Since the 2000s global emissions have continued to rise and Earth has gotten hotter. Scientists increasingly recognize that limiting warming to the Paris Climate Agreement goal of 1.5 degrees Celsius or even 2°C above preindustrial temperatures will require more than drastically cutting emissions—it will involve pulling hundreds of billions of tons of carbon dioxide out of the atmosphere this century. The most obvious way is planting trees. But even a trillion trees would not be nearly enough, and trees can burn or die of disease, emitting the carbon they’ve stored. In the 2000s the world wasn’t ready for direct air-capture (DAC), but now we are too late to do without it.