NEW YORK — The number of marine heatwave days has roughly doubled between 1982 and 2016 and will further increase as the planet warms, a recent study has found.
The study, conducted by a group of Swiss researchers, said 87 percent of marine heatwaves at present can be attributed to human-induced warming, while the ratio will increase to nearly 100 percent under any global warming scenario exceeding 2 degrees Celsius.
Marine heatwaves are prolonged periods of anomalously warm seawater temperatures that persist for days to months and can extend up to thousands of kilometers. They occur regionally throughout the global oceans, including marginal seas, continental shelves and the open ocean.
The study, published Wednesday in the journal Nature, warned that frequent and extreme marine heatwaves under global warming will probably push marine organisms and ecosystems to the limits of their resilience and even beyond, which could cause irreversible changes.
So far, marine heatwaves have caused changes in biological production, toxic algal blooms, regime shifts in reef communities and mortality of fish species. For instance, the Mediterranean Sea heatwave in 2003 caused many benthic marine communities to die off.
Earlier this month, the U.S. state of California has recorded an all-time high in seawater temperature off San Diego since daily measurements began in 1916. The record-high temperature of 81.3 degrees Fahrenheit (around 27.4 degrees Celsius) has made headlines worldwide.