Abstract:
Climate change is an emerging issue of 21st century. Agriculture sector in rainfed regions of
the world is mostly affected by climate change. The economy of developing country Pakistan
is dependent on agriculture. Potohar plateau is rainfed and is an important region of Pakistan
whose agriculture is adversely affected by abrupt climate. The objectives of present study
were undertaken to find out the projections of temperature and precipitation of 21st century
under RCP 4.5 and RCP8.5 and also assessment of farmers’ perception about climate
change. Observational data of temperature and precipitation for the period of 1981-2010
were used to plot historical trends. The future data of 14 CMIP5 models were used under
RCP4.5 and RCP8.5 for the period of 2021-2100. The study area was divided into two Grids:
Grid 1 (Islamabad, Rawalpindi and Jhelum) and Grid 2 (Attock and Chakwal). To find out
the change in the temperature and precipitation boxplots and time series were plotted. The
future projections were concluded by applying ground truthing. The ground-based survey
was evaluated through three statistical test Mann Kendall, correlation and Regression.
Models’ results show that under RCP 4.5 temperature will increases in both grids up to 4°C.
Under RCP 8.5 it will increase up to 7℃ in both grids. Large temperature variations will
occur in grid1. Precipitation will show variation in both regions along with large variations.
Under RCP8.5, temperature will more increase in both grids up to 5°C and large temperature
variations will occur in grid 1. In both grids, precipitation change will show variation.
According to MK and SS tests, the models show significant increase in grid 1 for historical
and future periods at 95% confidence level. Moreover. In the historic grid 1, models show
the increasing rate of temperature as: IPSL-CM5A-LR (0.05), MIROC-ESM (0.07),
MIROC-ESM-CHEM (0.06) and NorESM1-M (0.05). In historic grid 2, the models show
rate of increase of temperature as IPSL-CM5A-LR (0.04), GFDL-CM3 (0.03), MIROCESM (0.06), NorESM1-M (0.05). For future their outputs in grid 1 under RCP 4.5 are: IPSLCM5A-LR (0.03), MIROC-ESM (0.02), MIROC-ESM-CHEM (0.03) and NorESM1-M
(0.01). In grid 2 their outputs are: IPSL-CM5A-LR (0.02), GFDL-CM3 (0.03) MIROCESM (0.03), and NorESM1-M (0.02). For future their outputs in grid 1 under RCP 8.5 are:
IPSL-CM5A-LR (0.08), MIROC-ESM (0.10), MIROC-ESM-CHEM (0.10) and NorESM1-
M (0.05). In grid 2 their outputs are: IPSL-CM5A-LR (0.08), GFDL-CM3 (0.10) MIROCv
ESM (0.03), and NorESM1-M (0.01). For precipitation, only NorESM1-M shows
statistically significant results at 90% confidence level. In historic grid 1 it shows -0.96 rate.
For future under RCP 4.5 it gives 0.67 value in grid 1. Under RCP 8.5 in grid 1 it shows 1.21
rate. According to models’ results, noticeable change of temperature and precipitation will
occur. According to field survey, noticeable change in climate change variables is present in
Potohar region which was confirmed with models’ results. The methodology of the study
can be equally applied to the other districts not only in Pakistan but in the other parts off the
world for the purpose of future projections and impact assessment.
