I’ve just ordered the book “A Vast Machine: Computer Models, Climate Data, and the Politics of Global Warming” by Paul Edwards. It’s out next month, and I’m looking forward to reading it. I found out about the book a couple of weeks ago, while idly browsing Paul’s website while on the phone with him. What I didn’t realise, until today, is that Spencer Weart’s wonderful account of the history of general circulation models (an absolute must read!), which I’ve dipped into many times, is based originally on Paul’s work. Small world, huh?

On March 30, David Mackay, author of Sustainable Energy without the Hot Air, will be giving the J Tuzo Wilson lecture in the dept of Physics (Details of the time/location here). Here’s the abstract for his talk:

How easy is it get off our fossil fuel habit? What do the fundamental limits of physics say about sustainable energy? Could a typical “developed” country live on its own renewables? The technical potential of renewables is often said to be “huge” -but we need to know how this “huge” resource compares with another  “huge”: our huge power consumption. The public discussion of energy policy needs numbers, not adjectives. In this talk I will express power consumption and sustainable production in a single set of personal, human-friendly units. Getting off fossil fuels is not going to be easy, but it is possible.

The book itself is brilliant (and freely available online). But David’s visit is even more relevant, because it will give us a chance to show him a tool our group has been developing to facilitate and share the kinds of calculations that David does so well in the book.

We started from the question of how to take “back of the envelope” calculations and make them explicitly shareable over the web. And not just shareable, but to turn them into structured objects that can be discussed, updated, linked to evidence and so on (in much the same way that wikipedia entries are). Actually, the idea started with Jono’s calculations for the carbon footprint of “paper vs. screen”. When he first showed me his results, we got into a discussion of how other people might validate his calculations, and customize them for different contexts (e.g. for different hardware setups, different parts of the world with different energy mixes, etc). He came up with a graphical layout for the calculations, and we speculated how we would apply version control to this, make it a live calculator (so that changes in the input assumptions propagate like they would in a spreadsheet), and give each node it’s own URL, so that it can be attached to discussions, sources of evidence, etc. We brainstormed a long list of other features we’d want in such a tool, and we’re now busy creating a first prototype.

What kind of tool is it? My short description is that it is a crowd-sourced carbon calculator. Because I find existing carbon calculators to be very frustrating, because I can’t play with the assumptions in the calculations. Effectively, they are closed-source.

At the time we came up with these ideas, we were also working on modeling the analysis in David Mackay’s book (JP shows some preliminary results, here and here), to see if we could come up with a way of comparing his results with other books that also attempt to layout solutions to climate change. We created a domain model (as a UML class diagram), which was big and ugly, and a strategic actor goal model (using i*), which helped to identify key stakeholders, but didn’t capture the main content of Mackay’s analysis. So we tried modeling a chapter of the book as a calculation in Jonathan’s style, and it worked remarkably well. So we realized we needed to actually build the tool. And the rest, as they say, is history. Or at least will be, once we have a demo-able prototype…