The December 2009 issue of National Geographic had a short article on The Carbon Bathtub. It describes a simple model of carbon dioxide (CO2) in the Earth's atmosphere, by analogy with the flow of water into and out of a bathtub.
I have implemented the model using Xholon, based only on the rather brief information in the National Geographic article. It's not intended to be a complete model of CO2 flows in the atmosphere.
The Xholon implementation is designed in part to demonstrate that a model like this can be done entirely online. It builds on the Xholon Chameleon app, which can be launched from a server. Visit the server page, and click on the Chameleon Launch button. This will start the Chameleon app using JNLP. Chameleon provides basic capabilities, and can become whatever application you want it be.
The Carbon Bathtub is built on top of Chameleon. I have built several versions, each in a different programming language. If you don't have a favorite language, or don't really know anything about computer programming, I would recommend the default Java (BeanShell) version.
The current versions of the model are:
The following images show the Xholon GUI once the various classes have loaded and run, and also shows the changes in CO2 levels for different rates of change for emissions from all human sources.
CO2 in the atmosphere, increasing by 2% per year from 2008 to 2069 (in metric tons).
CO2 in the atmosphere, increasing by 1% per year from 2008 to 2069 (in metric tons).
CO2 in the atmosphere, at a constant rate each year from 2008 to 2069 (in metric tons).
CO2 in the atmosphere, decreasing by 1% per year from 2008 to 2069 (in metric tons).
CO2 in the atmosphere, decreasing by 2% per year from 2008 to 2069 (in metric tons).
Additional sources of information on the Carbon Bathtub model itself, and on CO2 levels and global warming, include: