The evil partner of climate change: Ocean acidification

Marine biologists are some of the most worried people on the planet. I am a marine biologist. And I am among the worriers. The acidification of our oceans is a big problem. Believe me:  it’s not a back-up plan of the environmental NGOs in case the climate fails to warm. It’s not the next hysteria or the apocalypse coming, but it’s very, very serious.

The Arctic is another acidification hotspot because colder water dissolves more carbon dioxide (CO₂) than warmer oceans and because melting sea ice leaves more of the sea surface in contact with the atmosphere and therefore able to absorb carbon dioxide. Arctic mussels and clams with their calcareous shells, vital food for walruses and seabirds, may already be suffering the impacts of rising acidity. This is because carbon dioxide forms carbonic acid when it dissolves in water. This acidic solution attacks the alkaline calcium carbonate many marine creatures use to build shells or skeletons, from corals to plankton to sea urchins.

The west-facing continental coastlines, where water that is already more acidic wells up from the depths are also particularly vulnerable, putting at risk some of the world’s most productive fisheries.

The good news is that we haven’t reached a point of no return to combat ocean acidification. First and foremost, we must reduce carbon emissions and rapidly decarbonise the global economy. Doing so will be a colossal challenge, but one that we can rise to. In the short-term, there are palliative measures that can be put in place. The creation of many more nature reserves, for example, will make oceans more resilient. Canada has a quite good track record for establishing national parks on land, but not when it comes to the sea: not even 1 percent of our ocean waters are protected. We must be precautionary when setting exploitation levels because global climate change puts additional stress on an already stressed ocean. We must also find new ways to properly fund conservation. But above all, we must alter our accounting systems so that living systems are given the value they deserve as literally priceless assets of natural capital.

That up to 85 percent of the human liberated carbon has soaked into the oceans and taken up by algae is a stroke of luck for us because the rates of greenhouse warming are sharply reduced as a result: were the oceans not performing this free service, the Earth’s temperature would be rising at double or triple today’s rate. But consuming excess carbon is a service the oceans perform at a substantial cost: by holding on to dissolved carbon dioxide they begin to change their chemical composition.
One of the most promising ways to protect the nature’s values is through payments for ecosystem services, for example, designing revenue streams or biodiversity credits or biodiversity offsets. While this may sound rather capitalistic, the language and practices of economics may offer the strongest tools today for use in nature conservation. Living oceans keep air breathable and maintain temperature for us, but to continue to perform these vital services they need to retain their complexity, diversity and resilience.