CO2 is a greenhouse gas. Human generated CO2 trapped in the atmosphere is raising the earth’s temperature, causing melting icecaps, rising sea levels, species extinctions, droughts, and massive weather changes. These are things we already know.
But that’s not the worst news.
Perhaps you remember from your high school chemistry class the formula
CO2 + H2O –> H2CO3.
Coca-Cola and Budweiser have built entire product lines around this equation. All you have to do is bubble CO2 through water and you get carbonic acid – add some sugar and a refrigerator and you have a carbonated beverage.
Now imagine exposing the world’s oceans to elevated CO2 levels, and what do you think happens? . . . that’s right, seawater becomes carbonic acid. And carbonic acid is . . . well, an acid.
Actually seawater is alkaline – pre-industrial pH was around 8.2. So carbonic acid lowers the pH, but not enough to cause the oceans to become acidic. Today the average pH has dropped to around 8.1, and is projected to reach 7.7 by 2100, which doesn’t sound like much of a change. Nevertheless, all ocean species have evolved in a stable alkaline environment, and acidification of the oceans is already having a devastating effect. Shellfish love seawater – carbonic acid, not so much – the lowered alkalinity dissolves their shells. Coral – more bad news. Pteropod snails, which are the main food source for cold-water fish like salmon, haddock, and cod, are already dying in record numbers. Plankton growth is threatened, and plankton is the base of the food chain for every creature living in the sea.
What about methane clathrates – stable solid forms of methane that comprise much of the oceans’ sediment? There is evidence that the warming, acidifying waters may already be causing accelerated methane release – the so-called “clathrate gun hypothesis.” Methane is a much more efficient greenhouse gas than CO2, and may have triggered major climate events in the earth’s past. It’s really not a gas we want to be releasing.
Coincidentally, today’s warming oceans and falling alkalinity levels mimic conditions that occurred on earth around 55 million years ago, during the Paleo-Eocene Thermal Maximum (PETM). During the PETM, shell-based life in the oceans died off or became severely depleted, and didn’t recover for more than 100,000 years. We are on track to match the PETM conditions by the end of the 21st century.
Why is this important? Well, 80% of all life on earth lives in the oceans. Sea life provides half of the earth’s oxygen supply. Vegetated sea habitats sequester 5 times as much carbon as tropical forests. More than 10% of the world’s human population derives their livelihood directly from the oceans.
Should we be worried? Honestly? It doesn’t take much imagination to project what would happen to life on earth if even a fraction of these devastating effects occurs.
Yes, people, if we can’t reverse these trends and quickly, we should be terrified.