Climate change for practical people

Business Standard, 24 January 2022

Climate scientists warn that an increase in the global average temperature of more than 1.5 degrees will trigger off catastrophic events. The baseline is pre-industrial conditions, the period from 1850-1900. So far, the rise in temperature for the world has been about 1 degree and for India it has been 0.7 degrees. These seem like small numbers. Many practical people think that a change of about 1 degree can't be that bad.

We should be very worried about climate change for two reasons. First, these modest changes in the average temperature go with disastrous changes in the extremes. Second, our knowledge of the field is rather limited, and we may have mistakes in our analysis ("model risk") through which the actual outcome could prove to be much worse.

These small changes matter

All of us are experiencing strange events in the weather. Age old patterns of the monsoon seem to be changing before our eyes. We seem to be getting long pauses in the monsoon and we have unseasonal clouds and rain in the oddest of times.

I was in Maharashtra on July 23 last year, when 594 mm of rain appeared in the Western Ghats. This kind of rain had just not been seen before. I remember waking up that night and thinking, in my entire life I have not heard such thunder and rain. Over 100 people were killed in that event.

In the old India, there were more cyclones in the Bay of Bengal, and the Arabian Sea was relatively benign. That's started changing: the frequency of cyclones in the Arabian Sea has gone up by about 50%. In Kerala, there was no significant flood from 1924 till 2004. In the recent period, dramatic rainfall events and floods have been experienced at a high rate in Kerala.

These facts show that the small changes in the average temperature, like 0.7 degrees in India or 1 degree for the world, are already generating significant impacts. Climate models predict that the rise in temperature will be least in south India and the increase worsens as we go north. The aggregate amount of rain will go up by about 7% for each 1 degree increase in temperature. In the analysis of monsoons, this rain will come down to the earth on a smaller number of days, and the dry spells within the monsoon months will become longer.

Model risk

The data that goes into these models is limited. Even with the most powerful computers, the simulations work on a coarse approximation where the atmosphere is cut into a grid with cells that are between 50 to 100 kilometres wide and 1 km high, and work in time intervals which are about an hour. A huge effort is on, worldwide, to improve the data and the models [example]. The models will get better, but the problem is daunting, and substantial uncertainty will remain.

This means that there is a reasonable chance that things will be worse than is presently projected, even if the rise in the global average temperature is contained to below 1.5 C.

Pathways to climate adaptation in India

We should think about the present variation of population density in India, across locations, which is derived from climate conditions of the last 50 years. When climate change takes place, things will become unbearable for many people, and they will need to migrate. This will happen on the coast, which will experience rising sea levels and changing patterns of cyclones. It will also happen in the interior, with a combination of heat waves and altered rainfall patterns. In Jacobabad in Sindh, which is 300 km from Jaisalmer, the temperature reached 52 C in June 2021. At that temperature, economic life comes to a halt. It is worse than the Indian Covid lockdown of 2020.

These developments are a challenge for human institutions. The Dutch dealt with the rising seas by building dykes and protecting their way of life. We in India have inferior state capability and will fare poorly when faced with these pressures. About 20 years ago, when faced with the twin looming threats of ageing and climate change, there was hope that India would become an advanced economy in time. With climate change, as with the ageing of the population, things seem to have turned out differently.

Pathways to mitigation

There will be more natural disasters. A greater focus on disaster relief and disaster risk resilience is called for. Agricultural incomes will become more volatile through fluctuations in quantities and prices. Food sector reform which makes the price system control the resource allocation is required, in order to efficiently absorb these shocks. Risk management at the farming household level calls for financial sector development in the form of crop insurance and commodity derivatives trading.

When the climate and the economy in certain places goes bad, and other places get better, households which are over-weighted with immobile assets in the wrong places will experience substantial destruction of wealth. The distribution of wealth in the country will experience considerable change.

A good path to adjustment lies in households relocating. For households that have no land, the frictions that they face are the factors that hamper intra-India migration. Migration will work better to the recipient regions that are more free of bigotry.

For the households that have land, the best path lies in selling the asset and moving, possibly buying land at the destination. The prices will of course be adverse, but it is better to move than to not move. The problem holding them in place is the imperfections of the Indian land market. The market for land is illiquid. There are large transaction costs and delays.

The human mind finds it difficult to think about far-reaching changes that unfold slowly. We are biologically prepared to think and respond to events that unfold on the time scale of a minute, such as the rush of an attacking tiger. The rise in sea level is projected to be about 10 to 30 centimetres over 20 to 30 years. To confront the climate problem, we each of us have to become more strategic in our thinking.

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