Figure 1 - Ocean warming, by decade, since the 40s
Figure 2 - Satellite image of Cyclone Yasa, December 17, 2020
The study, analyzing data from 2020, showed that today's value of ocean warming is the highest recorded so far
The first study on global warming of the oceans has been completed with data relating to the year 2020 elaborated by an international team of scientists including Italian researchers from the National Institute of Geophysics and Volcanology (INGV) and ENEA.
According to the study entitled 'Upper Ocean Temperatures Hit Record High in 2020', just published in the international magazine Advances in Atmospheric Sciences, The global average ocean temperature in 2020 is the warmest on record yet. But that is not all. The analysis also shows that the five warmest years on record have all occurred since 2015.
Data from 2020 show that the ocean layer between the surface and 2.000 meters deep absorbed 20 Zettajoules of heat compared to the previous year, equivalent to the heat produced by 630 billion hair dryers operating day and night for an entire year .
Because of the ocean's role in modulating Earth's climate, ocean heat content is the best indicator of whether or not the planet is warming. Furthermore, as stated a few days ago for the atmospheric sphere by the European service Copernicus Climate Change, 2020 and 2016 are the two hottest years ever recorded considering, however, that 2016 was the year of El Niño, the climatic phenomenon period that causes a strong warming of ocean waters.
“90% of the heat from global warming ends up in the oceans so really 'global warming' is nothing but 'ocean warming'”, underlines Simona Simoncelli of the INGV of Bologna and Italian co-author of the study together with Franco Reseghetti of the ENEA Marine Environment Research Center S. Teresa.
“Warmer oceans greatly affect local weather conditions, generating more powerful storms and driving sea level rise. The results of the research represent further clear evidence that indicates the need to act as soon as possible to limit the effects of climate change in progress"Simoncelli adds.
The heating value determined in this work also provides a long-term picture. In fact, each of the past nine decades has been found to be hotter than the previous decade. The graph below compares the value for 2020 with some previous decades.
“Observed warming has consequences”, highlights the ENEA researcher Franco Reseghetti. “Planet Earth is getting hotter every year, this is not just a problem of the academic world, because climate change affects our lives and our society on a daily basis. The lives of more and more people are being put in serious danger and sadly not enough is being done to try to limit the harmful effects of global climate change.".
Increasingly warming planet and oceans lead to surprising and terrible effects such as, for example, the huge fires that broke out in Australia, in parts of the Amazon region and in the western United States. Such extreme phenomena are, unfortunately, destined to become more and more common in the future. In addition, warmer oceans lead to greater warming of the atmosphere, and a warmer atmosphere causes more rainfall, more storms and hurricanes, and more intense ones, also increasing the risk of flooding.
For example, a record number of storms hit North America this year in the North Atlantic, Vietnam did the same, and the Fiji archipelago was recently devastated by a Category 5 hurricane ( maximum value). It is therefore the whole planet that is affected by the phenomenon of warming, not just some specific areas.
The countries of the Mediterranean area were also hit by major summer fires (Spain, Portugal, Greece and Italy), and suffered damage from tornadoes and extreme rainfall in the hottest year ever measured in Europe.
According to the researchers “The Mediterranean Sea is no less, on the contrary: among all the areas analyzed in detail in this research, the Mediterranean is the basin that shows the highest rate of warming in recent years, confirming what has already been found in the Report on the State of the Ocean of Copernicus European Marine Service of 2016 and 2018, continuing a process that began about thirty years ago but with a higher increase than in other oceanic areas".
The team scientists were able to complete the study, despite the difficulties associated with the pandemic, thanks to the use of new methodologies for analyzing sea water temperature data and various types of probes which made it possible to reach 2000 m . of depth.
“The results obtained are proof that far-reaching global effects are underway on the environment and society, therefore, the invitation to intervene to significantly limit greenhouse gas emissions and at the same time to adapt to the consequences is strong now inevitable due to the incessant warming that has occurred in recent decades”, conclude the researchers.
In addition to the international collaboration of the highest level, the study is the result of a solid multi-year partnership between INGV and ENEA relating to the analysis of data from the monitoring of the temperature of the water column along the commercial maritime line "Genoa-Palermo" which will continue in the coming three years as part of an INGV project.
Continuous monitoring along this stretch is in fact an important component of the global ocean observation system.