Phys.org December 17, 2024 Human-induced climate change, and other human activities in Antarctica and the Southern Ocean region are leading to several potential interacting tipping points with major and irreversible consequences. An international team of researchers (UK, Australia) examined eight potential physical, biological, chemical, and social Antarctic tipping points – Ice sheets, Ocean acidification, Ocean circulation, Species redistribution, Invasive species, Permafrost melting, Local pollution, and the Antarctic Treaty System. They discussed the nature of each potential tipping point, its control variables, thresholds, timescales, and impacts, and focused on the potential for cumulative and cascading effects because of their interactions. Their […]
Category Archives: Climatology
Wind alters snow crystals, impacting climate models
Phys.org December 16, 2024 Loose surface snow gets eroded and transported by wind, which influences the snow particles’ physical properties that determine the characteristics of the emerging wind-impacted snowpack layer. Researchers in Switzerland used cold-laboratory ring wind tunnel experiments to study the governing processes during airborne snow transport with stable water isotopes as tracers for these micro-scale processes. They documented the growing and rounding of snow particles with transport time, with a concurrent decrease in specific surface area and attributed this evolution to the process of airborne snow metamorphism. The changes showed a clear isotopic signature of metamorphic deposition, which […]
Scientist develops new equation to better predict behavior of atmospheric rivers
Phys.org November 4, 2024 Poleward water vapor transport in the midlatitudes mainly occurs in meandering filaments of intense water vapor transport, spanning thousands of kilometers long and hundreds of kilometers wide and moving eastward. The water vapor filaments, known as atmospheric rivers (ARs), can cause extreme wind gusts, intense precipitation, and flooding along densely populated coastal regions. Many recent studies about ARs focused on the statistical analyses of ARs, but a process-level understanding of ARs remains elusive. A team of researchers in the US (Argonne National Laboratory, University of Chicago) showed that ARs are streams of air with enhanced vapor […]
Scientists investigate contrail formation to reduce climate impact
Phys.org November 1, 2024 Aircraft contrails are important for aviation’s non-CO2 climate impact. An international team of researchers ( USA – Atmospheric Sciences Research Center, University at Albany, NASA Langley Research Center, Virginia, Germany) showed that the range of conditions for volatile plume particles to contribute significantly to the contrail ice number budget was likely determined by the sizes of primary soot particles rather than the effective sizes of soot aggregates. The smaller soot primary sizes compared to aggregate sizes delay the onset of contrail ice formation, increased the maximum plume supersaturation reached in the contrail plume, and thus increased […]
Study examines effects of Atlantic circulation on the Amazon rainforest
Phys.org November 4, 2024 The Atlantic meridional overturning circulation (AMOC) and the Amazon forest are viewed as connected tipping elements in a warming climate system. If global warming exceeds a critical threshold, the AMOC may slow down substantially, changing atmospheric circulation and leading to Amazonia becoming drier in the north and wetter in the south. An international team of researchers (Brazil, Morocco, Germany, Switzerland, the Netherlands, UK, France, China, USA – Keller Science Action Center) used pollen and microcharcoal data from a marine sediment core to assess changes in Amazon vegetation from 25,000 to 12,500 years ago and modeled vegetation […]
Melting Arctic sea-ice could affect global ocean circulation, study warns
Phys.org October 27, 2024 The Last Interglacial period (LIG) was characterized by a long-term Arctic atmospheric warming above the preindustrial level. The LIG thus provides a case study of Arctic feedback mechanisms of the cryosphere-ocean circulation-climate system under warm climatic conditions. Previous studies suggested a delay in the LIG peak warming in the North Atlantic compared to the Southern Ocean and evoked the possibility of southward extension of Arctic Sea ice to the southern Norwegian Sea during the early LIG. An international team of researchers (Norway, Germany) compiled new and published proxy data on past changes in sea ice distribution, […]
New ice core data provide insight into climate ‘tipping points’ during the last Ice Age
Phys.org October 22, 2024 Reconstructions of Earth’s past climate show evidence for instability and abrupt change, which are of great scientific and societal importance. The Dansgaard–Oeschger (DO) oscillation of the last Ice Age, which is most clearly observed in Greenland ice cores, is the prime example of such instability. An international team of researchers (Oregon State University, Pennsylvania State University, University of Miami, University of Colorado, Denmark, UK) presented ice-core records from south and coastal east Greenland to calibrate the local water isotope thermometer and provided a Greenland-wide spatial characterization of DO event magnitude. They used a series of idealized […]
The importance of wave modeling in predicting climate change’s effect on sea ice
Phys.org September 24, 2024 Researchers in Australia used a theoretical model to study water waves propagating into and through a region containing thin floating ice, for ice covers transitioning from consolidated (large floe sizes) to fully broken (small floe sizes). The degree of breaking was simulated by a mean floe length. The model predicted deterministic limits for consolidated and fully broken ice covers where the wave fields do not depend on the realization of the ice cover for a given mean floe length. The consolidated ice limit was consistent with classic flexural-gravity wave theory, and the fully broken limit was […]
Extreme weather to strengthen rapidly over next two decades, research suggests
Phys.org September 2024 While the magnitude of changes in mean and extreme climate are broadly studied, regional rates of change, a key driver of climate risk, have received less attention. Using large ensembles of climate model simulations an international team of researchers (Norway, UK) showed that nearly three quarters of the global population can expect strong and rapid changes in extreme temperatures and rainfall in the next 20 years unless greenhouse gas emissions are cut dramatically. Their research showed that 20% of the population could face extreme weather risks if emissions are cut enough to reach the aims of the […]
Earth’s oldest, tiniest creatures are poised to be climate change winners—and the repercussions could be huge
Phys.org August 14, 2024 Heterotrophic Bacteria and Archaea (prokaryotes) are a major component of marine food webs and global biogeochemical cycles. Yet, there is limited understanding about how prokaryotes vary across global environmental gradients, and how their global abundance and metabolic activity (production and respiration) may be affected by climate change. An international team of researchers (Australia, Spain, Austria, the Netherlands, Canada) used global datasets of prokaryotic abundance, cell carbon and metabolic activity to show that mean prokaryotic biomass varies by just under 3-fold across the global surface ocean, while total prokaryotic metabolic activity increases by more than one order […]