What will be the cost of one degree rise in temperatures?

Temperatures in the past week have been above normal for most parts of India, especially the northern and central plains. In Rajasthan, Madhya Pradesh, Haryana, parts of Gujarat and Uttar Pradesh and Delhi, maximum temperatures have consistently stayed at the 45 degree Celsius-level. In fact, as the India Meteorological Department (IMD) predicted earlier this year, temperatures across India will be 1-1.5 degrees higher this summer. But this is not an isolated phenomenon. Several scientific studies have borne out what has been our felt experience – that it's getting hotter by the year.

A study in Science Reports, a journal by researchers from IIT (Bhubaneswar), IMD and Florida State University has charted how surface temperatures have gone up over the past 70 years. While the daily maximum in the past decade has been above 40 degrees in large parts, in the 50s, it was only a small patch in south central India that saw such high temperatures. Further, the researchers found that the area in central India, which has traditionally had high temperatures, become even hotter.

Then there are other reports, most notably one published last year by the Centre for Science and Environment, which revealed that average temperatures had risen above 1.2 degrees Celsius since 1900. And that the pace of heating has picked up in the last few years with 2016 being the hottest year recorded, and the decade, 2007-16, the hottest on record. Another study by an international team of scientists led by University of California climatologist Omid Mazdiyasni, which analysed IMD data from 1960 to 2009, found that temperatures had gone up by 0.5 degrees in this period, that heatwaves had gone up by 50% in the 25 years between 1985 and 2009 compared to the 25 years before, and that heatwave days had increased by 25%. While everyone is discomfited by the growing heat, construction workers are affected more than the managers who work in air-conditioned offices. Here's an attempt to see how much the one degree rise in temperatures that the IMD predicted, would mean:

Health

Heatwaves are deadly – thousands die every year as a result of heat-related causes. As per figures given out by the central Ministry of Earth Sciences (which always tend to be conservative), as many as 4,620 people have died in the last four years – of these Andhra Pradesh and Telangana alone accounted for 4,246. The Mazdiyasni study, which was published in the journal Science Advances, showed that the 0.5 degree rise in temperature meant a 146% increase in the probability of heat-related deaths, especially given the low per capita incomes and thus lack of access of large segments to air-conditioning and medical care. "The substantial increase in mortality rates due to either a 0.5 degree increase in summer mean temperature or two more heatwave days suggests that future climate warming could have a relatively drastic human toll in India," the study concludes.

There's more. "Changing weather patterns have resulted in the difference between minimum and maximum temperatures decreasing. Besides, with rising humidity, there is a cumulative effect. This means that, unless you have an AC, or with load-shedding, a lot of people have restless sleep, which leads to lowered productivity the next day," says Nivedita Mani, of the Gorakhpur Environment Action Group, one of the partners of the Asian Cities Climate Change Resilience Network (ACCCRN), which was a project funded by the Rockefeller Foundation from 2008-16 to build an inclusive climate change resilience network that focused on poor and vulnerable segments. Also, summers are getting extended into winter, albeit with temperatures lower at 20-30 degrees, which provides a very conducive breeding ground – coupled with drainage problems of course – for mosquitoes. Hence, there has been a spike in cases of dengue, malaria, chikungunya and other vector borne diseases in recent years, the ACCCRN research found. This is an obvious fallout of higher temperatures – meaning more power needed to run fans and ACs, to draw water from borewells, etc.

Power

With rising temperatures, the demand for power has also risen over the years. Peak power demand, Delhi's power minister Satyendra Jain expects, will touch 7,000 MW – the highest ever – in June, which is generally the hottest month of the year. Last year, it was 6,526 MW. According to media reports, in March, peak power was 1,57,000 MW – a 15% increase from that a year ago, with Delhi and UP leading the list. The fallout of this – given that power generation has not kept pace with demand – is that governments are forced to buy power from the open market at a higher rate.

Rising food prices

Higher temperatures have a grim, direct impact on agriculture. Since a majority of farming continues to be rain-fed in India, it leaves them vulnerable to drought caused by prolonged hot weather and the drying up of water bodies, say experts. Over the years, this has led to a shrinking of farmers' livelihoods, affecting their yields of several crops, leading to scarcity, and higher prices. Vegetables and fish, both of which rely on a ready supply of freshwater, are affected.

In 2014, for instance, Delhi faced a huge shortage of onion owing to a prolonged heatwave, which affected the produce in Madhya Pradesh, and also led to the stocks in godowns in Rajasthan and Maharashtra getting spoilt. Naturally, prices doubled or went higher over the course of a few weeks. Another food crop that has been especially hit by rising temperatures over the years is wheat. A study published in 2014 by the University of Southampton found that warmer temperatures, especially higher minimum temperatures during the reproductive and ripening periods, had a significant negative impact on the produce. A more recent study, published last year in the Journal of Climatology & Weather Forecasting by two researchers from the Pandit Deendayal Petroleum University in Gandhinagar concluded that for every one degree Fahrenheit increase in temperature, crop yields in the kharif and rabi seasons would go down by 3% and 5% respectively.

Wildlife

Last year, researchers in Wayanad district, one of four climate change hotspots in Kerala, observed that Raorchestes charius, a bush frog species, which is listed 'endangered' by the International Union for Conservation of Nature, has moved to a higher altitude from its usual habitat, at a height of 900-1,500 metres in the Chembra peak region of Western Ghats. Raorchestes tinniens, another endangered frog species, which lives in these higher altitudes, they found, had also changed its habitat, moving higher up in the hills. The reason – rising temperatures, and changing precipitation patterns in Wayanad. These rare frog species are not the only ones facing the heat – snow leopards in Ladakh have been pushed to higher altitudes in the Himalayas by the receding snow line caused by higher surface temperatures – the most perceptible evidence of climate change.

A 2016 study by the University of Edinburgh found that for every one degree Celsius increase in temperature, birds, on an average, reached their summer breeding ground a day earlier. It is also the reason, among others such as deforestation and changing vegetation in forests, migratory birds are seeking nesting grounds in newer places, away from their traditional ones. A WWF study published this March makes the connection between rising temperatures and biodiversity – if global temperatures rise by less 2 degrees Celsius, 25% of species in 35 biodiversity hotspots around the world will be at risk of local extinction; if it rises by 4.5 degrees Celsius almost 50% of species will be at risk.

Need the dangers be spelt out any clearer?