Children play with water at a fountain during a heat wave at Stavros Niarchos foundation Cultural Center in Athens on July 21. A new study finds these intense and deadly hot spells gripping much of the globe in the American Southwest and Southern Europe could not have occurred without climate change.Between the record-breaking global heat and extreme downpours, it’s hard to ignore that something unusual is going on with the weather in 2023.Human-caused global warming does play the biggest role.
That warms the atmosphere above, which influences temperatures and weather patterns around the globe. El Niño’s opposite, La Niña, involves cooler-than-usual Pacific currents flowing westward, absorbing heat out of the atmosphere, which cools the globe. June 2023 was the hottest in modern record. July saw global records for the hottest days and a large number of regional records, including an incomprehensible heat index of 152°F in Iran.The Sun may seem to shine at a constant rate, but it is a seething, churning ball of plasma whose radiating energy changes over many different time scales.On human time scales, however, the Sun’s energy output varies only slightly, about 1 part in 1,000, over a repeating 11-year cycle.
In an unusual twist, the largest volcanic eruption of the 21st century so far, the 2022 eruption of Tonga’s Hunga Tonga-Hunga Ha’apai is having a warming and not cooling effect. For example, humans have increased the amount of carbon dioxide in the atmosphere by 50 percent, primarily through combustion of fossil fuels in vehicles and power plants.