By: Yuan Yuan
During Marcia McNutt’s tenure as the director of the U.S. Geological Survey, she had to deal with earthquakes in Haiti, Chile and Japan and the Deepwater Horizon oil spill.
However, none of these controversies prepared her for the controversy surrounding geoengineering, the deliberate large-scale intervention in the Earth’s natural systems to counteract climate change, McNutt said in her speech at MU Life Sciences & Society Program 12th Annual Symposium.
McNutt is the editor-in-chief of Science and is currently nominated to be the next president of the National Academy of Sciences. Before joining Science in June 2013, she served as the director of the U.S. Geological Survey for four years.
Formerly of MIT and Stanford, she led the National Academy of Sciences study that evaluated climate intervention options for slowing global climate change.
[VIDEO]Marcia McNutt gives a preview of her talk about climate modification at MU LSSP. Video by:@MUbondlsc
Geoengineering “was a very controversial topic,” McNutt said. “What is not controversial is that climate is changing.”
McNutt explained that climate change affects more than the environment; it affects people and the economy. Sea level rise may one day lead to the largest human migration ever. Climate change increases the probability of extreme weather events, including Hurricane Katrina and the California droughts.
McNutt said human actions are needed to solve this human-caused problem, and she presented several options.
The first is mitigation. “Mitigation is anything we do to stop climate change from happening in the first place,” McNutt said. “Those are things like switching to energy systems that don’t emit CO2 at the first place,” such as using solar panels. But considering the amount that has been invested in the current power systems, switching to cleaner power plants cannot happen overnight. Mitigation is a necessary step, but it takes time.
Adaptation was the second option McNutt presented. Adaptation means that “we learn to live with the amount of climate change that we’re going to see.” For example, people on the Mississippi Gulf Coast rebuilt their houses on stilts to deal with the rising sea levels. With the amount of CO2 already in the atmosphere, “we are going to have to adapt anyway,” she said.
The question remains: If these two approaches are insufficient, do we need a third approach? That third approach she presented was climate intervention, which is still under study.
One of two types of intervention is carbon dioxide removal and sequestration, which means to grab carbon dioxide from the air and store it somewhere, such as in the ground.
Carbon removal can be accomplished through industrial, geo-mechanical and agricultural methods. These all act slowly, McNutt said, so it takes time to see the results. Besides, some of the methods are currently expensive and need more research to make them competitive.
The second type of intervention is to change the Earth’s albedo, or reflection of the sun’s rays, to absorb less incoming solar radiation. One cheap and fast way to achieve this is to spray aerosols, or small particles, into the stratosphere. Stratospheric aerosols could reduce the amount of sunlight absorbed by the Earth to cool the surface quickly. “You could deploy today, and within months the planet will be cool,” McNutt said.
But there are many reasons not to deploy albedo modification at this time, McNutt said. It would make the ozone hole worse; it has regional effects on temperature and rainfall; and the outcome is uncertain. Besides, changing Earth’s albedo does not address the root problem; it does not reduce the amount of CO2 in the atmosphere. The process would have to be repeated again and again.
“Time is running out,” McNutt said. It’s more than just scientists involved into the decisions on research. “We need to engage civic society in dealing with the ethical, the equity and the legal considerations,” she said, and “we need transparent and inclusive conversations” to maximize the benefits of research and to minimize the risks.