There is a dangerous hope circulating in the world of people, that technology is going to save our hide at the last moment, ingenuity will slip us a file in our prison, that we will escape the momentous event in Earth's history that we've let loose to stalk us on the surface of the Earth. This hope is predicated on a deceptively simple wish -- that we can clean up our messes if we really, really want to. The tenet of this philosophy supposes that we must be able to assume the mantle of responsibility if we are able to don the sorcerer's cloak of power. This is a comforting myth because it suggests that there is an ordained program of education built into the planet; it means Earth is built to withstand our learning curve. Even more seductively, it implies that the narrative leads inexorably to our acquisition of supreme authority and capacity, once we are ready -- with the gems of our self-realized priorities cemented in our crowns. All we have to do is be very, very clever, figure out how to mop up after ourselves.
Looking around at the planet, we can easily observe the massive scale of our reworking of the natural world. The land is shaped in our image, and much of it has the look of a creature that was learning on the job. Two-thirds of the planet is ocean, however, and it is there that our heavy imprint hits hardest. The small shreds of plastic that populate all our seas and Great Lakes is just a piece of very large puzzle for which we've lost the box with the big picture on it. Beyond the acidification issue, and fishing the waters to their bitter end, there is our sheer ignorance of that environment. It is a strange truth that we have a greater certainty about the conditions inside a black hole than we do about the Mariana Trench (let alone the thousands of sea-mounts that have not been explored, yet are scoured by dragnets every day).
Rather than the "Sorcer's Apprentice" story-line, imagine rather that we have entered a fiddling contest with the devil, and he has provided us the instrument -- a thousand strings, stops and frets we've never heard of, tuned to a scale that sounds almost familiar, but isn't -- and now he shoves us out on stage as the orchestra launches into the most sublime and intricate movement...the Music of the Spheres, perhaps. Our last 150 years of notes were not exactly off, but now the tempo is furious and the harmony hangs by a thread.
What do we do now? As far as mitigating disastrous climate change goes, we have to create room in the carbon budget within these next four years. If we can't halt the machinery of progress (or haven't the stomach to halt it), then the only other option on such short notice is decreasing the amount of energy coming into our greenhouse atmosphere.
This is the hope that "geoengineering" offers us right now. Specifically, there are chemical aerosols we can spew into the stratosphere which will increase the Earth's albedo -- the amount of sunlight reflected directly back into space before it is absorbed by the Earth and re-radiated as heat. We can call this "Global Dimming." A flurry of research has sprung up, studying the most effective and practical methods of delivering these aerosols to the stratosphere. When we imagine doing this, we intend to imitate the natural cooling effect that volcanic plumes have upon the atmosphere.
There are dangers to geoengineering; do it wrong, and we can create conditions of extreme drought in localized areas on Earth, we can rain poisonous sulfates down upon the land and the water. Do it for a time and then stop the program abruptly, and the Earth will experience sudden, intense global warming. (The Greenhouse Effect takes centuries to play out, whereas aerosols fall out of the atmosphere in a matter of days or weeks.) Do it unilaterally, and the lopsided distribution of wealth, and even sustenance, on Earth will worsen. Unfortunately, there is a lot of motivation for a country or small group of countries to act unilaterally. Our track-record for demonstrating altruism with respect to the climate is abysmal. Many sociologists and ethicists fear we haven't the moral fortitude to become responsible gods of weather.
That gets to the most looming danger of geoengineering: if we shape it to fit the Sorcer's Apprentice story, if we pretend that geoengineering is our way of being clever enough to clean up our climate mess, then we will really be adrift in a rough sea without a rudder. This is because geoengineering is not a clever fix; to think so is to miss the humongous size of the lever that we have pulled. To give just one example, Greenland is now spotted all over with softball-sized holes containing a mixture of slushwater and carbon soot (primarily from Northern Hemisphere factories and vehicles). These are melting Greenland from the inside out, as it were, and are accelerating the collapse of the ice-sheet there -- a truly massive transformation of our planet that will be felt everywhere.
The long train of consequences that begins with changing the Earth's energy balance will follow an altered course for hundreds of millennia to come, not just this one century we are looking at in our studies. At best, geoengineering can buy time to implement a carbon-capture regime and steer our way to carbon-neutral energy. That is enough reason for people to come out from the shelter of their own private lives and demand that our government throw its weight into geoengineering research and implementation now.
However, we are not going to be filling the atmosphere with aerosols for the next 300,000 years or more. And even if we started the program today, the Earth has absorbed enough heat to raise the surface temperature by about another 0.8 degree C, which is almost double the temperature variation of the last 10,000 years of civilization, and may be enough to cross the threshold into triggering other climate feedback. So, although geoengineering is a useful lighthouse to set our course by in a stormy sea, we must not aim for it as our only strategy, or we will be like moths sailing for an open flame.
Then, too, there is the larger lesson: not everything we've done on Earth can be corrected in a way that is convenient to our preferred story of ourselves. Some of it cannot be corrected at all, for such an amount of time that our intentions and priorities will be dust past broken by then. The rapist who offers his victim an Advil afterward is not absolved of crime. We've known a long time that what we're doing to Earth is obscene. Geoengineering will not fix the sorrow in our hearts the way that renouncing the abuse of the Earth will. For, our hearts and our story come not from our own grandeur, but from the Earth itself.