“We need to stay within our carbon budget.To prevent the worst effects of global warming, we have to keep temperatures from increasing by more than 3.6 degrees Fahrenheit (2.0 degrees Celsius) above the preindustrial level — the upper limit agreed to in the 2015 Paris climate accord.That means we can’t send more than 2,900 gigatons of CO2 into the atmosphere. This is our carbon budget.We’ve already used about 73% of our budget.
The world has emitted 2,100 gigatons of CO2 since 1870, mostly from . . .
Choose one of the choices in the model for each group, and watch the graph on the right show the results of the choice.