Arctic heatwave shatters Greenland, Iceland records; could hit monsoons

Hindustan Times

2 days ago

New Delhi : A record-shattering heatwave that sent Greenland's ice sheet melting at 17 times the normal rate was made 3°C hotter by the climate crisis, scientists said in an analysis on Wednesday, amid new data that also showed the past month to be second-warmest May on record.
The World Weather Attribution analysis concluded that the seven-day period of extreme heat in Iceland was about 3°C hotter due to climate change. Similar events could become a further 2°C more intense if global warming reaches 2.6°C, scientists warned.
The findings matched with data from the Copernicus Climate Change Service showing May this year to be the second-warmest globally on record, with an average surface air temperature of 15.79°C — 0.53°C above the 1991-2020 average.
The month was 1.4°C above the pre-industrial level and interrupted an extended 21-month phase of global temperatures exceeding 1.5°C above pre-industrial levels. However, the 12-month period from June 2024 to May 2025 remained 1.57°C above pre-industrial levels, the climate service said.
In eastern Greenland, the hottest day in May was about 3.9°C warmer compared to the pre-industrial climate, the World Weather Attribution analysis found. The climate-driven heat corresponded with melting of the Greenland ice sheet that was approximately 17 times higher than average for the period, according to preliminary analysis from the National Snow and Ice Data Center.
'This event is the largest May heatwave we have seen, even in weather stations going back more than a century,' said Halldór Björnsson, group leader at the Icelandic Meteorological Office.
The arctic circle climate phenomenon holds implications far beyond the polar region. Recent scientific papers have found that loss of Arctic ice can impact the South Asian monsoon, and it is linked to a rise in extreme rainfall events over South Asia.
In Iceland's automated monitoring system, which has operated for two to three decades, 94% of stations recorded new temperature records. At Stykkisholmur, which has reliable data spanning more than 174 years, temperature records were broken. 'What we are witnessing is not just an isolated event, but a change in weather statistics,' Björnsson added.
The Arctic region has warmed at more than double the global average in a phenomenon known as arctic amplification. This rapid warming is driven mainly by melting sea ice — as ice vanishes, it is replaced by expanding areas of dark ocean water that absorb sunlight instead of reflecting it. The early spring heat could impact people in Iceland with underlying health issues, while thinning sea ice threatens the safety and livelihoods of indigenous communities in Greenland, the analysis highlighted.
Climate change, caused primarily by burning fossil fuels, intensified the temperatures through carbon emissions that heat the planet. If warming reaches 2.6°C — expected by 2100 unless countries rapidly move away from oil, gas and coal — similar heatwaves are expected to become worse.
In May, sea surface temperatures remained unusually high across many ocean basins. Large areas in the northeast North Atlantic experienced a marine heatwave with record-high temperatures for the month. Most of the Mediterranean Sea was much warmer than average.
Implications for India
Research published in IOPScience on May 6 found that rapid Arctic sea-ice decline will lead to increased intense precipitation events across South Asia, exposing populations to disasters associated with extreme rain.
Scientists from the Indian Institute of Tropical Meteorology and the ministry of earth sciences investigated tropical rainfall responses to declining Arctic sea ice using observations and climate model simulations.
The study suggested that intense rain events like those recorded during Kerala's 2018 floods or Uttarakhand in 2013 will increase in frequency. Both events exceeded the threshold of 150mm rainfall per day over small areas that defines extreme rainfall events. The IOPScience research found observational evidence that periods with higher intense precipitation events — or spells of heavy rain — in South Asia are associated with declining June, July and August Arctic sea ice. Larger increases in extreme precipitation in recent decades often coincide with greater Arctic sea-ice loss.
'Observational evidence and idealised model experiments in which the Arctic becomes seasonally ice-free under greenhouse warming reveal association between Arctic sea-ice decline and intense precipitation events over South Asia,' the study concluded.
The enhanced Arctic sea-ice melt increases mid-latitude atmospheric patterns and intensifies circulation that strengthens subtropical high-pressure systems over East Asia. Combined with La Niña-like responses in the Pacific, this enhances mean summer monsoon rainfall over South Asia. 'Arctic sea-ice decline weakens upper atmospheric circulation and alters energetics, providing a favourable environment for moisture convergence and intense monsoon precipitation,' researchers concluded. 'As Arctic warming accelerates under greenhouse gas forcing, extreme precipitation events over South Asia are projected to increase.'
La Niña refers to large-scale cooling of ocean surface temperatures in the central and eastern equatorial Pacific, coupled with changes in tropical atmospheric circulation including winds, pressure and rainfall. In India, La Niña is associated with strong monsoons, above-average rains and colder winters, whilst El Niño brings harsher summers and weaker monsoons.
'There is now growing evidence that arctic sea ice melting can have a serious impact on Indian monsoon. Both observations and model simulations suggest this relationship. It will affect both the mean and extremes. The pathways are through mid latitude atmospheric waves and increase in El Nino southern oscillation frequency,' M Rajeevan, former secretary, ministry of earth sciences said responding to the MoES-led study.