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.
How little is little?
Sarah at Skeptical Science tackles the old chestnut CO2 is just a trace gas. 390ppm is just a trace, right? Well so is 0.01ppm of arsenic in water (the WHO safe standard). Double it and it’s still a trace, but the consequences can be drastic.
A 200mg ibuprofen pill in a 60kg person is only 3ppm. I sometimes take a prescribed 1mg pill and I’m 74kg right now. I think that’s 0.0135ppm. It works!
Russia and America join to drill the Arctic
US oil major Exxon Mobil has clinched an Arctic oil exploration deal with Russian state-owned oil firm Rosneft. Exxon Mobil has cashed in where the initial deal with BP fell apart.
Under the agreement, the two firms will spend $3.2bn on deep-sea exploration in the East Prinovozemelsky region of the Kara Sea, as well as in the Russian Black Sea.
Exxon described these areas as “among the most promising and least explored offshore areas globally, with high potential for liquids and gas”.
New York dodges a bullet
Quite a few words have been wasted on whether Huricane Irene was due to climate change. Bill Nye, the “science guy”, went on Fox TV to argue the point. In the first link what interested me was the statement that sea levels in New York had risen 13 inches in the last century. I think the global average was about 7 inches.
Turns out (a) that New York is sinking by a few inches per century and (b) that this time it dodged a bullet. One inch higher and the subway system, FDR Drive, PATH, and the Brooklyn-Battery Tunnel would have been flooded.
The article goes on to explain that if you add a couple of feet and rerun the 20th century you can expect about 30 critical events in the next 100 years.
Oh, and if you want to know about extreme weather and climate change, President Obama will explain. Or you could scroll down and see what Kevin Trenberth says. See also Joe Romm for the specific contribution of global warming to hurricanes like Irene.
In 2010 only 55% of Americans believed climate change was a threat to them and their families, down from 64% in 2007-8. The percentage of people who believe climate change results all or in part from human causes is down a full 11 percentage points from 61% to just half.
In Japan both belief and threat perception also went down. In Russia threat perception went up with no change in belief. The results were more encouraging in India and China.
1. As linked by BilB on another thread, solar generators may produce the majority of the world’s power within 50 years, slashing the emissions of greenhouse gases that harm the environment, according to a projection by the International Energy Agency.
2. Climate Spectator talks about this too as well as about breaking ground on Australia’s first utility-scale solar project at Geraldton WA, due to be finished by the middle of next year.
“If we don’t develop renewable energy, we will make the biggest mistake in this nation’s history.”
At least he gets the rhetoric right.
4. New Scientist has an intriguing article about a new generation of multitalented materials which could herald the end of the battery as we know it, or at least act as a supplement. It seems you can store electricity in lots of materials, so you might have the body of your car as storage, or the case of your laptop.
5. OK, it’s years away from commercialisation, but ‘they’ are looking at bacteria in waste water and salt water to generate electricity.
6. German renewables hit a record of 20.8% in 2010, on track for 35% by 2020. So far the big ones have been wind and biomass, but recently the emphasis has been on solar PV.
This space is meant to also serve as an open thread on climate change.