The team found that, in the model, sunshade geoengineering leads to increased crop yields in most regions, both compared with current conditions and with the future projection of doubled carbon dioxide on its own. This is because deflecting sunlight back to space reduces temperatures, but not CO2. "In many regions, future climate change is predicted to put crops under temperature stress, reducing yields. This stress is alleviated by geoengineering," Pongratz said. "At the same time, the beneficial effects that a higher CO2 concentration has on plant productivity remain active."
Even if the geoengineering would help crop yields overall, the models predict that some areas could be harmed by the geoengineering. And there are other risks that go beyond the direct impact on crop yields. For example, deployment of such systems might lead to political or even military conflict. Furthermore, these approaches do not solve the problem of ocean acidification, which is also caused by carbon dioxide emissions.
"The real world is much more complex than our climate models, so it would be premature to act based on model results like ours," Caldeira said. "But desperate people do desperate things. Therefore, it is important to understand the consequences of actions that do not strike us as being particularly good ideas."
"The climate system is not well enough understood to exclude the risks of severe unanticipated climate changes, whether due to our fossil-fuel emissions or due to intentional intervention i
|Contact: Ken Caldeira|