I have trouble taking all this doom-mongering seriously. Not that atmospheric CO2 might not end up creating a crisis; it certainly might. That is what the best science we have on the subject says, and the logic is pretty straightforward.
The reason I am puzzled by all the howls of anguish is that we know, or think we know, how to cool the planet. Lots of ideas have been proposed. Two of the best thought-out involve dumping minerals into the ocean to create giant algal blooms, which would soak up CO2 and transport much of it to the sea bottom, and spraying reflective particles into the upper atmosphere. Honestly we don't really know how well either of these would work, but the science that says they would cool the planet is exactly the same science that says CO2 is warming it.
It seems to me that if we are really facing a climate catastrophe, as I read almost every day, we ought to be trying everything we can think of. But we are not, and this is the puzzle I want to write about.
Nature recently published a little essay on this topic by two scientists who chaired a UN working group on geoengineering. Their task was to assess the state of the field and propose a framework for how geoengineering efforts should be regulated. The found that so little work has been done that there was nothing to assess, and since no work seems to be ongoing there isn't anything to regulate.
Storing carbon in the oceans sounds promising to some. The oceans are vast, and there could be fewer political trade-offs to deal with than on land. For example, fertilizing the water with iron would speed up the growth of phytoplankton and thus take up CO2, some of which would sink into the deep ocean as carbon when the organisms die. Another proposal is to spray seawater into the air to help form clouds that reflect sunlight and cool the planet.Again, it's very puzzling. Are we in a crisis or not? If we are, why aren't we doing anything about it? It's a complicated question, but a big part of the reason is that research into geoengineering is strongly opposed by the same environmentalists who think climate change presents us with an existential crisis. The position statement of the Environmental Defense Fund, for example, says
Techniques such as these would need to be used on a massive scale to cap global warming at safe levels. For example, to mop up CO2 chemically, the entire Pacific Ocean would have to be sprinkled with one billion tonnes of powdered minerals similar to chalk. . . .
Little is known about the consequences. Scant research has been carried out for a range of reasons. The controversial nature of geoengineering divides researchers. And some research trials that have been funded have subsequently been abandoned, owing to a lack of rules for performing them and to conflicts of interest, such as patent applications. Even basic tests of equipment haven’t been done. . . .
This dearth of information is hampering the development of a global framework for regulating geoengineering research, despite more than a decade of debate. Researchers and policymakers need to know which negative-emissions technologies are worth investigating, and which will never work or are too damaging to pursue. The potential benefits and risks of the technologies need to be established before country leaders or companies decide to implement them prematurely.
Deliberate climate interventions such as albedo modification should not be undertaken for the foreseeable future as they present serious ecological, moral and geopolitical concerns.I agree! Geoengineering presents all those questions. But if climate change is a catastrophe that is already upon us and may kill (as some say) a billion people this century, wouldn't that outweigh a quite a few ecological, moral and geopolitical concerns?
(For an example of a research project stopped by such objections, see here.)
Why would you both believe that atmospheric CO2 threatens the existence of humanity and oppose efforts to do anything about it? I think it is because for many environmentalists atmospheric CO2 is not really the problem. It is more like a symbol of the problem, or perhaps a single case of a very broad phenomenon that is the deeper problem. That broad phenomenon is humans messing with the planet. Environmentalists as a group are worried, not so much about the level of CO2 in the atmosphere and how that might affect the climate, but by all the ways we are changing our home and all the ways that might be bad. Even if geoengineering worked, in that sense that it might undo the warming caused by all the CO2 we have pumped into the air, it would in the broader sense only be another way we are messing with the planet, which is the thing they want to put a stop to.
I think this is short-sighted. If the models are right and the planet is going to warm dramatically, we don't have time to prevent that by limiting our future CO2 emissions. Those are coming down as fast as I think will ever be feasible; despite what some environmentalists want, we are not going to junk our cars and turn off our air conditioners because of a vague future threat that nobody really understands. If atmospheric CO2 is an existential problem, geoengineering is the only feasible solution.
Climate change remains, as I have always said, a serious potential threat to humanity and earth's other residents. But I will believe we are in actual crisis when people who worry about this issue start acting like we are.