Climate change and spatio-temporal trend analysis of climate extremes in the homogeneous climatic zones of Pakistan during 1962-2019

water’s availability for millions of inhabitants [44,80]. Most of the HKHs’ glaciers are retreating since the mid-19th century [41,42,81]. In addition, some recent studies found that mass bal- ance of the glaciers in the Karakoram are nearly in balance during 1971–2010 [41,82,83]. Muhammad et al. [76] derived the mass balance of glaciers in the sub-basins of UIB with nega- tive mass balance except Shigar and Hunza in the central and western Karakoram, respectively. In another study, Muhammad et al. [84] investigated the mass balance of glaciers in Astore (a sub basin of UIB) and concluded that the glaciers in the basin (western Himalaya) are nearly in balance during 2000–2016 similar to the neighboring glaciers in the adjacent Karakoram. In addition to the direct glacier observations, climate data also show interesting signals and indi- rectly indicate glacier’s health status. For instance, [44] noted that mean temperature decreased at the stations (Bunji, Gilgit and Skardu) lying in the Karakoram region during 1961–2000. Their analysis shows that a decrease of 1˚C in mean summer temperature can cause a reduc- tion of ~20% in summer runoff. Fowler and Archer [44] concluded an expansion in contrast to the widespread retreat in the remaining parts of the HKH region. Latif et al. [85] investi- gated trends in maximum, minimum temperature in the northern part of Pakistan. They observed that maximum temperature has mixed (upward and downward) trend while the cooling in minimum temperature become stronger in the recent past. Ali et al. [86] investi-

gated temperatures’ changes in the UIB by considering meteorological data for two stations. They noted that the mean temperature increased by 0.63˚C in Skardu while decreased by Table 7. Seasonal MK test results in the Karakoram region for maximum temperature. The table shows the Ken- dall τ and their significance for the 1990–1999, 2000–2009 and 2010–2019. Station DJF MAM JJA SON Station Kendall τ P-Value Kendall τ P-Value Kendall τ P-Value Kendall τ P-Value Maximum Temperature (1990–1999) Astore 5.18e-02 0.021 9.51e-02 1.68e-05 9.22e-02 3.24e-05 -3.05e-02 0.169 Bunji 8.52e-02 0.000 6.23e-02 0.005 -1.41e-02 0.525 -4.92e-02 0.027 Chilas 1.32e-01 3.35e-09 7.49e-02 0.001 9.76e-03 0.659 -2.66e-02 0.232 Darosh 2.28e-01 2.2e-16 8.28e-02 0.000 -6.26e-02 0.005 -1.44e-02 0.515 Gilgit 1.40e-01 3.23e-10 8.06e-02 0.000 3.32e-03 0.881 -2.45e-02 0.27 Gopis 1.81e-01 1.90e-15 7.74e-02 0.000 -1.13e-01 4.14e-07 -5.00e-02 0.025 Skardu 3.85e-02 0.084 7.03e-02 0.001 -7.74e-02 0.000 -7.57e-02 0.001 Maximum Temperature (2000–2009) Astore -5.60e-02 0.012 9.88e-02 8.00e-06 6.90e-02 0.002 -6.35e-02 0.004 Bunji -8.24e-02 0.000 3.46e-02 0.119 -3.17e-02 0.156 -8.61e-02 0.000 Chilas -1.08e-01 1.53e-06 4.33e-02 0.050 -7.52e-03 0.735 -6.58e-02 0.003 Darosh -9.40e-02 2.54e-05 -1.08e-02 0.626 -3.63e-02 0.101 -8.58e-02 0.000 Gilgit -1.15e-01 3.1e-07 3.03e-02 0.171 -2.59e-02 0.244 -1.06e-01 2.01e-06 Gopis -1.17e-01 2.08e-07 5.18e-02 0.019 2.27e-03 0.919 -7.33e-02 0.001

Skardu -1.13e-02 0.614 3.27e-02 0.139 -1.47e-02 0.508 -1.18e-01 1.11e-07 Maximum Temperature (2010–2019) Astore 9.78e-02 0.000 9.92e-02 6.24e-05 9.77e-02 8.57e-05 -3.85e-02 0.122 Bunji 1.33e-01 1.54e-07 6.51e-02 0.008 1.90e-02 0.446 -8.71e-02 0.000 Chilas 1.01e-01 6.28e-05 8.18e-02 0.001 1.14e-01 4.30e-06 -7.29e-02 0.003 Darosh 1.00e-01 5.67e-05 8.03e-02 0.001 6.04e-02 0.014 -5.94e-02 0.016 Gilgit 3.87e-02 0.127 5.08e-02 0.041 -1.30e-02 0.602 -9.77e-02 9.50e-05 Gopis 9.21e-02 0.000 5.88e-02 0.018 1.17e-02 0.640 -8.01e-02 0.001 Skardu 7.72e-02 0.002 8.19e-02 0.001 1.79e-02 0.4704 -1.50e-01 1.58e-09 https://doi.org/10.1371/journal.pone.0271626.t007 PLOS ONE Climate change and extremes analysis using observed data (1962-2019) over Pakistan PLOS ONE | https://doi.org/10.1371/journal.pone.0271626 July 27, 2022 19 / 27