An often overlooked element of climate change is the impact that it will have on the fish that we eat. Of all the food production in Western nations, fish tends to be the most distant and ignored. Terrestrial animals get all the attention because they’re much more obvious and Australians eat more of them. You’ve only got to take a glance at the meat refrigerator in a supermarket to discern where the bulk of the protein is coming from.

Over the next fifty years, fish populations in the seas surrounding South East Asia could decline by 40% because of global warming – assuming that overfishing doesn’t worsen the problem. As the seas warm, modelling by the Sea Around Us project at the University of British Columbia predicts a massive global redistribution of fish species.

Many of the countries most reliant on fish as their primary source of protein would be hardest hit – nations that already struggle to feed their populace -  and inversely, more sparsely populated fisheries in far northern and southern latitudes could become more productive as a result of warmer oceans.

It is not so much a question as to whether or not we will see migrations of edible sea creatures but the scale and speed at which they will occur. These migrations are a trend that is already happening – earlier this year, researchers from the Arctic Ocean Diversity project documented “rising numbers of warm-water crustaceans in the seas around Norway” . The Guardian notes:

The team, led by Dr Rolf Gradinger, from the University of Alaska, also collected evidence from the polar Chukchi Sea, between Russia and Alaska, which showed that at least three species have extended their range northwards by up to 500km. The most notable is the snow crab, which has crossed the Bering Strait and is occurring in the Chukchi Sea for the first time.

"This is an example of a general trend we are observing where water is warming further north and making this region more suitable for southerly species," Gradinger said

The mass migration of fish populations over time and the ability to sustain those populations does assume that the oceans don’t become acidic first. When carbon dioxide is absorbed by water, it becomes carbonic acid which acidifies the ocean.

Changes in acidity have massive impacts on sea life as slight increases can inhibit the formation of the shells of molluscs and coral, knocking out links in the food chain. The full magnitude of such changes are yet to be quantified.