Marine heat waves already appear every year in the Arctic and will become more common in the near future due to greenhouse gas emissions, which are behind human-induced global warming.
That is the conclusion of a study carried out by researchers from the University of Hamburg and the Max Planck Institute for Meteorology (Germany), and published in the journal Nature Communications Earth.
Officially, a marine heat wave is considered when water surface temperatures exceed 95% of the values of the last 30 years for at least five consecutive days.
The study notes that Arctic conditions have changed since 2007. Between that year and 2021, the marginal areas of Earth's northernmost ocean experienced 11 marine heat waves, producing an average increase of 2.2 degrees above normal. normal in the summer season and lasted an average of 37 degrees.
Additionally, heat waves in the Arctic have occurred every year since 2015, according to researchers. The most powerful heat wave to date in that area of the planet occurred in 2020. It lasted 103 days and had maximum temperatures four degrees higher than normal.
The probability of such a heat wave occurring without the influence of anthropogenic greenhouse gases is less than 1%, according to the study, which indicates: “Annual marine heat waves will be the norm.”
On the other hand, researchers have shown for the first time that heat waves occur when sea ice melts early and quickly after winter. A considerable amount of heat energy is then accumulated in the water when maximum solar radiation is reached in July.
“In 2007, a new phase began in the Arctic,” says Armineh Barkhordarian, an expert in climate statistics at the University of Hamburg, before adding: “There is less and less ice that is thicker and several years old, while the percentage of thin, seasonal ice is constantly increasing."
Barkhordarian emphasizes: "Not only the continued loss of sea ice, but also warming waters can have dramatic negative effects on the Arctic ecosystem." Food chains could then collapse, fish populations reduce and biodiversity decline.
