New York | Climate Plus

Stuff happens. We have a household of three with separate access to our online service and last week the youngest member blew our monthly usage budget downloading games, 11 days out from when it renews automatically on 17 March. So the speed became truly painful. Bigpond have given us a once only ‘goodwill’ 2 gigs to go on with. Trouble is, by he time I found out what was going on we’d already used a third of it.

Trouble also is that when the speed slows my email connection just doesn’t happen.

Anyway I’ve prepared a CC for this week from material to hand, then I’m going to disappear to preserve my email.

1. You’ve been told

When a link came through on a feed about a conference on what the planet would be like with 4C warming it looked a bit familiar. Then I noticed the date – October 2009. The link is now broken, but the conference is here. There’s a lot of good material in the presentation downloads, mostly depressing, some of which I looked at before things gummed up.

In the article it said that Hans Joachim Schellnhuber, who advises Angela Merkel on climate change, had dropped in on President Obama’s top people, who told him that the political system couldn’t cope with what he was saying about the science. Prof Scellnhuber was not impressed. Continue reading Climate clippings 70 →

Climate sensitivity

James Wright at Skeptical Science has constructed a summary of some recent work done by James Hansen and colleagues. Climate sensitivity is the temperature change caused by a doubling of CO2. In this post I referred to a paper by Hansen et al, Earth’s energy imbalance and implications. Wright is working from a paper by Hansen and Sato entitled Paleoclimate implications for human-made climate change which contains much of the same material, including Table 1 on p16.

The bottom line goes like this:

The exact value of climate sensitivity depends on which feedbacks you include, the climate state you start with, and what timescale you’re interested in. While the Earth has ice sheets the total climate sensitivity to CO2 is up to 8°C: 1.2°C direct warming, 1.8°C from fast feedbacks, 1°C from greenhouse gas feedbacks, and nearly 4°C from ice albedo feedbacks. The slow feedbacks have historically occurred over centuries to millennia, but could become significant this century. Including CO2 itself as a feedback would make climate sensitivity even higher, except for the weathering feedback which operates on a geologic timescale. (Emphasis mine)

CO2 alone, not CO2e, of 450ppm is likely to give us an ice-free planet – eventually.

I take it that the stability we’ve had during the Holocene is unusual. Upset the balance with a bit of the trace gas CO2 and the system can go wild. Continue reading Climate clippings 42 →

Climate change, sustainability, plus sundry other stuff