2 A Simple Model of Future Climate

In this interactive app by EarthGames, you can try out reducing emissions at whatever rate you want, and see where global temperatures end up.

Try out Simple Mode first, in which emissions of everything are controlled by the single slider on the left. So if you keep the slider at the “Emissions in 2022” line, then carbon dioxide (CO₂), methane (CH₄), sulfate aerosols, and nitrous oxide (not shown) are all fixed at 2020 levels. If you move it downward halfway, each have their emissions cut in half.

Climate interactive tool by EarthGames.

Protips: Press the reset button to start over at the beginning of 2023. You can plot temperature or radiative forcing with the buttons on the top right.

Emissions are visually indicated by the particles coming out of the slider. Radiative forcing of carbon dioxide, methane and sulfates are indicated with the rectangles. Remember that sulfates always have a negative radiative forcing!

The app also has simple representations of uncertainty. The dark red line in the thermometer has a higher climate sensitivity, but also a more negative forcing from sulfates. The orange line has lower climate sensitivity and less negative forcing from sulfate aerosols.

A few suggested experiments: How rapidly do you need to reduce emissions to keep temperatures from overshooting 2^o C? Which of your pathways stay below 1.5^o C in 2100? Or 2^o C?

There are two additional modes

1. 1. By sector: A model that has emissions separated into different economic sectors (electricity generation, industry, transportation, agriculture, and buildings). With this model you can do experiments like decreasing energy emissions without affecting agriculture, or vice versa. In addition to having different total emissions, each sector has a different balance of heat-trapping gases. Agriculture, for instance, has higher emissions from methane and nitrous oxide.
   2. By gas: A model that has emissions separated into the individual gases (CO₂, CH₄, and N₂O) and short-lived pollutants like aerosols. In this model you can change emissions of the different gases separately.

Try out some experiments to better understand the role of each greenhouse gas and each sector in determining future temperatures. You should be able to verify the instantaneous effect of changing short-lived pollutants, the decadal persistence of methane, and the very long persistence of CO₂.

For the economic sectors, electricity is generally thought to be the easiest to decarbonize, while industry is the most difficult. Buildings here refers only to combustion within buildings, so is mostly from heating, with some additional cooking emissions.