by K. Richard, Dec 21, 2023 in NotricksZone

Warmer sea surface temperatures are associated with coral growth, not decline.

According to a new study, coral growth was slow during the ~1°C colder Little Ice Age (LIA), but grew rapidly as sea surface temperatures (SSTs) warmed after 1850. Warmth is associated with coral growth, whereas colder SSTs are linked to growth rate decline.

“The average growth rate of four colonies living in the LIA is 0.87 ± 0.11 cm/yr, which is significantly (t-test, p < 0.0001) lower than the colonies in the 20th century [1.23 ± 0.22 cm/yr].”

“The observed low average growth rates during the LIA can be explained by the ~1°C lower temperature.”

Ocean pH levels were as low or lower (more “acidified”) than recent decades during the LIA (e.g., 1500s to 1700s CE), suggesting that the atmospheric CO2 levels are not an ocean pH variability determinant. In fact, the authors point out that anthropogenic CO2 can only ever affect pH variability by 0.05 of a unit over centuries, whereas natural variations in pH units can reach 0.1 to 0.3 within a decade or less.

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