Summers are hot. But the heat waves around the world this summer have broken numerous records and are setting off alarms about what may lie ahead--especially if policymakers fail to get serious about reducing greenhouse gas emissions.

Here are a few of the numbers:

  • Los Angeles set an all-time high temperature record of 111°F on July 6.

  • Japan set a national temperature record of 106°F during a heat wave that followed deadly floods.

  • Ouargla, Algeria, may have set Africa's all-time highest temperature on July 5, with a reading of 124.3°F.

  • Quriyat, Oman, likely had the world’s hottest low temperature ever recorded on June 28, when the temperature failed to drop below 109°F.

  • Heat records have also fallen in Canada, the U.K., Ireland and France.

What’s cooking? The jet stream, the river of wind high above the Northern Hemisphere, has been weaker and wavier in the past few weeks, scientists say. Instead of pushing weather systems along as it usually does, it’s allowing the patterns to stagnate.

The heat wave searing northern Europe was made more than twice as likely by climate change, according to a rapid assessment by scientists. The result is preliminary, but they say the signal of climate change is “unambiguous,” according to an article in The Guardian.

Scientists have long predicted that global warming is ramping up the number and intensity of heat waves, with events even worse than the current one set to strike every other year by the 2040s. “The logic that climate change will do this is inescapable – the world is becoming warmer, and so heatwaves like this are becoming more common,” said Friederike Otto of the University of Oxford and part of the World Weather Attribution consortium that did the work.

"Near the Arctic, it's absolutely exceptional and unprecedented. This is a warning," said French heat wave expert Robert Vautard, who also worked on the study. "In many places, people are preparing for the past or present climate. But this summer is the future," he said.

“What has been really unusual in the Western U.S. this summer has been the sustained heat,” said Alex Hall, a UCLA climate scientist. “It really pulls water out of vegetation, and that sets up conditions for big fires.”

University of Arizona climate researcher and geographer Kevin Anchukaitis publicized several wildfire studies from the last 10 years that all show how and why global warming is making fires bigger, more destructive and longer-lasting. "Is climate change the only factor influencing wildland fire? No, of course not—but climate change is influencing area burned and fuel aridity," he wrote.

After a devastating 2017, California is facing an even tougher wildfire season this year. The state has reported 3,770 wildfires so far this year, up from 3,440 over the same period last year. The largest, the Carr Fire has destroyed more than 1,000 homes and killed six people. And the season has not yet reached its peak.

Anyone who’s wringing his hands about how much it would cost to speed up the transition to non-carbon energy sources should think about the tab that the heat waves and wildfires are running up. In England, as in almost all of Europe, growing patterns are changing. The drought has increased food prices, and staples may be in short supply this fall. In July, farmers had to fly in lettuce from overseas to meet contracts with supermarkets. One cargo firm said it flew in 30,000 heads of lettuce from Los Angeles during one hot July weekend alone. The drought in Ireland means that income for dairy farmers is likely to be cut in half this year, said Teagasc, the state’s farming advisory body.

Congress, over the past year, has passed a series of bills providing well over $100 billion in response to hurricanes, flooding, wildfires and other natural disasters, The Hill reported August 3.

The financial toll also includes health costs. A recent analysis of climate trends in several of South Asia’s biggest cities found that if current warming trends continued, by the end of the century, wet bulb temperatures — a measure of heat and humidity that can indicate the point when the body can no longer cool itself — would be so high that people directly exposed for six hours or more would not survive.

“These cities are going to become unlivable unless urban governments put in systems of dealing with this phenomenon and make people aware,” said Sujata Saunik, who served as a senior official in the Indian Ministry of Home Affairs and is now a fellow at the Harvard University School of Public Health. “It’s a major public health challenge.”

Excessive heat can lead to brain and kidney damage and cardiovascular stress, especially for those over 64. By the year 2099, even with economic growth and adaptation, 1.5 million more people will die each year around the world because of increased heat. By comparison, 1.25 million people died in 2013 in all traffic accidents world-wide. These findings came from an exhaustive new study by the Climate Impact Lab, a think tank based at the University of Chicago, and cited by Wall Street Journal columnist Greg Ip.

.More surprising, he wrote, is that temperate places fare worse, because they aren’t used to heat: In Seattle, a hot day is seven times deadlier than in Houston because fewer homes have air conditioning and people spend more time outdoors.

This summer’s heat waves and wildfires make it clearer than ever that the world’s second-largest emitter of greenhouse gases needs to take strong action. Most economists say the fastest, more efficient, and most effective step the United States can take is to adopt a national carbon fee. Tell those who represent you on Capitol Hill that you want them to support this commonsense approach.