The bleaching and heat stress narrative that says rising CO2 is an existential threat to coral reef habitat has not been realized.

Since reliable monitoring began 40 years ago, scientists (Ceccarelli et al., 2026) provide graphical evidence there has been no significant overall net change in coral cover throughout the Northern, Central, and Southern Great Barrier Reef (GBR).

In the last 15 years of widely varying trajectories of coral reef representation there even appears to be a slight relative increase in overall GBR coral cover.

Image Source: Ceccarelli et al., 2026

Previous research (Leonard et al., 2020) has indicated the GBR was ~1°C warmer and sea levels were ~1 m higher than today throughout large portions of the last 2500 years.

Declines in GBR coral cover are associated with cooling periods and coral growth is linked to warmer sea surface temperatures and higher sea levels.

“…increase in reef growth at Middle Island since the late 1970s associated with modern increases in average SSTs”

Image Source: Leonard et al., 2020