The purpose of this short article is to explain mathematical formulas linking global temperature to the concentration of CO2 in the atmosphere. In other words, our goal is to settle upon a simple equation, explaining how CO2 causes global warming. In turn, this is why our roadmap to net zero aims to reach ‘net zero’ by 2050, stabilize atmospheric CO2 below 450ppm, and we believe this scenario is compatible with 2ºC of warming.