The CO2 Campaign:
But they can shift catastrophically into other modes
The cold, oxygenated seas full of life that we know, and evolved alongside, are not the only way earth’s oceans can be. Jarring changes in the balance of the ecosystem can turn the seas deadly to complex life.
With too little CO2 in the atmosphere, the oceans can freeze solid, from poles to equator – and did so many times in the earth’s deep history. It is only recently this has been known. The microscopic ancestors of current life had to spend eons cut off from the sun, probably taking energy from volcanic seeps on the ocean floor. Only gradual volcanic eruptions restored the CO2 balance and freed the seas for the explosion of multicellular life.
Yet for large, complex life – like fish, whales, and humans – it’s even more disastrous to have too much CO2. This global heating melts polar ice caps and shuts down ocean currents, causing oceans to stratify and become anoxic. Ocean heating melts methane ice on the sea floor, speeding up the heating. The heating waters hold far less CO2, and push more back into the air like a warming cola.
Yet the increasing CO2 load winds up, for the most part, dissolved in the ocean where it becomes carbonic acid. And in a more acidic ocean, calcium shells can’t form. In fact, the existing ones fizz away, exactly like an antacid tablet in your stomach. All the coral. All the sea shells. All the animals, large, and small which can’t live without them – gone.
Purple bacteria which generate toxic hydrogen sulfide bacteria rise from the depths of the oceans to claim the deep seas, bubbling up poison gas which can sweep the land.
This has happened in the past multiple times. Frozen seas, and toxic purple seas. Those possibilities lie in wait for CO2 imbalance.
This won’t happen while you’re alive. But it can be irrevocably set into motion while you’re alive. With “business as usual” we will cross CO2 thresholds leading to the dissolving of shells in the entire ocean. It has already begun at high latitudes. And as we pass into regimes in which positive feedbacks like burning forests, heating oceans, and methane dominate atmospheric heating, we will lose what control we have now.
Slime oceans and the end of large complex sea life
We tend to think that larger, “advanced” organisms are more robust than small simple ones.
Hardly. They are in fact incredibly fragile.
Mass extinctions have a common theme. One never knows what will survive, but one can know ahead of time what won’t: the large, long-lived complex species. The species which take a long time to grow and mature, which reproduce slowly, and which exist at the apex of the ocean food chain. This is true both in the seas and on land.
We may imagine that a human-caused mass extinction will spare humans, because hey… we have air conditioners, cars, and the internet, right? Well, in the near future after coal and oil are played out, those abilities will go away, but the “new earth” will just be getting started.
We may look back on healthy, food-filled seas with some regret once sea breezes become charged with methane and hydrogen sulfide, and the formerly fish-filled seas are claimed by jellyfish, worms, and bacterial slimes.
Exaggeration? No. The fossil record shows very well what happens to the seas when CO2 rises too high. Corals disappear for not thousands, but millions of years. The planktonic food chains continue to support biomass, but it’s bacterial biomass which rots.
Humans have never tried to live in a world of dying, intoxicated seas. It’s an open question whether we can. Yet the odds are good you’ve heard more about “seal level rise” than about acidification and the inevitable collapse of oceanic food webs it will cause if not halted. Yes, sea level rise will be massively inconvenient for our infrastructure. But it is trivial compared to the impending loss of large complex sea life. Sea life which has already been fished, bombed, dredged and poisoned to its lowest levels in millions of years.
There’s little time and a lot to do. Join us.
Until recently, we just didn’t know what the effects of our actions might be. The oceans seemed limitless, invulnerable, mysterious, and endlessly bountiful.
Now we’re learning the scientific truths of biology, ecology, atmospheric physics, geochemistry and paleontology; and they paint a different picture. A picture of oceans which can “phase shift” into conditions utterly unlike those we’re used to, and which have done so many times in the past. We and most large complex life have evolved from tiny creatures since the last mass extinction, because that’s all that survives a CO2-caused mass extinction.
It’s not that saving the seas requires us to do anything different. We already need to stop our CO2 emissions in order to keep the earth from transitioning to a hellish climate in which much of the planet is too hot to support human life, much less food crops. It’s just that to save the oceans, we need to do that sooner.
Thresholds like “holding global warming to 2C” is essentially an arbitrarily political target, easy to talk about but with no particular validity. In contrast, there are absolute physical thresholds which define the “points of no return” in the seas. Thresholds like the acidic thresholds of aragonite and calcite crystallization. Those aren’t subject to political debate, they are realities of the physical universe.
It seems like these days everyone has an opinion on global warming, presumably under the assumption that a person with no training can understand the issue better than NASA can. (Rocket scientists are SO over-rated). But there’s no room for that with ocean acidification: the amount of CO2 in the air will absolutely acidify the oceans to a degree commensurate with its concentration. Once acidified past the point of calcium carbonate existence, the reefs and shells and calcareous skeletons go away for a long time; essentially forever on human time scales.
Here’s the deal: planetary heating is bad. It will destroy the rainforests, melt the glaciers, scorch the farmland and reduce the human carrying capacity of the the places we have always lived, causing immense migrations. But the death of complex life in the seas will happen first and last essentially forever.
The seas need to be the face of the CO2 issue.
Join us in making that happen.
The USA’s oldest and original Greenpeace, proudly unaffiliated with Greenpeace USA