Over and over again, we, as a species, have found ways to overcome the physical limits of growth. Each time the population seems to be hitting a ceiling, we find new ways to push that ceiling upwards and subsequently accelerate the growth rate of our population. Beginning with the agricultural revolution, cultivators required far less land than their nomadic predecessors without roaming across vast territories in search for food. This new abundance gave rise to magnificent civilizations, limited only by their ability to administer and cooperate at scale.
Over a long period of time, the edges of our maps stopped creeping forward but instead circled back. The whitespace diminished and so did our ability to feed our growing population. According to the Planet Remade, if we had continued with pre-industrial farming practices, today’s farmland would feed just over a third of the world’s population (even with our ancestors’ meager diets). The shifts towards fossil-fuel powered machines and the use of fertilizers to replenish the land’s Nitrogen have skyrocketed the calories we can produce per usable acre. Every time we arrived at a barrier in productivity, humanity found a way of identifying the limiting resource - whether chemical, physical or even genetic - and hacked its way back to growth.
However, the ability to feed our growing population will not be our only inhibitor to growth. In ‘Limits to growth’, MIT researchers simulate the population levels the Earth can sustain by modelling a range of complex, interdependent systems that include food, pollution, non-renewables and the industrial sector. The majority of these simulations ended in a catastrophic collapse of the human population.
Exponential growth creates imbalances in systems. After ‘overshooting’, these systems will re-calibrate and potentially do so in an irreversible and inhospitable way. For example, an over-farmed plot of land goes from a full yield to producing next to nothing once starved of Nitrogen. Similarly, an over-polluted planet can shift from hosting 10 billion people to just a handful.
“Archimedes is said to have said that, given a lever long enough and a place to stand, he could move the earth. But he gave no indication of what he imagined would serve as the lever’s unmoving fulcrum,... Geoengineering is about finding levers with which to move the earthsystem. It is also about finding worldly fulcrums that can take the pressure of those levers, and guide their force with precision - that stop the lever from slipping and doing damage.” -Oliver Mortan
Much of the hype around geoengineering has focused specifically on Stratospheric aerosol injection, which basically boils down to spraying sulphur pollutants into the upper atmosphere to reflect sunlight back into space. The hope here is that less sunlight counteracts the negative impacts of more carbon dioxide. Despite its appeal, I prefer Mortan’s broader definition encompassing all technology that alleviates the pressure greenhouse gasses exert on our planet.
Beyond initiatives for global cooling, geoengineers also need to build the imminent tools we need for those on the front line of climate change. Farmers will need to be armed with the technology to remain resilient to shifts in their immediate climate and coastal cities will have to adapt to different sea levels. We need technology that works both at a very local and personal level but also that can be deployed to transform the planet at a global scale.
Unfortunately, much of mainstream tech has been targeted at slowing the emissions train rather than finding ways to mitigate its impact. These approaches are at best incomplete or at worst just moral licensing. To even begin cutting down on the stock of CO2 in our atmosphere, we need to halve our production. So, an overnight shift to a world full of Tesla’s is unlikely to do the trick.
Thus, sustaining a planet of ~10 billion people without emissions would require a ground-up redesign of the way society functions. Till then, we need to think through how best we can deploy technology to save those that will be most impacted and - in parallel - start to de-risk some of the grander, global geonengineering initiatives (so that we don’t accidentally begin the next ice age…)
Anant, appreciate the informative article. In your opinion, what, if any, are the current technologies under development that are most likely to have an impact on our immediate future?