoengineering as an excuse for humanity to continue recklessly emitting carbon dioxide and other greenhouse gases. "[Geoengineering] should be considered as an emergency remediation while we wean ourselves off carbon," Watson said. "The question you have to ask is, is it worse without mitigation or with it? And that answer isn't obvious yet."