We’re changing the seas in ways impossible for them to adapt to…
But those direct attacks on the dolphins – as dire as they are – are not the ultimate threat to the existence of most species. That is coming from a more insidious direction.
The metabolic basis of human industry is now the burning of fossil carbon and hydrocarbons. We call them “fossil fuels” as if they exist to be burned. Yet continuing to burn them will clear the seas of dolphins. This may be “locked in” by 2050 or sooner, by the effects of ocean acidification and planetary heating, both effects of elevated biosphere CO2 from human burning.
The heating of the planet by CO2 has many effects. Coral bleaching, toxic algal blooms, and much more. Long-term, the disproportionate heat rise at the poles from greenhouse gasses means that ocean currents may slow and stop, creating stagnant oceans with anoxic depths, which increasingly are inhabited by purple bacteria giving off toxic hydrogen sulfide gas, implicated in past mass extinctions.
Yet long before that, we will have made the seas unlivable for most large complex life, due to the “evil twin” of global heating caused by CO2. That’s ocean acidification, and it’s happening new. Already at high latitudes, organisms at the base of the ocean food chains are having their shells dissolve in acidic seas. And it’s spreading.
For as the oceans soak up CO2, it is converted into carbonic acid. This is a big problem, because many organisms in the seas rely on skeletons and shells made of different crystal structures of calcium carbonate. These animals, including the world’s coral reefs, will fizz away like an antacid tablet in a glass of cola. These animals are integral to the food webs which support large complex animals like fish and marine mammals. There is utterly no reason to believe that a wholesale collapse of ocean food webs will spare large carnivores. Indeed, the large, long-lived species with low reproduction rates are least likely to survive.
Rather, we’re creating the conditions for jellyfish seas, worms, and bacterial slimes. Creatures which are adapted to rapid changes by being durable and by reproducing prolifically and quickly. A dolphin, or other high-metabolism creature like a fish, can’t survive by eating jellyfish – the nutrient level and calories just aren’t there.
And of course, changing the seas in such a way means that humans won’t get anything except jellyfish and algae out of them either. The dolphins aren’t our competitors, they’re showing us an important truth: humans have never existed during a time of stagnant, toxic seas either. We, like the dolphins, have evolved since that last happened. It can take millions of years for coral reefs to come back to the earth once acidity destroys them; and a huge percentage of fish need coral reefs to reproduce.
This dire sequence of events could be locked in by 2050 or before. A child in school today could outlive coral reefs, and outlive many dolphins species. And once the CO2 is released, the dolphins won’t have any hope, even if the acidification changes take a longer time.
To save the dolphins and the seas, we need to do the stuff we need to do anyway for climate change, but we need to do it faster.