A few degrees of warming over the coming decades could trigger a series of extreme and fatal heat waves in India.

In recent years, the number of deaths has skyrocketed as a result of extreme heat on the subcontinent, according to a new study published yesterday in Science Advances. That's expected to get worse as rising temperatures worldwide bring more frequent heat waves. Deaths in India and in other countries where large numbers of people live in poverty will likely be a grim symbol of climate change, according to the study.

“As the temperature goes higher, the impact can potentially become exponentially worse, so this is something that is very serious, very important,” said Omid Mazdiyasni, a researcher at the University of California, Irvine, and a lead author of the paper.

The warming effect is expected to sharpen summer temperatures that already average between 90 and 97 degrees Fahrenheit, he said.

The study was released on the heels of President Trump's announcement that the United States will withdraw from the Paris Agreement. Trump also canceled U.S. payments to a fund that would help developing countries mitigate the worst effects of climate change and cope with its impacts.

The agreement, signed by 195 countries, is intended to reduce carbon dioxide emissions, a primary driver of climate change. India, like the United States, is one of the world's biggest polluters in terms of CO2 emissions, and it has been building coal-burning power plants at a rapid pace.

But it's also a case study in climate vulnerability. Tens of millions of Indians live in poverty. Heat waves killed 1,300 people there in 2010, 1,500 in 2013 and 2,500 in 2015, according to researchers. About a quarter of the country's population, totaling 1.3 billion people, doesn't have electricity and lives on less than $1.25 a day. Air conditioners are seen as a status symbol — a luxury of the middle class — and many of those most likely to die from heat have no way to keep cool.

The uptick in extreme heat waves was caused by a 0.5-degree-Celsius rise in mean temperature over recent decades, researchers found. During that period, subtly climbing temperatures meant an extreme heat wave was more than 1 ½ times as likely to occur and to kill at least 100 people. The high heat intensifies other factors that can harm human health, including drought, reduced crop yields and air quality issues, researchers found.

'Terrible' U.S. diplomacy

The study shows that what might seem like a relatively minor temperature increase has already had a disastrous consequence, driving home the reality that climate change is already placing lives at risk, Mazdiyasni said.

“With regard to the Paris Agreement, I think a lot of people think, 'Oh, 1 ½ degrees, 2 degrees, what is that? Is it a big difference or not, half a degree, is that a big change?'” he said. “Well, yeah, it is a huge change, and you can see what half a degree can do in our study, what the difference is.”

Trump said in his announcement last week that the Paris Agreement would have a “tiny, tiny” impact on warming.

“Even if the Paris Agreement were implemented in full, with total compliance from all nations, it is estimated it would only produce a two-tenths of 1 degree — think of that, this much — Celsius reduction in global temperature by the year 2100. Tiny, tiny amount,” he said, holding two fingers close together.

The projected temperature increase of 2.2 to 5.5 degrees Celsius by the end of the century could make parts of developing nations in Asia, the Middle East, Africa and South America “practically uninhabitable” during the summer months, the research released yesterday found.

“The impact of global climate change is not a specter on the horizon, it is real, it's being felt now all over the planet,” study co-author Amir AghaKouchak, an associate professor of civil and environmental engineering at the University of California, Irvine, said in a statement. “It is particularly alarming that the adverse effects are pummeling the world's most vulnerable populations.”

The United States has spent years working with India on climate change in particular, through 15 different programs that include resilience and adaptation, said Andrew Light, a distinguished senior fellow at the World Resources Institute who worked on climate change issues in India with the Obama administration.

He said the study illustrates the importance of the United States acting as a diplomatic ally in regions of the world that are not currently able to grapple with the profound shift that climate change will bring. He said pulling out of the Paris accord puts a fine point on the risks that arise when the Trump administration ignores the type of scientific findings laid out in the study. More diplomacy, not less, is needed to address the risks, he said.

“This is exactly what is going to hurt American foreign policy. This is going to be devastating to one of the countries in the world that we've got to hold very tight and prove we're a good ally to,” Light said. “This study will just confirm to them the threat they already know is there and will give them even more concern, and they can be sure the United States is not going to be an ally to them on this, and that is terrible.”

Reprinted from Climatewire with permission from E&E News. E&E provides daily coverage of essential energy and environmental news at www.eenews.net.