Study: Humidity, Not Heat Alone, Is Important in Measuring Climate Change
2022-02-07
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1A new study has found that water in the air, not just heat, is important in measuring global warming.
2The combination of increasing heat and humidity can lead to increased weather extremes.
3The researchers said, when considering humidity and heat, the temperature increase was two times greater than earlier estimates.
4The researchers said temperature by itself is not the best way to measure the effects of climate change.
5They said using temperature underestimates conditions in the tropical areas of the world.
6The study was published January 31 in the science publication Proceedings of the National Academy of Sciences.
7The research team noted that the energy created in extreme weather, such as storms, is related to the amount of water in the air.
8For this reason, the team of scientists decided to use a special atmospheric measurement.
9It is called equivalent potential temperature, or theta-e.
10The complex measurement is used to show the amount of heat in an area of air.
11It is expressed in a scientific measurement for temperature known as degrees Kelvin.
12Veerabhadran Ramanathan was one of the writers of the study.
13He is a climate scientist at the University of California San Diego's Scripps Institution of Oceanography.
14"There are two drivers of climate change: temperature and humidity," Ramanathan said.
15"And so far, we measured global warming just in terms of temperature."
16But by adding the energy from humidity, "the extremes - heat waves, rainfall and other measures of extremes - correlate much better," he said.
17Warm air can hold more water, or moisture, than cold air.
18For every degree Celsius that air temperature increases, it can hold seven percent more water.
19When the water vapor in the air becomes liquid, it releases heat or energy, "that's why when it rains, now it pours," Ramanathan said.
20He added that water vapor is a powerful heat-trapping gas in the atmosphere that increases climate change.
21From 1980 to 2019, the researchers said the average world surface air temperature increased by 0.79 degrees Celsius.
22But when they considered energy from humidity,
23the researchers found their temperature measurement had increased by 1.48 degrees Celsius.
24In the tropics, they said the warming was as much as 4 degrees Celsius.
25Ramanathan said when looking at surface air temperature, it appears that warming is strongest in North America, areas further from the tropics and at the poles.
26But that is not the case, he said.
27The high humidity in the tropics creates more storm activity, from normal storms to severe ocean storms.
28Donald Wuebbles is a climate scientist at the University of Illinois.
29He was not part of the study.
30But Wuebbles said the idea makes sense because water vapor is important in extreme rainfall.
31He said, "Both heat and humidity are important."
32Katharine Mach is an environmental scientist at the University of Miami.
33She also was not part of the study.
34Mach said humidity is important "in shaping the impacts of heat on human health and well-being, at present and into the future."
35I'm Gregory Stachel.
1A new study has found that water in the air, not just heat, is important in measuring global warming. 2The combination of increasing heat and humidity can lead to increased weather extremes. The researchers said, when considering humidity and heat, the temperature increase was two times greater than earlier estimates. 3The researchers said temperature by itself is not the best way to measure the effects of climate change. They said using temperature underestimates conditions in the tropical areas of the world. 4The study was published January 31 in the science publication Proceedings of the National Academy of Sciences. 5The research team noted that the energy created in extreme weather, such as storms, is related to the amount of water in the air. For this reason, the team of scientists decided to use a special atmospheric measurement. It is called equivalent potential temperature, or theta-e. The complex measurement is used to show the amount of heat in an area of air. It is expressed in a scientific measurement for temperature known as degrees Kelvin. 6Veerabhadran Ramanathan was one of the writers of the study. He is a climate scientist at the University of California San Diego's Scripps Institution of Oceanography. "There are two drivers of climate change: temperature and humidity," Ramanathan said. "And so far, we measured global warming just in terms of temperature." 7But by adding the energy from humidity, "the extremes - heat waves, rainfall and other measures of extremes - correlate much better," he said. 8Warm air can hold more water, or moisture, than cold air. For every degree Celsius that air temperature increases, it can hold seven percent more water. When the water vapor in the air becomes liquid, it releases heat or energy, "that's why when it rains, now it pours," Ramanathan said. 9He added that water vapor is a powerful heat-trapping gas in the atmosphere that increases climate change. 10From 1980 to 2019, the researchers said the average world surface air temperature increased by 0.79 degrees Celsius. But when they considered energy from humidity, the researchers found their temperature measurement had increased by 1.48 degrees Celsius. In the tropics, they said the warming was as much as 4 degrees Celsius. 11Ramanathan said when looking at surface air temperature, it appears that warming is strongest in North America, areas further from the tropics and at the poles. 12But that is not the case, he said. The high humidity in the tropics creates more storm activity, from normal storms to severe ocean storms. 13Donald Wuebbles is a climate scientist at the University of Illinois. He was not part of the study. But Wuebbles said the idea makes sense because water vapor is important in extreme rainfall. He said, "Both heat and humidity are important." 14Katharine Mach is an environmental scientist at the University of Miami. She also was not part of the study. Mach said humidity is important "in shaping the impacts of heat on human health and well-being, at present and into the future." 15I'm Gregory Stachel. 16Seth Borenstein reported this story for the Associated Press. Gregory Stachel adapted it for VOA Learning English. 17_______________________________________________________________ 18Words in This Story 19humidity - n. the amount of moisture in the air 20tropics - n. the part of the world that is near the equator where the weather is very warm 21correlate - v. to have a close connection with something 22vapor - n. a substance that is in the form of a gas or that consists of very small drops or particles mixed with the air 23pole - n. either end of the imaginary line around which something (such as the earth) turns 24impact - v. to have a strong and often bad effect on (something or someone) 25We want to hear from you. Write to us in the Comments section, and visit our Facebook page.