Climate Change & the Big Payback

We’re causing a mass extinction now. Can we prevent the next one?

You've heard how humanity is currently causing a new mass extinction rivaling, in rate and numbers of species lost, the other five such events that have occurred since the Cambrian explosion 530 million years ago filled our planet with complex life.

But we’re not the first kind of life to radically change the environment. For example, 2.5 billion years ago, cyanobacteria began flooding Earth’s atmosphere with poisonous oxygen. The rise of oxygen triggered extinctions and a climate catastrophe, destroying a methane greenhouse and plunging Earth into a global deep-freeze. All because cyanobacteria figured out how to exploit solar energy — using photosynthesis to grow and releasing oxygen as a byproduct.

Today we humans see ourselves behaving in a similar way, and it seems deeply irresponsible. In theory, we, unlike microbes, have awareness of our actions and thus bear responsibility for them. But do we have awareness or control of ourselves as global actors? Sometimes it seems as though on a planetary scale we are watching ourselves from afar, unable to control our actions, as in a nightmare when you can’t stop yourself from doing something bad.

Yet I think we are awakening. The world is being knitted together electronically. Slowly we are developing more of a global view of ourselves and of the need to act collectively with some sense of intentionality and responsibility. This does not require any higher moral sense, only an enlightened sense of self-interest and self-preservation.

We may be in for a rough century, but hopefully we’ll get through it with an eventually stabilized population and by developing a new global energy system that does not wreck the natural systems upon which we depend. Then it may be time for payback. What can humanity do for Earth that would possibly help atone for the damage we are now doing?

We could build a planetary defense system. Sooner or later another huge asteroid or comet will be on course to strike Earth, but as long as our descendants are on the case, our biosphere never need suffer another mass-extinction-causing impact. Maybe this could be some kind of long-term compensation to the biosphere.

We could potentially intervene against harmful climate swings, even perhaps prevent future ice ages. Another ice age would be much more extreme than the climate changes we are facing now. We don’t want to try to live through that, and, if we get our act together, we’ll never have to. And we would save a lot of other species in the process.

If we last that long then we will have become a new kind of entity on the planet: self-aware world-changers with the sense to work with the planet, not against it. In the distant future, our successors may even be able to help defeat another threat to the biosphere: the eventual runaway greenhouse that will envelop Earth as the Sun heats up in its later years. Given billions of years of engineering prowess, we may be able to solve this problem and help Earth’s biosphere outlive the Sun. Someday we may be the best thing to ever have happened to life on Earth.

But first we need to get through this century.

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This Cosmic Relief column first appeared in print in the January 2015 issue of Sky & Telescope.