A study has warned that the dry-season irrigated rice in West Africa’s Sahel region has reached the critical threshold of 37 degrees Celcius – the tipping point. It added that further temperature rise could devastate rice yields in the region due to decreasing photosynthesis at high temperatures. According to the Intergovernmental Panel on Climate Change (IPCC), the Sahel will experience higher average temperatures as well as changes in rainfall patterns over the course of the 21st century. These changes threaten food security and the livelihoods of the region’s predominantly rural population. Sahel is a transitional zone separating the Sudanian Savannah on the south to the Saharan desert to the north. The area is located in the northern part of Africa stretching from the Red Sea to the Atlantic Ocean covering a distance of 3,360 miles and an area of 1,178,850 square miles.
“Our model shows that without adaptation, irrigated rice yields in West Africa’s Sahel region in the dry season would decrease by about 45 per cent, but with adaptation, they would decrease significantly less – by about 15 per cent,” explained the lead author Dr Pepijn van Oort, a Crop Modeler at Africa Rice Centre (AfricaRice). “Also, more investigation is needed to understand clearly photosynthesis processes at extreme temperatures, as there has been almost no research conducted on rice at such high temperatures,” Dr van Oort cautioned. Although rice thrives well in hot and warm climates, high temperatures of more than 35 degrees Celcius can damage plant processes and lead to lower yields. Rice is also vulnerable to cold temperatures, which can slow growth. The study forecasts that in East Africa, rising temperatures will create new opportunities for rice. In East Africa rice is grown mostly in the highlands, which are often too cold for the crop, and this will improve with higher temperatures. Also, rice could benefit from increased CO2.However, improved water and nutrient management will be needed to have the maximum benefit, the study added.