heat

Most research has studied marine heatwaves at the sea surface. Now, a study published in Nature Climate Change analyses the effects of these phenomena at depths of up to 2,000 metres. The research, based on data from waves occurring between 1993 and 2019, shows that these waves tend to be more intense between 50 and 200 metres, and that their duration increases up to twice as much with depth compared to the surface, which has an impact on the marine fauna living in that area.

Counting deaths attributable to the effects of high temperatures is basic as a public health surveillance tool, but it should not become the only research objective. It is necessary to know why the population in some places adapts better than others to heat waves, what variables influence them, and to modify them when possible.

In 64 % of the cases, the temperature thresholds that define a heatwave according to the Ministry of Health are below the heatwave threshold established by AEMET. This implies that the population does not perceive situations of risk to their health when they do exist.

An attribution study by World Weather Attribution (WWA) concludes that the heatwaves in Europe and North America this July would have been "almost impossible" without climate change. Over the past few weeks, southern Europe, parts of the United States, Mexico and China have experienced severe heatwaves with temperatures exceeding 45 °C. The WWA report notes that in China the heatwave was at least 50 times more likely due to the climate crisis.

The heat waves that took place in Europe during the summer of 2022 were associated with more than 61,000 deaths on the continent, more than 11,000 of them in Spain. These are the results of a modelling study published in the journal Nature Medicine and led by ISGlobal researchers.

From May to August 2022, 157,580 deaths were recorded, 20.5% more than in the same months of 2019, before covid. This increase in mortality was mainly among people aged 75 years and older. Of the causes of death directly related to the heat, heat stroke and dehydration stood out. These are some of the provisional data published by the National Statistics Institute (INE) in relation to deaths in 2022. Covid-19 was the most frequent cause of death, with 31,559 people dying, 20% less than in 2021.

Heat waves and other events accentuated by climate change affect health, especially for the most socially vulnerable people. To counteract these effects, mitigation and adaptation plans for cities are designed based on scientific evidence, the implementation of which belongs to the local political sphere. Two experts in urban health and climate governance analysed these problems and their possible solutions in a briefing organised by SMC Spain.

Climate change made the late April episode of record temperatures in the Iberian Peninsula, Morocco and Algeria 100 times more likely to occur, with temperatures up to 3.5°C higher than they would have been without the climate crisis. This is one of the conclusions of an attribution study conducted by World Weather Attribution.

The hydrological, meteorological and agricultural drought that is being experienced in Spain, especially in some regions, comes after a 2022 that was the warmest and one of the driest since records have been kept. Researchers Sandra García Galiano (UPCT) and Annelies Broekman (CREAF) participated in an informative session of SMC Spain in which they analyzed the causes, consequences and possible solutions to face this complex natural phenomenon.

The current situation is only the beginning of what may come in the coming decades, which should lead us to increase efforts in mitigation and adaptation strategies: more green and shaded areas, energy efficiency in buildings and avoiding working outdoors in extreme temperatures.