Conversations on Climate: How geoengineering has been used in the past

PlanetIn The Planet Remade, Oliver Morton argues that geoengineering, the process by which Earth’s systems are manipulated, can be used in a positive way to address the problems caused by man-made climate change. Geoengineering is nothing new. Chapter 7 of The Planet Remade describes how it was used in the twentieth century to feed a growing population. A summary:

At the end of the nineteenth century it became apparent that the yield of wheat would soon fall short of the demand. Sir William Crookes, one of the leading chemists of the time, gave a speech in 1898 on the subject. The number of people who wanted to eat wheat was increasing, but by that point there was no more land on which to grow it. The solution? Increasing the amount of nitrogen in the soil to increase the amount of wheat that a given parcel of land could yield. If this wasn’t done, Crookes warned, the world would face starvation.

Nitrogen was fixed on as the key to a solution because it is a necessary component of photosynthesis. It exists in the air we breathe in the inert form of two identical atoms attached to one another. In order to aid in sustaining life, it must be detached and fixed to some other element. This happens when bacteria in plants twist nitrogen molecules and insert hydrogen molecules into the resulting spaces, turning the nitrogen into ammonia. Later, the nitrogen is returned to its inert form. The process by which nitrogen is fixed and then unfixed makes up the nitrogen cycle. As this process has proceeded uninterrupted by humans for billions of years, it has been one component in supporting increasingly more complex life forms on Earth.

Crookes was hopeful that the problem could be solved. He called on scientists to figure out a way to fix nitrogen industrially. Fritz Haber, a professor at the University of Freiburg, rose to the challenge. He and his laboratory technicians created a process by which fixed nitrogen was created by passing a continuous stream of nitrogen and hydrogen over a hot catalyst at very high pressure. His colleague Carl Bosch scaled the process up so that it could be used on an industrial scale. The process was quickly adopted globally to produce more food. By the end of the 1960s, the amount of nitrogen fixed by the Haber-Bosch process exceeded that fixed by all the microbes in the world’s soil. Both men won the Nobel Prize for their efforts. Their discoveries have had profound implications beyond the world of agriculture.

The problem identified by Crookes had been solved, but at a cost. One cost can be seen in the Gulf of Mexico every summer. Between the 1960s and 1990s, the flow of nitrogen out of America’s heartland, through the Mississippi and into the Gulf has doubled. This abundant supply of nitrogen makes ideal food for photosynthetic algae to flourish, resulting in colossal algal blooms. As they decompose, they consume all the oxygen in the water, leaving none to support other life forms. As a result, large swaths of the Gulf of Mexico become dead zones every summer.

Does this episode in history prove that humans can’t be trusted with geoengineering? Or can it be used more responsibly in the future to address the challenge of climate change? To answer that question, check out The Planet Remade here.