The Paris Climate Accords of 2015 aimed to limit global temperature rise to 1.5 degrees Celsius above pre-industrial levels, but a recent study suggests we may have surpassed that threshold years ago. Conducted by the University of Western Australia Oceans Institute, the study examined long-lived Caribbean sclerosponges, creating a timeline of ocean temperatures dating back to the 1700s.
While the study suggests that we exceeded the 1.5 degrees Celsius mark in 2020, some scientists question whether data from a single region adequately represents the complex thermal dynamics of global oceans.
Irrespective of one’s stance on climate change, the call to action to prevent temperatures from exceeding 1.5 degrees Celsius has become widespread. This target, set after the Paris Climate Agreement, represents a critical threshold beyond which significant damage to both humans and the environment is expected.
The recent paper from the University of Western Australia Oceans Institute delivers concerning news: the world may have surpassed the 1.5 degrees Celsius threshold four years ago. Published in Nature Climate Change, the study utilized sclerosponges, which act as natural archives due to their slow growth rate, to analyze historical water temperatures.
By examining the strontium to calcium ratios in these sponges, researchers could estimate water temperatures dating back to the 1700s. The Caribbean habitat of these sponges offers relatively undistorted temperature readings, unlike regions affected by major ocean currents.
The study’s lead author, Malcolm McCulloch, suggests that the urgency for emissions reduction to mitigate climate risks has accelerated by at least a decade. However, some scientists are skeptical of the findings, highlighting the need for more comprehensive data before revising climate goals.
Regardless of the accuracy of the sponge-based findings, mounting evidence indicates that we are approaching or have already exceeded the 1.5 degrees Celsius threshold. January 2024 marked the hottest January on record, with temperatures approximately 1.7 degrees Celsius above pre-industrial levels.
In light of this evidence, urgent action to reduce emissions is imperative to mitigate the impacts of climate change and preserve the planet for future generations.
