How many people can Earth support?

According to the BBC, our home planet’s capacity is 11 billion people. And that is after we change our present consumption habits. As of March 2020, the world’s population is at 7.8 billion. According to a 2015 survey by the United Nations, it could reach over 11 billion by 2100.

One of the more imaginative solutions for the rehabilitation of humankind might just be ocean colonisation!

Oceans cover 70% of the Earth. If we only count equatorial and subequatorial territories, it is more than 5 million sq. miles for the Atlantic and about 7.8 million sq. miles for the Pacific. The current surface area of all habitable land on Earth is 24,642,757 sq. miles, which means we are looking at a surface area increase of more than 50%.

This raises the question: how will living underwater affect human health?

ISS expeditions usually last about six months. Russia’s Gennady Padalka currently holds the record for the most days spent in space. He was in orbit for a collective 878 days over the course of five missions.

According to Professor Nick Kanas, a NASA-funded expert in the psychological effects of space exploration, long stints in space result in “(…) increased feelings of isolation, homesickness, dysphoria, or even suicidal or psychotic thinking.”

Meanwhile, based on recent literature to date, living in a submarine city might not only be psychologically more comfortable but also help in reducing stress and promoting social relationships.

The physiological and physical aspects of living underwater are based on the information provided by aquanauts who are a part of the NASA Extreme Environment Mission Operations (NEEMO).

The higher density of air and relatively higher amounts of oxygen taken per breath underwater might eventually result in pulmonary toxicity, i.e., damage to human circulation systems.

Stepping out of carefully monitored areas present pronounced physiological stresses on humans. There is a danger of hypothermia in these waters without adequate thermal protective gear.

Researches have shown 6–12-hour immersions in water result in increased amino acids and potassium in the plasma, suggesting that the majority of the fluid is shifted out of the intracellular compartments. In spite of this, interstitial fluid volume and lymph do not change. Carbon monoxide levels are elevated and sustained throughout these immersions.

This data supports the contention that the intracellular reservoir of fluid is not diminished significantly.

Physically, acne and diaper rash, experienced by divers peeing in their wetsuits— given the extended diving time afforded by saturation, urination in a wetsuit is nearly impossible to avoid— might be a potential problem.

Ear infections are also common, but antiseptic solutions made with aluminium acetate can be used to take care of them before the infections can worsen. Besides that, other side effects of living in underwater bases include paleness and reduced vitamin D production, from lack of exposure to the sun.

Many aquanauts have reported that their sense of taste diminishes in the habitat. The current theory is that this happens since the higher density of air in these habitats mean that there are fewer parts per million of food odours diffused in the air for the nose to detect.

The greater air density also causes aquanauts’ speech to become slightly higher-pitched when they first enter the base, but either the pitch adjusts or people’s ears adjust to the higher-pitched conversation.

Don’t worry, despite it all, the conditions aren’t as bleak as they might seem.

According to Ian Koblick, the founder of La Chalupa— an underwater habitat and research facility– the technology to create a few underwater colonies already exists.

It appears that humans should not build colonies deeper than 1,000 feet (300 meters), and ideally at much shallower depths. This is because the pressure at these depths would not only require very thick walls but would also require lengthy periods of decompression when returning to the surface.

At these depths, humans need to take extra measures to ensure that there is a healthy ratio of oxygen to other gases in the air, as the body requires varying levels of different air components when at pressure. Plants and artificial light could be used to supply some oxygen. Depending on the depth, nitrogen, or helium would also be needed.

How humans breathe underwater, and the depth of the structure, are correlated, dictating how the structure should be created and the mixture of air humans will need to breathe in potential underwater cities.

However, we lack the technologies required to deal with emergency evacuation systems, and environmental controls of air supply, composition, temperature and humidity. Companies like Shimizu Corporation have announced their plans for an underwater city that will also help in restoring the earth.


So, is it time for a new dream?

Colonising oceans is profitable, challenging, feasible, and doable. Maybe in ten years, we’ll have an opportunity to look at an underwater city with our own eyes, and not only with our imaginations.

– Stuti, Delhi Public School, Noida



Leave a Reply