Mongabay · Climate & nature

New global maps chart 40 years of ocean heat and acidification extremes

Researchers have created the first global maps detailing the frequency, intensity, and duration of marine heat waves that occur simultaneously with ocean acidification events over the past 40 years.

Using satellite data and ship samples, scientists used machine learning to identify these compound "double-hit" events, finding they occur more often than by chance. One event in the Southern Pacific in 2016 lasted eight months.

The study reveals that while most compound heat-acidity events are short-lived, some can persist for extended periods and cover vast regions. These events were rare in the eastern equatorial Pacific and polar regions.

The research team attributed the co-occurrence of heat and acidity to ocean physics. In regions with strong upwelling, heat waves can increase acidity. In areas with less mixing, heat and acidity rise together.

The study used satellite data on temperature, salinity, and chlorophyll to indirectly deduce acidity where direct measurements were limited. This created monthly global acidity maps from 1982 to 2024, overlaid with heat wave data.

Sea-ice-covered regions were excluded. Findings link these extremes to El Niño/La Niña cycles, with increased likelihood in specific phases.

Experts urge more research on the impact of these compound events on marine life and fisheries. Understanding the interaction between heat waves and ocean acidity is crucial.

AI-samenvatting op basis van de bron.