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. 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.”
Scientists spotted warning signs of a tipping point in 2021 and know that the Amoc has collapsed in the Earth’s past. “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 realise.”
The study, published in the journal Environmental Research Letters, analysed the standard models used by the Intergovernmental Panel on Climate Change (IPCC). The scientists were particularly concerned to find that in many models the tipping point is reached in the next decade or two, after which the shutdown of the Amoc becomes inevitable owing to a self-amplifying feedback.
As first reported by TorrentFreak, Apple is preventing downloads of the iTorrent app on iPhones in the EU. Developer Daniil “XITRIX” Vinogradov’s app was a popular BitTorrent client available from AltStore PAL, which is among the most popular third-party iOS app stores overseas. The company revoked the app developer’s ability to distribute apps on such third-party marketplaces. While Apple has historically banned torrent clients from iOS devices in the United States, the EU’s Digital Markets Act that went into effect last year requires Apple to allow apps from third-party stores to be installed by users.
According to TorrentFreak‘s reporting, the motivation behind the revocation of XITRIX’s alternative distribution rights is not yet certain. The publisher spoke directly with TorrentFreak and said that Apple never reached out to him about the matter. “I still have no idea if it was my fault or Apple’s, and their responses make no sense,” Vinogradov told TorrentFreak. Apple has responded to Vinogradov with a generic message about app store issues.
Shane Gill, the co-founder of AltStore PAL, told TorrentFreak that the company’s request for information from Apple has not resulted in it explaining its justification for the takedown. “I can confirm that we are in communication with Apple about this issue. We’ve told them what’s going wrong, and they said they’re looking into it, but we haven’t gotten any further information as of yet,” said Gill.
Today’s electric vehicle boom is tomorrow’s mountain of electronic waste. And while myriad efforts are underway to improve battery recycling, many EV batteries still end up in landfills.
A research team from MIT wants to help change that with a new kind of self-assembling battery material that quickly breaks apart when submerged in a simple organic liquid. In a new paper published in Nature Chemistry, the researchers showed the material can work as the electrolyte in a functioning, solid-state battery cell and then revert back to its original molecular components in minutes.
The approach offers an alternative to shredding the battery into a mixed, hard-to-recycle mass. Instead, because the electrolyte serves as the battery’s connecting layer, when the new material returns to its original molecular form, the entire battery disassembles to accelerate the recycling process.
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To simplify the recycling process, the researchers decided to make a more sustainable electrolyte. For that, they turned to a class of molecules that self-assemble in water, named aramid amphiphiles (AAs), whose chemical structures and stability mimic that of Kevlar. The researchers further designed the AAs to contain polyethylene glycol (PEG), which can conduct lithium ions, on one end of each molecule. When the molecules are exposed to water, they spontaneously form nanoribbons with ion-conducting PEG surfaces and bases that imitate the robustness of Kevlar through tight hydrogen bonding. The result is a mechanically stable nanoribbon structure that conducts ions across its surface.
“The material is composed of two parts,” Cho explains. “The first part is this flexible chain that gives us a nest, or host, for lithium ions to jump around. The second part is this strong organic material component that is used in the Kevlar, which is a bulletproof material. Those make the whole structure stable.”
When added to water, the nanoribbons self-assemble to form millions of nanoribbons that can be hot-pressed into a solid-state material.
“Within five minutes of being added to water, the solution becomes gel-like, indicating there are so many nanofibers formed in the liquid that they start to entangle each other,” Cho says. “What’s exciting is we can make this material at scale because of the self-assembly behavior.”
The team tested the material’s strength and toughness, finding it could endure the stresses associated with making and running the battery. They also constructed a solid-state battery cell that used lithium iron phosphate for the cathode and lithium titanium oxide as the anode, both common materials in today’s batteries. The nanoribbons moved lithium ions successfully between the electrodes, but a side-effect known as polarization limited the movement of lithium ions into the battery’s electrodes during fast bouts of charging and discharging, hampering its performance compared to today’s gold-standard commercial batteries.
“The lithium ions moved along the nanofiber all right, but getting the lithium ion from the nanofibers to the metal oxide seems to be the most sluggish point of the process,” Cho says.
When they immersed the battery cell into organic solvents, the material immediately dissolved, with each part of the battery falling away for easier recycling. Cho compared the materials’ reaction to cotton candy being submerged in water.
“The electrolyte holds the two battery electrodes together and provides the lithium-ion pathways,” Cho says. “So, when you want to recycle the battery, the entire electrolyte layer can fall off naturally and you can recycle the electrodes separately.”
Validating a new approach
Cho says the material is a proof of concept that demonstrates the recycle-first approach.
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Cho also sees a lot of room for optimizing the material’s performance with further experiments.
Now, the researchers are exploring ways to integrate these kinds of materials into existing battery designs as well as implementing the ideas into new battery chemistries.
