Last updated on July 16, 2018
The met department says there is 47 per cent probability of maximum temperature being more than normal in states of northern and central India, with heat wave conditions expected
In line with the global trend, 2016 was one of the warmest years on record for India since 1901. The scene might be worse this time. The Indian Meteorological Department (IMD) said that temperatures — minimum, maximum as well as the mean — are likely to be “above normal” till June in every meteorological sub-division of the country. In other words, the IMD has predicted a hotter than usual summer. In its summer outlook for this year, the Indian Northwest India and the plains near the Himalayas are likely to face particularly warmer summer this year with temperatures likely to be more than 1°C above normal.
The IMD said the deviation from the normal temperature would reduce progressively while moving towards the southern regions of the country. It said there was “47 per cent probability” of maximum temperatures being more than normal in the states of Punjab, Himachal Pradesh, Uttarakhand, Delhi, Haryana, Rajasthan, Uttar Pradesh, Gujarat, Madhya Pradesh, Chhattisgarh, Bihar, Jharkhand, West Bengal, Odisha and Telangana, and a few other regions.
It warned that these areas were likely to experience “above normal moderate to severe heat wave conditions” during this period. The IMD said “border line” to “weak” La Ninaconditions were currently prevailing over the Pacific Ocean and these were likely to weaken further and become neutral ahead of the monsoon season. As such, the sea surface temperatures in the Pacific Ocean were unlikely to have any influence on the summer temperatures over the country, it said.
The MeT office said average temperatures in Delhi, along with neighbouring states of Haryana, Punjab and Rajasthan, can soar over 1.5 degrees Celsius above normal levels. It projected maximum rise of more than 2.3 degrees higher than usual temperatures in hilly states of Himachal Pradesh and Uttarakhand.
The temperature rise is likely to be moderate in south India and four north-eastern states. India normally experiences hot weather and heat wave conditions during March to July period. During the 2018 pre-monsoon Season (March to May) warmer than normal temperatures are likely in all meteorological sub-divisions of the country.
Seasonal (March-May) average temperatures over many of the subdivisions from northwest and neighbouring central India are likely to be above normal by more than 1 degree Celcius, the IMD said in a release. Normal to above normal heat wave (HW) conditions are likely over core heat wave zone of the country, the release adds.
There is about 52% probability of grid point maximum temperatures in the core heat wave zone during March to May 2018 to be above normal. Core Heat Wave zone covers states of Punjab, Himachal Pradesh, Uttarakhand, Delhi, Haryana, Rajasthan, Uttar Pradesh, Gujarat, Madhya Pradesh, Chhattisgarh, Bihar, Jharkhand, West Bengal, Orissa and Telangana and meteorological subdivisions of Marathwada, Vidarbha, Madhya Maharashtra and coastal Andhra Pradesh.
The forecast indicates above normal maximum, minimum and the mean (average) temperatures in all the subdivisions. Overall, the temperature anomaly patterns show an increase in the magnitudes of the anomalies from south-eastern parts to the north-western parts of the country. The seasonal average maximum temperature is likely to be warmer than normal by 1 °c over Jammu & Kashmir, Punjab, HCD (Haryana, Chandigarh & Delhi), Himachal Pradesh, west and east Rajasthan, Uttarakhand, west and east Uttar Pradesh, west and east Madhya Pradesh, Bihar, Jharkhand, Chhattisgarh, Vidarbha, Gujarat and Arunachal Pradesh.
It is likely to be 0.5°C more over Kerala, Tamil Nadu, south interior Karnataka and Rayalaseema. Remaining subdivisions are likely to experience maximum temperature anomalies between 0.5°C & 1°C. Environment experts feel that the IMD’s forecast of above-normal maximum and minimum temperatures across the country during the pre-monsoon
March-May period is a timely alert for state authorities to review their preparedness. Even a marginal rise above the normal will lead to enormous heat stress for millions of Indians. Moreover, there are distinct groups at particular risk for health-related problems during a heat wave, such as senior citizens and people with pre-existing disease, mental illness or disability, which prevents them from being able to care for themselves.
Experts say it is the responsibility of government to ensure that community-level interventions are taken up to help vulnerable groups. The advent of hot weather this year is marked by temperatures rising between 1.6° Celsius and 5° C above normal in States such as Rajasthan, Jammu and Kashmir, Uttarakhand, Uttar Pradesh, Himachal Pradesh and Madhya Pradesh; other northern, central and eastern states also show a small increase from March 1.
Of course, Tamil Nadu, Puducherry and parts of Rayalaseema have begun the season with a slight decrease in minimum temperatures, and will possibly have less oppressive temperatures in coming weeks. For most other states, though, the summer of 2018 may pose a public health challenge, for which they must prepare with the experience gained during the many previous heat waves.
One scientific estimate of annual mortality attributable to heat waves between 2010 and 2015 ranges between 1,300 and 2,500. A spike in summer temperatures in India is not new, but some scientists contend that a half-degree rise in average temperature in recent decades has resulted in a higher probability of extreme heat waves and caused a lot of deaths.
The World Health Organisation recommends that countries adopt heat-health warning systems, including daily alerts to ensure that people are in a position to deal with adverse weather, starting with reduction of exposure. Water stress is a common and often chronic feature in many states and timely steps must be taken to meet the scarcity. A silver lining is that the southwest monsoon this year will benefit from an (page 3) PF- 51/2018 expected moderate La Niña condition in the equatorial Pacific, marked by cooler-than-average sea surface temperature.
Taking a long-term view, India has to pursue mitigation of greenhouse gases vigorously, since there is a perceived link between increases in average temperature caused by climate change and the frequency and intensity of extreme weather events.