Climate Models

This week we’ll be looking at running some experiments with climate models. Before we get started, it’s helpful to understand the different types of models that are created for different purposes. In a paper published last year in Nature, Moss et al give an excellent overview, using the following diagram:

The Three Major Classes of Models for Understanding and Assessing Climate Change (click for detailed description)

In addition, models vary according to whether they cover the whole globe, or just a specific region. There are also separate models for each of the processes of interest (i.e. each oval in the diagram above). For example, there are ocean models, atmosphere models, cryosphere models, and so on. These are frequently coupled together in various combinations to study how processes interact. For example, an atmosphere model might be coupled to an ocean model to study how heat and moisture are passed between the two, and how this interaction affects climate and weather.

For this course, we’ll be looking at two models in particular that are relatively simple to work with:

• C-Roads – an integrated assessment model developed at MIT, aimed specifically at international policymakers. It’s a relatively simple model that allows the user to explore different emissions targets for different regions of the world, and relate these to temperature changes and sea level rise. A basic version, called C-Learn, can be run directly in a web browser
• EdGCM – a global climate model developed at Columbia University, based on a model originally developed at NASA. EdGCM is a fully functional atmospheric model, with simplied ocean and soil hydrology. It’s lower resolution than the newest research models, and hence can be run on a laptop. To download it, you need to submit your email address, and you’ll receive an email with instructions. You can use the demo version free for 30 days.

There are, of course, plenty more models out there, most of which are much more complicated to use. See for example:

• An introductory video on GCMs (we watched this in class a few weeks ago)
• An introduction to IAMs, produced by the UK ODI
• A detailed list of GCMs at Steve’s blog
• An example Adaptation and Impacts model, Cobweb, developed at U of T
• More details on what you might find in a Global Climate Model
• Some crazy experiments to try with climate models

If you come across other models, or you still have questions about the different types of model, post them in response to this post, and we explore further.