Trend of atmospheric oxygen (O2) from Cape Grim, Tasmania. This looks serious, right? Read on.
FOREWORD: I had to chuckle at this. This is the sort of story I would expect in the supermarket tabloids next to a picture of Bat Boy. For the UK Guardian to say there is a “oxygen crisis”, is not only ignorant of the facts, but simple fear mongering riding on the coattails of the “CO2 crisis”. Read the article below, and then read the reasons why myself and others are saying this story is worry over nothing.
UPDATE: Physicist Lubos Motl also takes this article and the author to task, here
UPDATE#2: According to the Guardian website: “It is the policy of the Guardian to correct significant errors as soon as possible” For those readers that think this Guardian article needs correction, here is the contact info:
Readers may contact the office of the readers’ editor by telephoning +44(0)20 7713 4736 between 11am and 5pm UK time Monday to Friday excluding public holidays. Email email@example.com, send mail to The Readers’ Editor, 119 Farringdon Road, London EC1R 3ER, or fax +44(0)20 7239 9997. The Guardian’s editorial code incorporates the editors’ code overseen by the Press Complaints Commission.
The oxygen crisis
The rise in carbon dioxide emissions is big news. It is prompting action to reverse global warming. But little or no attention is being paid to the long-term fall in oxygen concentrations and its knock-on effects.
Compared to prehistoric times, the level of oxygen in the earth’s atmosphere has declined by over a third and in polluted cities the decline may be more than 50%. This change in the makeup of the air we breathe has potentially serious implications for our health. Indeed, it could ultimately threaten the survival of human life on earth, according to Roddy Newman, who is drafting a new book, The Oxygen Crisis.
Read the rest of the story here.
Predictably, once again mankind gets the blame in the article:
Much of this recent, accelerated change is down to human activity, notably the industrial revolution and the burning of fossil fuels.
From a mailing list I subscribe to, there’s been a number of comments made about this story. Here are a few:
The O2 concentration of the atmosphere has been measured off and on for about 100 years now, and the concentration (20.95%) has not varied within the accuracy of the measurements. Only in recent years have more precise measurement techniques been developed, and the tiny decrease in O2 with increasing CO2 has been actually measured….but I believe the O2 concentration is still 20.95%….maybe it’s down to 20.94% by now…I’m not sure.
There is SO much O2 in the atmosphere, it is believed to not be substantially affected by vegetation, but it is the result of geochemistry in deep-ocean sediments…no one really knows for sure.
Since too much O2 is not good for humans, the human body keeps O2 concentrations down around 5% in our major organs. Extra O2 can give you a burst of energy, but it will harm you if the exposure is too long.
It has been estimated that global wildfire risk would increase greatly if O2 concentrations were much more than they are now.
Here’s one I remember reading about a long time ago:
Around 1920 when steel production began to expand to what looked like no limit, it was believed (and demonstrated) that the use of coal would consume all the oxygen in the atmosphere in 50 years.
So far, we are still breathing O2, even though we have increased the volume of coal and oil used steadily since then. More worry based on bad science.
For those wanting to brush up on the history of oxygen concentrations though the millenia, I suggest this essay in Science News:
Changes in the air: variations in atmospheric oxygen have affected evolution in big ways
Science News, Dec 17, 2005, by Sid Perkins
But the most interesting perspective on why there is no oxygen crisis comes from this article from Wallace Broecker of Columbia University titled Et tu, O2?
AN OFT-HEARD WARNING with regard to our planet’s future is that by cutting back tropical forests we put our supply of oxygen gas at risk. Many good reasons exist for placing deforestation near the top of our list of environmental sins, but fortunately the fate of the Earth’s O2 supply does not hang in the balance. Simply put, our atmosphere is endowed with such an enormous reserve of this gas that even if we were to burn all our fossil fuel reserves, all our trees, and all the organic matter stored in soils, we would use up only a few percent of the available O2. No matter how foolishly we treat our environmental heritage, we simply don’t have the capacity to put more than a small dent in our O2 supply. Furthermore, the Earth’s forests do not play a dominant role in maintaining O2 reserves, because they consume just as much of this gas as they produce. In the tropics, ants, termites, bacteria, and fungi eat nearly the entire photosynthetic O2 product. Only a tiny fraction of the organic matter they produce accumulates in swamps and soils or is carried down the rivers for burial on the sea floor.
While no danger exists that our O2 reserve will be depleted, nevertheless the O2 content of our atmosphere is slowly declining–so slowly that a sufficiently accurate technique to measure this change wasn’t developed until the late 1980s. Ralph Keeling, its developer, showed that between 1989 and 1994 the O2 content of the atmosphere decreased at an average annual rate of 2 parts per million. Considering that the atmosphere contains 210,000 parts per million, one can see why this measurement proved so difficult.
This drop was not unexpected, for the combustion of fossil fuels destroys O2. For each 100 atoms of fossil-fuel carbon burned, about 140 molecules of O2 are consumed. The surprise came when Keeling’s measurements showed that the rate of decline of O2 was only about two-thirds of that attributable to fossil-fuel combustion during this period. Only one explanation can be given for this observation: Losses of biomass through deforestation must have been outweighed by a fattening of biomass elsewhere, termed global “greening” by geochemists. Although the details as to just how and where remain obscure, the buildup of extra CO2 in our atmosphere and of extra fixed nitrogen in our soils probably allows plants to grow a bit faster than before, leading to a greater storage of carbon in tree wood and soil humus. For each atom of extra carbon stored in this way, roughly one molecule of extra oxygen accumulates in the atmosphere.
Now remember the graph I showed at the beginning of the article? Here is what Australia’s Ray Langenfelds from CSIRO Atmospheric Research has to say about the Cape Grim O2 measurement.
“The changes we are measuring represent just a tiny fraction of the total amount of oxygen in our air – 20.95 percent by volume. The oxygen reduction is just 0.03 percent in the past 20 years and has no impact on our breathing,” Langenfelds. “Typical oxygen fluctuations indoors or in city air would be far greater than this.”
So there you have it. So much for the “oxygen crisis”. I really wish the media would do a better job of researching and reporting science stories. This example from the Guardian shows how bad science and bad reporting combine to create fear mongering.