Washington, DC — Wind and solar power could generate most but not all electricity in the United States, according to an analysis of 36 years of weather data by Carnegie’s Ken Caldeira, and three Carnegie-affiliated energy experts: Matthew Shaner, Steven Davis (of University of California Irvine), and Nathan Lewis (of Caltech). Their work is published by Energy & Environmental Science. (more…)
Washington, DC— Geoengineering is a catch-all term that refers to various theoretical ideas for altering Earth’s energy balance to combat climate change. New research from an international team of atmospheric scientists published by Geophysical Research Letters investigates for the first time the possibility of using a “cocktail” of geoengineering tools to reduce changes in both temperature and precipitation caused by atmospheric greenhouse gases. (more…)
Washington, DC—New work from an international team including Carnegie’s Ken Caldeira demonstrates that the planet’s remaining fossil fuel resources would be sufficient to melt nearly all of Antarctica if burned, leading to a 50- or 60-meter (160- to 200-foot) rise in sea level. Because so many major cities are at or near sea level, this would put many highly populated areas where more than a billion people live under water, including New York City and Washington, DC. It is published in Science Advances. (more…)
Washington, D.C.— A great deal of research has focused on the amount of global warming resulting from increased greenhouse gas concentrations. But there has been relatively little study of the pace of the change following these increases. A new study by Carnegie’s Ken Caldeira and Nathan Myhrvold of Intellectual Ventures concludes that about half of the warming occurs within the first 10 years after an instantaneous step increase in atmospheric CO2 concentration, but about one-quarter of the warming occurs more than a century after the step increase. Their work is published in Environmental Research Letters.
The study was the result of an unusual collaboration of a climate scientist, Ken Caldeira, who contributed to the recently published Intergovernmental Panel on Climate Change report, and Nathan Myhrvold, the founder and CEO of a technology corporation, Intellectual Ventures LLC. It is the third paper on which they have collaborated. (more…)
Washington, D.C. — It is difficult to measure accurately each nation’s contribution of carbon dioxide to the Earth’s atmosphere. Carbon is extracted out of the ground as coal, gas, and oil, and these fuels are often exported to other countries where they are burned to generate the energy that is used to make products. In turn, these products may be traded to still other countries where they are consumed. A team led by Carnegie’s Steven Davis, and including Ken Caldeira, tracked and quantified this supply chain of global carbon dioxide emissions. Their work will be published online by Proceedings of the National Academy of Sciences during the week of October 17. (more…)
Washington, DC — Scientists have long debated about the impact on global climate of water evaporated from vegetation. New research from Carnegie’s Global Ecology department concludes that evaporated water helps cool the earth as a whole, not just the local area of evaporation, demonstrating that evaporation of water from trees and lakes could have a cooling effect on the entire atmosphere. These findings, published September 14 in Environmental Research Letters, have major implications for land-use decision making.
Evaporative cooling is the process by which a local area is cooled by the energy used in the evaporation process, energy that would have otherwise heated the area’s surface. It is well known that the paving over of urban areas and the clearing of forests can contribute to local warming by decreasing local evaporative cooling, but it was not understood whether this decreased evaporation would also contribute to global warming (more…)
Palo Alto, CA — Scientists have known for decades that black carbon aerosols add to global warming. These airborne particles made of sooty carbon are believed to be among the largest man-made contributors to global warming because they absorb solar radiation and heat the atmosphere. New research from Carnegie’s Long Cao and Ken Caldeira, along with colleagues George Ban-Weiss and Govindasamy Bala, quantifies how black carbon’s impact on climate depends on its altitude in the atmosphere. Their work, published online by the journal Climate Dynamics, could have important implications for combating global climate change. (more…)
Stanford, CA — Genghis Khan and his Mongol hordes had an impact on the global carbon cycle as big as today’s annual demand for gasoline. The Black Death, on the other hand, came and went too quickly for it to cause much of a blip in the global carbon budget. Dwarfing both of these events, however, has been the historical trend towards increasing deforestation, which over centuries has released vast amounts of carbon dioxide into the atmosphere, as crop and pasture lands expanded to feed growing human populations. Even Genghis Kahn couldn’t stop it for long. (more…)
