# Is it correct to say that “some degree of pollution is an inescapable consequence of the Second Law of Thermodynamics”?

The quote above is from ‘Enlightenment Now’ by Steven Pinker, I was just wondering if this was true or if it misrepresented the Second Law.

The full quote below...

...some degree of pollution is an inescapable consequence of the Second Law of Thermodynamics. When people use energy to create a zone of structure in their bodies and homes, they must create entropy elsewhere in the environment in the form of waste, pollution, and other forms of disorder

(Page 123)

• Might be seen as obvious, even. It would be strange if we call Law something that doesn't hold. – Alchimista Jan 25 '19 at 9:30

Yes, this is true. However, the question is where that increase in entropy occurs.

Since the industrial revolution, life on earth is a bit one-sided, with humans controlling the chemistry going on, and a lot of it. When we burn fossil fuels, there is an increase in entropy on earth. Before that, one organism's waste was some other organisms food, and the entropy increase occurred mostly in the sun (giant nuclear reaction slowly going towards equilibrium).

Humans (and all other animals) benefit from the $$\ce{O2}$$ "pollution" from cyanobacteria and plants. Plants benefit - to a degree - from the $$\ce{CO2}$$ "pollution" from animals. However, when global concentrations change too fast, some species might benefit a lot, but many other species will go extinct.

If the "plastic ocean" had built up over millions of years instead of 50, some microorganism that uses the polymers as its primary source of food might have evolved, and there would be a cycle instead of a build-up.

It does not have to be true that 'pollution' is a consequence of the 2nd law. All the low entropy, high energy sunshine will ultimately end up as heat (high entropy, low energy), a lot of which is radiated away to allow the planet to reach a steady state. This would not normally be called 'pollution'.

The quote is of course subjective, as is this answer, however, as a species it is certainly true that we produce waste 'stuff' and do so in enormous quantities, or rather we produce it and are then not prepared to spend money, or equivalently energy, to make further use of it. Perhaps this will change in the future if global warming restricts fossil fuel use.

The quote does have a let out-clause which is the 'other forms of disorder' as described in the first paragraph above.

As they say the devil is in the details.

The definition of "waste" or "polution" requires clarification. We might use the concept of thermodynamic efficiency, which is related to the amount of energy wasted for a specific application (which appears to be Steven Pinker's point), but should also consider the total amount of energy used, and the specific forms of waste we generate. We want to increase our efficiency, but if we insist on living in McMansions, that may not be enough. We may have found ways to produce McMansions very very efficiently, but still produce too many. In addition, our impact extends to the way we produce things (do we generate $$CO_2$$, do we destroy rainforests, do we polute rivers?). Nuclear power plants are very efficient, but what are we to do with the nuclear waste? Handling waste and environmental degradation also consumes energy. This requires consideration of the entire cycle of production to disposal.

• I just googled “McMansions” and I’m surprised there are houses that look like that. But why does a lot of people seem to dislike them and why are they so bad for the environment? – Alice.Sumarno Jan 24 '19 at 18:04
• @Alice.Sumarno McMansion is a term used to encapsulate two ideas: that of unfettered consumption, and lack of charm or originality. First, it calls into question whether we consume more than we need to (or more than would suffice to make us reasonably happy). Second, it reflects the nature of modern consumer culture, including its impresively high efficiency in terms of churning out huge amounts of identical consumer goods. – Buck Thorn Jan 24 '19 at 18:32