Over the last several decades, emissions reduction has received the most public attention of any strategy to address climate change. At a recent MIT Energy Initiative (MITEI) event, John Deutch, Institute Professor Emeritus in MIT’s Department of Chemistry, emphasized the importance of continuing to achieve emissions reductions while stressing the urgent need to deploy additional strategies to help mitigate the effects of climate change. “It is very unlikely that climate damages can be reduced to an acceptable level by the end of the century relying only on emissions reduction,” Deutch said.
In his talk, Deutch introduced a conceptual model to demonstrate ways to reduce global temperature rise. The model assesses the economic damage of climate change in the context of a monetary damage function in terms of monetary losses. The damage function includes four climate change control strategies: emissions reduction, carbon dioxide (CO2) removal from the atmosphere, adaptation to climate change, and geoengineering.
Two of these methods, emissions reduction and CO2 removal, impact the atmosphere by changing the concentration of CO2. Emissions reduction might involve switching from using fossil fuels and coal to renewable sources of energy like wind, solar, or hydropower. In CO2 removal, carbon is extracted directly from the atmosphere using carbon capture technologies.
Adaptation and geoengineering, on the other hand, act more indirectly to reduce climate damage. Adaptation helps mitigate climate change through alterations to the environment itself. For example, a city could respond to increasing temperatures by planting more heat-resistant trees. To adapt to increasing flood risk, a state might raise the street levels, alter the foundations of existing buildings, and use construction materials that are more resistant to water.
The type of geoengineering Deutch discussed would involve sending aerosols into the atmosphere, and is the most experimental of the four strategies. It would impact radiative forcing, which refers to the difference between energy the Earth absorbs and the energy it reflects into space. Reflective aerosol particles like sulfur dioxide could send some of the sun’s energy back into space, which could result in a cooling effect.
Deutch demonstrated that mathematical models and simulations are important tools in evaluating the costs and benefits of public action. By making abstract concepts like climate damage and reduction more concrete, the models can help inform climate goal assessment and climate change mitigation policies. Deutch noted that such objective models can “assist in guiding respectful discussion between individuals and groups with different points of view and interests.”
If the rate of environmental damage remains constant, “the combination of all four climate [change reduction] mechanisms is very likely to achieve lower damage levels than by the action of one of the mechanisms alone,” Deutch said. Further research into the three newer mechanisms (carbon capture, adaptation to climate change, and geoengineering) can provide insight into the most effective combinations of these strategies in order to reduce global temperature rise.
This event is part of MITEI’s IHS Seminar series.