Gorgan University of Agricultural Sciences International Journal of Plant Production 1735-6814 6 2 2012 08 11 Regional climate change scenarios and their impacts on water requirements for wheat production in Iran 239 266 778 10.22069/ijpp.2012.778 EN Gh.R. Roshan Department of Geography, Golestan University, Gorgan, Iran. S.W. Grab School of Geography, Archaeology and Environmental Studies, University of Witwatersrand, South Africa. Journal Article 2012 08 11 We simulate the effect of climate change on water requirements of cold season<br />wheat in various climatic zones of Iran. The research considers both observed<br />climate (temperature and precipitation) changes during recent decades (1960-2009)<br />based on instrumental records and projected future changes to 2100 based on the<br />MAGICC/SCENGEN 5.3 compound model. 20 General Circulation models are used<br />based on a single scenario known as P50, which is the average of SRES or emission<br />scenarios. Results indicate that whilst winter precipitation has marginally increased<br />across the country as a whole, a significant decline in mean spring precipitation is<br />recorded between 1960 and 2009. However, considerable variability in trends is<br />measured across various climatic regions of Iran. Mean annual temperature / rainfall<br />changes in the various climate zones of Iran for the period 1960-2009 follow: +0.1 °C<br />/ decade / +0.43 mm / decade in arid regions, -0.1 °C / decade / -1.7 mm / decade in<br />semi-arid regions, +0.1 °C / decade / -1.33 mm / decade in Mediterranean / semihumid<br />regions and -0.01 °C / decade / -0.04 mm / decade in humid / hyper humid<br />regions. Temperature projections to 2100 indicate an overall temperature rise of ca.<br />4.25 °C relative to that for 1961-1990, with increases projected for all climatic<br />regions of Iran. Despite an overall projected mean precipitation increase of 36% for<br />the year 2100, relative to that for 1961-1990, these are insufficient to compensate for<br />temperature increases. Consequently, calculated water deficits during the growing<br />season (autumn to spring) in Iran’s wheat producing areas are expected to increase<br />from 5.2% in 1980 to over 23% by 2050 and 38% by 2100. https://ijpp.gau.ac.ir/article_778_ae28ecee2a64b34fc54abf185a3fb8c0.pdf