What is the upper limit of Earth's economy?
One of the main reasons why it’s proving so hard to reduce our carbon emissions is that this objective is conflicting with economic growth. As it is correlated with a number of positive effects, including life expectancy, safety, peace, and what is generally considered a higher quality of life for the majority of people, economic growth is considered intrinsically desirable.
Hopefully, thanks to proactive or reactive changes, the world will eventually achieve zero carbon emission at some point. However, even if we successfully transition to a carbon-free economy, it won’t mean that Earth’s economy will be able to keep growing endlessly.
There are of course many reasons why the world’s economic growth could come to a stop or even reverse. For instance, there is a question on how far the biosphere can absorb pollution and waste from human activities. We might also at some point face limits on our ability to access and recycle the material resources necessary to support a our economy. Some people argue that technology progress could also face diminishing returns with most low hanging fruits already behind us.
All economic activities also consume energy. This implies that economic growth is linked to a growing consumption of energy. In a relatively near future, as hopefully the world starts to converge towards carbon neutrality, other factors might limit the economy.
The vast majority of solar irradiation currently remains untapped and leaves in theory a huge potential for the future. However, a growing number of studies puts serious limits on energy we can harness directly or indirectly from incoming sun radiations. This means that if we want to keep growing our economy, we will have to include in the mix new sources of energy.
Even if new energy sources eventually offer us an economy which size looks generous compared to the current size of our world economy, the nature of economic growth implies that this limit might be reached faster than expected.
If sustained economic growth is desired in the long term, either we’ll need to find a way to largely decouple economic activities from energy consumption or build a robust space economy.
Please check our research paper: Energy Limits to the Gross Domestic Product on Earth