Global temperature increased by 1.1⁰C and is expected to increase 3.5⁰C by 2100.The consequences are shifting in seasons, variability and intensity in rainfall, sea level rising and cyclone; other tectonic processes are becoming fiercer and frequent. There is an eternal relationship between climate, soil and agriculture. Soil has become part of the global agenda for climate change mitigation and adaptation through launch of high level initiatives (Amelung et al, 2020).

Sequestering organic C in soil may potentially, and in a technically feasible manner, removes  between  0.79 and 1.54 Gt C per year from the atmosphere, recognizing the substantial potential of soils in stabilizing the climate (Fuss et al, 2018; Rumpel,et al, 2018). Soil management for climate change mitigation has been drawing particular interest in recent years. While soil represents the largest pool of C in the terrestrial ecosystem, the emission N₂O, CH₄ and CO₂ from soil represent significant load and GHG balance.

Improving soil structure and fertility enhances the soil's capacity to sequester carbon, thereby mitigating the effects of greenhouse gas emissions. Moreover, the microbial activities are essential to maintaining soil biodiversity, a crucial aspect of ecosystem resilience. Soil microorganisms play a crucial role in the cycling of soil organic carbon and nitrogen, but we still lack sufficient scientific knowledge to build qualitative predictive models in the context of soil use and management.  

Soils potential to store CO₂ has not received enough attention over the last years while formulating the strategy against the greenhouse effect. Using the  soil’s capacity to bind large quantities of C could reduce the increase of the greenhouse gas CO₂ in the atmosphere by a third. At the same time agricultural yields in many regions would also improve significantly.

Nitrogen, an essential input for maintaining soil fertility and crop yield, remaining in excess , is converted to N₂O, a greenhouse gas which has  298 times  warming potential of CO₂ ( Hou, 2021). Nitrous oxide emission factors may be region specific and vary under different climate conditions.Limitation of C sequestration for climate change mitigation has several constraints viz. the quantity of C stored in soil is finite; the process is reversible and even if SOC is increased there may be changes in the fluxes of other greenhouse gases especially  N₂O and CH₄. The climate change benefit of increased SOC from enhanced crop growth, must be balanced against greenhouse gas emission with manufacture and use of fertilizers (Powlson, 2012)

The climate summit in Paris in 2015 was also the birth of the so-called "4 per 1,000" initiative. Its name stands for a link that has not received enough attention in climate research and politics for a long time: Every year, the amount of carbon in the atmosphere increases by more than four billion tons due to the man-made greenhouse gas CO₂. 

Over the past decade, agriculture has gone from sinner to saviour in the context of global warming. As per World Bank report “some 30 percent of global greenhouse gas (GHG) emissions are attributable to agriculture and deforestation driven by the expansion of crop and livestock production for food, fiber and fuel.”

Soil and soil science can play an important role in mitigating climate change, by enhancing carbon sequestration in soil, as well as reducing net emissions of N₂O, CO₂ and CH₄. As soil organic matter can also increase crop yield, enhance soil biodiversity and immobilize some soil pollutants, the intervention strategies aiming at improving SOC can also render great benefits in ensuring food security and soil health. Therefore, in mitigating climate change effects, sustainable soil use and management practices could provide multiple benefits for humanity.

References:

Amelung W et al (2020) Nat Commun. 2020 Oct 27;11(1):5427.doi: 10.1038/s41467-020-18887-7

Powlson DS  et al (2012)https://doi.org/10.1111/j.1365-2389.2020.01342.x

Hou D  ( 2021)https://doi.org/10.1111/sum.12718

Rumpel C et al (2018) Nature 564, 32-34

Fuss  et al (2018) Environ Res Lett 13,63002

Prof Dharani Dhar Patra, presently working as the Director of School of Agricultural sciences, JIS University, Kolkata, India (2020-2023), has been the Vice Chancellor of Bidhan Chandra Krishi Viswa Vidyalaya, Kolkata, India (2016-2020) and Professor-cum-Chief Scientist (Natural Resource Management) at CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India ( Under Ministry of Science and Technology, Government of India, New Delhi, India( 1987-2015). Prof Patra did his Graduation and post-Graduation from from BCKV, India did his PhD from Indian Agricultural Research Institute, New Delhi, India (1978-1982) and then went to Rothamsted, UK for post-doctoral research and subsequently joined Rajasthan Agricultural University, As an Assistant Peofessor in NRM (1982-1987).

      Prof Patra is a recipient of several Awards viz.National Fellowship, 1971; FAI Silver Jubilee Award, 1980; FAI Gold Medal, 1983; Commonwealth Fellow, 1983; STA Fellow, 1999;Mint Technology Award,  1999; PPIC (Canada) - FAI Gold Medal, 2000; FICCI Award 2005; 12th International Congress Commemoration  Award, 2005; UPCAR Eminent Scientist Award (NRM), 2006; ISCA  Platinum Jubilee Award 2008. Golden Peacock Eco-Innovation International Award, 2008. CSIR S&T Award for Rural Development, 2008.CSIR-Best Scientist Award on Agri-entrepreneurship, 2015.