Extreme heat is defined from a baseline of average temperatures at a single location, which vary widely around the world. Temperatures of 25 degrees Celsius (77 degrees Fahrenheit) could be record-breaking in parts of Canada in the spring, but may be below the average for the same period in the Middle East.
Gasses such as carbon dioxide, methane and nitrous oxide play a critical role in stopping heat from being reflected or lost from our atmosphere. When these processes are balanced, it keeps the planet at a habitable temperature.
According to Martin Jucker, lecturer at the Climate Change Research Center at the University of New South Wales in Australia, heat-trapping greenhouse gasses are the root of the problem. But an unsustainable increase in the amount of greenhouse gasses in the atmosphere means more heat is trapped, creating an overall global warming effect and other climate anomalies.
For example, warmer air holds on to more moisture, which results in stronger and more frequent storms. According to scientists, climate change is amplifying the duration, intensity, and geographic range of heat waves.
Effects on urban areas and health
Some places or cities are warmer than the surrounding rural areas. There is very little green plant to absorb heat, coupled with the use of cooling technology such as air conditioning creating a surge in demand for energy, including fossil fuels which are the main cause of the climate crisis.
As well as impacting the climate crisis, exposure to higher-than-normal temperatures is producing health problems ranging from heat stroke and dehydration to cardiovascular stress. The deadliest was the combination of soaring temperatures and high humidity, where the damp air impairs the body’s ability to cool off by sweating.
In May, a study warned that a fifth of the world’s population would be exposed to extreme and potentially life-threatening heat by the end of the century in our current climate path. Those with pre-existing heart conditions are especially vulnerable and at risk, because the body’s response to heat is to pump more blood to the skin to help with cooling.