Rethinking Lifestyle

The current discussion about the state of our planet has focused on the necessity for a massive transition from fossil fuels to renewable energy. This is critically – even existentially important. But the main reason that we find ourselves in such peril is hardly ever mentioned: We can’t seem to stop growing. Nevertheless we will shortly be forced to do so.

Between 1820 and today, the human population has grown eightfold and the average per capita energy use is 4-8 times what it was 200 years ago. For two hundred years, communities, governments, and economies have been built to maximize growth and, consequently, to need it. Today, reducing or even reversing growth is unthinkable. But why is that?

Governments and economists are quick to point out that growth is essential to the common good. To be fair, the only way we can continue to add 81 million people to the global population each year while also increasing material wealth is by building new houses and roads and products – in other words: by growing. But all of those things require new materials and, importantly, energy. Since 1650, energy demand in the US due to population and consumption is a surprisingly constant 2.9%. Even more surprising is what that means for us in the near future. As it turns out, there is no physical way that our current rate of growth can continue for much longer.
Astrophysicist Tom Murphy has applied a basic scientific technique to the world’s energy issues. Rather than exploring possible future outcomes, he started by defining the boundaries of what is not physically possible. Assuming no political limits, unlimited technological advancement, and total human cooperation, here is the simple math (which I’ve touched on in a previous article):

For a matter of convenience, we lower the energy growth rate from 2.9% to 2.3% per year so that we see a factor of ten increase every 100 years… I have always been impressed by the fact that as much solar energy reaches Earth in one hour as we consume in a year… But let’s not get carried away – yet. Only 70% of the incident sunlight enters the Earth’s energy budget – the rest immediately bounces off of clouds and atmosphere and land without being absorbed. Also, being land creatures, we might consider confining our solar panels to land, occupying 28% of the total globe. Finally, we note that solar photovoltaics and solar thermal plants tend to operate around 15% efficiency. Let’s assume 20% for this calculation. The net effect is about 7,000 TW, about 600 times our current use. Lots of headroom, yes? When would we run into this limit at a 2.3% growth rate? Recall that we expand by a factor of ten every hundred years, so in 200 years, we operate at 100 times the current level, and we reach 7,000 TW in 275 years. 275 years may seem long on a single human timescale, but it really is not that long for a civilization. And think about the world we have just created: every square meter of land is covered in photovoltaic panels! Where do we grow food?

~ Professor Tom Murphy

You may observe that tidal and nuclear power do not require sunlight. But Murphy goes on to show that even a zero-footprint, free, clean, unlimited energy source cannot save us from the relentless push of exponential growth. According to the first law of thermodynamics, essentially every watt of energy we use dissipates eventually as heat… and the amount of heat we would generate can’t radiate fast enough into space. If our population & energy consumption continue to increase at its current rate, the oceans would boil in 450 years. Many arguments can be made against this analysis which can’t be addressed here, so I encourage you to read Professor Murphy’s blog for greater clarity (a must read!).

The fact is that we cannot keep growing no matter where we get our energy. Fortunately, many others have come to the same conclusion, and are discovering exciting alternatives to economic growth (read the brilliant Herman Daly, for example). A no-growth future is not an option, it’s inevitable. It is a law of nature. So the next time you hear an economist or a politician celebrating “increased growth!” in the economy or your community… ask yourself whether that’s really what we want.