1705023384 The longest heat wave in the last 40 years occurred

The longest heat wave in the last 40 years occurred in the Mediterranean – Libre Média

Between 2022 and 2023, the Mediterranean experienced the longest heat wave since 1981. The extraordinary data emerge from the project's research CARE heat (Detection and Threat of Marine Heatwaves), funded by the European Space Agency (ESA), carried out in Italy by ENEA and Cnr and published in the journal Lettres de recherche environnement, which aims to develop and develop new methods for predicting and identifying heatwaves understand their spread She Effects on the environment, biodiversity and economic activities such as fishing and aquaculture.

In research it is Satellite data with those who come here In situ observations made by Lampedusa Spa, the only website in Europe that can provide information on the interactions between vegetation, atmosphere and ocean in both carbon exchange and all the processes and energy exchanges that regulate the region's climate. In addition, using modeling simulations and state-of-the-art data processing systems, researchers were able to characterize the anomaly that affected the period in question.

The Mediterranean has been proven to be a climate change hotspot

As we have said several times, the Mare Nostrum is considered real Hot spots of ongoing climate changethat is, one of the areas of our planet where the effects of global warming are accelerated and intensified and therefore manifest themselves more quickly and intensely than elsewhere.

But what do we mean by a marine heat wave? Similar to heatwaves on land, abnormal warming of the sea occurs, with levels above normal and lasting for days or weeks. Unfortunately, due to the global climate crisis, we are facing increasingly intense, frequent and longer-lasting marine heatwaves.

As if that were not enough, heat waves in the Mediterranean, as in all other basins, damage not only local ecosystems, but also our economy: the unusual increase in temperature leads to increased stress on underwater life and can lead to death. and biodiversity losses, even more serious.


Between May 2022 and May 2023, the worst heat wave since 1981

The summer of 2022 will be remembered as one of them The hottest and driest weather ever recorded in Europe: The stubborn persistence of anticyclonic conditions of African origin – which we know to be associated with the sun, stable and warm weather – has led to a significant increase in temperature not only on the continent but also on the ocean surface.

At the beginning of spring 2022, surface temperatures in the Mediterranean were within the climatic norm for this period, but from May onwards the temperature began to rise significantly. Starting on the 8th of the same month, the anomaly jumped to 1.5°C in less than a week. The warming was particularly exceptional in the western sectors, where local temperatures were reached 4°C more compared to normal. In the following weeks, new drops and rises in temperature followed. In July 2022, an intense heat wave hit the western Mediterranean and the Ionian Sea: it was during this phase that the anomalies reached 5°C difference. In the following months, the overall anomaly remained between 1 and 1.5°C until October. Between November and December the heat wave appeared to be coming to an end, but we saw a further increase in anomalies, with a new peak in January 2023.

Even if the peaks are comparable to those achieved during the hot summer 2003According to scientists, this intense marine heat wave lasted significantly longer: the one in 2003 lasted from June to November, the one in 2022 lasted 12 months.


The causes of the unusual heat wave in the Mediterranean

The exceptional duration of the marine heat wave also contributed to this wind, is considered one of the “atmospheric forcings” that influence the seas and oceans. As the wind caused vertical heat mixing between the ocean surface and the underlying layers, the excess energy was stored beneath the surface, favoring the persistence of warm anomalies for several months.

In addition there was this atmospheric configuration in autumn and winter which has experienced significant persistence and prevalence anticyclonic conditionswithout rain and snow, which means that the heat wave extends into the coldest months.

Gianmaria SanninoHead of Models and Technologies for Reducing Human Impacts and Natural Risks at ENEA, commented on the data from this study saying:

The CAREheat results only bring to our attention some of the signs of climate change, but we must be aware that we are only at the beginning of a larger process and that we are confronted with the signs of what is to come. They are becoming more and more common. In this context, research is and remains a key element to inform and guide future environmental policies, as COP28 finally concluded: In fact, the outcomes of the last Conference of the Parties in Dubai will guide the updating of plans for the National Climate Action Plans 2025, for more ambitious actions and targeted financing.