There are hundreds of tents pitched under the sun's rays in downtown Phoenix. There are thousands of homeless people in the hottest big city in America.

There was a heat wave earlier this month and it was only June. Last year, the high temperature was 118 degrees.

Chris Medlock, a homeless Phoenix man known on the streets as "T-Bone" who carries everything he owns in a small backpack, said it's hard to find a place to sleep at night during the summer.

At a dining room where homeless people can get some shade and a free meal, Medlock said that if a kind soul could just offer a place on their couch indoors, more people would live.

The United States has more weather-related deaths due to excessive heat than any other country.

About half of the people who die in heat around the country are homeless.

Due to global warming, temperatures are rising nearly everywhere, and there are more heat waves. Some summers have been the hottest on record.

There are at least 130 homeless people in the county that includes Phoenix.

It would be considered a mass casualty event if 130 homeless people were to die in any other way.

With rising global temperatures, heat is no longer a danger just in places like Phoenix.

According to a seasonal map created for the International Research Institute at Columbia University, this summer will likely bring above-normal temperatures over most of the world.

Seattle residents were forced to sleep in their yards and on roofs during a heat wave last year. Several people presumed to be homeless have died outside in the state.

The first 24 hour cooling centers were opened in Oregon. People fanned out with water and Popsicles to homeless people.

The Pacific Northwest heat wave last year was almost impossible without human-caused climate change.

Boston is exploring ways to protect diverse neighborhoods like Chinatown, where population density and few shade trees can cause temperatures to go up to 106 degrees during the summer. Increasing tree canopy, using cooler materials for roofs, and expanding its network of cooling centers are some of the strategies the city plans to use.

It is not just a problem in the U.S. Exposure to extreme heat has tripled and now affects 25% of the world's population according to an AP analysis.

In Pakistan and India, homelessness is widespread due to lack of housing and discrimination. The high in Pakistan in May was 122 degrees.

It is not known how many people die from heat exposure in India because of poor reporting.

Since a heat wave killed tens of thousands of people in Europe in 2003 a number of European countries have opened cooling centers during the summer.

Ice packs and water are distributed by emergency service workers on bikes. 1,300 people die in Spain every summer because of health problems caused by excess heat.

Climate scientist David Hondula, who heads Phoenix's new office for heat mitigation, says that with such extreme weather now seen around the world, more solutions are needed to protect the vulnerable.

As temperatures continue to rise across the U.S. and the world, cities like Seattle, Minneapolis, New York or Kansas City that don't have the experience to deal with heat have to adjust.

A vacant building in Phoenix has been converted into a 200 bed shelter for homeless people.

Mac Mais was one of the first to arrive.

It can be difficult. Mais said that he stays in the shelters or anywhere he can find. I can stay out of the heat and rest.

In Las Vegas, teams deliver bottled water to homeless people living in camps around the county and inside a network of underground storm drain.

The first heat action plan in the South Asian region was designed in Gujarat, India.

Nongovernmental groups use its warning system to reach out to vulnerable people. Bus stops, temples and libraries are used as shelters for people to escape the sun's harmful rays.

The deaths are getting worse.

A homeless woman was severely burned in October 2020 while lying on a blacktop in Phoenix. Her cause of death wasn't investigated.

The young man known as "Twitch" died from heat exposure as he sat on a curb near a soup kitchen in the hours before it opened.

Jim Baker said that he was supposed to move into permanent housing on Monday. His mother was distraught.

Many such deaths are never confirmed as heat related because of the stigma of homelessness and lack of family connections.

When a mentally ill woman named Shawna Wright died in a hot alley in Salt Lake City, her death only became known when her family published an obituary saying the system failed to protect her during the hottest July on record.

Making it easier for homeless people to get permanent housing would help protect them from the summer heat.

She could get through it, that's what we thought of her. No one is strong enough for that heat.

That's right.

AP writers in Rome and Madrid contributed to the report.

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That's right.

More about AP's climate coverage can be found at http://www.apnews.com/climate.