Monday, November 18, 2013
Now, When You Put It That Way...
Here's one to chew on. The oxygen in every second breath you take is supplied by the oceans. There, does that help connect you to our oceans, your oceans? Your life literally depends on them. That sure works for me.
We've tipped nature's balance enough that we have caused the oceans to acidify at rates not seen in 300-million years. That's a pretty abstract concept inviting a "so what" response. If you want to know what that means you should get your hands on a copy of Peter Ward's book, Under a Green Sky.
Ward, a paleontologist, has studied our Earth's various extinction events. He explains how, once oceans achieve a certain warming and pH level, they stop producing oxygen and start emitting hydrogen sulfide thusly -
First, the world warms over short intervals of time because of a sudden increase of carbon dioxide and methane... The warmer world affects the ocean circulation systems and disrupts the position of the conveyer currents. Bottom waters begin to have warm, low-oxygen water dumped into them. Warming continues, and the decrease of equator-to-pole temperature differences reduces ocean winds and surface currents to a near standstill. Mixing of oxygenated surface waters with the deeper, and volumetrically increasing, low-oxygen bottom waters decreases, causing ever-shallower water to change from oxygenated to anoxic. Finally, the bottom water is at depths were light can penetrate, the combination of low oxygen and light allows green sulfur bacteria to expand in numbers and fill the low-oxygen shallows. They live amid other bacteria that produce toxic amounts of hydrogen sulfide, and the flux of this gas into the atmosphere is as much as 2,000 times what it is today. The gas rises into the high atmosphere, where it breaks down the ozone layer, and the subsequent increase in ultraviolet radi8ation from the sun kills much of the photosynthetic green plant phytoplankton. On its way up into the sky, the hydrogen sulfide also kills some plant and animal life, and the combination of high heat and hydrogen sulfide creates a mass extinction on land. These are the greenhouse extinctions.
And, there you have it. Were you to look up you would gaze into a pale, green sky. Only that won't happen because you (or your descendants) would be extinct.
The evidence is plain. We're warming our oceans. We're acidifying the waters. We're observing the spread of ever increasing oceanic dead zones.
Make no mistake about it, kids. That's what we're playing for - an extinction event. Only this time it won't be volcanoes and flood basalts triggering the switch to anoxic oceans. It'll be our doing.