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Collapse of Critical Atlantic Current Is No Longer Low-Likelihood, Study Finds

2 months 1 week ago
An anonymous reader quotes a report from The Guardian: The collapse of a critical Atlantic current can no longer be considered a low-likelihood event, a study has concluded, making deep cuts to fossil fuel emissions even more urgent to avoid the catastrophic impact. The Atlantic meridional overturning circulation (Amoc) is a major part of the global climate system. It brings sun-warmed tropical water to Europe and the Arctic, where it cools and sinks to form a deep return current. The Amoc was already known to be at its weakest in 1,600 years as a result of the climate crisis. Climate models recently indicated that a collapse before 2100 was unlikely but the new analysis examined models that were run for longer, to 2300 and 2500. These show the tipping point that makes an Amoc shutdown inevitable is likely to be passed within a few decades, but that the collapse itself may not happen until 50 to 100 years later. The research found that if carbon emissions continued to rise, 70% of the model runs led to collapse, while an intermediate level of emissions resulted in collapse in 37% of the models. Even in the case of low future emissions, an Amoc shutdown happened in 25% of the models. Scientists have warned previously that Amoc collapse must be avoided "at all costs." It would shift the tropical rainfall belt on which many millions of people rely to grow their food, plunge western Europe into extreme cold winters and summer droughts, and add 50cm to already rising sea levels. The new results are "quite shocking, because I used to say that the chance of Amoc collapsing as a result of global warming was less than 10%," said Prof Stefan Rahmstorf, at the Potsdam Institute for Climate Impact Research in Germany, who was part of the study team. "Now even in a low-emission scenario, sticking to the Paris agreement, it looks like it may be more like 25%. "These numbers are not very certain, but we are talking about a matter of risk assessment where even a 10% chance of an Amoc collapse would be far too high," added Rahmstorf. "We found that the tipping point where the shutdown becomes inevitable is probably in the next 10 to 20 years or so. That is quite a shocking finding as well and why we have to act really fast in cutting down emissions." "Observations in the deep [far North Atlantic] already show a downward trend over the past five to 10 years, consistent with the models' projections," said Prof Sybren Drijfhout, at the Royal Netherlands Meteorological Institute, who was also part of the team. "Even in some intermediate and low-emission scenarios, the Amoc slows drastically by 2100 and completely shuts off thereafter. That shows the shutdown risk is more serious than many people realize." The findings have been published in the journal Environmental Research Letters.

Read more of this story at Slashdot.

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Mastodon Says It Doesn't 'Have the Means' To Comply With Age Verification Laws

2 months 1 week ago
Mastodon says it cannot comply with Mississippi's new age verification law because its decentralized software does not support age checks and the nonprofit lacks resources to enforce them. "The social nonprofit explains that Mastodon doesn't track its users, which makes it difficult to enforce such legislation," reports TechCrunch. "Nor does it want to use IP address-based blocks, as those would unfairly impact people who were traveling, it says." From the report: The statement follows a lively back-and-forth conversation earlier this week between Mastodon founder and CEO Eugen Rochko and Bluesky board member and journalist Mike Masnick. In the conversation, published on their respective social networks, Rochko claimed, "there is nobody that can decide for the fediverse to block Mississippi." (The Fediverse is the decentralized social network that includes Mastodon and other services, and is powered by the ActivityPub protocol.) "And this is why real decentralization matters," said Rochko. Masnick pushed back, questioning why Mastodon's individual servers, like the one Rochko runs at mastodon.social, would not also be subject to the same $10,000 per user fines for noncompliance with the law. On Friday, however, the nonprofit shared a statement with TechCrunch to clarify its position, saying that while Mastodon's own servers specify a minimum age of 16 to sign up for its services, it does not "have the means to apply age verification" to its services. That is, the Mastodon software doesn't support it. The Mastodon 4.4 release in July 2025 added the ability to specify a minimum age for sign-up and other legal features for handling terms of service, partly in response to increased regulation around these areas. The new feature allows server administrators to check users' ages during sign-up, but the age-check data is not stored. That means individual server owners have to decide for themselves if they believe an age verification component is a necessary addition. The nonprofit says Mastodon is currently unable to provide "direct or operational assistance" to the broader set of Mastodon server operators. Instead, it encourages owners of Mastodon and other Fediverse servers to make use of resources available online, such as the IFTAS library, which provides trust and safety support for volunteer social network moderators. The nonprofit also advises server admins to observe the laws of the jurisdictions where they are located and operate. Mastodon notes that it's "not tracking, or able to comment on, the policies and operations of individual servers that run Mastodon." Bluesky echoed those comments in a blog post last Friday, saying the company doesn't have the resources to make the substantial technical changes this type of law would require.

Read more of this story at Slashdot.

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