Context
The United Kingdom experienced its highest temperature ever recorded, surpassing 40°C. Temperatures in parts of France, Spain, and Portugal ranged from 42 to 46 degrees.
Relevance
GS Paper 3: Climate Change
Mains Question
Heat waves are among the most dangerous natural hazards, and their frequency and intensity will increase in the twenty-first century as a result of climate change. Discuss (250 Words).
Why in the news?
- Dozens of towns and regions across Europe have been devastated by what has been described as a “heat apocalypse” this year.
- Wildfires in southwestern France have destroyed 19,000 hectares of forest due to a combination of extreme heat and dry weather.
Heatwaves
- Between March and June, India experiences heatwaves.
- The IMD declares a heatwave event when the maximum (day) temperature in the plains exceeds 40 degrees Celsius.
- The temperature over the hills is 30 degrees Celsius.
Heatwaves Occurrence
- Heatwaves occur when high pressure aloft (3,000-7,600 metres) strengthens and persists over a region for several days to several weeks.
- This is common in the summer (both in the Northern and Southern Hemispheres) because the jet stream ‘follows the sun.’
- The high pressure area is located on the equator side of the jet stream, in the upper layers of the atmosphere.
- Summer weather patterns change more slowly than winter weather patterns. As a result, the upper level high pressure moves slowly as well.
- When pressure is high, the air subsides (sinks) toward the surface, warming and drying adiabatically, inhibiting convection and preventing cloud formation.
- Cloud removal increases the amount of shortwave radiation reaching the surface.
- Surface low pressure causes surface wind from lower latitudes to bring warm air, enhancing warming; alternatively, surface winds may blow from the hot continental interior towards the coastal zone, causing heat waves.
The Effects of Heat Waves
- Heat Strokes: Extremely hot or humid conditions increase the risk of heat stroke or heat exhaustion.
- Healthcare crisis: Extreme heat is also linked to an increase in hospitalizations and emergency room visits, an increase in deaths from cardio-respiratory and other diseases, mental health issues, poor pregnancy and birth outcomes, and so on.
- Productivity loss: Extreme heat reduces worker productivity, particularly among the more than 1 billion workers who are regularly exposed to high temperatures.
- Wildfire Risk: Heat domes act as fuel for wildfires, which destroy a lot of land area every year in countries like the United States.
- Prevents Cloud Formation: The condition also prevents clouds from forming, allowing more sunlight to reach the ground.
- Impact on Vegetation: Heat trapping can harm crops, dry out vegetation, and cause drought.
- Increased Energy Demands: The sweltering heat wave raises energy demand, particularly for electricity, causing rates to rise.
- Power Issues: Heat waves are frequently high-mortality disasters.
- Infrastructure failure: Avoiding heat-related disasters is dependent on the electrical grid’s resilience, which can fail if electricity demand from air conditioning use exceeds supply.
Europe’s extreme heat waves
- Scientists are nearly unanimous in their belief that the heat waves are the result of human-caused climate change.
- Global temperatures have already risen by more than 1°C, and studies in the United Kingdom have shown that a one-degree increase in temperature increases the likelihood of the country experiencing 40°C by tenfold.
- Rising global temperatures, which resulted in deviations from the norm of up to 15 degrees in Antarctica and more than 3 degrees in the north pole this year.
The major factor
- In the case of the United States, the record temperatures are being linked to changes in the jet stream, which is a narrow band of westerly air currents that circulates several kilometres above the earth’s surface.
- While a traditionally strong jet stream would bring cooler air from the northern Atlantic, the jet stream has weakened and split in recent years.
- This has resulted in more intense and frequent heat waves across parts of the American continent.
