The grand myth of environmentalism is that it's all about saving the Earth.

It's not. The Earth will be just fine. Environmentalism is all about saving ourselves.

That may seem a bit counter-intuitive; after all, the Earth is certainly central to the rhetoric, the memetics of environmentalism. Most environmental discussions focus on ecological dynamics, with references to human beings typically limited to enumerations of the various insults we've visited upon the planet. Given the degree of culpability we bear for the current state of the planet, this is entirely appropriate.

But the rhetorical focus of environmentalism on the planet obscures the fact that what human beings have done to the Earth pales in comparison to past disasters hitting our world, from massive asteroid strikes to super-volcano eruptions killing off 90+% of the Earth's species. In fact, over the course of our planet's lifespan it's experienced every form of (non-human-engineered) apocalypse on the Eschatological Taxonomy up to Class IV -- in comparison, humans have yet to unleash even a Class 0 Apocalypse. And in every case, the Earth has recovered, and life has once again flourished.

We sometimes make the conceptual mistake of thinking that the way the Earth's ecosystem is today is the way it will forever be, that we've somehow reached an ecological end-state. But even in an eco-conscious world, or one devoid of humans entirely, natural processes from evolution to geophysical and solar cycles would continue. The Earth's been at this for a long time, literally billions of years; from a planetary perspective, a quadrupling of atmospheric carbon lasting 10,000 years (for example) is little more than a passing blip. The fact of the matter is that, no matter how much greenhouse gas we pump into the atmosphere or how many toxins we dump into the soil and oceans, given enough time the Earth will recover.

But human civilization is far more fragile.

Human civilization could not withstand and recover from the same kinds of assaults the planet itself has shrugged off in eons past. We remain entirely dependent upon myriad Earth services and systems, from topsoil and clean water to carbon cycles and biodiversity. Activities that undermine those critical services and systems quite literally threaten the survival of human civilization. The fundamental resilience of the Earth's geophysical systems simply means that, when we ignore our effects on the planet, we're simply making ourselves disposable, just another passing blip in the planet's long history.

In trying to minimize the harmful impacts of human activities upon the global ecosystem, environmentalism supports the continued healthy existence of humankind.

To me, this too is entirely appropriate. Despite its many flaws, I'm a big fan of human civilization. I marvel at our capacity to organize matter and information, at our ability to learn from mistakes and pass that learning down to subsequent generations. Civilization -- writing, cities, trade, the whole lot of it -- makes us unique on this planet and, as far as we can tell so far, in our part of the universe. Destroying that through malice or negligence is the worst form of crime, and the height of tragedy.

Part of a focus upon civilization, however, is the recognition that we do not exist in isolation, that we are dependent upon an enormous variety of complex systems. As a result, our continued existence requires the continued success of those systems. In order to save ourselves, we have to minimize actions which damage and disrupt the environment.

Like any social movement, environmentalists argue over tactics and goals, and some eco-activists will disagree with my characterization of the purpose of environmentalism. But the reality is that -- at least with current technologies -- there's nothing that we can do to truly put the planetary biosphere at existential risk. It will recover from what we now do, albeit in a different form than today. But what we can do is so violate the integrity of the planet's ecosystem that the Earth can no longer support us.

Critics of environmentalism often claim that eco-activists hate humans, that we value the Earth more than we value ourselves. With very few exceptions, nothing could be further from the truth. Environmentalism is fundamentally about making sure that human beings, and human civilization, can continue to thrive on our home planet for centuries, millennia to come. Environmentalism, in its demands for respect for nature, ultimately demands that we respect ourselves.

Happy Earth Day -- and Happy Civilization Day.