For generations, the ocean has appeared to most humans as vast and impenetrable. Mysterious, dangerous, unfathomably large, but certainly not susceptible to being significantly altered by something humans might do.
But over the past century, that understanding has changed—first slowly and then more dramatically—and now, the ocean appears smaller and more fragile than we once thought. We have unimpeachable evidence that humans can have a devastating footprint on the ocean: 20th century whalers decimated global populations of blue, fin, and sperm whales over just a few decades; factory trawlers are depleting today’s fisheries; agricultural runoff has created enormous dead zones in the ocean; and plastic waste litters most of the ocean.
And there is a far more dangerous human-caused stressor that has largely gotten a pass from scrutiny, even though it is creating existential threats to the ocean. That stressor is the carbon dioxide pollution we have released into the atmosphere over the past 200 years, with a significant portion finding its way into the ocean’s upper layer.
Although we may not normally think of CO₂ as pollution, human enterprise since the dawn of the industrial revolution has emitted about 2 trillion tons of this invisible gas into Earth’s atmosphere that otherwise would not have been there. Over this time, we have increased CO₂ levels by 50% in the atmosphere and by 30% in the upper layer of the ocean.
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Brad Ack, Pew Trend Magazine, 24 August 2022. Full article.
