Arctic weather spells influenced India’s rains

A climate reconstruction study published in the ‘Global and Planetary Change’ finds that warm and cold climatic spells in the Arctic, over the past 1000 years, imprinted on India’s monsoon fluctuations during that period, as highlighted by a Mongabay-India report. The report says that the frigid Arctic is a key indicator of the ongoing shifts in Earth’s climate because it is warming two to three times faster than the global average and losing its sea ice cover.

The study’s Introduction states that high-latitude climate variabilities are interlinked to changes in the lower latitude regions. Arctic and sub-Arctic regions, in particular, are known to affect large-scale tropical circulations, such as the Indian monsoon system, and vice versa. Analysis of both instrumental and simulated climate data during the modern era reveals a multi-decadal association between warm (cold) episodes in the northern high latitude region and strong (weak) Indian summer monsoon, driven primarily by the warm and cold phases.

As the Mongabay-India report points out, in the study, scientists have reconstructed the past 1000 years of climate history from the Arctic, a region that’s warming faster than any other place on the planet and have detected warm and cold climatic spells in the Arctic over the past 1000 years. Warm Arctic conditions were linked to intense rainfall over the Indian subcontinent while cold conditions in the Arctic were associated with weak spells of rain over the Indian subcontinent over the past 1000 years, say scientists at India’s National Centre for Polar and Ocean Research (NCPOR). In collaboration with Norwegian counterparts, they reconstructed the past climate history from the Arctic region that’s warming faster than any other place on the planet. The scientists say the Arctic’s influence on the short-term changes in the Indian monsoon may become more pronounced as the region experiences further warming due to human actions.

Warm/cold Arctic spells most likely modified the temperature profile of the Tibetan Plateau. The Plateau is an elevated heat source to the atmosphere because of its height and can influence monsoons by influencing the prevailing North-South temperature difference that exists in many forms during the monsoon- such as the land-sea temperature contrast. Both natural and anthropogenic factors influenced the warm and cold spells, researchers said, as quoted by Mongabay-India. The frigid Arctic is a key indicator of the ongoing shifts in Earth’s climate because it is warming two to three times faster than the global average and losing its sea ice cover. In collaboration with Norwegian counterparts, they reconstructed the past climate history from the Arctic region that’s warming faster than any other place on the planet. The scientists say the Arctic’s influence on the short-term changes in the Indian monsoon may become more pronounced as the region experiences further warming due to human actions.

The Mongabay-India report points out that the Arctic is one of the batteries feeding the variations in Indian monsoons, over 7000 kilometres away. It highlights another 2018 study, where researchers showed accelerated glacial melting at Kongsfjorden post 1970s. Changes in remote Arctic such as glacial and sea ice melting, affect Indian monsoons as they contribute to its year-to-year variability that translates into devastating floods and droughts. Quoting another recent paper published in the ‘Journal of Climate’, the report states that researchers at the University of Gothenburg argue that the rate of warming will be much faster than projected but “climate models used by the UN’s IPCC and others to project climate change are not accurately reflecting what the Arctic’s future will be.”

The Introduction of the study published in the ‘Global and Planetary Change’ further points out that there is a lack of detailed and quantitative examination of potential causal mechanisms, including non-tropical factors. As a result, studies investigating the link between the Arctic climate and the Indian monsoon during the last millennium are scarce. This work presents a multi-decadal record of paleoenvironmental changes from an Arctic fjord during the last millennium. We then use our reconstruction to compare the relative strength of the Indian summer monsoon during contrasting climatic stages at the study site. High Arctic fjords are some of the most climate-sensitive regions globally due to their distinct glacial-marine landscape and strong biophysical coupling. In addition to high climate sensitivity, these locations have substantially higher sediment accumulation rates, making them ideal for Arctic paleoenvironmental research and their implications towards lower latitude climate.