There was a time when circular was bad. Going in circles was considered a bad thing. You had lost your way. Circular reasoning? Also not good. Those times are gone. The circular economy is popular today, embraced by many, and like so many concepts that have entered the popular psyche quickly, it has no exact definition. Its use is exploding even though most using it and most hearing it don't know what it means. They know it sounds good. But many of the implications of a circular economy are left largely unexamined, as talking points are cherry-picked to support an agenda while ignoring aspects that do not.
The foundation of the circular economy is that the earth’s resources are finite. Sustainable use of these finite resources dictates that we leave them for future generations, that we leave Earth with the resources she had at the time of our birth. From an atomic standpoint, this is easy. The mass of the earth is changing imperceptibly slowly, with some light elements lost into space, very heavy elements being lost to radioactive decay, some man made elements being conjured, and some elements being delivered from the cosmos by meteors. The number of atoms of each element – nitrogen, oxygen, carbon, and the rest of the periodic table – remains imperceptibly changed from what it was when I was born, or from when the dinosaurs roamed. The circular economy is not about atoms, but molecules and oxidation states. That makes it fundamentally a chemical issue.
Most elements are not found as lone atoms, they are found as compounds. Society’s use - my use- takes resources present as compounds and chemically transforms them. We take iron oxide, add energy to convert it to iron, use it in a way that inevitably takes it back to iron oxide. That is already a circle, but it isn't quite that simple. First, we take rich ores at the start. Entropy wins, as entropy always does, and we take a low entropy source of iron and turn it into a high entropy distribution of iron around the planet, leaving it in low concentrations in landfills, by the roadside, or other places. We also use energy in the process, energy that we can't recover to use again. This isn’t for lack of trying. We continue to push energy efficiency, energy recovery, co-generation and other technological solutions. Entropy wins, as entropy always does, and makes perpetual motion impossible. We can't start with a Joule and use it endlessly like we can with iron. We do a really great job closing the circle with iron, if you forget about the energy. Iron is easy to sort magnetically and easy to recycle, provided you have energy. Keeping materials in the economy at the highest value use is what the circular economy strives to do, with materials like steel being successes. With almost all cases, our gaze is on the mass flow, little on the energy flow.
Energy can’t be ignored in the circular economy. Again, it is a chemical problem. A circular economy is restorative and regenerative by design, and aims to keep products, components, and materials at their highest utility and value at all times. Our problem is that we use materials as energy sources and, through extraction of that energy, we make them useless. We take hydrocarbon compounds from reserves and react them with oxygen. The combustion reaction powers and moves the world. The reaction products are heat, water and CO2. Photosynthesis will take the carbon dioxide and water back to carbohydrates and other materials, and geology could take it back to hydrocarbons again. The problem is that the circle is too big. It takes too long. Future generations won't have the high utility resource. A truly circular economy requires renewable energy.
Earth is largely a closed system when it comes to mass, but an open system when it comes to energy. Energy flows in from the sun, nuclear decay and from gravity. It flows out as heat radiated to space. Entropy wins, as entropy always does, and energy is lost during our use. Try as we might, we can't truly conserve energy. Chemical energy converted to heat is used for work, light, and warmth, but can't be turned back into chemical energy. The same holds for nuclear energy. We can't get it back.
The chemical industry, like all other industries, burns hydrocarbon reserves for power. Future generations are robbed of fossil energy resource, just as they are when we drive our gasoline-powered cars or turn on our gas heat. Unlike most industries, the chemical enterprise covets the hydrocarbons too, keeping more than are burned in the products made. The largest volume products of the industry are plastics and plastics are, as Paul Hodges pointed out in his recent blog, at the heart of the circular economy discussion. Plastics are used because they cost effectively solve many problems. They are so cost effective that they allow single use. The single use, disposable economy is the opposite of the circular economy.
The weight of the world is really on us, fellow chemists. Chemistry is the central discipline in crafting a sustainable future. It is up to us to find the ways that preserve resources and the planet for future generations. It is not an issue of atoms, it is an issue of molecules and we are the masters of molecules.
Mark Jones is Executive External Strategy and Communications Fellow at Dow Chemical since September 2011. He spent most of his career developing catalytic processes after joining Dow in 1990. He received his Ph.D. in Physical Chemistry at the University of Colorado-Boulder doing research unlikely to lead to an industrial career and totally unrelated to his current responsibilities.