The world’s marine life will be irreversibly changed unless CO2 emissions from industrial society are drastically cut, warns a major scientific study.

Climate change is forcing fish out of their traditional habitats and into cooler waters. Many more species will soon be affected if climate goals are not met, the reports says, pointing to the need to limit emissions to help reduce the impact of rising atmospheric temperatures and acidifying oceans.

William Cheung, associate professor and co-director of the Nereus Program at the University of British Columbia, said:

“All the species and services we get from the ocean will be impacted and everyone, including Canadians, who benefit from these goods and services are vulnerable. On a positive note, we still have options to substantially reduce these impacts now but the longer we wait the fewer and fewer options we have.”

The study involved an international team of researchers, comparing the future of the oceans under two climate change scenarios.

In one scenario, the world limits atmospheric warming to two degrees by 2100, as outlined by the Copenhagen accord. In the other, we continue with the current approach, which researchers say would cause a five-degree increase in atmospheric temperatures.

The scientists say if warming continues unchecked, fish will migrate away from their current habitats 65 per cent faster, resulting in changes to biodiversity and ecosystem functions.

Cheung and his colleague Rashid Sumaila, co-authors of the study, looked at how climate change will affect fisheries and the coastal communities who depend heavily on fisheries resources for food and economic security.

“From looking at the surface of the ocean, you can’t tell much is changing,” said Sumaila. “The oceans are closely tied to human systems and we’re putting communities at high risk. While some regions will see increases in some fish biomass, these gains may be only temporary if carbon dioxide emissions continues.”

Gattuso J.P., Magnan A., Billé R., Cheung W. W. L., Howes E. L., Joos F., Allemand D., Bopp L., Cooley S., Eakin M., Hoegh Guldberg O., Kelly R. P., Pörtner H.­O., Rogers A. D., Baxter J. M., Laffoley D., Osborn D., Rankovic A., Rochette J., Sumaila U. R., Treyer S. & Turley C. Contrasting futures for ocean and society from different anthropogenic CO2 emissions scenarios. Science 3 July 2015: Vol. 349 no. 6243 DOI: 10.1126/science.aac4722

Illustration: Credit: D. Laffoley/Oceans 2015

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