Thursday is the first official day of summer in theory, but in practice Kentuckians have already been feeling the heat.
Warmer days and longer summers are a symptom of rising temperatures across the planet and Kentucky too, is hotter than it used to be.
Kentucky’s average temperature increased 1.41 degrees over the last 30 years, according to the latest climate data analyzed by the Associated Press.
That’s less than the country’s average, but still enough to have wide-ranging impacts on ecosystems, human health and weather.
“Generally, increasing temperature, it increases your variability of weather and climate,” said James Noel, service coordination hydrologist with the National Weather Service’s Ohio River Forecast Center. "You can get wetter patterns, drier patters you can get. Just much more variability because you are changing the amount of energy available in the atmosphere.”
Over the last 30 years, the world’s annual temperature has warmed nearly a degree, according to the National Oceanic and Atmospheric Administration. At the same time, the earth’s polar regions have lost billions of tons of ice, contributing to sea level rise around the globe.
The Ohio Valley and the surrounding region have warmed, but not as fast as other regions in the country. Living near large bodies of water has helped regulate warming temperatures, Noel said.
“The big thing is our warming has been a little slower than in other parts of the country just because of our proximity to things such as the Great lakes, Hudson Bay,” he said.
Kentucky’s temperatures increased at a slightly lower rate than most other states in the country, ranking 15th out of 50 states for temperature increases.
Western Kentucky saw the largest increase over the 30-year time-span at 1.59 degrees — about the same as the country as a whole.
Meanwhile, Louisville saw in increase of about 1.46 degrees.
The trend will continue over the next two to three decades with temperatures warming about a half-degree per decade on average, Noel said.
After 2050 “It could actually increase a little more towards about a degree Fahrenheit change warming per 10 years,” he said.
Warming temperatures mean more hot summer days, higher likelihoods for droughts and an increased risk of large storms.
In the city, that means more high ozone days, which can increase the risk of asthma, respiratory infections and other health problems. It also means more electricity will be used as people run their air-conditioning longer.
More variability in weather will also affect crop production, said Margaret Carreiro, associate professor at the University of Louisville researching the ecology of cities.
“The warmer it is, the more evaporation happens from the soil, so the soils get drier,” she said. “So if it doesn’t rain at proper times and we can’t irrigate, then we are going to lose crops to that as well.”
Despite all of that, Carreiro said Kentucky is well-placed geographically, for the long-term effects of climate change.
“We still have a lot of farmland so we could become a bread basket of sorts for our region, if we don’t pave over all that good farmland,” she said.
