Most die of heat stroke. Heat stroke is the most serious heat-related sickness. It can develop when body temperature reaches 40.5 degrees Celsius (or 105 degrees Fahrenheit).
Victims need water and other cooling measures. Untreated heat stroke can lead to organ failure and death. Those who survive can suffer permanent damage.
Deadly heat in Pakistan and India
A heat wave in Pakistan will join this year's heat wave in India as one of the 10 deadliest in world history. Extreme heat has killed more than 1,500 people in Pakistan. High temperatures a few months ago in India killed nearly 2,200 people. Temperatures in areas of India and Pakistan have reached as high as 47 degrees Celsius.
Children sit in plastic containers filled with water as they cool themselves on a hot summer day on the outskirts of Ahmedabad, India, May 2015. (PHOTO REUTERS)
For Pakistan, seasonal rains are expected to begin in the middle of this month which will cause temperatures to drop. The country should be free of the very hot weather that hit recently.
But Europe does not have a similar rainy season to help break the extreme heat. Millions there may continue to suffer temperatures as high as 40 degrees Celsius. The heat wave there began June 27.
Experts say extreme heat will continue in Europe
The World Meteorological Organization says it does not expect an immediate end to the extreme heat. It says extremely high temperatures and dry weather conditions will continue in many parts of Europe.
Clare Nullis is an official with World Meteorological Organization. She says many people are comparing the current heat wave in Europe to that in 2003. That heat wave killed tens of thousands of people. But, she says this latest heatwave began much earlier in the summer season. It is also affecting a much wider area.
However, she also says Europe is much better prepared to deal with the heat wave than it was in 2003.
Are humans to blame?
Omar Baddour is a climate expert at the World Meteorological Organization. He says it is too early to link the current heat waves to man-made climate change.
Villagers use pumps to get water from a partially dried-up pond as drought hits Penglai, Shandong province, China, July 8, 2015.
Mr. Baddour says scientists need to make computer models of the heat wave after it ends. He says the model will be created from information including affected areas, temperatures, the start and end dates and duration of the heat wave. The model will help scientists investigate the cause or causes of the extreme weather.
However, Mr. Baddour says the frequency and the intensity of heat waves seem to fit climate change predictions.
Many parts of the western United States are also suffering from high temperatures and extremely dry conditions. The WMO warns that the states of California, Washington and Oregon are at increasing risk of wildfires as the drought continues. The WMO says Canada is also preparing for severe wildfires.
Extreme heat is also affecting southwestern and southeastern China.
Recent temperatures there have risen above 35 degrees Celsius.
Words in This Story
massive – adj. very severe
duration – n. the length of time that something exists or lasts
frequency – n. the number of times that something happens during a particular period
drought – n. a long period of time during which there is very little or no rain