I actually think 3 degrees is a possible answer, although I rate it at upper limit. The uncertainties are such that it can’t measured accurately.
As I’ve stated before I have more issues with the economics of the IPCC predictions than the science. C02 emissions forecasts are economic and not scientific. I think we will be hitting peak coal sooner than later. This means that future projections of C02 emissions are way too high.
Of course, this isn’t really good thing. This means that countries that haven’t addressed their dependency on fossil fuels are going to experience an economic crises worse than the great depression.
Still, how do you explain the changes during the Ice Age cycles, which are far too large (I am talking about 6C or more) to be explained with such a low climate sensitivity, plus other factors are insufficient to cause such large changes by themselves. The most likely answer is that something amplified the effect of small changes in the Earth’s orbit, and that something is changes in CO2 levels, combined with ice sheets. There is additional evidence for a higher sensitivity as well. Also, current climate projections don’t take into account factors like methane release and related feedbacks.
Note: Methane has about 105 times the global warming potential of CO2 on a decadal timescale (still 30 times after a century), thus that is equivalent to 100 GT of CO2 (3 times the current annual output from human activity); the Arctic has also been absurdly warm lately despite a La Nina influence and I am sure you have seen all of the stories lately about methane emissions.
Not for the studies compared on the previous post.
Economics are still a science, and we are not talking about just stopping an increase, we are talking about the need of reducing the emissions levels just to avoid going over 2 degrees, peak or no peak.
It is also important to note that the definition of “economically viable” will change over time - shale gas wasn’t economically viable until fracking came along, and the same technique can be applied to shale oil, plus other reserves like Canada’s tar sands are being developed as higher oil prices make them economical (it is true though that conventionally produced oil is at or near a peak, if not already past). I suspect that we’ll wring as much fossil fuels out of the ground as we can if no alternatives can meet the demand* since the energy content of a barrel of oil is far higher than manual labor can provide, I have heard 25,000 man-hours, equivalent to $250,000 at $10/hour (example here); the same goes for natural gas and coal.
You seem to be engaged in circular reasoning. The C02 must be causing the climate change, therefore it has a high sensitivity. I’ve already addressed why I don’t accept paleo data since it must be inaccurate and incomplete compared to our current data. I’ve already the number of theories that are floating around about the PETM.
The whole methane story seems to be an admission of failure of the high sensitivity arguments for C02. There are conceding that C02 won’t cause a great deal of warming and now have found huge hidden reservoirs of methane that will cause warming instead.
The experts do not get good reasons from the current skeptics to say they are as inaccurate as skeptics claim.
There is a circularity reasoning, but it is not coming from the experts.
No, that is just one of the feedbacks added that allows the experts to report that assuming that just 2 degrees of an increase will the upper range to be really a flawed assumption.
But “economically viable” is different from “energetically viable”. There’s always a lower limit to the energy cost to extract the remaining fossil fuel, even if the demand is less elastic after a certain point. So even for highly concentrated energy needs, after a certain point, it might be a more efficient use of diffuse/nonmobile energy sources to create synthetic gasoline than to use them to mine extremely hard to reach fossil fuels, even if there are still plenty of known reserves left.
My definition of economically viable means that we actually generate more energy than it takes to get it out of the ground, refine it and take it to where it needs to used. You references to tar sand and fracking are proving my point that we are getting closer and closer to the peak. We are having to access less and less efficient sources of energy to keep civilization running.
For instance, 1 ton of coal generates about 2,460 kWh of electricity.
If you can’t mine the coal and haul it to power plant for a lot less than 2,460 kwh, then it doesn’t make sense to dig it up in the first place. That isn’t economics. It is phyciscs.
When I became interested in climate I started studying energy sources. What I discovered with coal is that it’s Achilles heel is logistics. We often spend several times as much energy hauling coal around than digging it up. A ton of coal in Montana often increases in price by a factor of 5 by the time it gets to Georgia.
Half the rolling stock in the United States is used just hauling coal around and a similar amount in China.
I realized that we are getting closer when China, the largest producer of coal in the world, started importing coal.
As pointed before, relying on suppositions that this will reduce the release of CO2 before we reach the levels that give us more bad than good outcomes is not a good idea, never mind that as per the news cited the coal will come from somewhere else and used.
Uh, like if several theories of theirs were not falsified on the latest economical meltdown, it may be dismal or “soft science”, but it is a science nevertheless as one can check the theories, new ones then come forth over the failed ones.
As mentioned, there is very little to assume they are not using good evidence to report that it is very unlikely that a coal peak will be there to save us, a peak that will manifest itself and with such a strength that it would reduce emissions by half in 40 years so we will be at safe levels.
You need actually read the IPCC reports. They are assuming increasing consumption of fossil fuel. I don’t expect any decrease in C02 emissions, but they should start flattening out. Real change will start when people realize that nuclear power is actually cheaper than fossil fuels.
It is obvious that the Chinese government believes in peak coal. They are doing everything they can to ramp up their production of nuclear power. Their own projections are that their own emissions of greenhouse will level out between 2040 and 2050.
I think it’s pretty well established that the earth is going through a warming cycle; just look at the arctic and many of the glaciers that are rapidly disappearing. However I don’t think that the politicians and scientific community have presented real evidence of human causation, at least to a significant degree. It seems that our efforts should be focused toward planning for the inevitable disaster by protecting the coastal areas and cities (similar to the Dutch)
as well as pre-planning possible relocation for a large part of the population. The real issue is the proposed carbon tax. Most of the population is painfully aware that this tax would be a licence to steal on a massive scale. There could never be evidence that the reduction of CO2 had been effective in reducing or slowing temperature increases.
As Faynman noted, that is needed in science is something to replace the main idea that is based on the best available evidence; as pointed before, there are no good natural causes that can explain the current warming rise.
Great interview by Germany’s Der Spiegel with Professor Dr. Fritz Vahrenholt, [del]a well-known denier who’s always been against preserving the environment and a hater of science[/del], sorry a leading researcher in alternative fuels and long time environmentalist who’s saying that the IPCC is wrong on many counts.
I’m sure he rapes blinds orphans for fun, too, but don’t worry, he’s just a guy with a blog; maybe even was in the same continent as Lord Monckton at some point.
Also, Der Spiegelis just a a flier photocoped at some small German town.
I especially like the part where that sentence – and paragraph! – ends right there: saying we should examine longer trends, but of course not going on to say how much longer.
Instead, they spell out that a decade isn’t significant, add that a somewhat longer trend would be significant, and then – move on to another point, because, hey, why bother establishing how they could be proven wrong? It’s much more important to simply assert, as usual, that it hasn’t happened yet.
Watching paint will be as useful, as pointed out before, it is not very likely that we will get to see what you want as they are referring to the tests already made. WE have to act according to what it has already been found, not on wishful thinking.
I merely note, as always, that they take the time to claim a given span of years is insignificant to falsifying the stuff – and then to spell out that a longer span of years would be significant to falsifying the stuff – and then for some reason can’t spare even one moment longer to specify; four words would do it, but they can only be bothered to say that more is needed to prove 'em wrong without, y’know, saying how much more.