DAVID W. KEITH
The Need for Climate Engineering Research
Like it or not, a climate emergency is a possibility, and geoengineering could be the only affordable and fast-acting option to avoid a global catastrophe. Climate change triggered by the accumulation of greenhouse gases emitted into the atmosphere has the potential of causing serious and lasting damage to human and natural systems. At today’s atmospheric concentrations, the risk of catastrophic damage is slight—though not zero. The risk will probably rise in coming years if atmospheric concentrations continue to increase. Although not everyone agrees with this assessment, it is supported by the bulk of the scientific evidence.
For the moment, the United States and other nations are trying to address this risk by controlling emissions of carbon dioxide (CO2) and other greenhouse gases into the atmosphere, with mixed success at best. The time may well come, however, when nations judge the risk of climate change to be sufficiently large and immediate that they must “do something” to prevent further warming. But since “doing something” will probably involve intervening in Earth’s climate system on a grand scale, the potential for doing harm is great.
The United States needs to mount a coordinated research program to study various options for mitigating climate change in order to ensure that damaging options are not deployed in haste. The United Kingdom and Germany have initiated research programs on such climate intervention technologies, and many U.S. scientists are already engaged in this topic, funded by a hodgepodge of private funds and the redirection of federal research grants. Some senior managers at federal agencies such as the National Science Foundation (NSF), Department of Energy (DOE), and National Aeronautics and Space Administration would like to initiate research funding, but they cannot act without political cover, given the understandably controversial nature of the technology. Given the rapid pace at which the research debate about governance is moving in the United States and abroad, delay in establishing a federal program will make it progressively harder for the U.S. government to guide these efforts in the public interest. There is, therefore, a need to establish a coordinated program with deliberate speed.
Making an objective analysis of the economics of CDR systems is one area where cross-cutting research is needed.
Of course, it remains critically important that the United States and other nations continue efforts to reduce emissions of greenhouse gases into the atmosphere. Indeed, much deeper cuts are needed. Reducing emissions will require, first and foremost, the development and deployment of low-carbon–emission energy systems. But even with improved technology, reducing emissions might not be enough to sufficiently reduce the risk of climate change.
Scientists have identified a range of engineering options, collectively called geoengineering, to address the control of greenhouse gases and reduce the risks of climate change. One class of geoengineering strategies is carbon dioxide removal (CDR), which removes greenhouse gases from the atmosphere after they have already been released. This approach may involve the use of biological agents (such as land plants or aquatic algae) or industrial chemical processes to remove CO2 from the atmosphere. Some CDR operations may span large geographic areas, whereas other operations may take place at centralized facilities operating in a relatively small area. Another class of strategies is solar radiation management (SRM), which involves a variety of methods for deflecting sunlight away from Earth or otherwise reducing the levels of solar energy in the atmosphere.
These two strategies are radically different. CDR seeks to address the underlying cause of the climate problem: elevated greenhouse gas concentrations. These approaches are not