The last time Greenland was green

+ science of rip currents; how to best work with ChatGPT US Edition - Today's top story: When Greenland was green: Ancient soil from beneath a mile of ice offers warnings for the future [View in browser]( US Edition | 21 July 2023 [The Conversation] [The Conversation]( Top headlines - [Daily life in Kyiv – a scholar of Eastern Europe reports]( - [Sweetener aspartame a ‘possible’ carcinogen – what to know]( - [How closely did you follow the news? Take our quiz to find out]( Lead story In the 1960s, at the height of the Cold War, the U.S. military operated one of its strangest covert bases. The base was constructed inside the Greenland ice sheet, more than 100 miles from the coast. Ice-lined tunnels held both military and scientific projects – including an ambitious effort to drill all the way through the ice sheet to the bedrock nearly a mile below. The ice core that scientists extracted provided new understanding about Earth’s past. But while the ice was extensively studied, several inches of soil from the end of the core was stashed away and largely forgotten. That soil core, recently rediscovered in a Danish freezer, is now revealing secrets about Earth’s history, including when the Greenland ice sheet last melted. Geoscientists Paul Bierman and Tammy Rittenour explain the techniques their team used to determine [the timing of Greenland’s last big meltdown and explain the warnings it holds about the future in a warming world](. [ [Get our Understanding AI series – four emails delivered over the course of a week, with experts explaining this confusing topic.]( ] Stacy Morford Environment + Climate Editor Water and sediment pour off the melting margin of the Greenland ice sheet. Jason Edwards/Photodisc via Getty Images [When Greenland was green: Ancient soil from beneath a mile of ice offers warnings for the future]( Paul Bierman, University of Vermont; Tammy Rittenour, Utah State University The soil sample was extracted in the 1960s from beneath nearly a mile of ice at one of the U.S military's most unusual bases. Environment + Energy - [Rip currents are dangerous for swimmers but also ecologically important – here’s how scientists are working to understand these ‘rivers of the sea’]( Emma Shie Nuss, University of Washington; Audrey Casper, University of Washington; Christine M. Baker, North Carolina State University; Melissa Moulton, University of Washington; Walter Torres, University of Washington Rip currents are a leading cause of near-shore drownings, but there are effective ways to survive one. And these phenomena also play important ecological roles that are an emerging research area. - [Is it really hotter now than any time in 100,000 years?]( Darrell Kaufman, Northern Arizona University Long before thermometers, nature left its own temperature records. A climate scientist explains how ongoing global warming compares with ancient temperatures. Science + Technology - [Gliding, not searching: Here’s how to reset your view of ChatGPT to steer it to better results]( James Intriligator, Tufts University ChatGPT can be very useful – if you shift how you view it. The first step is to stop thinking of it as a chatty search engine. Ethics + Religion - [How after-school clubs became a new battleground in the Satanic Temple’s push to preserve separation of church and state]( Charles J. Russo, University of Dayton The controversial – and often misunderstood – extracurricular groups tend to raise controversy. But under equal access laws, schools can’t discriminate against a club based on its point of view. Education - [Bluey teaches children and parents alike about how play supports creativity – and other life lessons]( Molly Scott, Temple University; Aria Gastón-Panthaki, Harvard University; Douglas Piper, Georgetown University The seven-minute episodes show characters dealing with difficult emotions like fear and grief through play. Politics + Society - [6 ways AI can make political campaigns more deceptive than ever]( David E. Clementson, University of Georgia Politicians and their campaigns use a lot of methods, including manipulation and deception, to persuade you to vote for them and give them money. AI promises to make those attempts more effective. - [In Kyiv, signs of the ongoing war are evident – but daily life continues uninterrupted as well]( Tatsiana Kulakevich, University of South Florida A scholar of Eastern Europe spent time talking with Ukrainians in Kyiv during a recent trip and observed that people are scarred from the war – but still determined to fight back against Russia. Health + Medicine - [WHO expert cancer group states that the sweetener aspartame is a possible carcinogen, but evidence is limited – 6 questions answered]( Paul D. Terry, University of Tennessee; Jiangang Chen, University of Tennessee; Ling Zhao, University of Tennessee An expert panel found a potential association with liver cancer, but too little research exists to assume a causal connection. For now, the WHO left current consumption guidelines unchanged. International - [Explainer: why was the winner of Thailand’s election blocked from becoming prime minister?]( Adam Simpson, University of South Australia Pita Limjaroenrat is clearly the people’s choice for prime minister. And under a more democratic system, he would already be sitting in the prime minister’s office. Trending on site - [As heat records fall, how hot is too hot for the human body?]( - [Exercise may or may not help you lose weight and keep it off – here’s the evidence for both sides of the debate]( - [First contact with aliens could end in colonization and genocide if we don’t learn from history]( The Conversation Quiz 🧠- Here’s a question from [this week’s edition:]( Former President Donald Trump is back in the hot seat. He announced on July 18 that he expects a grand jury to indict him for what? - A .Inciting the Jan. 6, 2021, attack on the U.S. Capitol - B. Illegal campaign fundraising - C. Mail fraud - D. 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