Climate Change & the Big Payback

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

Polar bear on ice

© Can Stock Photo Inc. / Freezing Picture

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.

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

Astronomy Blogs, Cosmic Relief with David Grinspoon
David Grinspoon

About David Grinspoon

David Grinspoon, Senior Scientist at Planetary Science Institute, is an astrobiologist who studies the possible conditions for life on other planets. He is also an award-winning science communicator and writer and writes the Cosmic Relief column for Sky & Telescope. His new book Earth In Human Hands will be published in December 2016.

4 thoughts on “Climate Change & the Big Payback

  1. Gerald-Hanner

    Before we go taking all those rash actions to mitigate global warming we really should work to understand how the biosphere has managed to keep from running amok for the past few billion years. Humans still lack the power to disrupt nature.

      1. Dieter Kreuer

        Maybe you consider NOAA more reliable? In awesome details: how do we know, that the rise in CO2 is due to fossil fuel burning (several pages):

        You ask, how the biosphere has managed to keep from running amok? Actually, it didn’t always, as the example of the oxygen catastrophe in the article above shows, or the extinction of the dinosaurs (the role of the Deccan Traps volcanism and associated climate change has recently gained more support, the asteroid alone probably wouldn’t have done it). It recovered eventually, but this took eons. E.g. when Earth froze over (possibly) completely, the weathering of rocks and CO2 to lime was interrupted, so volcanism could enrich the atmosphere with CO2, and just after a few million years, the ice would have melted again.

        On the other hand, increased CO2 levels increase weathering, which lowers the atmospheric CO2 content. So, the climate is balanced by this mechanism, which is well understood. The only problem we have is that the mechanism is way too slow to be relevant for us now, that we have increased the atmospheric CO2 content in just 200 years or so by more than 40% from 280 to 400 ppm now.

        It’s all just science. The same science that tells us how the universe works or how to build a computer, there’s only one science (it’s basically a method). I don’t understand how some people try to deny scientific results that do not fit their personal or political preferences (unless they personally profit from such a choice, and some certainly do). But in the end, nature couldn’t care less about anybody’s preferences, and just follows it’s good old laws, as it always did.

All comments must follow the Sky & Telescope Terms of Use and will be moderated prior to posting. Please be civil in your comments. Sky & Telescope reserves the right to use the comments we receive, in whole or in part, and to use the commenter’s username, in any medium. See also the Terms of Use and Privacy Policy.