From Peter Brannen at The Atlantic Magazine:
Since about the time of the American Civil War, CO2’s crucial role in warming the planet has been well understood. And not just based on mathematical models: The planet has run many experiments with different levels of atmospheric CO2. At some points in the Earth’s history, lots of CO2 has vented from the crust and leaped from the seas, and the planet has gotten warm. At others, lots of CO2 has been hidden away in the rocks and in the ocean’s depths, and the planet has gotten cold. The sea level, meanwhile, has tried to keep up—rising and falling over the ages, with coastlines racing out across the continental shelf, only to be drawn back in again. During the entire half-billion-year Phanerozoic eon of animal life, CO2 has been the primary driver of the Earth’s climate. And sometimes, when the planet has issued a truly titanic slug of CO2 into the atmosphere, things have gone horribly wrong.
Today, humans are injecting CO2 into the atmosphere at one of the fastest rates ever over this entire, near-eternal span. When hucksters tell you that the climate is always changing, they’re right, but that’s not the good news they think it is. “The climate system is an angry beast,” the late Columbia climate scientist Wally Broecker was fond of saying, “and we are poking it with sticks.”
The beast has only just begun to snarl.