Rising Temperatures in Europe
Ecology and Environment
28th Jul, 2023
Europe is experiencing scorching temperature that rose to an unprecedented level in the couple of days recently, accompanied by extreme heat waves.
Heat waves and standards:
- A heat wave is a period of unusually hot weather that typically lasts two or more days.
- Several countries have adopted their own standards on heat waves:
- United States: The US National Weather Service defines a heat wave as a spell of “abnormally and uncomfortably hot and unusually humid weather” over two days or more.
- Denmark:A heat wave occurs when the mean of the highest recorded temperature measured over three consecutive days exceeds 28°C (82.4°F).
- Australia:In Adelaide, Australia, a heat wave is defined as five straight days with temperatures at or above 35°C (95°F), or three consecutive days at or over 40°C (104°F).
- India: A heatwave is declared when an area logs a maximum temperature of 45 degrees Celsius.
What is contributing to Europe’s heat waves?
- AMOC: A slowdown in a major ocean current — the Atlantic Meridional Overturning Circulation (AMOC) — could also be contributing to European heat waves.
What is AMOC?
- AMOC is a large system of ocean currents that carry warm water from the tropics northwards into the North Atlantic.
- It moves around 15 million cubic meters of water per second
- Disturbed jet stream: Europe's climate is moderated by the jet stream, a current of fast-moving air that loops around the northern hemisphere from west to east. Sometimes the jet stream splits in two, called double jet. Double jets are normal, but climate change seems to be making them happen more often and last longer.
What are Jet Streams?
- Jet streams are narrow bands of strong wind that generally blow from west to east all across the globe.
- Earth has four primary jet streams:
- two polar jet streams, near the north and south poles
- two subtropical jet streams closer to the equator
- Formation: Jet streams form when warm air masses meet cold air masses in the atmosphere.
- The Sun doesn’t heat the whole Earth evenly. That’s why areas near the equator are hot and areas near the poles are cold.
- So when Earth’s warmer air masses meet cooler air masses, the warmer air rises up higher in the atmosphere while cooler air sinks down to replace the warm air. This movement creates an air current, or wind.
- A jet stream is a type of air current that forms high in the atmosphere.
- Jet streams are located about five to nine miles above Earth’s surface in the mid to upper troposphere.
Impact of Heat waves:
- Health effects: Hyperthermia (heat stroke), constant sickness, overweight and other heat-related illness.
- Psychological and sociological effects: In addition to physical stress, excessive heat causes psychological stress, to a degree which affects performance, and is also associated with an increase in violent crime.
- Increase in surface ozone: Ozone pollutionin urban areas is especially concerning with increasing temperatures, raising heat-related mortality during heat waves. During heat waves in urban areas, ground level ozone pollution can be 20% higher than usual.
- Lead to wild fires: If a heat wave occurs during a drought, which dries out vegetation, it can contribute to bushfires and wildfires.
- Power outages: Heat waves often lead to electricity spikes due to increased air conditioning use, which can create power outages, exacerbating the problem.