Climate Bathtub Model - Rising then Falling Emissions

Climate Bathtub Model - Rising then Falling Emissions

Part of our web series "Climate Bathtub Model of Earth's Carbon Cycle"

This animation shows a version of the "Climate Bathtub" model. In the Climate Bathtub (or Carbon Bathtub) model, the amount of water in the tub represents the amount of carbon dioxide in Earth's atmosphere. The flow of water into the tub represents human (anthropogenic) emissions of carbon dioxide into our atmosphere, mostly as a result of burning fossil fuels.

This version of the model shows one possible scenario for emissions, starting in the year 1900 and running through 2100. In this hypothetical scenario, emission rates continue climbing through the first half of the the 21st century, then rapidly decline throughout the remainder of the century. Click the green button in the upper right corner of the animation to start.

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Things to notice:

  • the flow into the tub from the faucet is initially very low
  • at the start, the flow in is about the same as the flow out via the drain - so the water level in the tub doesn't change
  • around 1950, the flow in starts to increase, so the water level in the tub begins to slowly rise
  • by 2040 the flow in has nearly peaked, and the water level is rising rapidly
  • after 2050 the flow in gradually lessens, but the water level in the tub continues to rise - the flow in is still greater than the flow out the drain
  • the animation ends at 2100 with a greatly reduced flow into the tub - but the flow in is still greater than the initial flow in at 1900 and is still greater than the flow out via the drain - so the water level is still slowly rising

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