Our recent messages overlapped in writing.
I add that the essential technical point is understanding, why the formula has the specific heat at constant volume. That’s where the properties of adiabatic expansion enter.
Comment on IPCC AR5 WG2 Report – draft SPM by Pekka Pirilä
↧
↧
Comment on Evidence of absence versus absence of evidence by Harold H Doiron, PhD
More important to the public policy decisions regarding whether to retain our nation’s current policy of costly unilateral CO2 emissions regulations, how does one make an accurate and well-informed cost vs. benefit decision of what to do about atmospheric GHG? I think we should be looking at a wider array of options to find more certain and cost effective remedies for potential problems such as slowly rising sea levels, whatever the true root cause(s). Unilateral CO2 emissions control by the USA will not prevent damage from rising sea levels. Sea levels are rising slowly enough so that local sea walls can be built in time, where needed. Why are we US citizens bearing the costs of unilateral USA CO2 emissions regulations when other growing world economies in China and India have no intention of controlling emissions and European nations are quickly realizing the folly of their green-energy initiatives? Unilateral USA CO2 GHG emissions control is a lose-lose situation regardless of what Null Hypothesis you support.
↧
Comment on IPCC AR5 WG2 Report – draft SPM by manacker
bob droege
During the Ordovician Period, CO2 was at around 4,200 ppmv and temperature was around 10ºC warmer than today. Land plants evolved and flourished during this period.
At the end of the Ordovician there was the “snowball Earth” period, when temperatures dropped to several degrees colder than today, resulting in mass extinctions, despite an atmospheric CO2 level of over 4,000 ppmv (or 10x that of today).
The Carboniferous was another period of rapid plant growth, with modern plants evolving and thriving. The average temperature was around 8ºC warmer than today and CO2 was at around 2,500 ppmv.
So it looks like plants like high CO2 and do well at temperatures well above what could ever be reached by AGW.
Max
↧
Comment on IPCC AR5 WG2 Report – draft SPM by Pekka Pirilä
I should have written “specific heat at constant pressure, not at constant volume”.
↧
Comment on Evidence of absence versus absence of evidence by GaryM
Which branch of physics tells you how to model a system you do not understand, for which you don’t know the initial conditions, and for which you aren’t even sure whether some feedbacks are positive or negative?
The one thing the GCMs are good at telling us is, the consensus doesn’t understand the physics well enough to model the climate as far as predicting temperature.
↧
↧
Comment on IPCC AR5 WG2 Report – draft SPM by manacker
Jim D
The “convention” to which you refer is purely hypothetical and arbitrary.
The Tol study is a but more practical than that.
It states that the next 2C warming above today’s temperature is likely to be beneficial, and that detrimental results begin around 2.5C above today’s temperature.
So it is silly to arbitrarily set a hypothetical limit at 1C colder than today. Makes no sense whatsoever, Jim. (That would simply add another 1C to Tol’s temperature limits.)
The rest of your comment is pure conjecture. 700 ppmv is a reasonable “upper limit” for BaU – and this could be reduced by around 100 ppmv by the no-regrets actions I listed.
That’s it, Jim.
“Leaving fossil fuels in the ground” is pie in the sky thinking unless a new economically competitive and environmentally acceptable alternate for fossil fuels is discovered and developed. This could happen of course – and, in fact is very likely to have happened before the year 2100 as a result of human ingenuity reacting to economic pressures.
So you can consider 700 ppmv an upper limit for BaU, 600 ppmv a reasonable estimate if “no regrets” initiatives are pursued and some even lower value if a new alternate energy source is developed
And these levels are unlikely to result in temperatures that could be detrimental to humanity on balance, as I have shown you.
As I said before, Jim, rejoice! The end is NOT near!
Max
↧
Comment on IPCC AR5 WG2 Report – draft SPM by Robert I Ellison
’1) work related to the change in potential energy
2) work related to the movement in the direction of the pressure gradient
3) work related to the expansion of the parcel
4) the internal energy’
1 and 2 are zero in hydrostatic balance and the delta of 3 and 4 are quite obviously equal – that seems to be the whole point
↧
Comment on Evidence of absence versus absence of evidence by Jim D
Relevant here is Stefan Rahmsdorf’s item
http://www.realclimate.org/index.php/archives/2011/11/on-record-breaking-extremes/
They showed that since the Moscow region’s mean temperature has risen by more than 1 C in 30 years, their July 2010 record was five times more likely to be broken than in a stationary climate, so they can attribute the new record to the warming trend with an 80% probability. They are careful to say this is not a CO2 attribution because separate studies have to connect the warming trend to CO2, but it does show that in fast-warming areas, these records have significantly increased probabilities. This is also expected when just shifting a Gaussian distribution. For example just shifting a Gaussian by 1 standard deviation (not broadening it), typical of what has happened for summer seasonal average temperatures, since the 1951-1980 baseline, means a 3-sigma extreme, relative to the baseline, goes from 1/200 to 1/10 in probability and a 2-sigma extreme in the current climate. It is, of course, common sense that warming increases the likelihood of records or extremes relative to older baselines, but this shows how it can be quantified. A 20-fold increase in the probability of an extreme 3-sigma summer, means when it happens it can be attributed 95% to the intervening warming.
↧
Comment on Evidence of absence versus absence of evidence by Tonyb
Mac
That was my point. The evidence is ambiguous and deserved far more scepticism than Rgates showd by linking to a study that gave a very one sided view.
I have a lot of time for R gates, but if you bill yourself as a sceptical warmist you need to be more even handed than he has been in recent months.
Tonyb
↧
↧
Comment on Evidence of absence versus absence of evidence by phatboy
R Gates, in case you missed my earlier comment – it is entirely possible to have overall ice loss despite the region cooling, if the summer ice melt is not matched by winter snowfall.
And, conversely, it’s also entirely possible to have overall ice gain despite the region warming.
↧
Comment on Evidence of absence versus absence of evidence by manacker
Jim D
Naw, Jim.
There are two separate “null hypotheses” (see my comment to Mosh).
The first (humans cause “perceptible” global warming through GH gases) cannot be rejected, but has also not yet been validated by empirical evidence (too many unresolved uncertainties regarding natural impacts).
The second (warming causes more extreme weather) has been falsified by the record which shows warming but no evidence of increase in extreme weather.
As a result the “combined” hypothesis (humans cause more extreme weather through GH gases) has been falsified by the evidence at hand.
Pretty simply, actually, when you break it down logically.
Max
↧
Comment on Evidence of absence versus absence of evidence by Jim D
gbaikie, no, I was not saying warming had to be caused by humans. Read what I wrote again. I was saying this hypothesis was really two questions, and the second was whether the warming was mostly anthropogenic. The first is whether warming increases extreme events. Anyway read it again, and it may become clearer second time through.
↧
Comment on Evidence of absence versus absence of evidence by Stephen Segrest
David — Dr. Doiron used the quote “costly unilateral CO2 emissions regulations”. I’m only aware of only 1 national reg specifically targeting CO2 — the prospective reg on new coal fired electricity generation (where coal is not currently cost competitive with natural gas generation anyway — straight up). The U.S. has no federal “Renewable Energy Portfolio Standard” — all the renewables are being approved at State levels (where Texas, a pretty conservative place) has been approving a lot of wind projects. Clearly, Gov. Perry (a prominent Republican) isn’t approving wind energy to comply with some CO2 objective. The vehicle fuel standards currently in place were not driven by CO2, but foreign oil imports. I don’t think some tax credits for renewables are driving our economy into the ground — compared to say a decade’s worth of military spending in Iraq.
↧
↧
Comment on Evidence of absence versus absence of evidence by Pekka Pirilä
The signal becomes the clearer the more it’s erroneous. That’s the unfortunate fact on that paper.
When a paper is known to be based totally on an erroneous method, and when it’s known that the error is large in comparison to what the paper presents as new results, science allows only one conclusion. The results cannot be used until the analysis has been done correctly. There should not be any question on that.
↧
Comment on Evidence of absence versus absence of evidence by Jim D
manacker, why not go back a step, and phrase the null hypothesis as whether adding CO2 can or ever has caused any warming, rather than man? This makes it a more academic question, and removes it from political viewpoints. That is your real question after all, isn’t it?
↧
Comment on Evidence of absence versus absence of evidence by JJ
R. Gates blathers (thankfully, not in triplicate)
“The gains or losses of net energy in the IPWP over longer periods of time is a very good proxy for net external forcing on the climate system– …”
Oh look, Gates has made a bald assertion as fact. If ya can’t support a conclusion, just assume it, eh Gates?
↧
Comment on Evidence of absence versus absence of evidence by Jim D
Pekka, I am still waiting for this “correct” analysis. Let’s phrase the question. How do we define extreme events from a monthly/seasonal gridded temperature record, such as GISTEMP? How do we define a baseline period to use and adequate region sizes to do this for, to get robust statistics? How do we evaluate the odds of these extreme events then and now in an independent period?
↧
↧
Comment on Evidence of absence versus absence of evidence by JGMachen
RGates, if the “record setting typhoon” was caused by AGW, why didn’t you predict it then? It seems you suffer from confirmation bias. If there are no “record setting” typhoons for the year, I guess that just means the invisible gardener didn’t show up, eh? But when there is one, you take that as definitive proof of CAGW. Can you see the problem? The world ponders.
o^o <3 ???
T
↧
Comment on Evidence of absence versus absence of evidence by ann ceely
Statistical HypothesisTesting requires a specific measurable assertion to be made first. This could be
(a) Surface temperatures have risen higher than has been seen during the past 150 years
(b) Surface temperatures will rise at a faster rate each decade than has been seen during the past 150 years
Then the Null Hypothesis, that (a) the temperature and /or (b) the rate of rise is equal to or less than the largest value found during the last 150 years.
So the alarmists just need to adapt assertion (b).
And they’re getting problems because folk point out that temperatures have been warming for ~500 years (with occasional slow drops in temperature for 30-50 years at a time)
↧
Comment on IPCC AR5 WG2 Report – draft SPM by WebHubTelescope (@whut)
Are you Aussie deniers just impediments to science?
↧
