Civilization-disintegrating acid rain?Korto wrote:A doco I watched, ("A Crude Awakening", I believe it was called), had the opinion that due to the increased CO2 in the air, the torrential downpours would be acidic, (carbonic acid?), with pretty devestating effects. [...]
Of course, massive torrents of acid rain wouln't be that brilliant for life on land, either.
Whether all these effects, along with the almost simultaneous Peak Oil (in a massive irony) cause the disintegration of our civilisation may just depend on how robust you think our civilisation is. Me, I suspect it isn't that robust, but that's only an uninformed opinion
Sure, just like those commercial greenhouses which use carbon dioxide injection for carbon-fertilization kill their plants by the resulting acidity of water inside.
Just like life hundreds of millions of years ago, when atmospheric CO2 concentrations were far higher, was devastated by acid rain resulting from such.
Oh wait, none of the above is true.
Such a claim in a documentary is a small amount of truth mixed with loads of bullshitting, presumably realizing that the target audience can't tell the difference, lacking any decent scientific education or tendency towards critical thought.
All water exposed to the atmosphere contains a small amount of a weak acid, carbonic acid, and the concentration is determined by the partial pressure of carbon dioxide.
Soda drinks are relatively acidic. To make the carbonated water for them, pressurized carbon dioxide at well above 1 atm pressure is used. The bubbles one sees when drinking Pepsi or Coke are from the excess carbon dioxide coming out of solution. In contrast, the partial pressure of CO2 in the atmosphere is a mere fraction of a thousandth of 1 atm, whether the carbon dioxide concentration is the 400 ppm of today or figures such as 500 to 800 parts per million which might be reached in a century.
Rain is and always has been "acidic" in the sense of less than 7 pH. But the concentration of carbonic acid in rain is and will remain literally orders of magnitude less acidic than a soda drink.
To a degree, the average pH of rain would change (though it already varies a lot in different locations). Slight change in the average pH of areas of ocean water as more carbon dioxide dissolves has been something of an environmental concern.
But it's not the kind of toxic acid rain you're envisioning.
What more truly deserves the term acid rain is different. In some localities, there has been large amounts of unregulated pollution with nitrogen oxides and sulfur oxides. Such can cause sulfuric and nitric acid in rainwater, making real acid rain ... a hell of a lot more acidic than traces of weak carbonic acid from a few hundred ppm atmospheric CO2. In the U.S., there's been a fair amount of progress on reducing acid rain since it gained attention as a concern in the 1970s and 1980s. Sulfur dioxide and nitrogen dioxide levels have been typically reduced by about 75% and 30% respectively.
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For hundreds of millions of years, atmospheric CO2 concentrations were much more than the relatively low levels of the past few million years, a lot more than the 500 to 800 ppm anticipated at the end of the 21st century. That and the lush biosphere of the time is where the carbon of today's fossil fuels came from.
In the following graph, the far left of the graph is the more recent past:
Global warming has some undesirable effects, but the fascination with looking for an excuse to believe civilization will disintegrate is seriously screwed up.
