Bishop Hill Falsifiability in my lifetime
Jan 16, 2014 Climate: Models An article on the Nature website looks at the failure of global temperatures to rise in line with the climate models and finds a possible explanation in the Pacific Decadal Oscillation. I notice what may be the start of a new meme emerging:
...none of the climate simulations carried out for the IPCC produced this particular hiatus at this particular time. That has led sceptics — and some scientists — to the controversial conclusion that the models might be overestimating the effect of greenhouse gases, and that future warming might not be as strong as is feared. Others say that this conclusion goes against the long-term temperature trends, as well as palaeoclimate data that are used to extend the temperature record far into the past. And many researchers caution against evaluating models on the basis of a relatively short-term blip in the climate. “If you are interested in global climate change, your main focus ought to be on timescales of 50 to 100 years,” says Susan Solomon, a climate scientist at the Massachusetts Institute of Technology in Cambridge.
The idea that the predictions of climate models are only good over periods this long seems to represent a considerable upping of the ante, but it's one that I have heard elsewhere in recent days - if I remember correctly it was also mentioned by David Kennedy in his evidence to the Energy and Climate Change Committee. In the past, the community has stood by a period of 30 years (at least when it suited them), but it may well be that the public start to realise that the models have been running hot over periods of several decades, the climate modelling community has been forced to extend the limits.
100 years should ensure that all concerned make it to retirement.
Reader Comments (202)
"Weather is the effect of climate, not its cause."
There is causation in both directions. There is a common notion that weather is only the ups and downs around an equilibrium. But equilibrium does not exist, never has and never will. What happens instead is that the weather patterns send energy to the poles or upper troposphere where it can be radiated away. Weather patterns dictate albedo.
Sure a lot of that weather is ups and downs around a climatic mean for any given location. But the ups can easily outnumber downs (or v.v.) for any time period from hours to decades. The counter argument is that, even decades later, there is reversion to the mean. But there is no physical reason to revert to a local mean since local equilibrium is impossible. Thus no reason to revert to a global mean either.
The logical next question is what keeps the climate at the mean? Several things: a nearly constant energy source and a number of negative feedbacks on warmth such as increases in latent heat transfer and radiation and a decrease in the lapse rate. Those are also negative feedbacks for cooling in some cases (preventing further cooling). We have the diurnal and annual cycles that pushes temperate locations to high and low temperatures where the negative feedbacks are able to kick. An important factor thermal inertia, a local effect that mostly maintains warmth when the sun is not around.
Entropic Man
What proxies are you talking about? I and Lapogus have given you one you vaguely mention others. Here is another the Vostok Ice Gore data. Now this is over a much longer timescale than the one posted by Lapogus but the trend looks the same tome. Gradually downwards with a series of reducing peaks. Now to my mind that suggests global even if it is difficult to say if they are in complete annual synchronisation (to preempt your next objection).