Those tired of cold summer days are about to get their wish. But they may get more than they bargained for if a study by Stanford scientists turns out to be true.

A recent climate study by Noah Diffenbaugh and Mark Shwartz found that parts of North America, Europe and China are likely to undergo “extreme summer temperature shifts” within the next 60 years.

Perhaps more alarming is the study also shows that many tropical regions in Asia, Africa and South America could see “the permanent emergence of unprecedented summer heat” within the next two decades.

“According to our projections, large areas of the globe are likely to warm up so quickly that, by the middle of this century, even the coolest summers will be hotter than the hottest summers of the past 50 years,” said Diffenbaugh, an assistant professor of environmental Earth system science and fellow at the Woods Institute for the Environment at Stanford.

To reach conclusions on the seasonal impacts of global warming, Diffenbaugh and Shwartz studied more than 50 climate model experiments.

When scientists talk about global warming causing more heat waves, people often ask if that means that the hottest temperature will become the new normal,” Diffenbaugh said. “That got us thinking – at what point can we expect the coolest seasonal temperatures to always be hotter than the historically highest temperatures for that season?”

The scientists ran computer simulations of the 21st century when global greenhouse gases are projected to increase and simulations that accurately predict the planet’s climate over the past 50 years to find their answers.

The experiments found that the tropics are heating up quicker than the rest of the planet. In that region, the findings show that up to 70 percent of seasons from 2010 to 2039 exceed the last 20th century maximum.

What this means is that the environment could have a dramatic impact on human health, ecosystem productivity and agriculture.

In the United States, the Midwest could see the temperature reduce the harvest of crops such as soybeans and corn by more than 30 percent.

The speed with which the temperature changes could impact the globe surprised the two Stanford scientists. But the two said they only used a moderate forecast of greenhouse gas emissions.

The findings are scheduled to be published later this month in the journal “Climate Change Letters.”