targets | Serendipity

Modeling challenge (part 2)

09. April 2009 · Write a comment · Categories: books, reducing emissions, research ideas · Tags: climate change, emissions, energy, ideas, models, requirements, stabilization, targets, visualization

Okay, here’s a slightly different modeling challenge. It might be more of a visualization challenge. Whatever. In part 1, I suggested we use requirements analysis techniques to identify stakeholders, and stakeholder goals, and link them to the various suggested “wedges“.

Here, I want to suggest something different. There are several excellent books that attempt to address the “how will we do it?” challenge. They each set out a set of suggested solutions, add up the contribution of each solution to reducing emissions, assess the feasibility of each solution, add up all the numbers, and attempt to make some strategic recommendations. But each book makes different input assumptions, focusses on slightly different kinds of solutions, and ends up with different recommendations (but they also agree on many things).

Here are the four books:

George Monbiot, Heat: How to Stop the Planet from Burning. This is probably the best book I have ever read on global warming. It’s brilliantly researched, passionate, and doesn’t pull it’s punches. Plus it’s furiously upbeat – Monbiot takes on the challenge of how we get to 90% emissions reduction, and shows that it is possible (although you kind of have to imagine a world in which politicians are willing to do the right thing).

Joseph Romm, Hell and High Water: Global Warming–the Solution and the Politics–and What We Should Do. While lacking Monbiot’s compelling writing style, Romm makes up by being an insider – he was an energy policy wonk in the Clinton administration. The other contrast is Monbiot is British, and focusses mainly on British examples, Romm is American and focusses on US example. The cultural contrasts are interesting.

David MacKay, Sustainable Energy – Without the Hot Air. Okay, so I haven’t read this one yet, but it got a glowing write-up on Boing Boing . Oh, and it’s available as a free download.

Lester Brown, Plan B 3.0L Mobilizing to Save Civilization. This one’s been on my reading list for a while, will read it soon. It has a much broader remit than the others: Brown wants to solve world poverty, cure disease, feed the world, and solve the climate crisis. I’m looking forward to this one. And it’s also available as a free download.

Okay, so what’s the challenge? Model the set of solutions in each of these books so that it’s possible to compare and contrast their solutions, compare their assumptions, and easily identify areas of agreement and disagreement. I’ve no idea yet how to do this, but a related challenge would be to come up with compelling visualizations that explain to a much broader audience what these solutions look like, and why it’s perfectly feasible. Something like this (my current favourite graphic):

Graph of cost/benefit of climate mitigation strategies

Why there’s no silver bullet

27. March 2009 · Write a comment · Categories: climate science, reducing emissions · Tags: emissions, evidence, feedbacks, greenhouse gases, IPCC, stabilization, targets

There is no silver bullet for climate change, just as there’s no silver bullet for software engineering. To understand why this is, you need to understand the magnitude of the problem.

Firstly, there’s the question of what a “safe” temperature rise would be. There’s a broad consensus among climate scientists that about a rise of around 2°C (above pre-industrial levels) is a sensible upper limit. I’ve asked a number of climate scientists why this threshold, and the answer is that above this level, scary feedback effects start to kick in, and then we’re in serious trouble. If you look at the assessments from the IPCC, the lowest stabilization level they consider is 450 ppm (parts per million), but its clear from their figures that even at this level, we would overshoot the 2°C threshold. Since that report, some scientists have argued this is way too high, and 350ppm would be a better target. Worryingly, the last IPCC assessment was based on climate models that did not include feedback effects.

Then, there’s the question of how to get there. Stabilizing at 350-450ppm requires a reduction of greenhouse emissions of around 80% in industrialized nations by the year 2050. Monbiot argues that if you think in terms of a reduction per capita, you have to allow for population growth. So that really means a reduction more like 90% per person. And again, due to our uncertainty about feedback effects, the emissions targets may need to be even lower.

How do reduce emissions by 90% per person? The problem is that our emissions of greenhouse gases come from everything we do, and no one activity or industry dominates. I was looking for a good graphic for my ICSE talk, to illustrate this point, when I came across this chart of sources of emissions:

World Greenhouse Gas Emissions by Sector

I think that’s enough on it’s own to show there is not likely to be a silver bullet. The only way to solve the problem is a systemic analysis of sources of emissions, and we have to take into account a huge number of different options. If you want more detail on the figures, Jon Rynn at Grist has started to put together some spreadsheets to add up all the sources of emissions, and some specific contributors.

BTW, the IPCC’s frequently asked questions is a great primer for anyone new to the physics of climate change.