A federal report on climate change released last week identified human activities as exclusively responsible for warming temperatures over the past century.
The Fourth National Climate Assessment documented effects on the environment, human health and the economy that are only expected to worsen if humans don’t take action to adapt and reduce greenhouse gas emissions.
While scientists have long expected grave effects of climate change, the report confirms that the changes are actually being seen, said Paul Staten, a professor in the earth and atmospheric sciences department.
“We’re seeing the beginning of it,” Staten said. “If we act now, we can prevent it from getting much, much worse.”
When breaking down effects by region, the report stated the Midwest will experience greater increases to warm-season temperatures than any other region. These temperatures and increases in rainfall could cause agricultural productivity in the Midwest to revert to levels seen in the 1980s.
More than 300 experts contributed to the second installment of the Fourth National Climate Assessment, which the U.S. Global Change Research Program is mandated to produce for Congress and the president at least every four years. It synthesized a huge volume of research on the effects, risks and adaptations associated with observed and predicted changes in the climate.
The observed warming trend can only be attributed to greenhouse gas emissions, according to the report. In fact, the authors wrote global climate would have slightly cooled over the last 50 years if human activities had not been involved.
Poor air quality, increased pollen and heat-related diseases could spread through the Midwest by mid-century.
By the same point, the Purdue-led Indiana Climate Change Impacts Assessment predicted Indiana’s average temperature will warm five to six degrees.
Future summers in Indiana could look like those of Mississippi and Arkansas, while winters will be milder like those in Pennsylvania, New Jersey and Maryland.
People across the country will experience greater health risks, especially in vulnerable communities, according to the national report.
The report painted a grim future with substantial losses to the national economy and dangers to human health through the 21st century.
Most economic sectors will face negative consequences from climate change by the end of the century, and some could lose up to hundreds of billions of dollars per year.
Since 2015, weather and climate disasters have cost the U.S. almost $400 billion, according to the National Oceanic and Atmospheric Administration.
The volume joins other recent compilations of studies on the effects of climate change, including one by the Intergovernmental Panel on Climate Change published last month. Locally, the Purdue-led group released the first in a series of reports last spring to focus on the statewide effects.
There is no guarantee these reports will spur action, but Staten said their publication is necessary.
“Without understanding science and the facts, why would anybody do anything?” Staten said
Federal action to prevent climate change is unlikely under the current political atmosphere.
When asked about the assessment Monday, President Donald Trump told reporters he did not believe it.
However, cities and states around the country are taking action on their own. A multidisciplinary team of researchers at IU’s Environmental Resilience Institute funded through a Grand Challenge grant are preparing research projects and tools to help communities across the state adapt.
While actions to reduce greenhouse gas emissions are generally increasing, the report said the scale of adaptation efforts are not at the level necessary to avoid significant damages.
Actions related to climate change can be reactive, in response to existing challenges, or proactive, to prevent climate change itself.
Fortunately, there is much that can be done, Staten said. Many sectors of the economy can reduce their impacts of greenhouse gas emissions at costs smaller than the long-term costs of climate change, Staten said. Some sectors already have means of doing this.
“The worst can be prevented still,” Staten said. “But we do need to act quickly.”