Global warming

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. People have been quick to blame climate change – and they’re right: human-caused global warming plays the biggest role. The weekslong heat wave that started in June 2023 in Texas, the U.S. Southwest and Mexico would have been virtually impossible without it, one study found. However, the extremes this year are sharper than anthropogenic global warming alone would be expected to cause. September temperatures were far above any previous September, and around 3.1 degrees Fahrenheit (1.75 degrees Celsius) above the preindustrial average, according to the European Union’s earth observation program. July was Earth’s hottest month on record, also by a large margin, with average global temperatures more than half a degree Fahrenheit (a third of a degree Celsius) above the previous record, set just a few years earli...

The water off South Florida is over 90 degrees Fahrenheit (32 Celsius) in mid-July, and scientists are already seeing signs of coral bleaching off Central and South America. Particularly concerning is how early in the summer we are seeing these high ocean temperatures. If the extreme heat persists, it could have dire consequences for coral reefs. Just like humans, corals can handle some degree of stress, but the longer it lasts, the more harm it can do. Corals can’t move to cooler areas when water temperatures rise to dangerous levels. They are stuck in it. For those that are particularly sensitive to temperature stress, that can be devastating. A transplanted coral in the Port of Miami that was healthy in early 2023 had bleached in the warm water by July 11, 2023. NOAA/University of Miami I lead the Coral Program at the National Oceanic and Atmospheric Administration’s Atlantic Oceanogra...

The blanket of wildfire smoke that spread across large parts of the U.S. and Canada in 2023 was a wake-up call, showing what climate change could feel like in the near future for millions of people. Apocalyptic orange skies and air pollution levels that force people indoors only tell part of the story, though. As global temperatures rise, fires are also spreading farther north and into the Arctic. These fires aren’t just burning in trees and grasses. New research on the exceptional Arctic fire seasons of 2019 and 2020 points to fires moving into the ground as well. These underground fires are known as “zombie fires,” and there are a number of reasons to worry about the trend. A volunteer fights ‘zombie’ peat fires in Siberia in 2020, a year when an estimated 100,000 square miles of forest, grassland and peatland burned, according to an International Association of Wildland Fire analysis. Alexa...

About 400,000 years ago, large parts of Greenland were ice-free. Scrubby tundra basked in the Sun’s rays on the island’s northwest highlands. Evidence suggests that a forest of spruce trees, buzzing with insects, covered the southern part of Greenland. Global sea level was much higher then, between 20 and 40 feet above today’s levels. Around the world, land that today is home to hundreds of millions of people was under water. Scientists have known for awhile that the Greenland ice sheet had mostly disappeared at some point in the past million years, but not precisely when. In a new study in the journal Science, we determined the date, using frozen soil extracted during the Cold War from beneath a nearly mile-thick section of the Greenland ice sheet. A brief look at the evidence beneath Greenland’s ice sheet and the lessons its holds. The timing – about 416,000 years ago, with largely ice-free conditions last...

Powerful storm systems that hit the U.S. Northeast starting July 9, 2023, dumped close to 10 inches of rain on New York’s Lower Hudson Valley in less than a day and sent mountain rivers spilling over their banks and into towns across Vermont. Vermont Gov. Phil Scott said he hadn’t seen rainfall like it since Hurricane Irene devastated the region in 2011. Extreme water disasters like this have disrupted lives in countries around the world in the past few years, from the Alps and Western Europe to Pakistan, India and Australia, along with several U.S. states in 2022 and 2023. The role of climate change is becoming increasingly evident in these types of deluges. Cars were stranded in floodwater on the campus of the United States Military Academy at West Point, N.Y., on July 10, 2023. U.S. Military Academy via AP Studies by scientists around the world show that the water cycle has been inte...