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Historically low water level in two crucial US reservoirs threatens water and power for millions

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By Laura Paddison, CNN.  Excerpt: The combined water level in two of the United States’ biggest reservoirs, Lake Powell and Lake Mead, has fallen to a historic low, in what experts are calling a significant moment in the Colorado River crisis — threatening a water system that supplies tens of millions. On July 12, Lake Powell was at 3,524 feet and Lake Mead was just under 1,043 feet, breaking a record set in March 2023, according to an analysis published by five Colorado River experts last week. Together, the two reservoirs haven’t been this low since 1957, during the construction of the Glen Canyon Dam, before Lake Powell even existed. ...The Colorado River is the lifeblood of the Southwest. It irrigates more than 5 million acres of farmland, generates enough electricity to power around 700,000 homes and provides water for 40 million people. ...The Colorado River has shrunk rapidly over the past 25 years as water demand has boomed and climate change has delivered hotter, drier...
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Trump demands review of scientific manual used by federal judges

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By Benjamin S. Weiss , Courthouse News Service.  Excerpt: The president said the government-backed compendium of scientific and technological information, used to help judges ruling on complex cases, has been “totally discredited” and accused its authors of misleading the courts on climate change. ...Writing in a post on his social media platform Truth Social on Sunday evening, Trump said he had ordered “federal suspension and debarment officials” to review the National Academy of Sciences’ “Reference Manual on Scientific Evidence,” [RMSE] a decades-old publication produced in partnership with the Federal Judicial Center and aimed at assisting federal judges on issues of science and technology. ...The latest edition of the judicial reference manual, published late last year, included a chapter on climate science and climate change. ...But in February, the Federal Judicial Center, the government’s education and research agency serving federal courts, said it had removed the climate ...
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Big Trouble from Little Wetlands

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By Taylor Mitchell Brown , Eos/AGU.  Excerpt: Wetlands are the largest natural source of methane on Earth. Though the waterlogged lands offer benefits that include hosting thriving ecosystems and protecting our shorelines from flooding, researchers are eager to better understand their contribution to the warming climate. In a paper published in Nature Climate Change , researchers report that typical global wetlands surveys overlook an astronomical number of small wetlands : about 160 million of them. These small wetlands, which range in size from a large swimming pool to 100 hectares (250 acres), are responsible for 25% of the present global methane emissions, the research found. ...“Methane emission rates are positively related to the temperature,” said Li. As the global temperature increases, these methane-emitting microbes become more productive. “It’s like a snowball that gets bigger and bigger,” he said. Rising global temperatures likely triggered the increased emissions and w...
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The “Eternity Glaciers” Are Almost Gone

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By Emily Gardner , Eos/AGU.  Excerpt: The equatorial glaciers atop Puncak Jaya, Oceania’s tallest peak, have shrunk by about 95% since 2002, according to a new photogrammetry mapping effort. ... Past research has suggested that in 1850, about 18.8 square kilometers of Puncak Jaya were covered by glaciers. By 2002, that area had shrunk by 88.6%, to 2.14 square kilometers....  Full article at https://eos.org/articles/the-eternity-glaciers-are-almost-gone . 
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Climate scientists sharpen tools for linking global warming to extreme weather

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By Julia Vaz , Science.  Excerpt: June’s European heat wave, in which temperatures above 40°C led to the deaths of more than 10,000 people, made headlines not just for its severity, but for what it said about climate change. Last week, a group called World Weather Attribution (WWA) linked it firmly to global warming, saying such a heat wave would have been “virtually impossible” 50 years ago. It was a high-profile claim from a field called extreme event attribution, which seeks to gauge how global warming impacted a particular heat wave, flood, or storm. The field is still evolving, according to a report released today by the National Academies of Sciences, Engineering, and Medicine (NASEM). ...In the past decade, attribution science has advanced rapidly , with the annual number of studies more than doubling since 2012, according to the report. Better climate models, longer observational records, and more sophisticated statistical techniques have all improved researchers’ abiliti...
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These “Clumped” Molecules Could Offer Clues About Earth’s Climate

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By Emily Gardner , Eos/AGU.  Excerpt: Methane is one of the most abundant greenhouse gases on Earth, and, when compared with carbon dioxide, it is 28 times more potent at trapping heat in the atmosphere. ...New research examined several hundred liters of air gathered from compacted snow in Greenland... published today in Science Advances . As the climate warms, it’s increasingly urgent to understand where methane comes from. Researchers can analyze the ratios of different carbon isotopes within methane to learn whether that sample came from fossil fuels or from other sources, such as wetlands or agriculture. ...Higher anthropogenic emissions result in lower clumped methane concentrations. However, clumped methane molecules take many years to reach equilibrium, so an increase in methane emissions might not show up in the clumped isotope signal for decades. ... NOAA data show that atmospheric methane levels have risen since the 1980s, with a plateau from 1999 to 2006. The new st...
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As the Arctic warms, gray whale boom turns into a bust

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By Warren Cornwall , Science.  Excerpt: Whale CRC-2293 was once part of a celebrated revival, a member of a burgeoning population of gray whales ( Eschrichtius robustus ) in the eastern Pacific Ocean. The population, once depleted by commercial hunting to just a few thousand animals, had flourished following the 1980 moratorium on most whale hunts, to the point that it was deemed to no longer need protection under the U.S. Endangered Species Act. ...Since 2019, gray whales have been washing ashore in unusually high numbers as they migrate from Mexico, where they overwinter and give birth, some 8000 kilometers to their Arctic feeding grounds. The death toll slowed for several years. But in the past 2 years it has surged again toward record levels up and down the North American coast while overall populations have fallen to less than half their peak. Scientists are now predicting a sustained decline. The likely cause: ...“a fundamental regime shift in their feeding grounds in the Arc...
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