The India Meteorological Department last week released its long-range forecast for this year’s monsoon. According to the IMD’s projections, the 2021 southwest monsoon season that begins in June and extends to the end of September is likely to be normal at 98% of the Long Period Average (LPA) of 88 cm. In terms of spatial distribution, while most regions in the country are expected to receive “normal” amounts of rain, the northeast and eastern regions could be in store for below-normal rainfall in the season. This is the third year “normal” monsoon year in a row, however recent years have also seen an increasing trend of extreme rain events concentrated over short time periods.
Global warming dominating monsoon dynamics in India, monsoons to be more chaotic
A new research paper has warned that summer monsoons in India will become stronger and more erratic unless tight reins are put on global warming. The Potsdam Institute for Climate Impact Research-led study analysed long-term trends of the Indian summer monsoon and its variability based on 32 models of the latest climate model generation(CMIP6). CMIP6 comprises the results from around 100 different climate models being produced across 49 different modelling groups. A majority of the climate models (28 out of 32) estimated that the increase in precipitation will be more prominent in the Himalayan region, northeast of the Bay of Bengal and in the Western Ghats. However individual models suggest decreasing rainfall along the southwest coast of India and around Myanmar.
Oceans locked-in to a fourfold increase in oxygen loss
The rise in temperatures is causing oxygen loss in the world’s oceans. Over the past half century, around 2% of the total oxygen inventory is estimated to have been lost due to the effects of global warming on the solubility of gases, ocean circulation and vertical mixing in oceans. New modelling from the GEOMAR Helmholtz Centre for Ocean Research, published in Nature Communications, shows that a fourfold increase ocean deoxygenation may be locked-in even if all CO2 emissions were stopped immediately. According to the model results, the deep ocean is currently committed to lose more than 10% of its pre-industrial oxygen content over centuries. At the surface though, ongoing deoxygenation will largely stop once CO2 emissions are stopped, the model shows. The projections are especially worrying since the availability of dissolved oxygen is a critical factor in maintaining life in the oceans, and continued oxygen loss is likely to have protracted implications on ocean biodiversity.
New research shines light on accelerating permafrost collapse in the Tibetan Plateau
New research assessing the changes in the extent of permafrost cover across the Eastern Tibetan Plateau has flagged rapidly increasing area of permafrost collapse. According to the analysis, conducted with combined data from in situ measurements, unmanned aerial vehicles (UAV), manned aerial photographs, and satellite images, the area of collapsed permafrost across the Eastern Tibetan Plateau increased by a factor of 40 between 1969 and 2017. Further, around 70% of the total collapsed area identified by the authors have formed post-2004. “These widespread perturbations to the Tibetan Plateau permafrost could trigger changes in local ecosystem state and amplify large-scale permafrost climate feedbacks”, warned the authors. Although the Tibetan Plateau is a major part of the third-largest repository of fresh water in the world, it is also one of the least studied regions in the world.
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