Climate change: Can humans be the Earth’s air conditioner?

It is not the first time that life on Earth has threatened its own existence. More than 2 billion years ago, photosynthesis by ocean cyanobacteria emitted massive amounts of molecular oxygen into the atmosphere. Known as the Great Oxygenation Event, it caused major cooling and glaciation of the Earth’s surface. It also drove evolution of species towards greater diversity and complexity that created the homo sapiens. 

Humans began polluting their environment on a massive scale during the Industrial Revolution. By the end of the 19th century the use of coal and heavy machinery made many workplaces hazardous. Areas around factories became unlivable. Besides affecting people’s health, the air filled with particles and chemicals created problems for industries. Printing, food and textile production suffered most. This, however, did not stop technological progress. It resulted in the invention of the air conditioner.

Can we air condition Earth instead of reducing our energy consumption and evolving backward into a kind of a leaf-eating three-toed sloth famous for the lowest rate of daily energy use by any mammal? The answer is Yes. If we have become so powerful that we can warm the Earth by a few degrees in a lifetime of one generation, we must be able to use that power to cool it down too. It is called geoengineering. 

The most promising two approaches consist of managing solar radiation that reaches the surface of Earth and removing excessive carbon dioxide from the atmosphere. Harvard researchers have been working on solar geoengineering for a long time. Later this year they are planning to test on a local scale whether the release of aerosol particles in the stratosphere can dim the sun sufficiently enough to cool the Earth’s surface.

The power of modern computers to make an accurate 10-day weather forecast brings hope that effects of solar geoengineering can be accurately incorporated into the computer models too. Nevertheless, concerns about climate mitigation going rogue remain. If aerosol management of the surface temperature of the globe becomes a reality, it will require cooperation of all countries and regions to avoid conflicts over weather.  

Controlling the amount of carbon dioxide in the atmosphere may be more straightforward but it is more expensive too. Projects range from growing massive amounts of biomass that absorbs carbon dioxide to direct removal of carbon from the air by specially designed power plants for which XPRIZE announced last month a $100 million contest. Elon Musk is sponsoring the competition. 

Collection and sequestration of atmospheric carbon at the level that can affect global climate requires an enormous amount of energy. Utilization of carbon-free nuclear energy for that purpose may be inevitable, with fission reactors employed first and fusion reactors used in the future. Clean nuclear fusion is a source of sunlight that sustains life on Earth and fusion power plants may not be that far from hitting the market.

One can ask: Why try to dim the sun or remove carbon dioxide from the air when we can stop releasing it by banning the use of fossil fuels? The answer must be sought in the law of life. Species have competed for the available energy throughout biological evolution. So have human societies — those that used more energy did more work and became more advanced. 

If the U.S. stops using certain forms of energy, the one who continues to use them will win economic competition. Believing that world economies will collectively agree to slow down is as naive as to think that competitors in the New York City Marathon can agree to run at the same pace. More in line with the law of life is a scenario in which economic competition will extend to technologies that allow control of the Earth climate. Not necessarily to cool it down but to warm it up when needed as well. We may be overdue for another glaciation period.

Human life has been made longer and more comfortable by using more energy, not less. This is how we evolved from living in caves to having climate-controlled homes, from riding horses to driving cars and traveling by air, from tribal medicine to modern hospitals, from mailing letters to texting. I refuse to become a three-toed sloth. Kudos to Musk. Air conditioned Earth must be the next step in human evolution.

Eugene M. Chudnovsky is a distinguished professor of physics at the Graduate School and Lehman College of the City University of New York (CUNY), where he teaches an Energy course and conducts research for the U.S. Department of Energy (DOE). The views expressed in this article are his own and do not necessarily reflect positions of the CUNY or DOE.