Assessing the climate change effects on climate variables and
meteorological drought using the Climate Change Toolkit in Karkheh River
Drought appears as an environmentally integral part of climate change.
This study is designed to investigate the effect of climate change on
meteorological drought in the Karkheh River Basin in near future
(2071-2043), and distant future (2100-2072) periods. The outputs of
GFDL-ESM2, HadGEM2-ES, IPSL-CM5A-LR, MIROC and NoerESM1-M models were
downscaled under the RCP 2.6 and RCP8.5 scenarios using the Climate
Change Toolkit (CCT) at 17 meteorological stations. To assess the
uncertainty of the models and scenarios, the model outputs of the two
future periods were compared with the base of the corresponding period
using R2, RMSE, MAE indices. The best performing models were chosen for
precipitation and maximum temperature, minimum temperature i.e.
GFDL-ESM2, HadGEM2-ES and MIROC, respectively. An index, the standard
precipitation-evapotranspiration index (SPEI) was also produced using
the combination of all five models and under both scenarios. The climate
change-induced changes were investigated by comparing the simulated data
of the near and distant future periods with the statistics of the base
period. The results showed that the basin annual precipitation will
likely increase in both future periods, particularly in the near future.
The annual maximum and minimum temperatures may also increase especially
in the distant future. The rise in the maximum temperature will be
possibly greater than the minimum temperature. Seasonal changes in
maximum and minimum temperatures and precipitation indicate that the
greatest increase in temperature and decrease in precipitation may occur
in summer. Hence meteorological drought was also found to increase in
the distant future.