The environmental movement, which began in earnest in the United States in the early 1970s, is not about saving the planet. Earth does not need to be saved, nor does life on earth need our protection. As much as we care about polar bears, their extinction would mean little to life as a whole. And life as a whole is mostly about life we can't see with our naked eyes. Prokaryotic organisms (bacteria, archaea) have been around for an estimated 3.7 billion of the planet's 4.5 billion years. Eukaryotes, the complicated cells from which all large life forms originated, are about 1.7 billion years old. As for animals and land plants, we have been on earth for less than a quarter of the history of life. And life will still be here long after we split.

So the environmental movement is not about the third rock itself but about one of its many worlds: the world of human beings. Our world, which is very new to this planet (only about 250,000 years old) is what we mean when we say Save the Earth. What is happening is that this world is being transformed by our own activity. We are destroying the world that made us, that evolved us, and we have no idea if we will have a home in the world that is now replacing it.

On November 21, Daily Kos posted: "This week will be the last time anyone alive experiences a CO2 level below 400 ppm." One world is going under and another is coming up. "As a human," explained Katharine Hayhoe, an atmospheric scientist at Texas Tech University, "passing both the 400 ppm and (potentially) the 1° C threshold within such a short time period makes it clear we are already living in a different world." The reason we are condemned to live in this different world is certain humans have the political power to maintain and increase the burning of fossil fuels.

This is indeed the most important and sobering message in the rather melancholy documentary Bikes vs. Cars . It's not so much that automobiles are dangerous to pedestrians and bicyclists (ghost bikes appear all over the world), or that cars cause psychological damage to those who spend hours in traffic snarls in Los Angeles, São Paulo, and Toronto (the main cities in the doc), but their makers have successfully (meaning, politically) blocked the way to alternatives to their products and the form of energy they use (fossil fuels). Yes, there are now lots of electric cars on the market, but as the doc points out, in 2013, they represented only 1 percent of all new cars (83 million) sold in the world. The number of automobiles is growing. More and more people are buying them, despite their destruction of the only world we know for sure.

"It is totally useless to own a car because you can't go anywhere, because we are stuck in the middle of traffic," says Raquel Rolnik, a São Paulo–based urban planner. As she says this, we see a Brazilian driver sitting in a car and chewing his thumb knuckle as he waits and waits. This is the image of complete madness, and yet he and the rest of humankind are stuck in this situation. The car industry is just too powerful; it spends more money on advertisements than any other industry. It defines success and middle-class status for billions of humans. The rise of this class in China has resulted in the 45 percent drop in cyclists in that country. German car manufacturers basically buy politicians by giving them free cars and donations. In short, we can expect nothing of any importance to come out of the Paris talks on climate change. If you leave this documentary not feeling this way, then you watched a different film. recommended