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The Recent Normalization of Historical Marine Heat Extremes

February 01, 2022

We study heat extremes in marine ecosystems to better understand the dramatic changes currently occurring in marine environments.

Climate change exposes marine ecosystems to extreme conditions with increasing frequency.

In this study we take advantage of the global reconstruction of sea surface temperature (SST) records from 1870-present, we present an index of extreme marine heat within a coherent and comparable statistical framework.

Significant increases in the extent of extreme marine events over the past century resulted in many local climates to have shifted out of their historical SST bounds across many economically and ecologically important marine regions.

For the global ocean, 2014 was the first year to exceed the 50% threshold of extreme heat thereby becoming “normal”, with the South Atlantic (1998) and Indian (2007) basins crossing this barrier earlier.

By focusing on heat extremes, we provide an alternative framework that may help better contextualize the dramatic changes currently occurring in marine systems.


Tanaka KR, Van Houtan KS. 2022. The recent normalization of historical marine heat extremes. PLOS Climate. 1(2): e0000007.  https://doi.org/10.1371/journal.pclm.0000007.

Last updated by Pacific Islands Fisheries Science Center on 03/07/2022

Marine Heatwave