Removing atmospheric CO2 is critical because we are currently at a level not seen since before humans evolved. For about 800,000 years, until the Industrial Revolution, global CO2 levels were, on average, 280 ppm. That's the level at which our species and civilization evolved, and the optimal level needed to cement a healthy future for our planet. That level of CO2 should also be the stated goal of the Green New Deal (GND).