COLD WAVES 

A cold wave (known in some regions as a cold snap or cold spell) is a weather phenomenon that is distinguished by a cooling of the air. Specifically, as used by the U.S. National Weather Service, a cold wave is a rapid fall in temperature within a 24-hour period requiring substantially increased protection to agriculture, industry, commerce, and social activities. The precise criteria for a cold wave are the rate at which the temperature falls, and the minimum to which it falls. This minimum temperature is dependent on the geographical region and time of year.

In the United States, a cold spell is defined as the national average high temperature dropping below 20 °F (−7 °C).[2] A cold wave of sufficient magnitude and duration may be classified as a cold air outbreak (CAO)

A cold wave, sometimes known as a cold snap or deep freeze, is a weather event involving a cooling of the air, or the invasion of very cold air, over a large area. It is marked by a drop of average temperature well below the averages of a region. Cold waves can have negative impacts on people, crops, properties and services. They can be preceded or accompanied by significant winter weather events, such as blizzards or ice storms. And they can feel even colder during periods of high winds.

Cold waves are caused by two natural patterns rendered more extreme by climate change. La Nina is a climate pattern responsible for making winters colder in northern countries which include Jordan, Lebanon, Syria, Egypt, and Iraq. Aggravated by climate change, la Nina started in October 2021 and reached its peak in January 2022. The second pattern is the polar vortex. It brings cold air from the north pole into countries situated in midlatitudes, such as the countries affected by this cold wave, when destabilized by a warmer earth caused by global warming. 

The effects of this cold wave, like every impact of climate change, weren’t felt equally by all communities as some suffer more greatly than others. These weather events mostly affected the poor and the displaced. Living in camps, with no appropriate clothing and lack of heating, Syrian refugees and the Yazidis are examples of those groups. Trapped in the snow, they faced food shortages, had some of their tents destroyed and witnessed the death of children.

In Lebanon, the lack of electricity and the soaring in fuel prices following the economic crisis affected the poor who had no means for heating.

Finally, farmers around the region saw the death of their cattle and their yields greatly impacted by the cold wave leading to financial losses.

Many animals who were not able to bear such cold temperatures were impacted as well. This includes the death of cows and chickens in farms but also certain animals that the cold froze such as donkeys in Turkey and iguanas in the US. Also, many trees fell as a result of the high wind speed.

Extreme events will become more frequent as climate change intensifies. To reduce their harm, two steps must be taken by countries: reduce GHGs emissions to limit the effects of climate change, especially for the most highly emitting countries in the global North, and drafting and implementing policies around measures to adapt to those extreme events. 

COLD WAVES IN INDIA

The weak La Nina conditions in the Pacific Ocean are favourable for cold waves in India. Based on departure of minimum temperatures, cold and severe cold waves are regarded as negative departures from normal i.e. 4.5°C to 6.4°C and more than 6.4°C, respectively. According to the Accidental Deaths and Suicides in India reports, the intense cold wave killed roughly 26,167 people in various States from 1972 to 2019. Per the IMD, the number of fatalities due to cold wave has risen sharply to 722 in 2011 from 490 deaths in 2001.

The impact of cold wave fatalities varies across States due to their diverse geo-climatic conditions and varied socio-economic vulnerability.

Vulnerable States

Central and northern India — Punjab, Himachal Pradesh, Uttarakhand, Delhi, Haryana, Rajasthan, Uttar Pradesh, Madhya Pradesh, Chhattisgarh, Bihar, Jharkhand — are most vulnerable to cold wave.

According to data, Uttar Pradesh, Bihar, Punjab, Madhya Pradesh, Haryana, and Rajasthan have been impacted severely in terms of fatalities from a cold wave. Between 1972-2019, cold waves claimed 1,796 lives in Uttar Pradesh, followed by Bihar (3,941), Punjab (3,261), Madhya Pradesh (1,635), and Haryana (1,499).

On average, 38 people were killed per 10 million populations per year due to cold waves in Himachal Pradesh, which is the highest among the States, followed by Punjab, Uttarakhand and Jharkhand. Kerala accounted for the least number of cold wave fatalities. Cold waves have posed serious constraints to productivity and growth by causing extensive human and environmental losses. Cold waves have a variety of consequences, including negative effects on human health. Frostbites, hypothermia, and other major medical problems might occur due to an unexpected cold spell. In locations where there are frequent cold waves, the mortality rate is significantly higher.

Several initiatives and measures have been undertaken to mitigate and adapt to other extreme weather-related shocks, but such initiatives are not adequate to prevent human fatalities. Still, it remains a challenge to take standardised preventive, mitigation, and preparedness measures.

To mitigate the impact of cold waves, adequate disaster adaptation measures and better disaster management policies are essential.

As deaths due to cold waves are preventable, the government must prioritise preparing long-term action plans to safeguard human lives, livestock, and wildlife.

Greater spending towards disaster management activities, including improving early warning systems, better rehabilitation measures, and providing shelter facilities during cold days, would help minimise the loss of human lives.

Formation of Cold Waves

In the Northern Hemisphere, cold waves occur when very cold, dense air near the surface moves out of its source region in northern Canada or northern Asia.

The core of a cold wave at the surface is a strong high-pressure center that forms during winter in high latitudes. Cold polar or Arctic air masses are relatively shallow, extending one to several km above the surface. The surface high-pressure center of the cold air is accompanied with a upper-level convergence. The most extreme area of all is northern Asia (Siberia), where the formation of cold surface air is enhanced by the large distance to the nearest unfrozen ocean, isolating the area from warmth and moisture, and the presence of mountains to the east and south, serving as barriers to trap and further isolate the cold surface air once it has formed.

Effect on persons and economic activity

  Exposure to extreme and especially unexpected cold can lead to hypothermia and frostbite. Which require medical attention due to the hazards of tissue damage and organ failure. 

 They can cause death and injury to livestock and wildlife. 

 Exposure to cold mandates greater caloric intake for all animals, including humans. 

 If a cold wave is accompanied by heavy and persistent snow, grazing animals may be unable to reach needed food and die of hypothermia or starvation. 

 They often necessitate the purchase of foodstuffs at considerable cost to farmers to feed livestock . Such cold waves have caused famines.

  At times as deadly to plants as drought, cold waves can leave a land in danger of later brush and forest fires that consume dead biomass. 

 Water mains may break and water supplies may become unreliable, making fire fighting more difficult.

  People can stock up on food, water, and other necessities before a cold wave.

  Some may even choose to migrate to places of milder climates, at least during the winter.

 Effects of cold wave on other sectors 

 Deaths caused by cold weather in comparison to hot weather is true as a result of the after effects of these temperatures

  Demand for electrical power and fuels rises dramatically during such times 

 Some metals may become brittle at low temperatures.

  Motor vehicles may fail as antifreeze fails and motor oil gels, resulting even in the failure of the transportation system. 

 Fires become even more of a hazard during extreme cold.