August, usually one the driest months of the year, has instead been a wet one for Indianapolis and other parts of the state.
The month started off with a torrent of rain that flooded areas around Indy. Two weeks later, historic flooding of the White River spilled over into homes and businesses in the Broad Ripple, Ravenswood and Rocky Ripple neighborhoods. Rivers also flooded communities from Muncie and Anderson to Cambridge City.
It’s been a life-altering year for many Hoosiers, but what is extreme today could be the new normal.
The Earth is getting warmer, and that has kicked off changes in climate patterns that have disrupted the rhythms of nature we’re used to. That includes how much rain falls, how long heat waves last, how often tornados blaze by and even the presence of pests and allergens.
In 2018, the Purdue University-led Indiana Climate Change Impacts Assessment looked at how climate change has affected Indiana and what these changes might look like in the future.
Mirror Indy spoke to climatologist Melissa Widhalm, who helped develop the assessment and is now associate director and regional climatologist for the Midwestern Regional Climate Center.
We asked her about climate change and how it is expected to affect Indianapolis and the rest of the state.
What is climate change?
According to Widhalm, climate change is the phrase used to describe long-term shifts in weather patterns we’re seeing across the globe.
Those changes are being driven by changes in our atmosphere due to increasing levels of carbon dioxide over the last hundred years created by human activities like the burning of coal and oil for fuel.
Carbon dioxide is a greenhouse gas that traps heat from sunlight on earth instead of letting it escape into space, making the Earth hotter than it normally would be.
“The way we’ve industrialized and modernized our lives, which is a fantastic thing, comes with a consequence,” Widhalm said. “We’ve converted a lot of carbon that used to be stored in the Earth in solid form into a gas form. It’s like adding an extra blanket around the world when we’re already perfectly warm.”
Climate change is normal, but the speed at which it is happening is not.
“We’ve been seeing that change in the last hundred years, when more natural changes would take thousands of years,” Widhalm said. “It’s really an acceleration of a natural process that we are really driving with our modern lifestyle.”
Is climate change happening now?
For Widhalm, the answer is clear.
“Climate change is definitely affecting Indiana already. We see it in our climate data records. We can go back and see just over the last 100 years that our temperature has been warming, our rainfall patterns have been shifting and the amount of rainfall is increasing.
Precipitation and temperature records for Indianapolis date back to 1871, and climate scientists can compare how much carbon dioxide was present in the Earth hundreds of thousands of years ago through data like ice core samples from Antarctica.
“We have very specific measurements that we’ve been tracking over a long period of time that show this is not a problem for a faraway place at a distant point in the future. It’s something that’s already happening here in Indiana and it’s affecting each and every one of us,” Widhalm said.
How climate change is affecting Indiana
Widhalm said Indiana is getting hotter, on average.
According to the impacts assessment Widhalm helped develop, average annual temperatures across the state are expected to rise at least 2 degrees by 2050.
But the worst parts aren’t happening during the daytime and aren’t confined to the summer.
“Our overnight temperatures are warming at about twice the pace as our daytime temperatures, and that has some really important implications,” she said.
In the past, no matter how hot the days were, people could count on relief from the temperatures at night. That might no longer be the case, meaning injuries and deaths from extreme heat will rise, especially in Indianapolis, where net temperature-related deaths are projected to rise from 43 to 71 every year. That’s up from 33 per year in 1990.
Warmer temperatures throughout the year means we won’t get the deep freezes that kill off pests, like mosquitos and ticks.
That means they’ll increase their populations and expand their ranges. The diseases they spread, like West Nile Virus, Zika and Lyme disease will most likely be seen in places where they weren’t common before. That could include simply walking in your neighborhood.
Another side effect of warmer temperatures is that it will extend allergy season by allowing allergy-causing plants like ragweed to produce pollen for longer periods of time, which can trigger asthma attacks, inflammation and other annoying allergy symptoms.
“I used to start my kids on their allergy medicine at a certain time of the year. I’ve had to adjust that just in their 15 years of life,” Widhalm said. “So these are real things that happen in our day-to-day lives that we can tie back to shifts in these large-scale weather patterns.”
Widhalm said Indiana is also experiencing much more rain than it has in the past.
“When we go back 125, 150 years and we look at that long-term average, our rainfall for Indiana is dramatically increasing. We get about six and a half inches more rainfall now than we did 125 years ago. Some years it’ll be more, some years it’ll be less, but overall we’re seeing that steady march upward,” she said.
Besides the quantity, rainfall patterns are also being affected by climate change. Instead of falling steadily throughout the year, we’re getting heavy downpours followed by periods of little rain. According to the National Weather Service Precipitation Scorecard for Indianapolis, this pattern was clear to see in the last two years.
At the beginning of 2025, the city experienced below-average precipitation that was followed by a 96-hour storm in early April that dropped more than 5 inches of rain. Following that, there were 10 months of below-average rainfall before we experienced the eighth wettest March on record this year with 7.66 inches of rain.
“The bottom line is that in a changing climate, our rainfall patterns are more unstable. We have better chances of getting higher amounts of rainfall in storm events. We see that in our data, and we need to be preparing for those extreme rainfall events,” Widhalm said.
Can climate change effects be avoided?
We’re locked in to the effects of climate change for the near future.
“This is like a fast-moving train. You can apply the brakes, but we’re still going to slide a bit until we come to a complete stop,” she said. “Even if we were to apply the brakes today, that level of warming that’s baked into our system for the next 10, 20, 30 years is going to have to play out.”
But Widhalm said there is still time and opportunities to change the future to prevent climate change impacts getting even worse.
Doing that, though, would require change at a large scale.
“Individual efforts are important, but we need to be talking about global scale, national scale changes that are beyond any one of us as an individual,” she said.
According to the Massachusetts Institute of Technology, the fastest way to stop the buildup of carbon dioxide in the atmosphere is to stop adding more. That can be done by replacing fuels that emit high levels of carbon dioxide, like coal, oil and gas with alternative fuels, such as solar, wind or nuclear power.
Learn more about climate change
NASA has a climate change website that can answer many of the most important climate change questions, like how we know climate change is happening and its evidence, causes and effects.
To learn more about how climate change impacts will affect Indiana, check out the Indiana Climate Change Impacts Assessment, which has reports on how climate change will affect facets of Hoosier life including health, tourism, water availability and agriculture.
Indiana University’s Environmental Resilience Institute is also spearheading an effort to update the nearly decade-old assessment.
The Midwestern Regional Climate Center has data anyone can use to see how climate change has affected different states and areas around the Midwest.
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Mirror Indy reporter Enrique Saenz covers west Indianapolis. Contact him at 317-983-4203 or enrique.saenz@mirrorindy.org. Follow him on Bluesky at @enriquesaenz.bsky.social.
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