Heat is a killer—and climate (气候) change is driving up its body count. According to a new study, about 37 percent of heat deaths can be tied back to climate change.

The study looked at data (数据) from 732 places in 43 countries, from 1991 — 2018. They used information collected from those places to count how many deaths were caused by climate change. The numbers differed depending on places, with a larger number of climate-change related (相关的) deaths happening in warmer countries than cooler ones.

In all, about 166,000 people died of heat between 1998 and 2017. Thanks to climate change, more people are being exposed to heat waves than ever before.

But while hundreds of places were included in this new study, many areas of Africa and Southeast Asia were not, because there wasn’t data of these places. Collecting that information in the future will be extremely important for new efforts to create a global accounting of heat-related deaths and illnesses.

“The countries where we do not have the necessary health data are often among the poorest and easiest to be affected by climate change,” climate change researcher Dann Mitchell wrote in an article. “Getting these data will be key for science to provide the information needed to help these countries adapt (适应). ”

“We are thinking about these problems of climate change as something that the next generation will face,” said Ana Maria, the lead author of the paper. “It’s something we are facing already. We are throwing stones at ourselves. ”

That’s in line with other research, which has found that climate change is already a disaster for human health. Older people are especially easy to be affected. Some areas of the planet are getting hit worse than others, with extreme conditions happening even more often than expected.

Escaping predators (食肉动物), digestion and other animal activities—including those of humans—require oxygen. But that essential ingredient is no longer so easy for marine life to obtain, several new studies reveal.

In the past decade ocean oxygen levels have taken a dive—an alarming trend that is linked to climate change, says Andreas Oschlies, an oceanographer at the Helmholtz Center for Ocean Research in Germany, whose team tracks ocean oxygen levels worldwide. “We were surprised by the intensity of the changes we saw, how rapidly oxygen is going down in the ocean and how large the effects on marine ecosystems are,” he says. It is no surprise to scientists that warming oceans are losing oxygen, but the scale of the drop calls for urgent attention. Oxygen levels in some tropical (热带的) regions have dropped by an astonishing 40 percent in the last 50 years, some recent studies reveal. Levels have dropped less significantly elsewhere, with an average loss of 2 percent globally.

A warming ocean loses oxygen for two reasons: First, the warmer a liquid becomes, the less gas it can hold. That is why carbonated drinks go flat faster when left in the sun. Second, as polar sea ice melts, it forms a layer of water above colder, more salty sea waters. This process creates a sort of lid that can keep currents from mixing surface water down to deeper depths. And because all oxygen enters the surface, less mixing means less of it at depth.

Ocean animals large and small, however, respond to even slight changes in oxygen by seeking refuge in higher oxygen zones or by adjusting behavior, Oschlies and others in his field have found. These adjustments can expose animals to new predators or force them into food-scarce regions. Climate change already poses serious problems for marine life, such as ocean acidification, but deoxygenation is the most pressing issue facing sea animals today, Oschlies says. After all, he says, “they all have to breathe.”

Aside from food web problems, animals face various other physiological challenges as their bodies adjust to lower oxygen levels. Chinese shrimp (虾) move their tails less vigorously to preserve energy in lower oxygen environments. Some creatures, such as jellyfishes, are more tolerant of low oxygen than others are. But all animals will feel the impact of deoxygenation because they all have evolved their oxygen capacity for a reason, says Oschlies. “Any drop in oxygen is going to damage survivability and performance,” he says.