A very interesting conversation! There are lots of things to say. Here's something about "green mathematics".

For me, the manageable portion of "green mathematics" is "network theory": understanding the mathematics governing the many networks that make up the world, from food webs to smart grids, and also the networks we use to understand the world, like Bayesian networks.

I'm working hard with my grad students to develop the foundations of network theory. I'm advertising this project whenever I can, and some academics - mainly mathematicians, physicists and highly theoretical computer scientists - are getting interested. I have a huge amount to say about it that I haven't had time to say yet.

So, I'm happy with how the "green mathematics / network theory" project is proceeding, except for two things:

1. It's very theoretical, and I'm having a bit of trouble spinning off "bite-sized sub-projects" that would be good for people who like to write programs. I bet such projects could be invented, and could be useful... but someone may have to nudge me in that direction, because I naturally focus on figuring out stuff just by thinking. So, for example, Jim Stuttard and David Tanzer and [[Ken Webb]] have done work on software for stochastic Petri nets: either reviewing the existing software, or writing blog articles about Petri net programming, or actually doing such programming... but so far there's been a relative lack of "published products", perhaps because I never jumped in and said _yes, I need you to simulate this particular stochastic Petri net!_ Why not? I can imagine some questions about Petri nets that require a lot of experiments to answer, where simulations would be crucial. But since I don't program, I tend to focus on other questions... and none of you have _pushed_ me to change this habit.

1. It's not very practical _yet_. It would be great to choose a specific practical application project to work on, a kind of test case to focus the research a bit and let people see what the theoretical work can do. I have an idea: using climate networks to study El Niño. This is something [in the news](http://www.wunderground.com/blog/JeffMasters/an-el-nio-coming-in-2014), something that lots of people are excited about and arguing about. Programming would be really essential here! Graham proposed another example: [[Zero carbon Britain]]. I don't understand this well enough yet, but it could be great. One advantage is that it's about _saving the planet_, not just _understanding the planet_.

What do the rest of you think about this? Can these reflections help us pick a specific project that programmers can get involved in? A project that's manageable, yet exciting enough to galvanize people into action?