Indiana University experts comment on climate change report

  • May 6, 2014


BLOOMINGTON, Ind. -- Climate change, once thought to be a problem for future generations, "has moved firmly into the present" and is having an impact in all corners of the United States, according to a comprehensive government report released today. Indiana University experts comment on the report; they address the following topics:

Changing climate will affect Midwest crops, forests, public health

Sara Pryor, Provost Professor of Atmospheric Science in the Department of Geological Sciences at IU Bloomington, is a member of the panel of scientists that produced the report and is the convening lead author of the chapter on climate change in the Midwest. The section has six key messages:

  • Longer growing seasons and rising carbon dioxide levels will initially increase yields of some crops, but those gains will eventually be offset by extreme weather events, including wet springs and hot, dry summers. "In the long term, the combined stresses associated with climate change are expected to decrease agricultural productivity," she said.
  • The composition of Midwest forests is expected to change as rising temperatures drive habitats for many tree species northward, with potential impact on forest-based industries. The ability of the forests to absorb carbon -- and potentially slow climate change -- may be reduced by projected increases in fire, drought and insect outbreaks.
  • More frequent and intense heat waves, increased humidity and worsening air and water quality will jeopardize public health. "The frequency of major heat waves in the Midwest has increased over the last six decades, and the occurrence of excessively hot and humid conditions is projected to increase," Pryor said.
  • The Midwest has a highly energy-intensive economy, and its per-capita emissions of greenhouse gases are more than 20 percent higher than the national average. That means the region has a large potential to reduce emissions; and it is moving in that direction, turning to natural gas to replace coal and developing solar and wind energy sources.
  • Extreme rainfall and flooding are expected to increase, causing erosion and affecting transportation, agriculture and infrastructure. One problem: the discharge of sewage from outdated combined sewer systems. "Cities are already working to remedy this problem -- for example, the Indianapolis 'Indy Tunnel,’ a federally mandated plan to reduce raw sewage overflows into our waterways."
  • Climate change will cause problems for the economically crucial Great Lakes, including changes in the range and distribution of fish species, increased invasive species and algae blooms and declining beach quality. On the plus side, reduced winter ice cover will lengthen the commercial navigation season.

Pryor is the author of numerous publications on atmospheric science and climate, including "Climate Change in the Midwest: Impacts, Risks, Vulnerability, and Adaptation" (IU Press, 2013). She can be reached at Top

Report signals need to move away from fossil fuels

Atmospheric scientist Phil Stevens, Rudy Professor in the School of Public and Environmental Affairs at IU Bloomington, said the report establishes that U.S. temperatures continue increasing and the effects of climate change are already being seen -- despite the cold weather that hit much of the nation this winter and the perception by some that global warming is not occurring.

"Unfortunately, we will likely continue to see these and other impacts for the next several decades as the increased greenhouse gases that we have already added to the atmosphere will lead to additional warming, even if we were to stop emitting greenhouse gases today," Stevens said. "However, we can minimize the impacts if we begin reducing emissions of carbon dioxide and other greenhouse gases soon, which will require moving away from combustion of fossil fuels."

Stevens said there are additional benefits, beyond climate change, to reducing CO2 emissions from the burning of fossil fuels. These include "a reduction in emissions that lead to the formation of smog and fine particulate pollution, which is still a health concern in the U.S."

Stevens' research focuses on chemical mechanisms in the atmosphere that influence regional air quality and global climate change. He can be reached at 812-856-0863 or Top

Recognize that other nations may not be able to adapt

A. James Barnes, professor in the School of Public of Environmental Affairs and the Maurer School of Law at IU Bloomington, called the report "another siren alerting us to the reality that we have set in motion changes in our physical, chemical and biological environment of a nature and at a pace not seen for hundreds of thousands -- if not millions -- of years."

Barnes said the report should focus public and policymakers' attention on how climate change is already affecting people living in the United States and on how its effects will increase in the future.

"At the same time," he said, "we cannot -- and should not -- rest smugly or comfortably with the notion that we will be able to mitigate some of the impacts that might affect us individually, and ignore the fact that for many others on the planet this will not be possible."

Barnes, a former deputy administrator and general counsel for the U.S. Environmental Protection Agency, is an authority on environmental law and international environmental policy. He can be reached at barnesaj@indiana.eduTop

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