Canvi climàtic

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Climate change

Heat Wave Accentuation

RISKS DESCRIPTION

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Heat waves are periods of abnormally high temperatures (more than 5 ºC above average) that last at least five days. They normally occur due to the existence of slow-moving, dense masses of very hot and dry air, which in the Mediterranean regions emanate from North Africa and are loaded with dust. In cities, the heat island effect increases the risks associated with this weather phenomenon.

Outside of the cities, a heat wave may cause a drought that affects plants and animals, increases forest fires and damages electrical circuits, electronic devices and roads.

In urban areas, the high degree of impermeability of large tracts of land that absorb heat, the large number of buildings, and the high demand for energy represent in and of themselves a significant increase in the ambient temperature (a heat island), generating serious implications and heightened negative consequences for the human population and for other species that inhabit the city.

These phenomena prevent the air from being renewed and the temperature from decreasing at night, they increase the number of days with high temperatures, they alter the phenological rhythms of species, and they make it increasingly difficult to benefit from physically and mentally restorative nocturnal rest.

 

HEALH EFFECTS

Excess heat causes the body to lose vital liquids and mineral salts and if it persists, it produces an increase in deaths due to respiratory and cardiovascular diseases, especially in certain sectors of the population, such as newborns, small children, the elderly and sufferers of chronic diseases.

When exposed to very high temperatures without constantly hydrating or protecting yourself, you may run the risk of suffering heat stroke. The symptoms are variable and include: profuse sweat, paleness, fatigue, weakness, cramp, headache, dizziness, nausea and vomiting, the skin may be cold and wet, the pulse may be quick and weak and breathing may be quick and shallow.

Potential sufferers are advised to drink water frequently, seek protection from direct sunlight and minimise physical activity during the hottest part of the day.

OBJECTIVE

General

  • Mitigate the effects of heat waves in the city and consequently their effects on people's health. Advocate for cities being an integral part of the solution in the fight against climate change.
  • Reduce the heat island effect through correct urban planning.

Specific

  • Increase green spaces in the city, given that they are one of the elements that can help temper the microclimate in squares and streets and they contribute to the reduction of diurnal temperatures.
  • Study the heat island effect in the metropolitan territory and avoid the creation of large expanses that accumulate the heat of the sun.
  • Study areas in the metropolitan territory that have access to water or contain water bodies with a view to their activation in the event of heat waves.
  • Raise public awareness about the effects of heat waves.
  • Increase the thermal comfort of the population, especially in big and compact cities.

PROPOSALS AND RECOMMENDATIONS

  • In heat wave episodes, issue weather warnings and civil defence and emergency alerts.
  • Have preventive measures in place for vulnerable people. Issue recommendations to be followed when at home, at work, in the street, in the car, and in relation to food and drink.
  • Update the census of vulnerable people and the list of air-conditioned healthcare resources and day centres, and strengthen a network of weather shelters.
  • Ensure there are adaptation measures in place to protect workers exposed to severe weather conditions (especially those who work in the open air).
  • Increase the quality and quantity of green spaces and water fountains in the city. Plants release humidity into the environment. The shade provided by trees in the city reduces the ambient temperature in the hottest months of the year. Increase the surface area allocated to green spaces and the number of trees on the streets, where feasible.
  • Foster energy rehabilitation to improve the thermal comfort and characteristics of buildings and public facilities. 
  • Foster the generation and self-supply of renewable energy to prevent dependence on the power grid at peak times.
  • Design the city in such a way that pedestrian routes and spaces are suitably protected from sunlight in summer. Foster the use of balconies, galleries, corbels and other projections to help control the amount of sunshine that reaches the street.
  • Increase the number of green and blue areas in municipalities to increase their cooling effect.
  • Increase the use of draining and permeable flooring.
  • Use light colours for road surfaces and pavements, facades and urban furniture to reduce heat retention.
  • Improve the insulation of buildings to reduce the need for air-conditioning.
  • Include bioclimatic solutions in the design of buildings.
  • Increase air circulation, especially in compact municipalities.
  • Use awnings and plant cover to increase the amount of shade in public spaces. 
  • Publish guides on how to cope with days of extreme heat in order to reduce harmful effects on the health of the population.

REFERENCE EXPERIENCES

LEGISLATION

STUDIES AND TECHNICAL DOCUMENTATION

More information about addressing the Public Health Service: entornurbasalut@diba.cat

Date of last update:
dc., 12 de maig 2021 06:01:02 +0000