And while we're at it, we should also do something, anything to limit plate tectonics!

And Marc chips in with another unfunny and deliberately derailing comment.

How about we compare some other natural events with a man made alteration of natural events. Say, people dying of old age versus people being murdered. People will die anyway, so lets just let murder go on.

Any more specious reasoning Marc? Or do you want to start talking about reducing emissions of GHGs before we ruing the planet? Because we need to start doing something instead of having this pointless denial argument.

This geologist is definitely math-challenged -- compare plate tectonics time-scales with current Arctic-warming time-scale.

I believe 300 people recently died in Europe from a heat wave, or was that a cold snap.

"Logged in via Twitter" is very seriously challenged by his understanding of geophysics.

Very small changes in the earth's behaviour can trigger huge variations in the temperature. Easily measurable changes in climate result from small variations in the length of day (LOD) which results from planetary or otherwise induced, very small variations in the rate of rotation.

Such changes in LOD are measured in milliseconds, They can also be induced by relatively small changes in the distribution of matter in the earth's crust - minute movements associated with plate techtonics, which alter the angular momentum (AM = MI X Omega where MI (Moment of Inertia) depends on the mass and shape of the earth and Omega is the angular velocity, aka rate of rotation.) Very, very small variations over the large area of a "plate" involves in fact a huge mass which changes MI and hence Omega, hence rate of rotation, hence LOD , hence climate.

By the way, I didn't catch your real name. John Nicol jonicol18@bigpond.com

Hello Tim,

Sea ice loss in the Artic has been offset a little by sea ice gain in the Antarctic.

http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.anomaly.antarctic.png

The rate of change in the Arctic summer sea ice minimum has indeed been significant during our observations but it has only been observed since 1979 so we have no apples to apples comparison to say if this is unusual in a historical context compared to say during the Roman Warm Period or other climate optimums.

The most pessemistic predictions for an ice free Arctic summer are summer 2013 or 2014. Al Gore's nobel acceptance speech in 2007 was used to re-iterate that the arctic summer ice could be gone within 7 years. Until we precidely understand all of the mechanisms (including what drives arctic wind patterns to break up and flush the ice south) such predictions are just a guess.

It will be interesting to see if trends for sea ice loss in the Arctic Summer continue rapid decline with a flatter trend seen in OHC, sea level and atmospheric temps on a global scale or will summer sea ice decline also level off? Id say ice will decline unless we see a change in the dominant arctic wind patterns to keep the ice contained to nothern lattitudes.

James, I'm not sure where you are getting that information from but it is incorrect. There is no net gain in ice, as you have to account for the volume not just the area covered. All the research indicates that the rises in sea level have been driven by the loss of ice and warming of the seas.

Please read this article that nicely and simply explains the science conclusions:
http://www.skepticalscience.com/antarctica-gaining-ice.htm

Tim,

The information on "sea ice" area (not to be confused with ice sheets and glaciers) I posted above comes from Department of Atmospheric Sciences at the University of Illinois. I said that Antarctic sea ice gain is offset a little (not completely!) by sea ice increases in the Antarctic. You best tell them they are wrong if the blog site you linked to has better information that falsifies their measurements of sea ice area.

The Arctic is completely sea ice - if it melts completely there will be no change in sea level. In the southern hemisphere the area of the sea covered by ice has been increasing since 1979. Sea levels have nothing to do with Arctic Sea summer sea ice losses.

Only melting land ice can raise sea levels. That includes Antarctic and Greenland ice sheets as the main sources and yes they are melting during an interglacial period. During a glacial period they will gain ice.

So I'm guessing you didn't go and read the references cited in the article I linked.

Didn't think so.

You might want to read some of those studies on world ice, because it isn't pretty. Especially seeing as your comments are contrary to both this article and the science referred to.

Nope. It's just you Marc: you aren't funny, nor correct about climate change.

Matt, the questions you ask are a regular part of a paleoclimatologists work. They look at them every day and have a surprisingly good understanding of the links. As recently as November 2011 a paper came out which used the exact methods you have described here to determine there was a significant and consistent drop of carbon dioxide in the atmosphere that led up to the formation of the Antarctic ice sheet.

In regards to the mating of polar bears with grizzlies, this is expected because the two are very closely related. However, the point of the polar bear observation is that they are yet another indicator that climate change is happening now, adding further to the already abundant evidence of man-made global warming.

As for scientists convincing the skeptics with "meaningful data, models and summaries of findings that also note caveats", you will find all this and more in the published peer-reviewed literature.

To remain skeptical when what you have asked for is presented clearly every day in the peer reviewed journals is bemusing to say the least.

Alvin,

If the polar ice cap melts it may well become a problem for polar bears.

BUT it will be no more an indicator that carbon dioxide was responsible for the warming between 1979 and 1997, which everyone accepts, even though some of the data used is a bit dodgy, coming from recording stations which were relocated or urbanised, with "estimated" corrections. Some were omitted without any explanation. However, accepting the warming claimed is not a problem. What is a problem is that there has been no evidence which shows that it is caused by CO2, and the plight of Polar bears is simply an emotive attempt to couple the thawing of the arctic to human beings. Computer models do not evidence make!! See IPCC AR4 2007 Section 8.1.2.1 and 8.1.2.2 where you will see that the models are yet to be tested against empirical data.

However, Alvin, if you could refer me to one or two "peere reviewed" journals to which you refer, I would be delighte. Please feel free to email them to me at jonicol18@bigpond.com
John Nicol

Hi John. Of course there have been estimates, errors, wobbly models,problems with data collation, political interference, genuine mistakes, unexplained phenomena and some (educated) guess work in the years of research into climate, and we certainly don't understand variability very well even still. However none of these things disprove the AGW theory. The mechanisms are just so simple and so well understood and provide by far the most complete answer to the Earths warming.

I find some of your work interesting (although fatal flaws appear often) and maybe you will advance our understanding of some short term variability somehow, but until you can prove, at least, that a) CO2 levels have not been raised by humans and b) CO2 does not absorb and re radiate IR as is currently understood you have absolutely no hope of overturning the current understanding. More CO2 = more heat retention = rising temps. Seems so simple I always wonder why anyone can't understand it.

You say there is "no evidence" which is absolutely totally absurd, arrogant and obtuse. (And before you demand me run around doing collation for you and emailing it I can assure you there are thousands of papers that provide evidence all over the internet and print so enlighten yourself if you dare.) John the most pragmatic and respected organisations in the world disagree with you including every national or international scientific organisation there is as well. Not to mention several physical laws. Either they are right or you are. They base their view on the available evidence. You say that this does not even exist. Sorry John that position is indefensible. For you to be right (ie "no evidence") we have to dismiss ALL, yes every bit, of these organisations work and some of the physical laws that govern our planet. That is not only unlikely, it is laughable.

Hi Nick. Nice to hear from you and that you recognise the erros and wobbly models a bit like I said. So we are in agreement there. I have written a few things below which also show that there are many other aspects of this discussion where you and I can agree, sometimes fully.

First, no one is talking about these things, these vast errors, the failure of the models as yet to be able to reproduce future climates which are then verifiable, as disproving AGW theory. In the words of the IPCC AR4 2007 Sectiion 8.1.22 “What does the accuracy of a climate model’s simulation of past or contemporary climate say about the accuracy of its projections of climate change? This question is just beginning to be addressed, exploiting the newly available ensembles of models.” So in this sense the IPCC recognised at least in 2007, that the models did not actually produce forecasts of the warming. Perhaps they will be more confident in AR5 which I think will come out late this year or early in 2013.

In 2008, after discussing this very subject for two years with the head of CSIRO climate, as a fellow scientist interested in the basic effects of carbon dioxide in the atmosphere, she, like you, was also unable to provide me with some definitive papers, after promising to try to find some. Two years it took, for her to let me know upon what they based the introduction of an assumed CO2 “forcing”, as they call it, into the models. She could only say that said ”We believe that most of the increase in Global temperatures during the last part of the 20th century were very likely due to increases in the concentration of atmospheric carbon dioxide”. I had hoped from what you wrote that you might have been able to do better.

The point is Nick that there are no definitive papers which demonstrate that carbon dioxide is the cause of the warming from 1979 to 1998, which again, from their own statements, is the ONLY period when there was a monotonic correlation between increases in CO2 and Global temperatures. There are many periods in both the geological records, from anecdotal history over the past millennium, and from temperature measurements since the end of the LIA (about 1850) when there is no such correlation and the temperature fluctuated up and down under some other mechanism. From 1860 to 1880 it rise faster than between the more recent dates. Yet because there was not a corresponding increase in CO2, the IPCC dismisses this as not being a useful period to study. The last fifteen years have not bee a very good period for them to study either.

If you take time to go very carefully through the IPCC AR4 references for the scientific sections, you will find at least fifty papers which actually make some reference to carbon dioxide. Many are concerned with demonstrating of course that human beings are making significant contributions to atmospheric CO2. There is no doubt about this and one only needs to collect the statistics on fuel use in all of the world’s major countries to get a pretty good measure of the huge amount of carbon dioxide being put into the atmosphere. Just like the increase in temperature from 1979 to 1998, no one with any sense, which includes most if not all “sceptics” understand this. So over those years, yes there were increases in both CO2 and global temperatures.

Again, then, we are agreed on that point.

But back to the IPCC references, the main papers they use in clued Fourier (1825), Tyndall (1847) and Arrhenius (1895). Later authors such as Callendar and Hansen, tried to extend these but never changed the basic approach to the physics. You do make mention of carbon dioxide absorbing infra red radiation and there fore warming the atmosphere, most of the energy being absorbed within about 100 m of the ground but some radiation in the far wings of the lines which make up the absorption bands, being absorbed in the upper troposphere and stratosphere, and in the very far wings, a little actually escapes. So yes, this does warm the atmosphere.

Another point of agreement.

However, the crunch comes when we try to estimate the amount by which the increased absorption in these very far wings of the lines, where some radiation at present escapes, will cause further warming and where in the atmosphere that will take place. This effect is known as the Enhanced Green House Effect, which is significantly different from, and more difficult to analyse than, the Green House Effect (GHE) which contributes about 20% to the warming of the atmosphere at present, most of the energy from the sun which strikes the earth, goes into the atmosphere because of conduction (20%) at the earth air interface, effected of course by wind, and the major source which is evaporation over the 70% of the earth’s surface covered by oceans. Evaporation thus comprises about 605 of the total. Of the 20% absorbed by GHGs, about 25% is by CO2 the remainder by water vapour. Now by how much will the energy in the atmosphere be increased if we double the concentration of atmospheric carbon dioxide. This is where Dr Penny Whetton’s statement that “We believe...” is important, because there is no definitive or even approximate estimate of this. The very approximate estimate by Arrhenius that the increase in temperature will be proportional to the logarithm of the ratio of the concentrations is still used by the IPCC and they rely on their models to calculate a warming figure for a given amount of carbon dioxide, assume that the warming from 1979 to 1998 is “mostly due to increases in carbon dioxide”, a number which is well known, and so derive a quantity which is referred to as the “Climate Sensitivity” Thus Delts_T = Lambda x ln(C/Co) where C is the new concentration of CO2, Co, the original concentration and Delta_ the resulting increase in temperature derived from the models. Lambda is the climate sensitivity which has been plucked from the change in temperature between 1979 and 1998 and the known change in the concentration from Co to c, of carbon dioxide. This feature does not correspond to a “proof” it is based on the continuous and coincidental increase in CO2 between these years – a sample of 19 years at most.

So no. The failures of the IPCC do NOT disprove AGW.

So again we are in agreement on that one also.

If you talk to any atmospheric physicist, even to a simple climatologist you will soon be disabused of the idea that the mechanisms are simple.

So here we do disagree.

Perhaps, given the difficulty I had in obtaining papers from Dr Penny Whetton, and from others at the various Climate Units in Australia, the fact that I already have copies of papers by Fourier, Tyndall, Arrhenius, Callendar, Hansen, Pierrehubert, Zastawney and others, I am hoping you might reconsider your declining of my request for other references which you obviously are aware of, demonstrating the effects of increased carbon dioxide in further warming of the planet.
Cheers,
John Nicol jonicol18@bigpond.com

Thanks for taking the time for providing a detailed response John. Let me try understand your logic.

1. You believe Human activity has increased CO2 levels in our atmosphere....agreed?
2. You believe CO2 absorbs long wave radiation and re radiates it in all directions, including back towards earth....agreed?
3. You believe slowing the rate of heat escape (of anything with a fairly constant input) will cause it to warm up...agreed? (jumpers and blankets would be a waste of time if not)
4. You believe it is not CO2....agreed?

Where is the logic there?

If I have your understanding right, and going by what you said you agree with me on, do our views turn out in simple terms something like this (?);

Nick: More CO2 = slower heat escape = rising temps.
John: More CO2 = slower heat escape = no effect on temps.

So John I stick by my assertion that the actual underlying mechanism of global warming is well understood and very simple. It is an inescapable fact that more CO2 equals less heat escaping. It is an inescapable fact that by keeping on adding CO2 it will cause even less heat to escape. Sure there are other processes which enhance or reduce the warming. Sure we don't understand them all yet. Sure some models, predictions and forecasts will still be out as we learn more about how changing the composition of our atmosphere so fast effects natural systems. Most of these are certainly open for dispute, debate and need more research. But as in the situation of arctic ice above, our forecast was too cautious and it's actually worse than expected. My personal gut feeling is we will see more mistakes as underestimations rather than the opposite although this is nowhere near certain.

Knowing the properties of CO2 and the changing levels of CO2, watching the world warming is like watching an apple fall out of a tree and saying that is because of gravity. They are indisputable physical processes. Getting into the specific predictions and intricacies so many people are arguing about is like watching the apple fall out of the tree and considering the quantum physics behind it. This does throw out questions to which we don't have an answer for and has areas we can't explain yet. Doesn't mean gravity didn't cause the apple to fall.

Oh yeah and none of this even mentions the thousands of other reasons we should move away from burning fossil fuels, regardless of temperature. So not only do your views appear illogical, ultimately they are irrelevant as well. This is what is so ironic about the deniers of AGW. Even if they are right, the course of action we require is the same! Unless of course they deny the finite capacity of fossil fuels, deny all the other poisonous properties they emit, deny all the health issues, water pollution, land degradation, oil conflicts and so on and so on.