GeoEngineering: Back on the Table?

March 3, 2023


More than 60 prominent climate scientists this week called for breaking a taboo about solar geoengineering—artificially cooling the planet by making it more reflective—by boosting research on it. Some activists and scientists are staunchly opposed to even studying geoengineering, arguing that it distracts from the necessity of cutting greenhouse gas emissions.

But the open letter says decisions on implementing geoengineering schemes are likely in the coming decades, and that simulations and field experiments are needed to understand the schemes’ effectiveness and risks. Among the signatories are retired NASA scientist James Hansen, one of the first to warn about the dangers of global warming, and Harvard University climate scientist David Keith, who has for years tried to gain permission to perform a small-scale geoengineering experiment.


5 Responses to “GeoEngineering: Back on the Table?”

  1. rhymeswithgoalie Says:

    The embittered cynic in me sadly agrees with GS’ “clear moral hazard” of giving any country or company an excuse to slack on emissions reduction.

    OTOH, people have never needed an actual rationale to avoid doing the right thing. Like the oil-from-algae nonsense that spent more money on greenwashing than on actual technology, I think Gavin may be underestimating board room talking points where the suits convince themselves that they’re doing enough.

  2. neilrieck Says:

    Here’s the big problem with geoengineering in this context: advocates will attempt to solve “a heat problem” by “reducing the full spectrum of light” received from the sun. Let me remind everyone here that Earth’s atmosphere is currently overheating due to the emissions of greenhouse gases (primarily due to increased CO2 starting with the industrial revolution starting in the early 1800s) which reduce the amount of energy radiating back to space. Meanwhile, most life capable of photosynthesis is only 1% efficient with the smaller Rubisco-based variety being a couple of points higher. Any reduction in solar radiation hitting Earth means less much less photosynthesis which means that CO2 will rise faster while O2 will drop faster. One last point, do we really want to reduce photosynthesis with human population recently passing 8 billion?

    • John Oneill Says:

      One of the albedo modification proposals I read involved a fleet of planes seeding aerosols in the stratosphere at high latitudes, to keep the polar ice caps from melting so fast. This would hopefully reduce the effects on the tropical and temperate zones, where most people live, and crops are grown.
      As for the ‘moral hazard’ argument, humanity has been pretty effectively ignoring the problem, or talking about it but doing little, for forty years. If we continue in ignorance of whether the techology would do any good, it could still be a moral hazard. People can argue, ‘If things start to get really bad, we can always go for the sulfur dioxide!’ If that’s proven to be ineffective, the case for emissions reduction would be much stronger. Anyone who really believes the science is fairly sure that things will get bad anyway, in which case it would be hard to argue against trying just about anything. Better to have some idea of the results in advance, rather than try a last minute gamble.

      • neilrieck Says:

        Agreed on most points but need to mention that “albedo modification” backs up my main point. They are trying to solve “a heat-centric problem” by tinkering with “a light-centric solution”. Something else to think about: if country “a” implements geoengineering which affects agriculture in country “b”, how does country “b” order country “a” to stop? Also, does country “a” now owe some sort of food debt to country “b”? With the current state of politics in the world, I don’t see any of this working.

        • John Oneill Says:

          Earth absorbs light, re-emits heat – standard entropy. Negotiating over geoengineering, or even initiating it, is much better done from a position of knowledge than in last-resort desperation. (We’ve had natural experiments like the Pinatubo eruption, plus proxy climate records such as volcanic ash in the ice cores, so it’s not completely unknown territory.)
          Considering the billions of tonnes of greenhouse gases, and millions of particulates, discharged into our common atmosphere every year without any real regulation at all, stopping a few kilos of research SO2 makes no sense.

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