Heat waves and their relation to climate change

Many places suffer from high temperatures throughout the summer season. In fact, the heat can be really extreme for several days, weeks or even months. This phenomenon is known as heat wave, and has very important consequences on health, climate and the environment.

What is a heat wave?

A heat wave is a episode with abnormally high temperatures that lasts for several days, weeks or months, affecting a large part of a country’s geography. As for the duration, there is no consensus on how many days this episode must last in order to be considered a heat wave. In addition, the criteria will depend on each country.

In Spain is considered to be experiencing a heat wave. when extremely high temperatures[1] are recordedat 10% of the weather stations for at least 3 consecutive days. However, in the United States, this weather event will be considered to be occurring when temperatures exceed 32.2 degrees for at least 3 days.

[1] Above the 95th percentile of its daily maximum temperature series for the months of July and August.

When do heat waves occur?

The vast majority of the time, heat waves occur during the canicular period, which usually coincides with the summer season. The heat wave is the hottest period of the year, which usually coincides with the summer, specifically between July 15 and August 15.

This is because, as the summer progresses, the ocean water and the earth’s soil heat up, which is why the highest temperatures tend to occur in mid-summer. In any case, these dates are approximate, as they will depend on the location.

How are heat waves related to climate change?

On August 9, 2021, the Sixth IPCC Report was published (
Intergovernmental Panel on Climate Change)
. The paper concludes that climate change is a present problem and that the average global temperature has risen by 1.1°C since pre-industrial times. Climate change is affecting the entire world and the process is rapid and intense, so we need to act as soon as possible.

According to experts from the World Meteorological Organization, these increasingly intense and long-lasting heat waves bear the signature of the climate change that mankind’s actions are causing. Experts also warn that if greenhouse gas emissions continue to increase, temperatures will rise by 4.5°C by the middle of the 21st century. However, the rise in temperature in some parts of the planet has devastating consequences. Thus, high temperatures migrate from Europe and Africa to the north of the globe, causing what we know as the melting of the poles. This phenomenon, already catalogued by international experts as irreversible, has its reference point in Antarctica, where the rise in sea level is most evident as a result of this melting.

Human action in climate change

Taking all these data into account, it is clear that heat waves are nothing more than the consequence of the increase in global temperatures due to the concentration of greenhouse gases.

Furthermore, the IPCC Fifth Assessment Report stated that, with a high probability, the evolution of our society has contributed negatively to these changes. The IPCC has also studied the health risks associated with rising temperatures. Climate change undoubtedly negatively affects food security, economic growth and water supply, among other factors.

Heat wave and hydrological consequences

Periods of high temperatures only worsen the most vulnerable drinking water supply situations in certain parts of the world. According to a University of California paper published in ‘Nature Sustainability’, nearly one-fifth of the world’s population lives in an overexploited water basin. The top 10 percent of the most stressed watersheds supply about 19 percent of the world’s population, 19 percent of thermal electricity generation, and one-third of irrigated agricultural production.

In addition, the researchers found a significant decrease in water quality in the regions most affected by water stress during the 37-year study period. This lack of quality, which affects drinking water in particular, could be compensated by the application of new techniques and technologies, such as the use of
Atmospheric Water Generators
among others.

In short, heat waves are a reality that brings with it devastating consequences for the planet. Worsening health, increased mortality (especially in the most vulnerable people such as the elderly, children and people with some disease), as well as forest fires, increased electricity and water consumption, are just some of the most serious consequences of this phenomenon against which we must continue to fight every day.