Society has four general options for addressing human caused changes in climate. We could take no upfront preventative action. I’ll call this the wait-and-see approach. We could reduce our greenhouse gas emissions (mitigation). We could improve our ability to cope with climate impacts (build our adaptive capacity). For example, building codes could require structures to withstand more severe storms, or we could restrict development in flood prone areas. Finally, we could deploy global changes that attempt to counteract the effects of our greenhouse gas emissions (geoengineer). One prominent geoengineering idea is to inject reflective particles into the atmosphere to decrease slightly the amount of the sun’s energy that reaches the earth’s surface.
Each of the four options has proponents and critics, advantages and disadvantages. A full treatment will take many posts, but for today I’ll set the stage with a broad overview.
If we wait-and-see, and the impacts of climate change end up being minor, no resources or effort would get wasted. But climate change impacts could be severe. If so, we’ll have done nothing to reduce the magnitude of the changes or to increase our ability to cope with them. As a result, wait-and-see leads to the maximum potential for suffering from climate impacts.
Mitigation will lead to lower greenhouse gas concentrations, which will produce more modest changes in climate. This means fewer and less severe impacts to society. Mitigation policies may provide additional benefits as well, such as less traditional air pollution or greater energy independence. The potential downside of mitigation arises because we cannot accurately quantify future climate damages. If we overestimate the potential damages when deciding how much to mitigate, then we could waste resources by unnecessarily reducing emissions. Mitigation also does little to help us cope with the changes in climate that our past emissions have already committed us to endure.
Building adaptive capacity can help us handle the unavoidable changes in climate. Another benefit is that better adaptive capacity can help reduce our vulnerability to existing weather related events. The downside with adaptation is that some impacts of climate change may remain too severe or too unpredictable to handle. A wide range of potential climate impacts also makes it difficult to know how to focus adaptation efforts on the most pressing needs. As a result, investments may be ineffective or even counterproductive for the actual impacts we face. If so, investment in avoiding climate damages altogether would be more effective.
Geoengineering may be the cheapest and fastest option, and particularly beneficial if catastrophic impacts appeared unexpectedly, or if mitigation and adaptation could not prevent them. The downside of geoengineering is the potential for serious unintended consequences. These may be difficult to recognize prior to deployment and irreversible afterwards. Geoengineering also cannot overcome all the consequences of our greenhouse gas emissions. Ocean acidification and the effects of CO2 on biological systems, for example, would not necessarily be dealt with by geoengineering.
So what’s the best option for a well-informed society? No single approach can deal with all the risks of climate change but each of the proactive solutions (mitigation, adaptation, and geoengineering) can help if used as part of a thoughtful combination. In the weeks and months ahead, we’ll delve in to each of the approaches in more detail and explore how they might work together.