Carbon budgets tell us how much carbon dioxide the global economy can emit while keeping global warming below some specific limit. We can estimate the total carbon budget consistent with staying below the given temperature limit of 1.5°C. If we subtract the CO2 emissions humanity has emitted over the past two centuries we get an estimate of the remaining carbon budget. Based on this calculation alone, we can clearly see the climate crisis looming.  The chart below shows the percentage change in temperature from their long run-averages for seven cities around the world from 1820 to 2020. Humans are warming…