From Climate Central:
In 1895, Svante Arrhenius first calculated the impact that increasing carbon dioxide could have on Earth’s temperature. Since then, scientists have further refined their understanding of the greenhouse effect and the role our rising carbon emissions are having on it. From the first Earth Day in 1970, carbon dioxide in the atmosphere has risen 24 percent. And because carbon dioxide remains in the atmosphere for centuries, the impacts of our emissions today will linger long into the future.
Chief among the impacts is the rise in the global temperature. That’s why countries around the world have agreed to limitthat warming to well below 2°C above pre-industrial temperatures.