Should We Create Larger Ice Caps?

Earth’s climate is vulnerable to potential climate catastrophes that could threaten the longevity of civilization. Continued increases in greenhouse gas forcing could lead to the collapse of major ice sheets, which would cause catastrophic sea level rise and could cause the oceanic thermohaline circulation to halt. Further warming could cause the heat stress index to exceed survival limits, inducing hyperthermia in humans and other mammals. Even more extreme warming could shift Earth into a runaway greenhouse regime that would lead to the loss of all oceans, and the end of all life.

Geoengineering refers to the large-scale use of technology to alter Earth’s global climate, and geoengineering has been suggested as a way to ameliorate contemporary climate change. Addressing these immediate climate challenges through a combined strategy of adaptation, mitigation, and (if needed) geoengineering is a critical issue facing us today. Whether or not we decide to engage in geoengineering today, we must still devise a long-term strategy to address our changing climate.

But in the longer-term, could we also use geoengineering techniques to increase the size of the polar ice caps? In a paper published in a special issue of the journal Futures, I raise the question, “Should we geoengineer larger ice caps?” By doing so, the global average temperature of Earth could be lowered from its current state to a new stable regime with much larger ice caps. Earth has experienced shifts in ice coverage in its past, and a prolonged program of geoengineering–say, lasting a thousand years or more–could allow us to permanently shift the energy balance of Earth. More ice at the poles increases the amount of sunlight reflected back to space, leading to cooler temperatures.

Of course, the unfortunate side effects of this idea would be mass migration of populations near the poles, shifts in global agricultural zones, and a required commitment of millenia in order to avoid undesired side-effects. Human civilization today probably lacks the fortitude to embark on such a long-term goal. Nevertheless, thinking about the long-term management of our planetary system helps us realize that we have already entered the epoch of the Anthropocene. Our civilization itself is fundamentally intertwined with our global climate, and we should allow humility, rather than hubris, guide decisions to control our environment.

Geoengineering Double Catastrophe

If geoengineering by injection of aerosol particles into the stratosphere is deployed, then the occurrence of a global catastrophe could cause intermittency in geoengineering and lead to total damages far greater than if either situation occurred in isolation. While the outcomes of the double catastrophe are difficult to predict, plausible worst-case scenarios include human extinction. In a paper published this month in the journal Environment Systems & Decisions, on which I am a co-author, we develop this double catastrophe scenario, which strengthens arguments for greenhouse gas emissions reductions and demonstrates the value of integrative, systems-based global catastrophic risk analysis.

Global catastrophic risks are risks of events that would significantly harm or even destroy humanity at the global scale, such as climate change, nuclear war, and pandemics. To date, most research on global catastrophes analyzes one risk at a time. A better approach uses systems analysis to capture the many important interactions between risks. This paper analyzes a global catastrophe scenario involving climate change, geoengineering, and another catastrophe. We call the scenario “double catastrophe”.

The rising temperatures of global climate change pose great risks to humanity and ecosystems. Climate change can be slowed by reducing emissions of greenhouse gases like carbon dioxide and methane. But humanity has been struggling to reduce emissions. One alternative is geoengineering, the intentional manipulation of Earth systems. The most promising geoengineering option may be stratospheric geoengineering, in which aerosol particles are put into the stratosphere. The particles block sunlight, lowering temperatures on Earth’s surface.

One problem with stratospheric geoengineering, known as intermittency, is that the particles must be continuously replaced in the stratosphere. If they’re not, then in a few years they fall out, and temperatures rapidly rise back to where they would have been without the geoengineering. The rapid temperature increase would be very damaging to society. Because of this, society is unlikely to let intermittency occur–unless some other catastrophe occurs, knocking out society’s ability to continue the geoengineering. Then, the rapid temperature increase hits a population already vulnerable from the initial catastrophe. This double catastrophe could be a major global catastrophe.

Because of how damaging global catastrophes would be to human civilization, decision making is often oriented towards minimizing the risk of global catastrophe. Stratospheric geoengineering can prevent global catastrophe from climate change alone, but it can also lead to global catastrophe from the double catastrophe scenario. If global catastrophe is more likely from climate change alone, then society should decide to implement stratospheric geoengineering. Otherwise, society is better off without stratospheric geoengineering. This assumes (among other things) that the goal should be minimizing global catastrophic risk and that stratospheric geoengineering is the best form of geoengineering.

An “Ecological Compass”

Only recently have humans gained the capability to willfully and technologically manipulate the environment on a global scale. This sort of planetary engineering includes present-day geoengineering proposals to counteract anthropogenic climate change by reflecting away a fraction of incoming sunlight. Although such a feat seems technically achievable, whether or not we should engage in such geoengineering is a question of ethics. Other, more futuristic, kinds of planetary engineering include plans for terraforming Mars to increase global temperatures and make the red planet habitable for Earth life. For terraforming as well, the technology for terraforming may be available today, but whether or not we should deliberately modify another planet is a question of ethics.

I recently published a paper in the journal Astrobiology that develops a two-axis framework for comparing different views about how we value organisms, environments, planetary systems, and space. The ecological compass is shown in this figure with a scale from “space” to “intelligence” along the horizontal axis. This axis is intended to represent the vast diversity of life on Earth, from humans and other animals on the far right, to microscopic organisms near the middle, to planetary systems and space on the far left. The vertical axis of the ecological compass contrasts two types of value: instrumental value and intrinsic value. Instrumental value describes the usefulness or purpose that an object, organism, or system provides; for example, a logger may assign instrumental value to trees that are grown for lumber. Intrinsic value describes the an object, organism, or system as valuable for its own sake; in this sense, a hiker may view a tree as valuable simply by virtue of its being a tree. With this two-axis system, we can describe and compare various attitudes toward nature and their implications for planetary engineering.

An anthropocentric view, which assigns instrumental value to all life other than humans, may find no environmental objection to planetary engineering. This is because anthropocentrism is only concerned with the effects of planetary engineering on humans. A zoocentric (or ratiocentric) framework extends intrinsic value to animals and gives at least some consideration to how human actions affect these organisms. As such, zoocentrism suggests that some consideration should be given to the effects of geoenginering on non-human animals. Likewise, a macrocentric viewpoint considers large, visible organisms as intrinsically valuable, while a microcentric viewpoint considers even microorganisms to possess intrinsic value. Under these ethical frameworks, the decision to terraform a planet such as Mars will depend upon the organisms that are already inhabiting it. Finally, a cosmocentric framework places intrinsic value across the entire biological spectrum from intelligent creatures and microorganisms to planets and space. This suggests that a cosmocentric ethical framework would refrain from any sort of planetary engineering because a planet is valued for its own sake.

This ecological compass is intended to be used as a tool for discussions of human valuation of nature. As a tool it cannot provide the answer to whether or not we should engage in planetary engineering, but it can at least help us raise important questions about how we value nature in advance of any decisions.

Think Before Geoengineering

Geoengineering describes the large-scale use of technology to manipulate the Earth system. Geoengineering strategies are currently gaining attention as possible ways to avert the undesirable consequences of climate change. One of the most plausible geoengineering ideas is known as “solar radiation management”, which proposes to offset global warming by reflecting away a portion of incoming sunlight. The easiest way to do this would be to fly a bunch of airplanes into the stratosphere to release sulfate aerosol particles. These particles would reflect away sunlight and, perhaps, could help us to avoid what would otherwise have been a climate disaster.

In a recent paper published in Ethics, Policy and Environment, on which I am a co-author, we discuss how scientific study of geoengineering is intertwined with the ethics of geoengineering. For example, if we decide that geoengineering is a fundamentally bad idea–perhaps because it could cause political turmoil or perhaps because we disagree with the idea of intentionally altering our atmosphere–then we should move on to other potential solutions to the climate problem. If we do decide that geoengineering is at least worth discussing, then we need to be careful to identify when scientific decisions are also ethical decisions. An experiment that seeks to test the effects of geoengineering over a small region will necessarily affect the local environment; whether or not such an experiment should occur is a question of ethics, not science. If geoengineering remains on the table, then these ethical issues carry as much importance as the scientific know-how. Perhaps we should therefore create an international board for the ethical, social, and legal implications of geoengineering so that our science doesn’t get too far ahead of our conscience.