How is rising temperature reducing crop yield in India?

Climate change Punjab; Climate change is projected to reduce maize and cotton in Punjab by 13% and 11% respectively by 2050,

By Ground report 01 Aug 2023

New Update

Rising temperatures threaten wheat yields in India: Study

India is a major producer of wheat, ranking second in the world. Since 2000, there has been a 17% increase in the area of land used for wheat cultivation, resulting in a 40% increase in wheat production. This growth is mostly seen in the central semi-arid regions, known as the traditional wheat bowl of the Northwest. By contrast, land used for sorghum cultivation in uniformly semi-arid zones has decreased by 21 per cent over the same period.

A recent study compared the impact of climate change on these two crops. The findings indicate that rising temperatures pose a concern for wheat production around the world. Specifically, in India, the study predicts that rising temperatures could lead to a 5% reduction in wheat yields by 2040 and a 10% reduction by 2050. Surprisingly, sorghum appears to be less affected by rising temperatures. temperatures, and does not show a significant decrease in productivity.

In a recent development, the Government of India has conducted an extensive study to assess the potential impact of climate change on crop yields.

The study, carried out under the National Innovations in Climate Resilient Agriculture (NICRA) project, reveals worrisome projections for several key crops. According to the findings, the projected reduction in crop yield by the year 2050 is substantial, with rainfed rice facing a decline of 20.0%, wheat 19.3%, kharif maize 18.0%, and rainfed sorghum 8.0%.

However, even more concerning are the projected reductions for the year 2080, which are significantly higher, with rainfed rice expected to witness a staggering decline of 47.0% in crop yield, wheat 40.0%, kharif maize 23.0%, and mustard 15.0%. These alarming statistics raise concerns about food security and the livelihoods of millions of farmers who heavily rely on these crops.

publive-image — A farmer gazes over a field of maize suffering from waterlogging. Source: Flickr

Under the scenario of rising temperatures, the study also projects a nine percent increase in total water requirements for wheat by 2030 and a six percent increase for sorghum.

Climate-adapted alternative to wheat

Professor Ruth DeFries, the lead author of the study, suggests that, if balanced properly, sorghum could serve as a climate-adapted alternative to wheat in rabi cultivation. Sorghum, also known as millet, is resistant to dry conditions and consumes 1.4 times less water than wheat. However, the advantage of wheat's higher yield, which means more crops per drop, may diminish in the future. The study reveals that the "water footprint" of wheat is expected to increase by 12 per cent around 2050, while that of sorghum is projected to increase by four per cent.

Crop	2050 Scenario	2080 Scenario
Rainfed rice	20.0%	47.0%
Irrigated rice	3.5%	5.0%
Wheat	19.3%	40.0%
Kharif maize	18.0%	23.0%
Rainfed sorghum	8.0%	-
Mustard	7.9%	15.0%

Wheat is particularly vulnerable to the impact of rising temperatures due to its summer crop, making it more exposed to heat waves and increasing the risk of such incidents. Last February, record heat damaged the wheat crop, prompting export bans due to supply disruptions caused by the conflict in Ukraine. India's position as the second-largest wheat producer inspired the study.

Between 1998-2002 and 2012-2017, total wheat production in India increased by 42%, driven by higher acreage and yield. In contrast, sorghum production decreased by five per cent despite a 37 per cent increase in yield, mainly due to a 21 per cent reduction in cultivated area.

Although both wheat and sorghum are grown in the semi-arid central region, wheat production continues to increase. Yields for both crops have increased since 2000, with wheat consistently yielding almost twice as much as sorghum. One of the reasons for lower sorghum yields is a lack of research and attention compared to improvements made to wheat varieties.

Climate change in Punjab

This study assessed the impacts of climate change on the productivity of major rabi and kharif crops in Punjab. Data was collected for 35 years (1986-2020) using 5 crops in Punjab to estimate the impact of climate change using temperature and rainfall. The results indicate that productivity decreases with increasing mean temperature in most crops.

The researchers collected climate data from five meteorological observatories of the Punjab Agricultural University i.e. Ludhiana, Patiala, Faridkot, Bathinda and SBS Nagar.

The researchers, agricultural economist Sunny Kumar, scientist Baljinder Kaur Sidana and PhD Smily Thakur, said long-term changes in climate variables show that rising temperatures are driving most of the changes, rather than the change in the rain pattern.

“One of the most intriguing findings is that changes in minimum temperature have resulted in changes in mean temperature throughout all growing seasons. It means that the minimum temperature has shown an upward trend,” the report says.

Decline of crops due to climate change

“Climate impacts on crops will vary widely in the kharif and rabi seasons. Among kharif crops, maize yields are more responsive to temperature and rainfall than rice and cotton. By 2050, maize yields would decline by 13 per cent, followed by cotton (about 11 per cent) and rice (about 1 per cent)," the report read.

Negative impacts will be cumulative by 2080. Yield losses would increase from 13% to 24% for corn, 11% to 24% for cotton, and 1% to 2% for rice.

"The yield response of wheat and potato would be about the same by 2050. By 2080, with a significant change in climate, wheat and potato yields will each be about 1% higher", the report said.

“Our results indicate that productivity decreases with the increasing average temperature in most crops. The adverse impact of climate change on agricultural production indicates a threat to the food security of the farming community,” the researchers said.

Effects of climate change on agriculture over past decade

In India, many state studies have provided empirical evidence on the effects of climate change on agriculture over the past decade. In Punjab, the study (Hundal and Kaur, 2007) concluded that a minimum temperature increase of 1.0°C to 3.0°C above normal has led to a decrease in the productivity of wheat and rice by 10 per cent and 3 per cent, respectively.