Three million years ago, there were no humans, global temperatures were possibly four degrees celsius warmer and sea levels were high enough to cover most of modern-day Manhattan. This was also the last time in geologic history that global atmospheric carbon dioxide (CO2) levels exceeded 400 parts per million (ppm), a benchmark that was permanently and ominously passed once again in 2016. Carbon emissions, largely as a result of burning fossil fuels, are not likely to halt anytime soon. Some scientists have started organizing backup plans; most notably, finding a way to grab some of this atmospheric carbon and store it in the Earth. “The critical thing at this point in time is to reduce emissions as rapidly as we are able to do so.