NASA ranked 2017 as the second-warmest year on record, while scientists at the National Oceanic and Atmospheric Administration ranked it third. University of Michigan experts are available to discuss today's announcement.
Jonathan Overpeck is dean of the School for Environment and Sustainability. He has active climate research programs on five continents, focused on understanding drought and megadrought dynamics worldwide. He also served as a lead author on the authoritative Intergovernmental Panel on Climate Change 2007 and 2014 reports.
"The unusual, near-record warmth of 2017 is important for two reasons," he said. "First, 2017 was the warmest year in the instrumental record that didn't coincide with the warming impact of an El Niño. This confirms that greenhouse gases are driving inexorable warming. Moreover, the lack of substantial global cooling after the El Niño-warmed years of 2015 and 2016 highlights that the record warmth in those years wasn't just due to natural variability and that, instead, anthropogenic global warming is now dominating global climate."
Ben van der Pluijm, an expert on geological hazards and their impacts on society, is a professor in the Department of Earth and Environmental Sciences.
"Whereas 2017 is 'only' the second-warmest year globally and third-warmest year for the U.S., most concerning is the fact that the four warmest years on record are in the decade since 2010," he said. "Decadal patterns are better indicators of climate change than yearly records, and certainly much better than seasonal weather patterns, such as the current cold spell in the Northeast and earlier storm activity in the South.
"The urgency for climate action is ever greater, including emissions reductions exceeding those of the Paris Accord and consideration of active climate intervention, particularly atmospheric carbon dioxide removal."
Richard Rood, professor of climate and space sciences and engineering at the College of Engineering, can discuss the intersections of weather and climate, and climate and society. He is a blogger at Weather Underground and teaches a class on climate change problem solving.
"The warmth of 2017 is perhaps the most significant of any of the recent years because it is a year we would expect to be cooler because of the La Niña," he said.