Sunday, July 14, 2019

Why ocean acidification could make some geoengineering schemes irrelevant

The idea of runaway ocean acidification has now joined the idea of runaway global warming as a threat so large that it stands almost co-equal in its danger.

Part of the problem with ocean acidification is that geoengineering schemes for lowering Earth's temperature by reducing the sunlight that reaches the Earth's surface won't affect ocean acidification. And recent research from the Massachusetts Institute of Technology suggests that there is a tipping point in acidification beyond which the process becomes self-reinforcing and could lead to a mass extinction.

The idea of runaway global warming has been around for a while. In its original form it was speculation about whether the Earth could enter an unstoppable process that appears to have occurred on Venus billions of years ago and boiled its oceans away—leaving a planet so hot that surface temperatures today are high enough to melt lead.

A less catastrophic but still frightening form of runaway warming has been called "Hothouse Earth," an Earth 4 to 5 degrees Celsius warmer, that is, up to 9 degrees Fahrenheit hotter. Such warming would likely devastate existing farming, lead to extensive permanent droughts in currently habitable areas, sea levels ultimately hundreds of feet higher and many other untoward results.

Such scenarios have scientists thinking about geoengineering schemes that could stop such extreme scenarios from occurring. The scientists are considering these schemes because human civilization seems incapable of taking the one truly critical step that those scientists believe is the best option: dramatically reducing greenhouse gas emissions.

But those geoengineering schemes which block a portion of sunlight do nothing to prevent the ongoing acidification of the oceans. This occurs as more and more carbon dioxide dissolves in ocean waters. The dissolved carbon dioxide turns into a mild acid, carbonic acid, which interferes with the formation of shells of marine life and many other life processes in the ocean. When those shells fail to form, carbon dioxide previously removed from the water by their formation instead increases in a self-inforcing manner. The greater the concentration gets, the worse the effects will be on marine life. It's difficult to predict how mass death in the world's oceans would affect land species like ourselves, but it is highly doubtful it would be anything but negative.

The study cited above demonstrates the possibility that beyond a certain concentration, the carbonic acid triggers a cascade of change in ocean chemistry similar to that believed to have occurred during previous mass extinction events. Given the current pace of acidification, the world's oceans are likely to reach this trigger point by the end of the century.

No doubt some scientists will try to figure out how to geoengineer the oceans to avoid this catastrophic outcome. My response is that we humans have already done enough geoengineering (albeit unintentional). It's called industrial civilization. Now, it's time to stop geoengineering the world.

But giving up a bad habit is no easy task, especially when it benefits so many people in the short run. We should remember, however, that 99 percent of all species that have ever lived on the planet have gone extinct. Will we join them, or do humans collectively have a choice about whether to avert the threat that catastrophic climate change poses?

Kurt Cobb is a freelance writer and communications consultant who writes frequently about energy and environment. His work has appeared in The Christian Science Monitor, Resilience, Common Dreams, Le Monde Diplomatique,, OilVoice, TalkMarkets,, Business Insider and many other places. He is the author of an oil-themed novel entitled Prelude and has a widely followed blog called Resource Insights. He is currently a fellow of the Arthur Morgan Institute for Community Solutions. He can be contacted at


  1. "The scientists are considering these schemes because human civilization seems incapable of taking the one truly critical step that those scientists believe is the best option: dramatically reducing greenhouse gas emissions."

    yes, and there is the issue isn't it?
    we clearly see we are causing our own near term extinction and yet for 99%, their lifestyle is non-negotiable, so i guess today's entitlement party is more important than tomorrows extinction event. (smfh)

    i have been a "walk the talk", "be the change" person my whole life. i have been a near vegan since 1977, stopped air travel in 2010, and lived on ~3 tons of carbon a year. it is beyond frustrating to continue to try to be an example when clearly next to no one else gives a shit.

    so, i try to enjoy these remaining good days because clearly this will not end well.

  2. Aaron C.11:29 PM

  3. worse than irrelevant, Kurt...sulfate particles or sulfur dioxide aerosols will actually make acidification worse...remember the acid rain problem of the 60's and 70's? that was from burning coal, before they cleaned the sulfur out...

  4. Timothy DC3:29 PM

    Using sulphate aerosols is solar radiation management and indeed a form of geoengineering that doesn't adress the root of the climate problem: elevated levels of greenhouse gases in the atmosphere. There are proposals for geoengineering that aim to remove greenhouse gases. One that looks very promising is explained at
    Next month there will be a public talk in London on this subject.
    public talk/discussion on the climate cooling benefits of Iron Salt Aerosol, nature’s ancient atmospheric cleansing and cooling substance, 6:00pm Wed Sep 11th, Institute of Mechanical Engineers, 1 Birdcage Walk, London SW1H 9JJ

    '...Iron Salt Aerosol looks likely to be critically important for Climate Repair - Sir David King FRS, Chief Scientific Advisor to the UK Government under both Tony Blair and Gordon Brown, and Head of the Government Office for Science 2000 – 2007

    Registration is free:

    Further information is on these two websites: (Australians' site, well-organised and informative.) (My website, goes deeper into technicalities.)