1. Bathtub Dynamics and Climate Change
Notes for this presentation can be found on the Activity 2 webpage:
Supplemental Systems Exercise for Activity 2

2. Bathtub System
Inflow
Stock
Outflow

3. Bathtub System Net flow = Inflow - Outflow
Stock is increasing
Stock
When inflow is greater than outflow, the stock increases.
Outflow
Net flow = Inflow - Outflow
Net flow = 5 gal/min – 3 gal/min = + 2 gal/min

4. Bathtub System Net flow = Inflow - Outflow
Stock is decreasing
Stock
When outflow is greater than inflow, the stock decreases.
Outflow
Net flow = Inflow - Outflow
Net flow = 1 gal/min – 3 gal/min = – 2 gal/min

5. Bathtub System Is A Model
Burning fossil fuels
Inflow
Deforestation
Stock = Atmospheric greenhouse gases
This bathtub actually provides a simple model of the climate system. Here, the stock of water in the tub represents the stock of greenhouse gases in the atmosphere.
The faucet represents the flow of greenhouse gases into the atmosphere from fossil fuel emissions and deforestation.
The drain represents processes that draw down atmospheric greenhouse gases, such as afforestation (growing more forests to store carbon) and dissolving carbon dioxide into the ocean.
Afforestation
Outflow
Oceans

6. Carbon Flows
Source: