Earth and Planetary Sciences · Atmospheric Science
A study finds that the Arctic Ocean and Nordic Seas were sometimes largely isolated from the North Atlantic during past ice ages. The connection appears to have reopened rapidly as the ice ages ended, raising questions about effects on the global ocean circulation system.
A review of observations, computer models and climate records finds strong evidence that Antarctic sea ice affects ocean and atmospheric circulation, ice sheets, marine productivity and the carbon cycle. Records from the past glacial cycle show that sea-ice changes occurred alongside shifts in ocean circulation, ocean productivity and carbon, although their individual effects are difficult to separate.
A study finds that Antarctica is very likely to experience mass loss during the twenty-first century, even under aggressive emissions-reduction scenarios. Under very high emissions, Antarctic ice loss could contribute up to 25.4 centimetres of sea-level rise by 2100, although the estimate remains uncertain.
A study of fossil charcoal from a Palaeocene lake record identifies several phases of wildfire intensification during and after an ancient warming event. Early increases coincided with drying and the spread of flowering plants, but a later rise in fire activity appears to have been linked more to the type of vegetation available than to continued warming.
Researchers found that shallow, linear trenches on Australia’s Nullarbor Plain are surface signs of collapse and sagging above deep cave conduits. The findings provide criteria for distinguishing these subdued cave-collapse systems from fluvial or tectonic landforms.
Fossil coral communities in southern Okinawa preserve evidence of at least four relative sea-level cycles during the late Middle Pleistocene. The researchers identified seven coral groups linked to reef settings ranging from less than 5 meters to about 30 meters deep.
The Northern Patagonian Icefield could retain between 6% and 62% of its current volume by 2200, depending on future emissions. Researchers found that ice loss would accelerate from the middle of this century under climate-change scenarios.
The Devil’s Arrows, Britain’s tallest surviving standing stone alignment, were probably deliberately quarried at Brimham Rocks and transported about 18 kilometres, a study finds. The conclusion is based on matching geological age patterns, regional ice-flow evidence and similarities in surface weathering.
A sediment record from a lake in southern Iceland suggests its insect community remained broadly stable through two centuries of agricultural intensification. Statistical warning signs of growing instability increased, but the lake did not reach a detected ecological tipping point.
Sediments from Lakes Bolshoye Miassovo and Maloye Miassovo in Russia’s Southern Urals contain evidence of several past warming, cooling and drying events. The researchers linked changes in the sediments to regional and global climate stages, including a warming about 14,700 years ago and later dry periods.
Rare underwater observations at a retreating glacier in South Greenland found unexpectedly high biological activity at the point where ice meets the ocean. Zooplankton, fish and other organisms appeared to respond to glacier material, rather than mainly to deeper nutrient-rich water.
Researchers used an AI image-recognition system to identify benthic foraminifera, tiny seafloor organisms used to assess ecosystem quality. It identified species and, in one low-diversity setting, whether specimens were living or dead, reaching up to 94.2% accuracy.
Water stored beneath Glacier de Bonne Pierre may have contributed to the severe June 2024 flood at La Bérarde in the French Alps, a study finds. The researchers estimate that subglacial barriers could theoretically have held water on the order of 10^5 cubic metres, but observations cannot confirm that such pockets existed or drained.
