Carnegie Science News - Department of Global Ecology

Could replacing coal-fired electricity plants with generators fueled by natural gas bring global warming to a halt in this century? What about rapid construction of massive numbers of solar or wind farms, hydroelectric dams, or nuclear reactors—or the invention of new technology for capturing the carbon dioxide produced by fossil-fueled power plants and storing it permanently underground? Nathan Myhrvold of Intellectual Ventures teamed up with Carnegie Institution’s Ken Caldeira to calculate the expected climate effects of replacing the world’s supply of electricity from coal plants with any of eight cleaner options.

With Audio
Carbon dioxide emissions from the burning of coal, oil, and gas have been increasing over the past decades, causing the Earth to get hotter and hotter. There are concerns that a continuation of these trends could have catastrophic effects, including crop failures in the heat-stressed tropics. This has led some to explore drastic ideas for combating global warming, including the idea of trying to counteract it by reflecting sunlight away from the Earth. However, it has been suggested that reflecting sunlight away from the Earth might itself threaten the food supply of billions of people. New research led by Carnegie’s Julia Pongratz examines the potential effects that geoengineering the climate could have on global food production and concludes that sunshade geoengineering would be more likely to improve rather than threaten food security.

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Over the past 10 years, the death of forest trees due to drought and increased temperatures has been documented on all continents except Antarctica. This can in turn drive global warming by reducing the amount of carbon dioxide removed from the atmosphere by trees and by releasing carbon locked up in their wood. New research led by Carnegie researcher and Stanford University PhD student William Anderegg offers evidence for the physiological mechanism governing tree death in a drought.

With Video
Solar radiation management is a class of theoretical concepts for manipulating the climate in order to reduce the risks of global warming caused by greenhouse gasses. But its potential effectiveness and risks are uncertain, and it is unclear whether tests could help narrow these uncertainties. A team composed of Caltech's Doug MacMynowski, Carnegie’s Ken Caldeira and Ho-Jeong Shin, and Harvard's David Keith used modeling to determine the type of testing that might be effective in the future.