Subject: Stocks and Flows

Posted by Elisabeth Roberts on 3/3/2004
In Reply To:Stocks and Flows Posted by Richard Turnock on 3/2/2004

Message:

Me too! It's a bit confusing. Unless you understand how emissions impact C02 in the atmosphere, its extremely difficult to understand whether emissions is a stock or a flow. And I find economics generally unintuitive. Can we talk bathtubs here? My understanding is the water flowing into the bathtub is the flow (a part of a system that provides input to a stock at a controlled rate), and the stock is the amount of water in the tub at any given time. The flow of water coming into the bathtub (an input into the system) could be something that we humans control, like turning on the tap, OR it could be a natural process driven by other stocks, such as a pond overflowing into another pond after a flood. I tend to always think of the smallest "unit" in a system as having three parts: an input, an accumulation, and an output. (The output of the bathtub is either water going down the drain or water going over the edge onto your floor and into the bathroom of the crazy neighbor downstairs who then accumulates resentment and starts flowing insults your way).


Does this make sense or am I off base?


Elisabeth Roberts
Tucson