There is hot, and then there is hot! Extreme heat is a period of high heat and humidity with temperatures above 90 degrees Fahrenheit for at least two to three days. Extreme heat is responsible for the highest number of annual deaths among all weather-related hazards (危害).

It’s not your imagination. Summers have been getting hotter and hotter with extreme heatwaves occurring earlier and more frequently. But why is this happening and can we better predict heatwaves in advance to give people time to prepare?

“Climate change is here and it’s already been changing human behavior and causing significant influence in the society. As global temperatures rise, historically excessive (过高的) temperatures are more likely to occur.” says Craig Ramseyer, an assistant professor who studies climate modeling in the department of geography at Virginia Tech.

Ramseyer says heatwaves are the most concerning because of the lack of attention they normally receive. “Hurricanes, tornadoes, and flash floods drive more media attention because of the natural attraction with the visual impact of those types of hazards. However, heat does not tend to be as attractive and it becomes very difficult to communicate the danger to the public,” said Ramseyer. “Around the world, more deaths occur due to extreme heat than from hurricanes, flooding, and drought combined. It impacts the most helpless of our citizens who do not have enough access to air conditioning, water, and other important resources.”

Since the Earth is running warmer than it used to, Ramseyer says that when these heatwave-related weather patterns take place, it results in higher extreme temperatures than we used to experience 30 years ago.

“As a global community, we need to decrease carbon emissions as soon as possible. We have rapidly developing technologies that are going to help advance the process, but the faster the better, there is no time to waste.”

Scientific reports show the destructive effects of climate change, but many scientists say it is important to remain positive. If the world continues to change, don’t give up, and we can still prevent some of the worst effects of climate change.

Recently, however, many scientists are dealing with the feeling of doom about climate change or “doomism.” Jacquelyn Gill is a climate scientist at the University of Maine. She says that around 2018 she noticed an increase in these “doomers,” or people who think that saving the earth is hopeless. They refuse to change their behavior or consider how they can work to prevent climate change.

The United Nation’s Intergovernmental Panel on Climate Change (IPCC) recently published its third report. This report explained the damage caused by the burning of traditional fuels, like oil and coal. New investments in traditional fuels and removal of forests for farming are preventing the world from helping stop climate change.

Anderson is the Environment Program Director for the United Nations. She says officials are trying to get people to take action because there is a climate crisis. Their goal is not to scare people into doing nothing.

“We are not doomed, but rapid action is absolutely essential. With every month or year that we delay action, climate change becomes more complex, expensive and difficult to overcome,” Andersen said.

The UN IPCC report stated that without fast and extreme measures to cut carbon pollution, the world is not likely to limit warming to 1.5 degrees Celsius. The global temperature has already increased by 1.1 degrees Celsius. After 1.5 degrees, climate change will quickly worsen causing environment to be in danger. It will cause an increase in weather disasters.

James Skea is a leader from the UN IPCC Report. “We don’t fall over the cliff at 1.5 degrees. Even if we were to go beyond 1.5, it doesn’t mean we throw up our hands in despair,” Skea said.

Michael Mann is a climate scientist at Pennsylvania State University. He says that scientists used to think Earth would continue to warm decades after we balance emissions. Balancing emissions to net zero means not creating more carbon in the atmosphere than oceans and forests can remove. New research suggests that it will only take a few years to decrease carbon levels in the air after we balance emissions.

Population and climate

The human population on Earth has grown to the point that it is having an effect on Earth’s atmosphere and ecosystems. Burning of fossil fuels, deforestation, urbanization, and cultivation of rice and cattle are increasing the concentration of carbon dioxide, nitrogen oxides and dust in the atmosphere. About 70 percent of the Sun’s energy passes through the atmosphere and strikes Earth’s surface. This radiation heats the surface of the land and ocean, and these surfaces then reradiate infrared radiation back into space. This allows Earth to avoid heating up too much. However, not all of the infrared radiation makes it into space; some is absorbed by gases in the atmosphere and is reradiated back to Earth’s surface. A greenhouse gas is one that absorbs infrared radiation and then reradiates some of this radiation back to Earth. Carbon dioxide and nitrogen oxides are greenhouse gases. In fact, without greenhouse gases in the atmosphere, scientists calculate that Earth would be about 33℃ cooler than it currently is.

The current concentration of carbon dioxide in the atmosphere is about 360 parts per million. Human activities are having a major influence on atmospheric carbon dioxide concentrations, which are rising so fast that current predictions made by scientists are that atmospheric concentrations of carbon dioxide will double in the next 50 to 100 years.

Some scientists predict that a doubling of carbon dioxide concentration will raise global temperatures anywhere between 1.4℃ and 4.5℃. The increase in temperature will not be uniform, with the smallest changes at the equator and changes two or three times as great at the poles. The local effects of these global changes are difficult to predict, but it is generally agreed that they may include alterations in ocean currents, increased winter flooding in some areas of the Northern Hemisphere, a higher incidence of summer drought in some areas, and rising sea levels, which may flood low-lying countries.