How would you feel if I told you that one-half of your extended family is going to be killed in a matter of seconds, that a few are already dead, and many more are about to die? Even if you don't know many of them well, and maybe not at all, how would you feel?

Something very like that is happening right now, but the family at risk is the family of life, our kin who are also part of this magnificently blue and beautiful world that is our one and only home. The family members that have died, and the many more that may soon be dead, are whole species of plants and animals: whole species of primates and lizards and flowers and trees and beetles and spiders and fish and whales and many, many more.

Biologists are now telling us that we are in the midst of what they are predicting will be the Seventh Extinction, the seventh major episode of extinction in the history of the planet. In each of the six previous extinction episodes, at least one-quarter, and averaging one-half, of the world's species were wiped out over a relatively short period of time. The last extinction episode—the Sixth Extinction—occurred about 65 million years ago and ended the age of the dinosaurs.

No one can say exactly what the dimensions of the current extinction are. Still, biologists estimate that from 17,000 to 100,000 species are being driven to extinction every year. Dozens, at least, and possibly hundreds, are extinguished every single day (most of the variation in the estimates is due to the fact that we don't know how many species there are and estimates vary, from 5 million to 100 million).

That's not the worst of it. It's now projected that one-half of all the species currently alive will be driven to extinction over the next one hundred years—if current trends continue—which is the reason many scientists are convinced the Seventh Extinction has begun.

Now, please don't let the reality of what I've told you get lost in the mind-boggling numbers. Stop, take a breath, and focus on that projection: One-half of all the world's species could be wiped out in the next 100 years. Millions of species could be exterminated within the lifetime of a baby born today. I'm not kidding—please, stop reading and take a moment to imagine what it would be like to live in that kind of world. I'll wait here.

Thanks for coming back. Do you feel like screaming in the streets? If you're thinking "No," I feel I must ask: What happened to you? What unspeakable things have been done to your heart?I'd run screaming through the streets if I thought people would listen to me that way. One hundred years is not all that long, and no mass extinction has ever taken place over such a short period of time. Is that the kind of barren, ravaged, and fragile future we want to bequeath to our children and grandchildren?

If we let the Seventh Extinction continue, it will be the end of life as we know it. It's not a random or unavoidable end, though. Earth hasn't been hit by a massive meteor like the ones that are thought to have been the primary factors in the Fourth and Sixth Extinctions. Nor are species simply "going extinct," the way it's usually phrased, as if these extinctions were just happening for no apparent reason. No, the people of civilization are driving thousands of species to extinction every year through the expansion of our claim on the planet's ability to support life. In other words, if we don't act to stop the Seventh Extinction, we will be the killers of the world as we know it.

Not killers in the sense of murderers, mind you. I've never met anyone who truly intends to kill the world. No, what we're perpetrating is a sort of reckless world-slaughter. We kill the world by pursuing a lifestyle that wasn't designed to destroy the world, that doesn't destroy the world on purpose, but that does so all the same because of its inherent character.

What character am I talking about? Simply put, we live a lifestyle founded on growth: growth of our population, of our towns and cities, of our economy. We see only two choices, growth or death, so we are convinced that we must keep growing. As long as we cling to this addiction, the Seventh Extinction cannot be averted. Why is that?

The world, by all evidence, is a finite place, which means it can only support so much of what is called biomass, or living matter. As we turn ever more of the world's biomass into us and our stuff, ever less of it can be anything else in the community of life. Consequently, our continued growth is a direct attack on the biodiversity of the world, and it's an attack that will ultimately result in our own destruction if we persist in carrying it out.

Just how do we "turn ever more of the world's biomass into us and our stuff?" Most fundamentally, we do it by working to manufacture more food year after year, which fuels population growth year after year. In just the last century, we've increased food production to such an extent that we've fueled population growth from less than 2 billion people to more than 6.5 billion people at present. If the current level of annual population growth (estimated at between 75 and 80 million people per year) continues, we will add another billion people in less than 15 years.

Population growth isn't just happening "somewhere else," either. The U.S. population recently reached 300 million, and the Census Bureau estimates it will grow by about 2.7 million this calendar year. Their projection for the most likely U.S. population level in "A.D." 2050 is just shy of 420 million.

Increasing food production isn't the only way we turn ever more of the world's biomass into us and our stuff. We also do this by increasing our use of other life forms for things other than eating, like felling trees for wood products, or growing cotton and hemp for fiber, flowers for decoration, and tobacco, coca, cannabis, hops, and poppies to cope with the stresses and strains of our lives—plus so much more. Though this consumption doesn't directly increase the number of people in the world, increasing the share of the world's life-giving energy that supports our nonfood crops is also a direct attack on the diversity of life.

It's vital that we recognize our way of life is killing the world. It's at least as important we understand that, though we're destroying the world, this doesn't mean that humanity, by its very nature, destroys the world. The genus Homo, which includes all the human species that have ever existed, emerged in the community of life some three million or so years ago—and no mass extinction ensued. Humans thrived quite nicely through those millions of years without waging war on their kin in the community. Even if we only consider our own species, Homo sapiens, the evidence shows that anatomically-modern humans have lived as part of the world for more than a hundred thousand years without causing a Seventh Extinction episode. This doesn't mean that ancient humans didn't cause any extinctions—in fact, there's evidence to suggest they may have—but I'm not aware of any evidence to indicate they caused the kind of progressive and expanding global wave of extinctions most biologists are convinced is now occurring.

Eventually, however, something changed, but the change only took place among the members of one culture of humanity. That change began about 10,000 years ago in the Fertile Crescent when the people of that one culture began to develop a lifestyle founded on farming, settlement, and growth. Over the years that followed, this culture spread out in all directions from the Fertile Crescent, swallowing up and destroying other cultures, until today it encompasses more than 99% of the world's people. Even so, there still are other cultures, with other lifestyles, in existence, cultures which are not taking part in the destruction of the world.

All of this evidence makes quite clear the fact that people are not world-destroyers by their nature, but can become world-destroyers through their culture. In other words, what's important to understand is that it is not humanity but that one growth-addicted culture—now our culture—which set in motion the Seventh Extinction.

Destroying the world isn't in our genes, it's in our minds. We can stop. Even if self-preservation is our only concern, we'd be wise to do so, because one of the species wiped out in the Seventh Extinction could very well be our own. The forces we've set in motion that are destroying tens of thousands of other species every year are very likely to prove lethal to us, as well, eventually. Every bit of evidence we have tells us that we are woven into the web of life with all the rest. If we keep tearing strands from the web, it will eventually collapse, and we will destroy ourselves along with it.

Let's choose life instead.