Climate science

Honolulu has lost more than 5 miles of its famous beaches to sea level rise and storm surges. Sunny-day flooding during high tides makes many city roads impassable, and water mains for the public drinking water system are corroding from saltwater because of sea level rise. The damage has left the city and county spending millions of dollars on repairs and infrastructure to try to adapt to the rising risks. Future costs will almost certainly be higher. More than US$19 billion in property value, at today’s dollars, is at risk by 2100 from projected sea level rise, driven by greenhouse gas emissions largely from the burning of fossil fuels. Elsewhere in Honolulu County, which covers all of Oahu, many coastal communities will be cut off or uninhabitable. Unwilling to have their taxpayers bear the full brunt of these costs, the city and county sued Sunoco LP, Exxon Mobil Corp. and other big oil companies in 2020. Their case – one of more than two dozen involving U.S. ci...

Cold spells often bring climate change deniers out in force on social media, with hashtags like #ClimateHoax and #ClimateScam. Former President Donald Trump often chimes in, repeatedly claiming that each cold snap disproves the existence of global warming. From a scientific standpoint, these claims of disproof are absurd. Fluctuations in the weather don’t refute clear long-term trends in the climate. Yet many people believe these claims, and the political result has been reduced willingness to take action to mitigate climate change. Sen. James Inhofe brought a snowball to the Senate floor in February 2015 to argue that because it was cold enough to snow in Washington, D.C., climate change wasn’t real. That year became the hottest on record and has since been surpassed. Why are so many people susceptible to this type of disinformation? My field, psychology, can help explain – and help people avoid being misled. The allure...

Atmospheric rivers, those long, powerful streams of moisture in the sky, are becoming more frequent in the Arctic, and they’re helping to drive dramatic shrinking of the Arctic’s sea ice cover. While less ice might have some benefits – it would allow more shipping in winter and access to minerals – sea ice loss also contributes to global warming and to extreme storms that cause economic damage well beyond the Arctic. I’m an atmospheric scientist. In a new study of the Barents-Kara Seas and the neighboring central Arctic, published Feb. 6, 2023, in Nature Climate Change, my colleagues and I found that these storms reached this region more often and were responsible for over a third of the region’s early winter sea ice decline since 1979. More frequent atmospheric rivers By early winter, the temperature in most of the Arctic is well below freezing and the days are mostly dark. Sea ice should be growing and spreading over a wider area. Yet the...

Over the past century, the Earth’s average temperature has swiftly increased by about 1 degree Celsius (1.8 degrees Fahrenheit). The evidence is hard to dispute. It comes from thermometers and other sensors around the world. But what about the thousands of years before the Industrial Revolution, before thermometers, and before humans warmed the climate by releasing heat-trapping carbon dioxide from fossil fuels? Back then, was Earth’s temperature warming or cooling? Even though scientists know more about the most recent 6,000 years than any other multimillennial interval, studies on this long-term global temperature trend have come to contrasting conclusions. To try to resolve the difference, we conducted a comprehensive, global-scale assessment of the existing evidence, including both natural archives, like tree rings and seafloor sediments, and climate models. Our results, published Feb. 15, 2023, suggest ways to improve climate forecasting to avoid missing some...

If you look back at the history of Atlantic hurricanes since the late 1800s, it might seem hurricane frequency is on the rise. The year 2020 had the most tropical cyclones in the Atlantic, with 31, and 2021 had the third-highest, after 2005. The past decade saw five of the six most destructive Atlantic hurricanes in modern history. Then a year like 2022 comes along, with no major hurricane landfalls until Fiona and Ian struck in late September. The Atlantic hurricane season, which ended on Nov. 30, had eight hurricanes and 14 named storms. It’s a reminder that small sample sizes can be misleading when assessing trends in hurricane behavior. There is so much natural variability in hurricane behavior year to year and even decade to decade that we need to look much further back in time for the real trends to come clear. Fortunately, hurricanes leave behind telltale evidence that goes back millennia. Two thousand years of this evidence indicates that the Atlantic has experie...