Caribbean Coral Reefs Have Been Bleaching for at Least 100 Years

A new study examines 150 years of sea-surface temperature data from the Greater Caribbean region, indicating substantial warming patterns that have harmed coral reef ecosystems.

On March 9, Colleen Bove of the University of North Carolina at Chapel Hill and colleagues publish their findings in the open-access journal PLOS Climate.

Climate change increased water temperature in Caribbean waters

According to the journal of PLOS "A century of warming on Caribbean reefs," emissions of greenhouse gases are warming the globe, exacerbating natural disasters, and altering a plethora of other aspects of the ecosystem.

This is causing extinctions, changing the mix of species, and destroying practically every ecosystem on the planet.

Although we commonly conceive of surface temperatures as a terrestrial event, the seas have kept around 93% of the additional stored heat since 1955.

Climate change produced by human activity not only heats the atmosphere but also heats the world's waters, affecting marine ecosystems.

Previous research has demonstrated substantial warming-induced changes to coral reef ecosystems across the world, particularly in the Caribbean, finding consequences, such as mass coral death due to coral bleaching and loss of reef-dependent species.

Bove and colleagues have done an updated study of sea-surface temperature changes for Caribbean coral reefs, building on previous studies.

They began by compiling a database of 5,326 Caribbean coral reefs, each of which was assigned to one of eight sub-regions.

As per ScienceDaily, the researchers examined the history of warming from 1871 to 2020 using three open-access datasets of satellite and on-site sea-surface temperature readings.

Sea surface temperature rises

They discovered 5,326 distinct reefs in the Caribbean basin and allocated them to eight ecoregions based on World Wildlife Fund (WWF) marine ecoregion classifications.

Ecoregions included reef sites ranging from 84 (Gulf of Mexico) to 1,277 (Greater Antilles).

The researchers also discovered that Caribbean reefs have warmed by 0.5 to 1°C over the last century, with distinct sub-regions experiencing differing rates of warming from one another and over time.

The statistics indicated that if warming continues at its current rate, these ecosystems will warm by an average of 1.5°C by the year 2100.

The study also looked at the occurrence of marine heatwaves, which are brief episodes of abnormally high water temperatures.

They discovered that the frequency and duration of these occurrences are increasing throughout the Caribbean, with reefs now witnessing an average of five per year, up from one in the 1980s.

Based on their findings and previous research, the researchers advocate for immediate reductions in greenhouse gas emissions, as well as initiatives to address local and regional stresses of coastal ecosystems, such as fishing and environmental destruction, in the Caribbean and elsewhere.

According to scientists, coral reefs have been warming for at least a century, and several reefs in the Caribbean already have warmed by a degree Celsius.

This explains why they've witnessed, such drastic losses in the health of this priceless environment.

Anthropogenic emissions of greenhouse gases have resulted in a 1°C increase in global surface temperature since pre-industrial times.

This has resulted in unprecedented mass coral bleaching episodes, which, when paired with increasing local stressors, have rendered coral reefs one of the most vulnerable ecosystems on the planet.