School of Natural Sciences (SNS), National University of Sciences and Technology (NUST), Islamabad, Pakistan.
Global Change Impact Studies Centre (GCISC), Ministry of Climate Change, Islamabad, Pakistan.
PLoS One. 2022 Jul 27;17(7):e0271626. doi: 10.1371/journal.pone.0271626. eCollection 2022.
Climate extremes, such as heat waves, droughts, extreme rainfall can lead to harvest failures, flooding and consequently threaten the food security worldwide. Improving our understanding about climate extremes can mitigate the worst impacts of climate change and extremes. The objective here is to investigate the changes in climate and climate extremes by considering two time slices (i.e., 1962-1990 and 1991-2019) in all climate zones of Pakistan by utilizing observed data from 54 meteorological stations. Different statistical methods and techniques were applied on observed station data to assess changes in temperature, precipitation and spatio-temporal trends of climatic extremes over Pakistan from 1962 to 2019. The Mann-Kendal test demonstrated increasing precipitation (DJF) and decreasing maximum and minimum temperatures (JJA) at the meteorological stations located in the Karakoram region during 1962-1990. The decadal analysis, on the other hand, showed a decrease in precipitation during 1991-2019 and an increase in temperature (maximum and minimum) during 2010-2019, which is consistent with the recently observed slight mass loss of glaciers related to the Karakoram Anomaly. These changes are highly significant at 5% level of significance at most of the stations. In case of temperature extremes, summer days (SU25) increased except in zone 4, TX10p (cold days) decreased across the country during 1962-1990, except for zones 1 and 2. TX90p (warm days) increased between 1991-2019, with the exception of zone 5, and decreased during 1962-1990, with the exception of zones 2 and 5. The spatio-temporal trend of consecutive dry days (CDD) indicated a rising tendency from 1991 to 2019, with the exception of zone 4, which showed a decreasing trend. PRCPTOT (annual total wet-day precipitation), R10 (number of heavy precipitation days), R20 (number of very heavy precipitation days), and R25mm (very heavy precipitation days) increased (decreased) considerably in the North Pakistan during 1962-1990 (1991-2019). The findings of this study can help to address some of the sustainable development goals related climate action, hunger and environment. In addition, the findings can help in developing sustainable adaptation and mitigation strategies against climate change and extremes. As the climate and extremes conditions are not the uniform in all climate zone, therefore, it is suggested to the formers and agriculture department to harvest crops resilient to the climatic condition of each zone. Temperature has increasing trend in the northern Pakistan, therefore, the concerned stakeholders need to make rational plans for higher river flow/flood situation due to snow and glacier melt.
气候极端事件，如热浪、干旱、极端降雨，可能导致歉收、洪水泛滥，并因此威胁到全球粮食安全。更好地了解气候极端事件可以减轻气候变化和极端事件的最坏影响。本研究的目的是通过利用来自 54 个气象站的观测数据，在巴基斯坦所有气候区考虑两个时间切片（即 1962-1990 年和 1991-2019 年），来研究气候和气候极端事件的变化。利用不同的统计方法和技术对观测站数据进行了分析，以评估 1962 年至 2019 年期间巴基斯坦气候极端事件的温度、降水和时空趋势变化。Mann-Kendal 检验表明，在 1962-1990 年期间，喀喇昆仑地区的气象站的降水（12 月至 2 月）增加，最高和最低温度（6 月至 8 月）减少。另一方面，年代际分析表明，1991-2019 年期间降水减少，2010-2019 年期间温度（最高和最低）增加，这与最近观察到的喀喇昆仑异常相关的冰川轻微质量损失一致。在大多数气象站，这些变化在 5%的水平上具有高度显著性。在温度极端方面，除第 4 区外，夏季日（SU25）增加，1962-1990 年期间除第 1 区和第 2 区外，TX10p（冷日）减少。TX90p（暖日）在 1991-2019 年期间增加，除第 5 区外，在 1962-1990 年期间减少，除第 2 区和第 5 区外。连续干燥天数（CDD）的时空趋势表明，从 1991 年到 2019 年呈上升趋势，除第 4 区外，该趋势呈下降趋势。在 1962-1990 年期间（1991-2019 年期间），巴基斯坦北部的 PRCPTOT（年总湿日降水）、R10（暴雨日数）、R20（特大雨日数）和 R25mm（特大暴雨日数）增加（减少）。本研究的结果可以帮助解决一些与气候行动、饥饿和环境有关的可持续发展目标。此外，这些结果可以帮助制定针对气候变化和极端事件的可持续适应和缓解战略。由于所有气候区的气候和极端条件并不均匀，因此建议农业部门根据每个区的气候条件收获对气候有弹性的作物。由于积雪和冰川融化，巴基斯坦北部的温度呈上升趋势，因此相关利益相关者需要为更高的河流流量/洪水情况制定合理的计划。
