Standing on the ruins after the fire where his house had been, Peter Ruprecht admitted that he was not sure how or when to rebuild. He was still shocked by what Australia’s increasingly changeable climate had already delivered: first a drought, then a destructive bush fire, then a foot of rain from a storm.

“It’s unstoppable,” said Mr. Ruprecht, a former dairy farmer. “We speak about the warmth of Mother Nature, but nature can also be vicious and wild and unforgiving.”

Australia’s hellish(地狱的)fire season has eased(缓和),but its people are facing more than a single disaster. With floods destroying homes not far from where fires recently spread, they are facing a cycle of what scientists call “compound extremes”: one climate disaster strengthening the next.

Warmer temperatures do more than just dry out the land. They also heat up the atmosphere, which means clouds hold more moisture(水汽)for longer periods of time. So droughts get worse, giving way to fires, then to heavy rains that the land is too dry to absorb.

Many Australians in disaster zones complain that their government, after ignoring climate change for years, has not yet to draw up recovery plans that are clear and that take future threats into account.

At the same time, the economic costs of a changing climate are rising quickly. Philip Lowe, the governor of the Reserve Bank of Australia, warned recently that Australia was already paying a price, and that it would only go up.

For decades, climate scientists have named hurricanes and ranked them according to the damage. “Naming and categorizing (把……归类) heat waves is also a must,” states a newly formed international union, called the Extreme Heat Resilience Alliance. “Hurricanes get attention because they cause obvious physical damage,” says Jennifer Marlon, a climate scientist at Yale University. Heat waves, however, have less evident effects, since the primary damage is to human health.

Heat waves kill more people in the United States than any other weather-related disaster. Data from the National Weather Service show that from 1986 to 2019, there were 4,257 deaths as a result of heat. By comparison, there were fewer deaths by floods (2,907), tornadoes (2,203) or hurricanes (1,405) over the same period. What’s more, climate change is increasing the possibility of high temperature events worldwide, getting tens of thousands of people dying each year because of heat.

Some populations are particularly easily harmed by high heat, including people over 65 and those with potential medical conditions. Historical racial discrimination also puts minority communities at higher risk. Due to housing policies, they are more likely to live in urban areas, heat islands which lack green spaces that help cool down neighborhoods.

Part of the naming and ranking process will include defining exactly what a heat wave is. No single definition currently exists. Without a universally accepted definition of a heat wave, “We don’t have a common understanding of the danger we face,” says Aaron Bernstein, an expert of the new group. “Defined categories for heat waves could help local officials better prepare to deal with potential health problems in the face of rising temperatures. And naming and categorizing heat waves could increase public awareness of the health risks caused by these silent killers.”

The union is having conversations with the National Oceanic and Atmospheric Administration, the World Meteorological Organization and other institutions to develop a standard naming and ranking practice.

For parents in the Pacific Northwest, one constant fear is how safe their children will be at school if an earthquake strikes. Now, children at one school in the Stanwood-Camano School District in Washington State will get a warning ahead of time to take cover before the most sharp shaking begins.

Stanwood Elementary School is the first in the state to be able to send warnings over the loudspeaker before a large earthquake. The school has connected to the ShakeAlert early warning system, which is a system that gathers data from seismometers (地震仪) that can detect the earliest seismic (地震的) waves of an earthquake, sending warnings before the more powerful shaking hits.

Bill Steele, director of communications and outreach worker for the Pacific Northwest Seismic Network at the University of Washington, said the amount of warning students will get depends on where the earthquake happens.

“If it’s an earthquake on the Southern Whidbey Island Fault, it may only be a couple of seconds warning,” Steele said. “But if it’s an earthquake, say, on the Seattle Fault or the Cascadia Subduction Zone, you could have a warning of 20 or more seconds.”

Students across the state of Washington will practise earthquake safety this Thursday. Stanwood Elementary School will explain how it uses the public-address system to tell students to “drop, cover and hold on” after it receives a ShakeAlert.

“The main idea is to protect your head and get down so that you don’t get knocked over by the earthquake,” Steele said. “And then afterwards, teachers will decide whether they wish to make an orderly escape or not.”

“At least eight other school districts are exploring connecting to the ShakeAlert system,” Steele said. The earthquake warnings are not available to the general public now. Steele said the aim is to have that ready by October next year.