“New record high temperatures will be set for the planet”

By Dr. John J. Hidore

Defining Heat Waves

At the time of this writing the northern hemisphere is experiencing widespread heat waves. When it seems unusually warm someplace there is a tendency to describe it as a heat wave. The reason is simple. Normal high temperatures vary greatly from place to place. So what would be defined as a heat wave in one location would not be appropriate for another location, perhaps one not even too far away. Perhaps an adequate definition might be, “A heat wave is an unusually warm or hot period lasting for days or perhaps weeks.” We associate them with summer but by this definition they can actually occur at any season.

At least one country makes a clear definition of a heat wave and that is Pakistan. India defines heat waves and uses different temperatures in different parts of the country to establish what constitutes a heat wave. In the plains regions temperatures above 40degrees C (104degrees F) constitute a heat wave. They also define a severe heatwave for this region as experiencing temperatures over 46degreesC (114.8degrees F).

Indian Heat Wave of 2016: Prolonged and Widespread Extreme High Temperatures

India experienced unusually high temperatures this year. Temperatures were above normal most of the spring. Normally, the hottest months of the year are April, May, and June, before the summer monsoon rains begin. In May a severe heat wave alert was issued for several states. A severe heat wave is one in which temperatures of at least 117°F (47.2°C) occur. In the city of Philodi, in western India, unofficial temperatures reached 124°F (51°C). This is the highest temperature on record in India. Temperatures averaged above 104degrees F (40°C) over large areas. Some urban high temperatures were:

New Delhi 47 °C (117 ºF)
Churu 50 °C (122 ºF)
Philodi 51.°C (124 ºF)

The impact on the country was immense. More than 300 million people were adversely affected. Crops failed or were below average in 13 states in the last growing season. Thousands of farmers abandoned their farms. In places, the asphalt on the streets partially melted. At Bikaner, the streets were being sprinkled with water to reduce the heat. Some 17,000 villages had, or were facing water shortages. Several Indian states shut down schools to reduce risk to students. Heatstroke was a widespread problem and many deaths were reported across the region .Fortunately, the government responded in a variety of ways to reduce the suffering and mortality.

Asian heat waves of 2015

This year a May heat wave in India claimed at least 2,500 lives. Heat waves are fairly frequent in India, but this was the greatest loss of life from a heat wave in over 30 years. Extremely high temperatures were reached in cities scattered over the country. Power outages were wide spread as a result of high demand for air conditioning. The city of Khammam recorded the highest temperature ever recorded there at 48o C (118.4 degrees F). Other high temperatures that were recorded were:

Allahabad 47.8 degrees C (118.0 degrees F)
Delhi 45.5 degrees C (113.9 degrees F)
Hyderabad 46 degrees C (115 degrees F)
Jharsuguda 45.4 degrees C (113.7 degrees F)

In June the deadliest heat wave known to have occurred in Pakistan took place in the southern part of the country near Karachi. The death toll is unknown for certain but may have reached more than 1000. It followed by several weeks the severe heat wave that struck India. The heat wave struck during the month of Ramadan which made the impact of the event more severe than it might have been. Unfortunately, city services were not in condition to cope with the heat.

2003–A deadly heat wave in Europe

Perhaps the most deadly heat wave of the 21st Century was that which occurred in Europe in August of 2003. Temperatures in France reached as much as 40°C (104oF) and remained exceptionally high for two weeks resulting in nearly 15,000 deaths in that country alone. The death toll over Europe reached 35,000 at least and may have been as high as 50,000. A large contributing factor in the high death toll was warmer nighttime temperatures. Nighttime temperatures were much warmer than normal. As a result people without air conditioning could not cool down during the night. The heat stress accumulated over time. Extreme heat waves also can devastate agriculture. In Europe in the heat wave of 2003 temperatures averaged 5.5°C (10°F) above normal. In Italy corn yields dropped 36% below average. In France fruit yields fell 25% and wine production 10%. Heat also affects the rate of plant pollination.

As the planet warms it can be expected that: (1) there will be more severe heat waves. and (2) they will become hotter, more frequent, last longer, and occur in more varied places. New record high temperatures will be set for the planet. As cities grow larger in area and population they will experience increasing heat waves.

Heat Waves