Right now, we’re in a car, hanging on for dear life as we hurtle around a mountain bend. If we don’t hit the brakes soon, we’re going to lose control, crash through the guardrail, and careen into the abyss. We’ve been fully warned about the danger ahead, but now here we are, testing our fate.

Already, the effects of climate change are clear and significant. Last year was the hottest in recorded history, and it’s all but certain that 2015 will set a new record, according to the National Oceanic and Atmospheric Administration. Wildfires in the West this year have consumed a massive eight million acres of land and counting, while superstorms like Katrina and Sandy are becoming stronger and more frequent. But that’s just the beginning. By the end of the century, the planet will become unrecognizable. The western United States will face Dust Bowl-like conditions that will persist for more than 30 years. As the oceans rise, island nations like the Maldives could disappear completely, while millions of people in Miami, New York, and Bangladesh will be forced from their homes. Looking further out, over the next several hundred years, the melting ice caps could cause sea levels to surge up to 200 feet, high enough to sink a ten-story building.

These are not fantasies dreamed up by some Hollywood studio. They’re ripped from the pages of sober scientific journals and official reports. The Intergovernmental Panel on Climate Change, which operates under the auspices of the United Nations, foresees environmental impacts that are “severe, pervasive, and irreversible.” The World Bank has warned that humanity may not be able to adapt to this warmer world.

By certain measures, it’s already too late. Politicians, climatologists, and environmental activists have long rallied around 2 degrees Celsius of warming as a decisive point, after which we can no longer stave off disaster. Today, however, we’re already at 0.9 degrees of warming above preindustrial averages, and we’re on track to blow past 2 degrees by the middle of the century and well over 4 degrees by the end of it. At the rate we’re going, just limiting global warming to 2 degrees is a pipe dream.

That doesn’t mean the planet is doomed, however. We can still prevent the most devastating effects of climate change if we take action now. The 2-degree target isn’t a hard and fast cut-off, says NASA climate scientist Gavin Schmidt. Instead, it’s more like a speed limit. “The faster you’re going around that curve, the more dangerous it is going to be,” he told me. We may end up scraping the guardrail on our way around the mountain bend, but it’s still possible to keep the car on the road.