Fish – Missing from Climate Models

Various climate models show what the future may hold for us on this planet. An important factor is how much carbon dioxide the ocean can absorb without having too great an impact on the climate.

New research now shows that if fish and plankton are included in the models, the results will be completely different from previous calculations. Quite simply, the impact of marine animals on the ocean has been excluded in the past. And since we are currently fishing our oceans to extinction, this fact could have devastating consequences – on the climate.

^{Text: Lena Scherman}

Like all ecosystems, it is complex. Fishing affects fish, but so does climate change, which can alter nutrient concentrations, which in turn has effects that spread through food webs. In order to make accurate predictions about the future, we need to factor in the number of fish and how much we fish, something that has largely not been done before.

The new research, led by Dr Helen Powley at Plymouth Marine Laboratory (PML), shows that when fish were included in the models, the predictions of how much carbon dioxide the ocean can absorb changed fundamentally. It may be that we have greatly overestimated the ocean as a climate buffer.

‘The missing feedback loop is important,’ says Dr Helen Powley. Fish feed on plankton communities, and plankton plays a central role in regulating how much carbon dioxide the ocean absorbs from the atmosphere.

‘Without representing the real interconnected processes, models risk underestimating how marine ecosystems respond to environmental change – and how much the ocean can help us mitigate global warming.’

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