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As the Arctic's Winter Sea Ice Hits a New Record Low - What Happens Next?

2 months ago
The Washington Post reports that after months of polar darkness, the extent of sea ice blanketing the Arctic this winter "fell to the lowest level on record, researchers announced this week... the smallest maximum extent in the 47-year satellite record, according to the National Snow and Ice Data Center. "Since then, the ice has already begun to melt again." "Sea ice is acting like the old canary in the coal mine," Dartmouth University geophysicist Don Perovich said. "It's saying loud and clear that warming is occurring...." In the summer, when the sun's radiation shines down on the Arctic for 24 hours a day, the ice acts as a shield, reflecting more than half of the light that hits it back into space.... With so little sea ice in the Arctic this year, more sunlight will be able to reach the open ocean, which absorbs more than 90 percent of the radiation that hits it. This will further warm the region, accelerating ice melt and exposing even more water to the light. This feedback loop helps explain the rapid warming of the Arctic, and it is expected to lead to a complete lack of summer sea ice in the region within decades, [said explained Melinda Webster, a sea ice scientist at the University of Washington]. The consequences would be dire for seals, polar bears and other wildlife, which depend on a stable sea ice platform to birth their young and hunt for food. It would also expose miles of coastline to pounding ocean waves, accelerating the erosion that threatens to tip some communities into the sea. But the effects will also be felt in places far from the poles, Perovich said. Studies suggest that a complete loss of Arctic sea ice would raise global temperatures as much as adding a trillion tons of carbon dioxide to the atmosphere. Changes in the Arctic could also affect the jet stream, the river of winds that flows through the upper atmosphere, contributing to more extreme weather around the globe. "What happens in the Arctic doesn't stay in the Arctic," Perovich said. Earlier this year sea ice also fell 30% below the amount typical in the Antarctic prior to 2010, the researchers report. The total amount of sea ice on earth has now reached an all-time low, declining by more than a million square miles (2.5 million square kilometers) below the pre-2010 average. "Altogether, Earth is missing an area of sea ice large enough to cover the entire continental United States east of the Mississippi."

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EditorDavid

New Ubuntu Linux Security Bypasses Require Manual Mitigations

2 months ago
An anonymous reader shared this report from BleepingComputer: Three security bypasses have been discovered in Ubuntu Linux's unprivileged user namespace restrictions, which could be enable a local attacker to exploit vulnerabilities in kernel components. The issues allow local unprivileged users to create user namespaces with full administrative capabilities and impact Ubuntu versions 23.10, where unprivileged user namespaces restrictions are enabled, and 24.04 which has them active by default... Ubuntu added AppArmor-based restrictions in version 23.10 and enabled them by default in 24.04 to limit the risk of namespace misuse. Researchers at cloud security and compliance company Qualys found that these restrictions can be bypassed in three different ways... The researchers note that these bypasses are dangerous when combined with kernel-related vulnerabilities, and they are not enough to obtain complete control of the system... Qualys notified the Ubuntu security team of their findings on January 15 and agreed to a coordinated release. However, the busybox bypass was discovered independently by vulnerability researcher Roddux, who published the details on March 21. Canonical, the organization behind Ubuntu Linux, has acknowledged Qualys' findings and confirmed to BleepingComputer that they are developing improvements to the AppArmor protections. A spokesperson told us that they are not treating these findings as vulnerabilities per se but as limitations of a defense-in-depth mechanism. Hence, protections will be released according to standard release schedules and not as urgent security fixes. Canonical shared hardening steps that administrators should consider in a bulletin published on their official "Ubuntu Discourse" discussion forum.

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EditorDavid