There were three heat waves in the Balearics between June and August, and there were also three marine heat waves over the same period.
While qualification for a heat wave for high temperatures is a minimum of three consecutive days, a marine heat wave requires water temperature to be above normal for at least five consecutive days. As there have been three this summer, the director of the Socib coastal observation system, Joaquín Tintoré, says that these are a "very serious" sign of climate deterioration.
The last of these heat waves occurred on August 9, when there was an average seawater surface temperature of 29.1C. This was 3.3 degrees above the average for the same day for the period 1982-2015 and equals the record of 29.1C on August 10, 2003.
On July 20, there was an average surface temperature of 28.2C, 3.4 degrees above the average for this day over the past 40 years. In the third week of June, temperatures reached 26C, unusual for the time of year.
Tintoré explains that "climate change implies a general increase in temperature and in extreme weather phenomena, which are heat waves in summer and storms in winter". "The Intergovernmental Panel on Climate Change has been warning for years that extreme events are going to be more and more intense as well as longer and earlier. This is what has happened this year. Heat waves have come earlier than before, they have been longer in duration and very intense."
He adds that rising temperatures and extreme heat events threaten marine ecosystems and will affect marine species and habitats such as posidonia sea grass because of impacts like sea acidification. They are likely to mean more jellyfish and harmful algae.