The Decline of Global Oxygen Levels

So, I came across this article the other day called “Climate Change: Falling Oxygen Levels May be More Dangerous Than Flooding”. I have been reading books and watching videos on climate change for the last decade or so and not once had I come across this important little fact. Sure, excessive amounts of CO2 are bad, but to humans CO2 is a waste product. But to learn that oxygen levels are declining at a rate faster than CO2 is increasing? Yeah, I sat up and read this article with interest. Over the last couple of days, I’ve been reading some of the sources the article is based on. And  my surprise and anxiety have only escalated.

Here is a nice overview of the data on global oxygen depletion: O2 Dropping Faster than CO2 Rising

In a nutshell, we’re fucked. But you probably knew that already. The oxygen levels on the planet have gone up and down over the past many millions of years.

28%     130million years ago
29%     115m years ago
35%     95m years ago
33%     88m years ago
35%     75m years ago
35%     70m years ago
35%     68m years ago
31%     65.2m years ago
29%     65m years ago

Today, the average is around 21%. But one of the surprising things is that “the levels are even less in densely populated, polluted city centres and industrial complexes, perhaps only 15 % or lower.” That means that a person in Los Angeles is breathing only 70% of the oxygen that a Kalahari bushman is.

Between 50% and 85% of the planet’s oxygen is generated by the oceans’ phytoplankton. And guess what’s happening to those little critters?  According to one source at NASA, the number of phytoplankton have decreased 30% since 1980. These days, the number is diminishing at a rate of 1% a year.

Trashing the forests and oceans of the world, we can expect that oxygen levels will continue to decline. I guess the threshold is 6% or 7% oxygen before we can all kiss the place goodnight.