Climate change and chemical pollution are often discussed separately, but in the ocean they interact in ways that amplify both problems. Warming waters, acidification, and changing currents are altering how pollutants behave — with potentially devastating consequences.
Temperature and Toxicity
As water temperatures rise, the toxicity of many chemicals increases. Marine organisms under heat stress are also more vulnerable to pollutant exposure — their detoxification systems are already working overtime. The combination can push species past tipping points that neither stressor would reach alone.
Melting Ice, Releasing Pollutants
Decades of persistent organic pollutants have accumulated in Arctic and Antarctic ice. As climate change accelerates ice melt, these stored chemicals are being released back into the ocean in a pulse of contamination. Legacy pollutants banned years ago — like DDT and PCBs — are getting a second life.
Permafrost thaw is releasing mercury that has been locked away for thousands of years, adding to the burden on Arctic marine ecosystems.
Ocean Acidification
The ocean absorbs about 30% of human CO₂ emissions, making it more acidic. This acidification can change the speciation (chemical form) of metals, potentially making them more bioavailable and toxic. It also stresses organisms like corals and shellfish, reducing their resilience to chemical exposure.
Changing Currents
Climate-driven changes in ocean circulation patterns are redistributing pollutants. Chemicals that were confined to certain regions may spread to previously clean areas. Upwelling patterns that bring nutrients to surface waters can also bring contaminants from the deep.
The Research Challenge
Understanding these interactions requires interdisciplinary research combining climate science, chemistry, and marine biology. The CONTRAST project is contributing to this effort, studying how climate variables modify the effects of CECs on marine organisms.
A Unified Response
Addressing climate change and chemical pollution together — rather than in silos — is essential. Reducing fossil fuel use, for example, reduces both greenhouse gas emissions and the release of pollutants from combustion. A circular economy approach addresses both plastic pollution and carbon emissions.
This article is part of the CONTRAST project, funded by the European Union under Horizon Europe. Views expressed are those of the author(s) only.