Climate Change and its Impacts across Pakistan

Abstract

Climate change and variability is best manifested by persistent global temperature rise, changing precipitation
patterns, increasing frequency of extreme weather events, rapidly shrinking ice sheets & glacier melting and sea-level
rise. This study analyzed the rainfall (for three major seasons; monsoon, winter & spring), temperature (in three indices;
annual mean, annual daytime and annual nighttime temperatures) and extreme events recorded at 56 data sites across
Pakistan over 63-years period (1961-2023) to investigate the climate change and diagnose the trends. We did time-series
analysis to assess the annual variability and applied the Mann-Kendall statistical trend test to determine the trend’s
significance. Results showed a significant rise in annual-average temperature, annual maximum as well as annual
minimum temperatures all over Pakistan and at 27 stations individually, annual maximum temperature at 28 and annual
minimum at 25 stations across Pakistan. In rainfall, the annual and spring (AMJ) rains have shown significant rising trend
throughout Pakistan, while, the summer monsoon (JAS) rainfall showed a statistically significant increase at 8 stations
in the north with decrease at 2 sites in southwest, winter (DJFM) rainfall witnessed an increase at 3 sites and so was the
spring (AMJ) at 7 sites mostly in the south, while a decrease at 3 sites in north of the country (all changes being significant
at 95- 99% CI). Extreme events include an increase in annual high-temperature extreme (Tmax > 35 °C), decrease in
annual cool nights (Tmin < 10 °C) and increase in wet days. The snowfall has decreased in both amount and frequency of
snow days in KP, GB and Punjab hilly station, Murree. There is an increasing frequency of cyclone formation in the
Arabian Sea, particularly the intensity being significant. Sea-level data analysis depicted a 2.02 mm/year sea-level rise at
Karachi coast. Increased cyclones frequency coupled with potentially heightened storm surges and sea-level rise may
prove fatal to coastal areas