written 7 April 2024
published 14 April 2024
Humanity has added 1 trillion tons of carbon dioxide (CO2) to the atmosphere in the last two centuries, increasing the atmospheric content for 280ppm to 425ppm, a level not experienced on Earth for millions of years. This change in atmospheric chemistry, at a rate 25 times faster than the end of the last ice age, traps more heat, raising average temperatures about 1.5°C so far. Not only are we living in a world never before inhabited by humans, threatening our civilization, the rate of change is disrupting all other life forms as well, risking possible human extinction. Despite the well-funded denial by the fossil fuel industry, more people are beginning to understand that there is no economy if the society crashes.
We see increased discussion of geoengineered solutions as a way out of our situation. Most common are proposals which reduce the amount of sun reaching the surface of the Earth. Such as, orbital solutions of a sunshade (similar to putting sunglasses on the planet), or inflatable silicon bubbles (acting like a cloud), or using mirrors to reflect sunlight away from the planet. Closer to Earth, there are plans to inject sulphates, salt particles, or water droplets, into the upper atmosphere, to induce a cooling effect.
All these high-tech engineering solutions raise serious concerns. They would have to be ongoing, regularly replenished, for if application was disrupted, abrupt heat spikes could occur. Questions of financing and control are unresolved. Unintended consequences, such as disrupted rainfall patterns or crop production, are possible.
In addition, these "solutions" only treat the symptom, increased heat, not the cause, increased atmospheric CO2. Much of this CO2 is absorbed into the ocean, which increases acidity, stressing oceanic life forms, increasing their extinction rates, which threatens the livelihood of more than a third of humanity. Clearly, to actually deal with this issue we must address atmospheric CO2: stop adding more (decarbonization) and begin reducing what is already there (sequestration).
Last year humanity added another 36 billion tons of CO2. Efforts have begun to decarbonize the economy, but progress is slowed by vested interests, focused only on their own short-term profit. Further, this will be a huge change in our energy infrastructure, which frightens people who demand certainty. However, the increasing destruction caused by the climate crisis, and the growing economic impact of "peak oil", will build further support for decarbonization.
But sequestering the existing CO2 is still relatively unaddressed. We need to return to a climate we know can sustain humans for millennium, the sooner the better, because there are irreversible tipping points that can make the situation much worse quite rapidly. Last year, I wrote several articles inspired by "Climate Restoration", a book by Fiekowsky and Douglis, which details several viable paths for carbon sequestration. The goal is to remove 50 billion tons a year above what we are adding each year, for 20 years. Solutions require using existing processes, as we can't afford to wait. They need to be affordable, with very low costs, or producing valuable by-products already used in the economy. They need to be scalable to a magnitude relevant to the problem.
While several direct air carbon capture installations have made news recently, these are all inadequate to the task. Costs are more than $1,000 per ton of CO2 removed, without mentioning where the energy comes from, while capturing only a few ten thousand tons a year.
My favorite Climate Restoration solution is ocean iron fertilization. In much of the ocean, plankton life is limited by the lack of trace amounts of iron. When this is strategically added, massive plankton blooms happen immediately, rapidly followed by all kind of higher oceanic lifeforms. This pulls CO2 from the atmosphere, and what isn't eaten falls to the ocean floor.
This is relatively low tech, powered by sunlight, working with life to enhance more life. A few small trials have already been accomplished, showing proof of concept. As with any new large-scale process, there could be unintended consequences, but this is essentially a natural phenomenon. Iron dust from the land has historically fed the oceans, but has been reduced by man made changes to the environment. In depth assessments have been made, indicating costs as little as $24-$94/ton of CO2 captured, including costs of verifying what is actually happening.
As the reality of our situation grows, the push for action will increase. Do we have the political will to act?
