STANFORD UNIVERSITY – Exceptionally long heat waves and other hot events could become commonplace in the United States in the next 30 years, according to a new study by Stanford University climate scientists.
“Using a large suite of climate model experiments, we see a clear emergence of much more intense, hot conditions in the U.S. within the next three decades,” said Noah Diffenbaugh, an assistant professor of environmental Earth system science at Stanford and the lead author of the study.
Writing in the journal Geophysical Research Letters (GRL), Diffenbaugh concluded that hot temperature extremes could become frequent events in the U.S. by 2039, posing serious risks to agriculture and human health.
“In the next 30 years, we could see an increase in heat waves like the kind that swept across Europe in 2003 that caused tens of thousands of fatalities,” said Diffenbaugh, a center fellow at Stanford’s Woods Institute for the Environment. “Those kinds of severe heat events also put enormous stress on major crops like corn, soybean, cotton and wine grapes, causing a significant reduction in yields.”
The GRL study took two years to complete and is co-authored by Moetasim Ashfaq, a former Stanford postdoctoral fellow now at the Oak Ridge National Laboratory. The study comes on the heels of a recent NASA report that concluded that the previous decade, January 2000 to December 2009, was the warmest on record.
In the study, Diffenbaugh and Ashfaq used two dozen climate models to project what could happen in the United States if increased carbon dioxide emissions raised the Earth’s temperature by 1.8 degrees Fahrenheit (1 degree Celsius) between 2010 and 2039 – a likely scenario, according to the International Panel on Climate Change.
In that scenario, the mean global temperature in 30 years would be about 3.6 F (2 C) hotter than in the preindustrial era of the 1850s. Many climate scientists and policymakers have targeted a 2 C temperature increase as the maximum threshold beyond which the planet is likely to experience serious environmental damage. For example, in the 2009 Copenhagen Climate Accord, the United States and more than 100 other countries agreed to consider action to reduce greenhouse gas emissions “so as to hold the increase in global temperature below 2 degrees Celsius.”
The study projects that from 2030 to 2039, most areas of Arizona, Utah, Colorado and New Mexico could endure at least seven seasons equally as intense as the hottest season ever recorded between 1951 and 1999.
But that target may be too high to avoid dangerous climate change, Diffenbaugh said, noting that millions of Americans could see a sharp rise in the number of extreme temperature events before 2039, when the 2-degree threshold is expected to be reached.
The GRL study was supported by the U.S. Department of Energy and the National Science Foundation. The high-resolution climate model simulations were generated and analyzed at Purdue University. GRL is a publication of the American Geophysical Union.
- Mark Shwartz
Communications manager at the Woods Institute for the Environment at Stanford University
Also on Stanford Knowledgebase: