The 2021 Nobel Prize for Physics recognising the research of three climatologists, Professors Syukuro Manabe, Klaus Hasselmann and Giorgio Parisi has brought under sharp focus the threat of what is commonly known as global warming, which is nothing but anthropogenic warming. In simple terms, “man made” atmospheric warming. Announcing the prize, Mr. Thor Hans Hansson, Chair for Physics Nobel Committee, said, “The world leaders that haven’t got the message yet, I am not sure they will get it because we are saying it. But… what we are saying is that the modelling of climate is solidly based in Physics theory”. The Nobel Committee said it was sending a message with its prize announcement just weeks before the COP26 (Conference of Parties) climate summit in Glasgow, Britain, as global warming sets off alarm bells around the world.

The International Panel for Climate Change (IPCC, 2014) has predicted dramatic changes in climate patterns in the current century that will inevitably adversely affect food production. If one juxtaposes the global population increase with changes in ambient temperature, a grim scenario emerges. Current projections suggest that global temperature will rise by 1.8-4 degree Celsius and the corresponding global population increase might touch 10 billion by the next decade – an increase of 142.9% from the current level of + - 7 billion, which works to about an annual increase of 1.8%.

While discussing anthropogenic global warming, one must take into account primarily carbon dioxide, the center-piece of Prof. Manabe’s research at Princeton University, US, occurring primarily because of industrial activities, including automobile exhaustion. Automobile emissions contributed to an increase of 200% at 40 ppm (parts per million) post-industrial phase, compared to 20 ppm pre-industrial phase. But, more insidious is the emission of nitrous oxide, a gaseous product from urea hydrolysis, a chemical process when applied urea molecules react with soil moisture, which contributes to almost 35% global warming (Nair, 2019b).

This gas, commonly known as “laughing gas” (dinitrogen monoxide) is a byproduct of unbridled use of urea in ramping up both wheat and rice production. Dinitrogen monoxide is a major scavenger of stratospheric ozone leading to global warming (Nair, 2019b), and is 310 times more effective in its heat trapping capacity compared to carbon dioxide (Nair, 2019b). The average life span of this gas is 120 years (Nair, 2019b). It is a serious environmental hazard that steep ramp-up of nitrous oxide in the stratosphere coincided with the green revolution of the 1960s (Nair, 2019a).

A consequence of the unbridled urea use is soil degradation and ground water pollution due to high residues of nitrates which makes water non-potable (Nair, 2019a). Of India’s 328.43 million hectares, more than 120.40 mha have degraded soils, mostly in Punjab, the “cradle” of India’s green revolution (Nair, 2019a). This has been highlighted in Indian Space Research Organisation’s recent report. When high food production is targeted through excessive use of N-fertilizers like urea, soil microbes convert N in the urea into nitrous oxide at a faster rate than normal (Nair, 2019a). This has been a major factor leading to global warming with all its attendant environmental consequences (Nair, 2019b). The unseasonal rains that India experienced in September are also an offshoot of this phenomenon (Nair, 2019b).

Global warming is a reality man has to live with. This is a very important issue to recognise, because of all the parameters that affect human existence, it is food and its security that is of paramount importance to life on earth and which is most threatened by global warming. In this context, the author proposes a look at the possibility of utilizing “Crop Wild Relatives”. Those plant species which are very closely related to field crops, including their progenitors, which have the potential to contribute beneficial traits for crop improvement, such as resistance to an array of biotic and abiotic stresses and enrich the gene pool, can facilitate enhanced crop yields (CWRs, (Nair, 2019b). In fact, CWRs have tremendous potential to sustain and enhance global food security and contribute to humanity’s well-being. Therefore, their search, characterisation, and conservation in crop breeding programmes assume great importance.      

CWRs are a key tool to address the limits of genetic variation in the domestic crops to adapt them to climate change. However, extension of their conservation and promotion of more systematic exploitation is hindered by a lack of understanding of their current and potential value, diversity and how they might be conserved and exploited – an important task Indian agricultural research fraternity must immediately address.  

References:

1)      Nair, K.P.P. 2019a. Intelligent Soil Management for Sustainable Agriculture – The Nutrient Buffer Power Concept (Springer Nature, Switzerland)

2)    Nair, K.P. P. 2019b. Combating Global warming – The Role of Crop Wild Relatives for Food Security (Springer Climate, Switzerland)