Feb 21 2023

A Circular CO2 Economy

Big picture time – as I have discussed before, we have just passed 8 billion people on this planet and will likely top 10 billion before populations stabilize (which is quite possible, but that’s another story).  What this means is that anything we collectively do is big. It affects every other species on Earth, it can affect the climate, and it can push the limits of natural resources. We are also getting to that point in the arch of human history that we are feeling those limits. We basically already use most of the reasonably arable land on the planet. We have already used up most of our carbon budget, assuming we don’t want the massive expense, inconvenience, and displacement caused by climate change.

Up until recently we had the luxury of treating the Earth like an unlimited resource, because it functionally was. Also, every time we think we are getting to the limits of a resource, we either find a way of extracting more or find a different way of doing things. England, for example, basically ran out of wood to heat homes and maintain its navy, but this just spawned the age of coal and ultimately the industrial revolution. Warnings of peak whatever have so far turned out to be premature. We appear to be running low on lithium, but oh wait, there is enough lithium in sea water to last for literally a million years at current use levels. What about uranium? There is 500 times as much in sea water as land-based reserved.

But this is not true for everything always. We also have to consider the consequences. In my opinion (and I think many people agree) we don’t just want to be able to continue the growth of the global economy, we also would like to preserve as much of nature as possible. Nature itself is a precious resource; it’s good for human psychology, it’s an invaluable natural laboratory, and it’s beautiful (even if we don’t consider the ethics of crowding out other species). All things being equal, it’s probably better not to figuratively and literally just pave over all of nature for our own purposes.

Ideally, therefore, we would like to do more with less. This is part of the “finding a different way of doing things”. Efficiency is good but only gets you so far. If we imagine the perfect future society (a good exercise if we want to get there) what would this look like in terms of resource management? Many people feel, and I agree, that the best path forward is toward a more circular economy. What this means is that physical resources are recycled as much as possible. Again – this just makes sense. A linear economy is based on the model of extraction, use, waste. The stream goes one way, with a depleting of resources on one end and the buildup of waste on the other. But such a system is obviously finite. Plus we have all that waste to deal with.

A more logical economy is circular, where waste gets fed into the stream as a recycled raw material. A 100% circular economy is fully sustainable, with no build up of waste or depletion of resources. Getting as close to this as possible seems like a worthy goal. Of course, the economics have to work as well. Often economics favor a circular economy, because waste is wasteful. But not always – a cheap abundant resource may simply be cheaper than any attempt at recycling. But here’s the thing – we should include the full costs of extracting and using any resource in the real-world cost. Many resources are only cheap if you allow those who are profiting from them to ignore all the societal costs, land use, degradation of the environment, pollution, and negative health effects. Factoring in these externalized costs shifts the bar in favor of a circular economy.

Technological advancement is another way to shift the bar toward a circular economy, which is why it’s a good thing that there is increasing research in this direction. I will give one example from recent science news, and the topic of the headline – researchers are making progress in understanding the underlying chemistry that allows copper compounds to be effective CO2 reducers. What this means is that copper compounds can be used as catalysts to convert CO2 into fuel and other useful compounds (including ethylene, ethanol, and propanol). Basically this means putting the energy back into the CO2, and combining it with water, to create high energy compounds that can be used or made into fuel or used in industrial processes.

CO2 is one of the most useful waste compounds to feed back into a circular economy. This is the same idea as biofuels – you make fuel with CO2 and then release the CO2 back when you burn the fuel, but no net CO2 is being added to the atmosphere. Biofuels, however, use up land and other resources and will likely have only a limited role to the play in a circular CO2 economy (but I could be wrong if a real breakthrough happens). Using catalysts, however, separates the process from living things. Then we could use any energy source – solar, wind, nuclear, and hopefully one day, fusion – to make fuel from CO2. Fuel becomes an energy storage medium, not a source of energy and CO2.

That is the ultimate goal, in my opinion – to have a technological society that just needs energy, with the addition of either no or only minimal physical resources. Matter is simply recycled and converted into whatever form we need. The other piece to this puzzle is connecting digital information with physical creation, such as with additive manufacturing, and eventually higher tech such as programmable matter and even nanotechnology. Then all our civilization needs is information, energy, and infinitely recyclable raw material. We also need space to live and to allow nature to do its thing, but with the other three there is a lot of universe to spread out into.

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