Indian Institute of Technology (Indian School of Mines), Dhanbad, 826004, India.
UFZ-Helmholtz Centre for Environmental Research, Leipzig, 04318, Germany.
Nat Commun. 2022 Sep 12;13(1):5349. doi: 10.1038/s41467-022-32942-5.
Increased occurrence of heatwaves across different parts of the world is one of the characteristic signatures of anthropogenic warming. With a 1.3 billion population, India is one of the hot spots that experience deadly heatwaves during May-June - yet the large-scale physical mechanism and teleconnection patterns driving such events remain poorly understood. Here using observations and controlled climate model experiments, we demonstrate a significant footprint of the far-reaching Pacific Meridional Mode (PMM) on the heatwave intensity (and duration) across North Central India (NCI) - the high risk region prone to heatwaves. A strong positive phase of PMM leads to a significant increase in heatwave intensity and duration over NCI (0.8-2 °C and 3-6 days; p < 0.05) and vice-versa. The current generation (CMIP6) climate models that adequately capture the PMM and their responses to NCI heatwaves, project significantly higher intensities of future heatwaves (0.5-1 °C; p < 0.05) compared to all model ensembles. These differences in the intensities of heatwaves could significantly increase the mortality (by ≈150%) and therefore can have substantial implications on designing the mitigation and adaptation strategies.
在世界不同地区，热浪的发生频率增加是人为变暖的特征之一。印度拥有 13 亿人口，是 5 月至 6 月期间经历致命热浪的热点地区之一，但导致此类事件的大规模物理机制和遥相关模式仍未得到很好的理解。在这里，我们使用观测数据和受控气候模型实验，证明了遥远的太平洋经向模态（PMM）对印度中北部（NCI）热浪强度（和持续时间）有显著影响——这是一个容易发生热浪的高风险地区。PMM 的强正相位导致 NCI 热浪强度和持续时间显著增加（0.8-2°C 和 3-6 天；p<0.05），反之亦然。目前一代（CMIP6）气候模型充分捕捉了 PMM 及其对 NCI 热浪的响应，预计未来热浪的强度将显著增加（0.5-1°C；p<0.05），与所有模型集合相比。热浪强度的这些差异可能会显著增加死亡率（增加约 150%），因此对制定缓解和适应策略具有重大意义。
