patterns in India have led to speculation about the future, some dire,
some benign, and others outright dismissive of the fears. I think the
reality is somewhere in between. As an agricultural scientist working with soil
and plants in Europe, Africa and Asia during the last three decades, I have
seen perceptible changes in the climate pattern.
Soil is a gift to life and could be described as the “Soul Of Infinite Life” or “soul”. There was some amusement over this acronym when I used it at a conference on global soil management in Hamburg, Germany, more than 30 years ago. During the coffee break, some delegates asked me why I called soil “soul”.
This is my explanation.
We talk of water at great length (“water conservation”, “water management”, and so on), so why not soil and water? Why just soil or water alone? Without soil, there is no water. Water cannot exist in space as it can in soil, except in the form of a vapour.
In the soil, it is in its original form as H2O: two atoms of hydrogen bonded to an atom of oxygen. Soil has three principal particle size components—clay, silt and sand—of which the clay particle (less than 2 ångström units in size where 1 ångström = 1/1000th of a millimetre; named after a Swedish physicist), is the seat of all dynamic electro-chemico-physico reactions. The surface of a clay particle carries an excess negative electrical charge; particles like silt carry some electrical charge while sand carries nothing. It is this excess negative charge that sets off a chain of fascinating and dynamic reactions. A molecule of water has two hydrogen atoms and an oxygen atom. The hydrogen carries a positive charge, while the oxygen carries a negative charge. The hydrogen atom is at the periphery of the molecule.
The positive charge attracts it electrically to the excess negative charge on the clay particle to affect an electrical neutralisation or electro-chemical atomic balancing process. But, as the hydrogen atom is already bonded to an oxygen atom, because of the latter’s negative charge, an electro-chemical bonding results. A chain of water molecules is thus built around a clay particle, with more and more water molecules, contribute to what we know as “soil water”.
The impact of one kilogram of nitrous oxide on global warming is over 300 times that of the same amount of carbon dioxide. Agriculture is the largest source of nitrous oxide emissions. We cannot ignore the role of nitrous oxide in global warming. It is a purely manmade phenomenon.
This is how the water from rainfall that does not flow into the sea is held in the soil. It explains why Indian soils that carry a large amount of clay, such as the alluvial soils of the Tarai region in the Himalayan foothills, conserve a lot of water. On the other hand, Kerala’s coastal soils, laden with sand, cannot hold enough water when it rains heavily. The water runs off into the Arabian Sea and in the process carries away a lot of top soil from agricultural fields.
In the former, water is stored; in the latter, almost all is lost as “run off”. This also leads to the conclusion that while the former is termed a “fertile” and “productive” soil the latter is described as “infertile” soil. A critical examination of rice and wheat growing in these two areas shows why we get high yields in the Tarai, but not in the sandy soils of Kerala. The question, though, is what has all this got to do with climate change?
Soil is the
repository of a load of carbon atoms. A fertile soil has tons of it, while an
infertile sandy soil has less. Carbon has a great capacity to absorb and retain
heat. Correspondingly, sandy soil with low carbon content loses heat faster.
Now, when we compare the climate difference between deserts, on the one hand,
and a fertile zone like the Tarai, on the other, the outcomes are easily
What happens in the deserts of the Persian Gulf countries? Day temperatures in summer are unbearable, but once the sun sets the mercury drops dramatically. Most of the heat radiates away, but not in an alluvial soil which contains a lot of clay. Anyone who has experienced a north Indian summer knows both day and night temperatures can be excruciating, but in the desert you can take a walk after nightfall. It is cool. The experience is available right here in Rajasthan. There is no need to visit the Gulf region just for this.
The above explanations show that soil is indeed a great regulator of ambient heat. So what is the fallout of this unique property of soil in climate change when we bring in a disruptive influence? The first is that it will affect our soil resources. In the last four decades, this country has seen the introduction and widespread use of chemically-powered factory farming that we call the Green Revolution, with profound environmental consequences.
Most of us have been taught, or we believe firmly, that automobile emissions and industrial plants contribute the most to global warming through the emission of carbon dioxide. This is the view of the textbook environmentalist.
If we consider warming patterns, there are two types of gases that contribute to it, the “long-lived” gases and the “short-lived” gases. For example, when an automobile moves, the internal combustion engine sends mostly carbon dioxide, plus some carbon monoxide, through the exhaust. When a woman sprays an expensive perfume, minute vapour-like particles crowd the atmosphere. They are called aerosols.
Carbon dioxide belongs to the long-lived category, while the aerosol belongs to the short-lived category. Both can trap sunlight and retain its heat and that contributes to global warming. These are called greenhouse gases (GHGs). But there is one other among the long-lived category of which many are unaware, or they pay only fleeting attention to it. That is nitrous oxide (N2O). This is a long-lived gas and its main source is human activity, primarily agriculture.
In 2011, N2O emissions into the atmosphere accounted for about five per cent of all GHGs in the United States originating in human activity, primarily agriculture. N2O is present in the atmosphere as part of the earth’s nitrogen cycle, and has a variety of natural sources. But agriculture, especially the “high input” industrial-type agriculture, is the main contributor.
When urea or ammonium sulphate or any other nitrogenous fertiliser is applied to soil to supply nitrogen to the crop, a chemical reaction called “hydrolysis” (mixing of the urea or ammonium sulphate granule with water) takes place. While the plant can take up the nitrogen only as an oxidised molecule (NO3, called nitrate), another by-product escapes into the atmosphere, as N2O, nitrous oxide. Laughing gas, as it also known, has the capacity to capture an enormous amount of energy (heat) from sunlight, and retain the energy, as such leading to global warming. N2O molecules stay in the atmosphere for an average of 120 years before being removed or destroyed by chemical reactions.
The impact of one kilogram of nitrous oxide on global warming is over 300 times that of the same amount of carbon dioxide. Agriculture is the largest source of nitrous oxide emissions. We cannot, in any reckoning of the factors behind global warming, ignore the role of nitrous oxide. It is a purely man-made phenomenon.
Why is there so little
talk about this gas, which is the more dangerous polluter, and why so much
about carbon dioxide only? Perhaps it is the clout, financial and
political, of the fertiliser lobby that keeps the buzz on nitrous oxide down.
Take the example of what happened in India from the early Sixties.
The “miracle” dwarf
wheat brought to India from the International Centre for Maize and Wheat
Research (CIMMYT) in Mexico needed high doses of nitrogenous fertiliser to
produce maximum yield. We had no manufacturing facilities those days. Every bit
had to be imported from the US.
It is important to note that in the post-World War II period, factories in the US which had manufactured war chemicals began shutting down because there was no demand. Unemployment increased. The Haber-Bausch process for the manufacture of synthetic nitrogenous fertiliser was activated and these factories were put to work principally manufacturing nitrogenous fertiliser.
With the advent of the Green Revolution, India became the biggest user of these fertilisers as farmers saw spectacular yield increases in dwarf wheat. The Union government opted for an agricultural policy under which thousands of tons of dwarf varieties like Sonora were imported from the US.
Punjab’s farmers took to this high input agriculture in no time and the state became the cradle of the so-called revolution which required massive doses of nitrogenous fertiliser. Though yields jumped initially, by the early Seventies, they started to plateau or decline. Soils started getting degraded, ground water was loaded with nitrates, rendering it non-potable, and aquifers started to fail from the excessive use of water for irrigation. Finally, biodiversity started to wither under the impact of rice-wheat monoculture. An environmental disaster was starting to build up.
This activity also meant N2O emissions peaked and no one, least of all soil scientists, cared to draw up a balance sheet for the excess of this gas in the atmosphere. Ambient temperatures were gradually scaling up. Summers were getting hotter. At the time, the idea of carbon footprinting was unknown. Worse, the soil’s ability to sequester carbon was not studied in detail (“sequestration” is a locking-up process of carbon in soil to enhance its fertility).
Punjab, Haryana, and western Uttar Pradesh were becoming disaster zones in environmental terms. Invariably, environmental activists saw industrialisation as the major culprit, neglecting what was happening in the soil due to the build-up of nitrous oxide.
Another gas that contributes substantially to global warming is methane (CH4), released by wet paddy cultivation. Though a short-lived gas, it is much more potent at trapping heat, somewhat like nitrous oxide. Emissions have risen by 150 per cent compared to carbon dioxide emissions.
A lot of paddy cultivation in Punjab and Andhra Pradesh is through copious irrigation and the standing water contributes a lot of methane. One can smell it when walking through huge and widespread paddy fields. This is another example of industrial-type agriculture making global warming worse.
In this connection, consider this data in the report of the United Nations’ Intergovernmental Panel on Climate Change (IPCC), made public late last month. Global climate in the past decade-and-a-half has not been warming up at the rates earlier predicted. In fact, the rate of warming from 1998-2012 at 0.05°C per decade is less than that during 1951-2012, which is 0.12°C per decade. In absolute terms, in the six decades between 1951 and 2012, the increase was 140 per cent, which is nearly 24 per cent per decade, a substantial increase, given the global scale, compared to the later period, 1998-2012. It shows that the rate of increase in global warming is lower now than pessimists try to make out.
But it is no solace.
In India, we have many other contributory factors.
The IPCC report
warns that a large part of the changes described above cannot be reversed over
the next few centuries unless GHG emissions are brought down fast. It is in
this context that Indian agriculture has to change direction. Our use of
chemical fertilisers, especially nitrogenous fertilisers like urea, has to be
But if we take up this battle, we will surely come up against the fertiliser lobby. Under the slogan of producing more, farmers will be prodded to use ever more quantities of nitrogen-carrying fertilisers. Indian farmers have to break free of the propaganda that only chemical fertilisers sustain and increase crop yields.
The lead could be provided by a campaign from the Centre for Sustainable Agriculture in Hyderabad, where a large group of farmers—men and women—have successfully turned to organic farming, devoid of chemicals, in Warangal district. It is a fallacy to think that a shift from a regime dependent solely on chemicals to organic agriculture leads to a fall in crop yields.
My own experience is that in the first three years after the shift, yields do fall, but they stabilise after that. This is also the lesson from Europe, especially Germany, which has hundreds of organic farms spread over thousands of acres.
There are other alternatives as well, one developed by this author. It is based on a simple idea: that the soil’s capacity to supply plant nutrients can be precisely calculated on the basis of an approach based on physical chemistry, the ionic equilibrium concept. It takes note of a particular soil’s inherent nutrient supplying power, which I call the “Buffer Power”, and fertiliser recommendations are calibrated against this intrinsic property. It means vastly reduced use of chemical fertilisers, minimising soil degradation and environmental pollution, while at the same time greatly enhancing the efficiency of their use. This concept was developed as a result of prolonged laboratory and field experimentation in Europe, Africa, and Asia. Incidentally, this approach was shortlisted for the United States’ $1 million Rolex Award for Enterprise in 2012, the only one from Asia to be included.
The IPCC summary notes, “It is very likely that more than 20 per cent of emitted CO2 will remain in the atmosphere for periods longer than 1,000 years after anthropogenic emissions have ceased. CO2–induced warming is projected to remain approximately constant for many centuries following a complete cessation of emissions.”
This will have long-lasting impacts on the environment. It is virtually certain that global mean sea levels will continue to rise beyond 2,100 for many centuries. It is almost certain that if mean temperatures rise and stay on a sustained basis between 1°C and 4°C higher, the Greenland ice sheet could all but disappear.
We have fairly
precise measurements for the accumulation of carbon dioxide, but none for the
other two major culprits, nitrous oxide and methane. This is where Indian
scientists, especially those connected with agriculture, like the monolith
Indian Council of Agricultural Research, have an extremely proactive role to
play. Unfortunately, that is not the case at the moment. There is a lot of hot
air going round at conferences, both national and international, but little
action on the ground. The last Global Climate Change Conference of the
“Conference of Committed Parties”, held in Copenhagen, Denmark, where some of
India’s perpetually pontificating scientists were present, at enormous cost to
the national exchequer, is a classical example of this national waste.
India will soon be in a sticky position. Its per capita emissions are among the lowest among the large emerging economies. India will require greater carbon space and time to let emissions peak.
What is the political angle to all this? The US has repeatedly warned at earlier climate negotiations that it is not keen to share the burden of reducing emissions with other countries on the principle of “historical responsibility”, meaning what its earlier industrial impact contributed to climate change. The European Union also is following, albeit covertly, a similar line of thought, though it has shied away from explicitly agreeing with the idea.
Largely, their positions at climate negotiations suggest that they are open to a burden-sharing formula to limit future emissions. But they are averse to factoring in responsibility for accumulated carbon dioxide emissions.
In other words, they also cleverly follow the US line. Japan is the one exception. It has steadfastly stuck to limit emissions, clearly enunciated in the Kyoto protocol.
The idea of an overall carbon budget, more than half of which is already consumed inequitably, will naturally be raised at future climate negotiations by developing countries, especially emerging economies like India. That is where India can expect a real road block.
What is India’s position vis-à-vis the above scenario? India will soon be in a sticky position. Its per capita emissions are among the lowest among the large emerging economies, while China has raced far ahead. India will require greater carbon space and time to let emissions peak than China, or even Brazil. But this is not going to be an easy task given the global scenario and the political posturing of different countries: some clear, but others quite opaque.
Given the daunting unfolding scenario on climate change, my best bet would be to set our own house in order, not just in the factories but in the fields as well. The million dollar question is: who will bell this cat?