Life, Energy & Waste

David Galbraith
3 min readOct 16, 2020
Photo by Tim Foster on Unsplash

There is an instinctive mental model of the earth as a finite planet, a closed system with limited resources.

This fits with the view of our destruction of the environment and is true to the extent that we are confined to one planet and there isn’t another, but it isn’t strictly correct in terms of how our environment works. The environment itself is much more like a living thing with inputs and outputs.

In order to fix things we should view it as an open system, where preserving the environment necessarily involves energy consumption and waste, so that we can switch the argument to how we consume sustainably not whether we should at all.

In order to describe this system we can look at the principal energy flows, if there were no life on earth and if there was no atmosphere.

Sun and Earth with no life and no atmosphere.

The sun heats the earth to -18°C with high energy sunlight photons and the earth heats space with 23 times the amount of 23 times cooler, lower energy, infrared photons) so that the energy input is the same as the energy output and energy is conserved.

There are more ‘waste’ photons so the waste or entropy has increased as it has to, according to physical law.

Sun and Earth with the Atmosphere.

The atmosphere traps some of the sun’s heat, warming it to an average of less than15°C and releasing approx. 13% less waste photons (<20x not 23x).

(The next diagram explains why the temperature would be less than 15°C without life).

Sun and Earth with the atmosphere and life.

The earth has more order (decreased entropy) by creating life, compensated by more waste produced by life and eventually more photons into space, so the temperature of earth is slightly reduced by the biomass of living things and increased more by their action (this is really what we mean by energy consumption).

Life increases temperature and the more life, the more waste that must be created by it, that’s what life does, it increases entropy or waste, as it grows. The more sophisticated life is, the more temperature and waste increase. There is nothing wrong with this in theory, but in practice if it changes too much or too fast we will kill us and everything else, and life is what we want to preserve.

In addition because the environment itself is like a living system we can create feedback loops if we change things too much, and that is exactly what is happening with our environment, now.