Earth's Insulation and the Water Cycle
Space is really cold. Earth relies on water to maintain a stable and comfortable temperature. Water is excellent at absorbing a lot of heat. As our Sun's energy evaporates water off of the Earth's surface, the resulting water vapor acts as insulation for the planet. Water vapor accounts for 2-3% of the Earth's atmosphere which allows the Earth to store energy and remain warm.
Water itself is a short-lived insulator owing to Earth's natural water cycle. After being evaporated by the Sun, the stored energy is dissipated as wind and rain. This cycle pulls water out of the atmosphere and back to the planet's surface where it can evaporate once again.
Water is not alone in helping to insulate Earth. Gasses like CO2 also accumulate and store heat in the atmosphere though they cannot store quite as much heat as water. CO2 is significantly more dangerous to Earth's temperature regulation because it lacks a process that can effectively remove it from the atmosphere. There is photosynthesis, which can convert water and CO2 into oxygen and sugar, but human emissions currently outpace plants' CO2 removal. Without a water cycle equivalent, they become permanent insulators, trapping more of the heat that should have been radiated into space.
When more heat is kept on Earth, water has to absorb less energy from the Sun in order to evaporate. The Sun's energy output does not change, so the rate at which water evaporates from the planet's surface increases.
In response to increasing water vapor in the atmosphere, the Earth's water cycle begins to change. Storms grow more frequent, and more energy is trapped on Earth at any given moment, which further increases evaporation. Insulation from additional water vapor combined with human emissions of permanent insulators are decreasing the planet's ability to regulate temperature and shed the Sun's energy.
Evaporation and precipitation make up crucial elements of the water cycle, but higher temperatures mean more water is being carried away from already dry areas and raining down somewhere else on the planet. In these dry regions, rain becomes increasingly scarce, increasing the rate at which they dry. This migration of water from land into the atmosphere is leading to global water scarcity and record freshwater shortages. In 2019, there were several major shortages that affected tens of millions of people around the world.
Chennai, India entered a water crisis after several years of deficient monsoon rainfall and extreme heat. Four reservoirs supplying water to the city have run completely dry leaving almost 9 million people without water. To access drinking water, poorer citizens had to travel far outside the city while wealthier citizens paid to have water shipped in on trucks.
In Basra, Iraq, government corruption and high temperatures has left around 2 million people without water. Just as in India, the wealthy had water trucked in and those without means were left to fend for themselves. In the summer of 2018, 120,000 people were hospitalized for drinking polluted water.
Sydney, Australia has also been experiencing declining dam reserves due to drought. As of November 2019, water levels have fallen to 47% of capacity. Should the drought continue, Sydney could run out of water by 2021.
Increasing water scarcity is an extremely dangerous symptom of a warming planet. The World Health Organization estimates that half of the global population will live in water-stressed areas by 2025. As a resource critical for survival, declining water reserves will lead to an increase in global political tension. The CEO of DOW Chemical, Andrew Liveris, was quoted in 2008 by The Economist saying, “Water is the oil of the 21st century.” There have been 9 major conflicts over oil since 1932. While many people still take it for granted today, I suspect we will also see armed conflict over water in the future.
Rising global temperatures are causing water locked up in land-bound ice sheets to flow back into the ocean. The continent of Antarctica is covered by a sheet of ice that averages 1.2 miles in thickness. The rocky landmass buried under the ice is the fifth largest continent and twice the size of Australia. The continent actually receives so little precipitation that it is a polar desert, yet 80% of the world's freshwater is stored there. Chunks of the ice shelf, some twice the size of New York City, are at risk of falling off into the ocean.
To the north, Greenland, a nation with 80% of its surface covered in ice, is also beginning to see anomalous melting. In 2019, the worst recorded heat wave on record in Europe caused the loss of 12 billion tons of freshwater ice in a single day.
As more ice-bound freshwater moves off of Earth's surface into the sea, the oceans begin to rise.
As of 2017, 2.4 billion people live within 60 miles of the coast. Sea level rise has already begun to affect low lying nations. Jakarta, Indonesia sits just a few feet above sea level. The city of 32 million people has begun to 'sink'. In 2019, the Indonesian government announced plans to relocate their capital.
If the targets set forth in the Paris Agreement are met, sea level rise is predicted to be kept at 17 inches by 2100. However, research shows that seas could rise by as much as 8 feet since the rate of climate change is outpacing predictions.
Pre-industrial revolution, CO2 levels hovered around 280 parts per million (ppm). In 2019, NOAA recorded atmospheric CO2 levels at 415.64 ppm. Ice cores show that the last time atmospheric CO2 levels were that high was about 3 million years ago. At that time, sea levels were 50-80 feet higher than those of today.
Rising atmospheric CO2 levels can impact oceans directly. Oceans absorb CO2 which reacts with seawater to produce carbonic acid. Since the industrial revolution, the ocean's pH has dropped from 8.21 to 8.10 (a 26% increase in acidity). Ocean acidification damages the organisms that make up the base of local food chains, impacting current ocean life and depleting a major source of food.
Investment in Water
With scarcity comes opportunity. Institutional capital is flowing into water resources. Goldman Sachs, JP Morgan Chase, Citigroup, Deutsche Bank, the Blackstone Group and many others are beginning to invest in water. Private equity investment in water resources was even mentioned at the end of the 2015 film The Big Short. Lakes, aquifers, water rights, and water utilities are becoming attractive commodities for investors. In 2006, the Bush family purchased 298,840 acres located on top of the world's largest aquifer in Paraguay. In 2018, Harvard's endowment fund received media attention when it paid well above market rates for 10,000 acres of California vineyards. Following the purchase, the fund acquired rights to drill 16 wells at a depth of 700 to 900 feet, several times deeper than residential wells.
Paying for Solutions
Our ability to build better and better tools made it possible for us to shift from agrarian societies to the hyper-connected world in which we live today. The global economy binds nations together through the marketplace of food, resources, energy, and technology. World order is currently decided not by conflict and military hegemony, but instead by participation in this marketplace. Large scale war simply costs too much for everyone involved and, inevitably, progress and technology will drive nations to become increasingly codependent. Climate change is a truly global problem impacting each nation in many different ways. Hopefully it can also be a forcing function for international cooperation.
Major global economic and political stagnation could occur if we cannot make the effort to finance and develop the technologies we need to fix increasing temperatures. If climate change further impacts productivity or water scarcity increases, we risk living on a planet that cannot support today's society. It is becoming clear that CO2 in the atmosphere is a debt we've exchanged for progress. That debt is coming due. The money we must spend to fix this problem can be paid back, but the effects of climate change are increasingly irreversible on human time scales.
Weathering the Storm
After 4.5 billion years, the Earth has proven itself to be more than capable of handling significant climate shifts. Through ice ages and asteroid strikes, it’s soldiered on. Regardless of the state of the planet, life must conform to its environment or it will not survive. An incredible variety of different species have lived on this planet since the first bacteria existed 3.7 billion years ago, but most of those creatures were far simpler or very different from life seen today. An annually stable global temperature and the resulting water cycle, as well as healthy oceans, are critical for life as we know it.
Humanity faces the enormous task of simultaneously preparing for climate change and also preventing it from getting worse. Luckily for us, we're very hardy creatures when we band together. In exchange for our progress as a species, we've mortgaged our atmosphere and planet. If we fail to repay our debts, we risk losing not only our progress, but an environment in which we can thrive. The effort required to keep the planet healthy will require enormous investment and significant political effort, but we do not have any other option. It's the only planet we've got.