Earth's climate more sensitive to carbon dioxide than previously thought

Ancient climates on Earth may have been more sensitive to carbon dioxide than was previously thought, according to new research. Scientists examined nahcolite crystals found in Colorado's Green River Formation, formed 50 million years old during a hothouse climate. They found that carbon dioxide levels during this time may have been as low as 680 parts per million (ppm), nearly half the 1,125 ppm predicted by previous experiments. The new data suggests that past predictions significantly underes