Analysis Of Down To Earth Magazine: "Impact Of Rising Temperature on Crop Yield"

Analysis Of Down To Earth Magazine: ”Impact Of Rising Temperature on Crop Yield”

One study published in Global Change Biology in 2018 found that a 1.5°C rise in temperatures could decrease global wheat production by 2.3-7 per cent.

Analysis Of Down To Earth Magazine
”Impact Of Rising Temperature on Crop Yield”

Relevance

”GS 3: Disaster Management, Environmental Pollution & Degradation”

Context

Above normal rains in January and record-shattering temperatures in March have reduced wheat yield throughout the country which resulted in price rise.
Many other crops were also affected due to adverse climatic conditions.

Ideal Conditions for wheat Crop?

Wheat requires cool and moist conditions for most of its growing period.
The optimum temperature range for germination of wheat seed is 20-25 degree C.
The crop is typically sown in late October or November and harvested in April.
The grains develop in February and March.

What was unusual this year?

But this year, India saw an early onset of summer, with large parts of central and western India recording 40 degrees C in March.
The month was the warmest in 122 years, according to the India Meteorological Department (IMD).
In the third week, maximum temperatures were 4.5 C above normal in the major wheat-producing regions of Punjab, Haryana, Rajasthan, West Madhya Pradesh and a few parts of Gujarat.

March Became May!

Temperatures typically seen in May were observed in March this year.
Due to which, Wheat crops matured 10-15 days earlier and the grain size remained short By the end of March, heatwaves had hit large swaths of north-western India and a few pockets of central India.
The number of heatwave days during the month was significantly higher than normal, as per imd.

Rainfall Deficit

Heatwaves typically strike north, north-west, central, east and northeast India in May.
The month was also unusually dry, receiving the third-lowest rainfall since 1901.
Overall, the country witnessed a “deficient” pre-monsoon (showers between March and May), with a deficiency of 32 per cent from March to April, compared to the normal range.

Adverse Impact Of Higher Temperature on Crop Yield

High temperatures at night force plants to redirect energy meant for grain formation to transpiration—a process that helps keep plants cool.
This tends to reduce the duration of grain filling and, as a result, the grains lose weight, leading to low yield.

What immediate reasons triggered the high temperatures in March and April?

There were some changes in the atmospheric patterns.
Anti-cyclones, which cause hot and dry weather by sinking winds around high-pressure areas, had formed over western parts of Rajasthan in March.
Even western disturbances that bring showers were inactive this year.

Climate Change is Real

There is enough study which shows that the main reason is climate change.
One study published in Global Change Biology in 2018 found that a 1.5°C rise in temperatures could decrease global wheat production by 2.3-7 per cent.
A 2021 paper published in the journal Geophysical Research Letters found that wheat yields in Punjab, Haryana and Uttar Pradesh could reduce by 12-27 per cent by 2100 if greenhouse gas emissions are not lowered.