Atmospheric science

Summer 2024 was officially the Northern Hemisphere’s hottest on record. In the United States, fierce heat waves seemed to hit somewhere almost every day. Phoenix reached 100 degrees for more than 100 days straight. The 2024 Olympic Games started in the midst of a long-running heat wave in Europe that included the three hottest days on record globally, July 21-23. August was Earth’s hottest month in the National Oceanic and Atmospheric Administration’s 175-year record. Overall, the global average temperature was 2.74 degrees Fahrenheit (1.52 degrees Celsius) above the 20th-century average. That might seem small, but temperature increases associated with human-induced climate change do not manifest as small, even increases everywhere on the planet. Rather, they result in more frequent and severe episodes of heat waves, as the world saw in 2024. The most severe and persistent heat waves are often associated with an atmospheric pattern called a heat dome. As a...

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to curiouskidsus@theconversation.com. Can rainbows form in a circle? – Henry D., age 7, Cambridge, Massachusetts The legend goes that there is a pot of gold hidden at the end of every rainbow. But is there really an “end” to a rainbow, and can we ever get to it? Most us go through life seeing rainbows only as arches of color in the sky, but that’s only half of what is really a circle of color. Normally, when you look at a rainbow, the Earth’s horizon in front of you hides the bottom half of the circle. But if you are standing on a mountain where you can see both above and below you, and the sun is behind you and it is misty or has just rained, chances are good that you will see more of the rainbow’s circle....

If you’re feeling the misery of allergy season in your sinuses and throat, you’re probably wondering what nature has in store for you this time – and in the future. Pollen allergies affect over 30% of the global population, making them a significant public health and economic issue as people feel ill and miss work. Our research shows that, as greenhouse gases warm the planet, their effects are driving longer and more intense pollen seasons. To help allergy sufferers manage their symptoms in our changing climate, we’re building better pollen forecasts for the future. As atmospheric scientists, we study how the atmosphere and climate affect trees and plants. In a 2022 study, we found that the U.S. will face up to a 200% increase in total pollen this century if the world continues producing carbon dioxide emissions at a high rate. Pollen season in general will start up to 40 days earlier in the spring and last up to 19 days longer than today under that scen...

To get a sense of the enormous amount of water atmospheric rivers dumped on the Western U.S. this year and the magnitude of the flood risk ahead, take a look at California’s Central Valley, where about a quarter of the nation’s food is grown. This region was once home to the largest freshwater lake west of the Rockies. But the rivers that fed Tulare Lake were dammed and diverted long ago, leaving it nearly dry by 1920. Farmers have been growing food on the fertile lake bed for decades. This year, however, Tulare Lake is remerging. Runoff and snowmelt from the Sierra Nevada have overwhelmed waterways and flooded farms and orchards. After similar storms in 1983, the lake covered more than 100 square miles, and scientists say this year’s precipitation is looking a lot like 1983. Communities there and across the West are preparing for flooding and mudslide disasters as record snow begins to melt. Tulare Lake, long dry, begi...

Meteorologists began warning about severe weather with the potential for tornadoes several days before storms tore across the Southeast and the Central U.S. in late March 2023. At one point, more than 28 million people were under a tornado watch. But pinpointing exactly where a tornado will touch down – like the tornadoes that hit Rolling Fork, Mississippi, on March 24, and towns in Arkansas, Illinois and multiple other states on March 31 – still relies heavily on seeing the storms developing on radar. Chris Nowotarski, an atmospheric scientist, explains why, and how forecast technology is improving. Why are tornadoes still so difficult to forecast? Meteorologists have gotten a lot better at forecasting the conditions that make tornadoes more likely. But predicting exactly which thunderstorms will produce a tornado and when is harder, and that’s where a lot of severe weather research is focused today. Often, you’ll have a line of thunderstorms in an envi...