This month’s open thread. Current topics are focused on the laughingly bad Daily Mail article by David Rose, the fallout from the Wall Street Journal’s latest regurgitation of why no-one should ever do anything ever. And perhaps someone might want to audit some of David Whitehouse’s arithmetic and reading comprehension…
Or anything else. Within reason.
err… some belated research shows The Catholic Herald is jointly owned by Rocco Forte and Conrad Black, so may be it isn’t such a surprising vehicle for ACC denial.
138 ray
139 Sec A
141 Pete D
I wasn’t trying to be contentious..
You will have gathered from my previous comment at #137 that I am a layman, and as such, I thought that there was long term evidence of a gently warming planet and that this was the consensus viewpoint – but that this warming had increased in the last 50 years or so at a rate that could only be attributable to man’s additional input via increasing CO2 output.
Is this not the case?
Are we therefore saying that the underlying trend is flat or downward and that CO2 is the reason for any increase?
#147–Thanks, SA, I missed the story yesterday, and it’s a vivid report about what the drought is like ‘on the ground.’ I sent an email to the show, pointing out the missing context that you highlighted.
Just in case anybody else had the problem I did with SA’s link–the page kept crashing my browser, due I think to the video–you can listen to the story instead. There’s an index for 2/7/12, from which you can pull up the drought piece audio:
http://www.npr.org/templates/rundowns/rundown.php?prgId=3&prgDate=2-7-2012
It’s only about 4:30 or so.
Hank – I wonder if you could clarify just what is the current thinking on the period of timelag for GHGs affecting global surface air temperature due to oceans’ thermal inertia ? For as long as I can recall the period of 35 to 40 years has been quoted without challenge, but the renowned meteorologist Jeff Masters has recently posted an article using 25 years, without referring to any fresh research on the issue.
So I wonder if you may know of such research, or perhaps of some other explanation ?
Regards,
Lewis
Pete Dunkelberg @146
Do bear in mind that Dr Nick Bone @143 was asking for “discussion on Hansen & Sato.” I did fail to comment on his point 2 which may have given you the impression I was being “off message.” (I will make amends below.)
While I wholly agree that ‘sanity should prevail sooner rather than later,’ and also that sea level rise will be damaging by 2100 probably whatever emissions there are before then, I remain convinced that the sea level rises from melting ice considered by Hansen & Sato 2010 are much too pessimistic.
Dr Nick Bone @143
Regarding your second point & discussion – If you have a tiger cub by the tail, do not wait until it grows into an angry adult tiger. Your grip will fail soon enough so it is crazy not to let go a.s.a.p.
James,
Going back to 1880 (the start of the industrial revolution), the planet has warmed at a rate of ~0.6C / century. However, the warming has not been a constant linear trend. Slight cooling was observed until ~1910, then the planet warmed until the 1940s. The planet then experienced another 30 years of falling temperatures. Starting in the late 70s, the planet began warming again, up until the end of the century. Since then, the trend has been flat to slightly downward. The graph can be viewed here:
http://www.woodfortrees.org/plot/hadcrut3vgl/plot/hadcrut3vgl/from:1880/to:2012/trend
There are many theories as to what has constituted this variation, usually with a combination of natural and manmade contributions. The overall trend has not changed significantly over the past two centuries, however, changes that have lasted several decades are quite evident.
Explanations for the recent deviation range from sulfer aerosols from coal burning in China, to a change in the ocean currents resulting in more frequent and stronger La Ninas, to a solar minimum.
Lewis, in your question above, what data set is Jeff Masters writing about? (I can’t make the link behind your name work, so I don’t know if you’ve written something elsewhere). Given a particular data set you can follow Robert Grumbine’s or Tamino’s discussions on detecting trends to assess an article; without that (shrug) I’d try looking it up.
I’d start at The 40 Year Delay Between Cause and Effect and by looking at papers citing Levitus et al. (2000), Warming of the world ocean, which Scholar lists as having been
“Cited by 821”
But remember, I’m just some guy on a blog; I sometimes point out examples of what can be found by looking online for those who can’t easily get to a library and ask a reference librarian for help — which is the way to go for non-experts. I can’t provide critical thinking beyond that.
I used to rely on the old Usenet approach — “Post what you believe and await correction” — but the ‘corrections’ from opinion without citation are really discouragingly bad, mostly evidence of the backfire effect.
James above asked about the underlying trend in climate if people weren’t affecting it. I didn’t find a simple clear answer with a brief glance at the “Start Here” link (top of page, still the best place to start looking and I know it’s in there in one of the linked readings).
But I recalled this:
http://news.nationalgeographic.com/news/bigphotos/images/090903-arctic-warming-ice-age_big.jpg
from this: http://news.nationalgeographic.com/news/2009/09/090903-arctic-warming-ice-age.html
That says it’s referring to a paper “Gifford Miller of the Institute of Arctic and Alpine Research at the University of Colorado, Boulder.”
I didn’t dig down to exactly what paper that means, but this looks like related work:
http://www.sciencemag.org/content/325/5945/1236.short
The typical pattern is a rapid warming after an ice age then a slow cooling, thus: http://www.globalwarmingart.com/images/thumb/8/8f/Ice_Age_Temperature_Rev.png/350px-Ice_Age_Temperature_Rev.png
As you see at the National Geographic link, the warm peak after the ice age was about 8,000 years ago, followed by slow cooling — the period during which civilization emerged.
Good Morning James,
I was just agreeing ;) that you might be missing something.
As for trends, underlying or otherwise, they don’t just happen for no physical reason, and are measured in principle via top of the atmosphere energy balance. Causative factors are called forcings.
I think what you mean by “underlying trend” is whatever is not human-caused. So far so good. But CO2 is hardly the only positive forcing, nor are all human-caused forcings positive. Aerosols are a large negative forcing (cause of cooling, resulting in less warming).
Perhaps the simplest thing for you to do is search google images for climate forcings.
Other links:
https://www.realclimate.org/index.php/archives/2007/02/aerosols-the-last-frontier/
http://www.skepticalscience.com/a-comprehensive-review-of-the-causes-of-global-warming.html
http://www.esrl.noaa.gov/gmd/about/climate.html
This page with updated charts should help you sort out the non-human factors. Look at Figure 13 (about the fourth one from the top, the numbering is based on the source for the page). Figure 13 has several parts. Note volcanoes (top part). These cause cooling if they are large enough. We have some medium large ones in the last 50 years, but nothing out of the ordinary. Figure 11 on that same page shows that the sun has given us slightly less energy in recent decades, but again this is nothing out of the ordinary. On the other hand the NOAA link above has a chart of “The global mean radiative forcing of the climate system for the year 2000, relative to 1750.” This shows that the sun is a small positive forcing compared to 1750.
You might be pleased, James, that after all that one might say that the aerosol cooling very approximately cancels other greenhouse gasses + black carbon so that CO2 forcing is close to net forcing. Still keep in mind that most of the planet’s energy gain goes into the oceans and so forth.
But if you want to know what should really matter to all of us, it is ongoing changes in precipitation patterns (big words meaning more drought and floods) and consequences for agriculture (more big words meaning famine).
12, Thomas Bleakney: It is sad that reputable scientists from other fields are sowing so much confusion and doubt among the innocent lay public. In my opinion they are doing a very bad thing with severe consequences for the planet.
As written, you have not distinguished between criticism that have merit and those that do not. For criticisms that have merit, are you really advocating that those be ignored? Writing in the Journal of the American Statistical Association last summer, Magnus, Melenberg and Muris referred to “cavities” in the knowledge base. In “Principles of Planetary Climate” Raymond T. Pierrehumbert frequently draws attention to the fact that the mathematics of the steady-state/local-thermal-equilibrium is pretty accurate — but at the same time an alert reader can notice that the inaccuracy of the models (> 10%) cast doubt on the ability to make an accurate forecast over a span of decades (since the system is never in steady state). Add in the fact that all necessary parameters are known only with some degree of inaccuracy, and that ability to make accurate forecasts over a span of decades has not been demonstrated, then it seems to me that researchers ought to focus on the legitimate criticisms by reputable scientists from other fields.
James, no offense intended. I am a snarky SOB by nature. Basically, though, the whole contention that “the planet warms naturally” is an unscientific position. Warming implies increasing energy, and that energy must come from somewhere. It is not the Sun. It isn’t the oceans. It looks exactly like what we expect from increasing greenhouse gasses.
So the question that I would ask–and that I would suggest you consider as well–is where are you getting your information. If they are wrong about something as fundamental as conservation of energy, what else could they be misinforming you about? Anthropogenic causation of warming from burning fossil fuels is an idea that is 112 years old. It is in no way controversial among actual scientists–at least not those who can claim any expertise on climate. Yes, there are cranks, but there are cranks who don’t think smoking causes cancer (many of them are the same). Listen to the experts.
Septic Matthew,
Horse puckey! The evidence is overwhelming that anthropogenic CO2 is causing the planet to warm. The evidence is overwhelming that the warming is within errors of what we expect from the models. The evidence is overwhelming that even now warming is adversely affecting agriculture and increasing severe weather events.
Do you expect all of this to suddenly freakin’ stop? This is science. You go where the evidence points, and you have bupkes to support your position.
Quit looking for “uncertainty monsters” under the bed. What we do not know does not invalidate what we do.
Oh, and James — where “Dan H.” writes above that
“… the end of the century. Since then, the trend has been flat to slightly downward.”
He’s lying.
He knows he’s lying.
He won’t stop lying.
What’s needed to claim a trend in a climate data set:
http://www.woodfortrees.org/notes#trends
http://moregrumbinescience.blogspot.com/2009/01/results-on-deciding-trends.html
another waste-to-fuel enterprise:
http://www.biofueldaily.com/reports/Enerkem_and_GreenField_Ethanol_Announce_Quebec_First_Waste_to_Biofuels_Production_Facility_999.html
162, Ray Ladbury: What we do not know does not invalidate what we do.
That’s a good one.
Re #124, MARodger:
“Given then that GISSTEMP is a measure ‘useful for estimating’ global temperature (as is HadCRUT3), why do you legitimise the erroneous scribbling of Whitehouse, which was you message @108?”
He doesn’t use GISTEMP as an estimate for global temperature nor for its anomalies. He just says that 54.8 is less than 55.4. That’s as true as to say that .548 K is less than .554 K. For his statements an index is all he needs. They aren’t flawed because of the factor of 100.
Re: 145 and 155. Point noted, but it is clear that Hansen is not just wildly extrapolating, since there is Paleo evidence for multi-meter-per-century rises. I found a concise Scientific American article from 2009 which references original papers by Paul Blanchon and others. See http://www.scientificamerican.com/article.cfm?id=ancient-corals-provide-record-of-rapid-sea-level-rise .
Also, these fast rates of rise in the Eocene seem consistent with those at the end of the Holocene.
P.S. Sorry, I meant rates of rise at start of Holocene of course…
James,
Look at the data, and decide for yourself. By the way, the planet has warmed and cooled naturally in the past. The contributions from natural and manmade causes are constantly being evaluated. Those who think we know everything, are only fooling themselves.
Here is recent research on an unknown that might matter:
http://www.agu.org/pubs/crossref/2012/2011GL050506.shtml
It requires confirmation from future research, and I have only seen the abstract, but it looks to be worthy of discussion.
Dan H. wrote: “Those who think we know everything, are only fooling themselves.”
And those who pretend that we don’t know what we DO know, are only trying to fool others.
re: 170.
Oh puh-lease! You are dredging up very long-ago addressed points. We are talking about the warming that has occurred since the 1970s which can not be explained by natural causes alone. The warming can only be explained when the additional forcings from greenhouse gases are considered. You really need to read about the forcings because it is quite clear you do not know about them. Or understand them. We know what warmed and cooled the planet thousands of years ago. That is a huge red herring for you to bring up. Especially since it is such old news even in the denialist, anti-science world you live in. What happened thousands of years ago is all but irrelevant to the cause of warming over the past 40 years. The natural causes are still in effect and may vary but you are completely ignoring the additional impact of greenhouse gases since the 70s.
BTW, do please explain why the stratosphere has essentially been cooling over the past recent decades? If natural causes (e.g. the sun) were the cause, the stratosphere ought to be warming. And solar trends do not explain/track the warming. Oh…you can’t explain it? Gee, wonder why? Maybe you ought to read the science. It is the height of scientific arrogance to claim that natural causes are the cause of warming since the 70s. Especially on a blog run by peer-reviewed climate scientists. And your climate science expertise? (crickets chirping) Thought so.
A. Read about the scientific method (which is how science has been done for centuries). Especially about how science is reviewed and debated through scientific conferences and journals. By actual climate scientists as opposed to magazine writers, newspaper editorial writers, and talk show hosts who have no clue about what they are talking about.
B. Read the peer-reviewed science re: warming over the past 4 decades.
> look … and decide for yourself
Or, you can check what he’s offering you to work with and see how it spins.
“… statistics, ‘…like veal pies, are good if you know the person that made them, and are sure of the ingredients.'”
http://en.wikipedia.org/wiki/Statistics
Dan H. has never said where he gets the notions he posts here repeatedly.
From the references cited above, for those who didn’t check them:
“… in doing science. We try to avoid having choices. Choices can be made differently by different people, for different reasons, and not all those reasons will turn out to be good ones. Finding a scientific principle and then looking for how to satisfy that principle is far better. Here, the principle is that the length of data used should not affect your conclusion about what the climate trend is. This is a strong principle. So when you see someone violating it (say by using a 7 year span without doing some real work to justify it — work like I’m doing here), they’re probably not doing good science.
… let’s look at what the trends are like if we use 7 years of data, versus using 25 years….”
http://moregrumbinescience.blogspot.com/2009/01/results-on-deciding-trends.html
“Temperature trends – pick a timescale, any timescale! … trend-lines … can be fairly dangerous…. Depending on your preconceptions, by picking your start and end times carefully, you can now ‘prove’ that:
Temperature is falling!
Temperature is static!….”
http://www.woodfortrees.org/notes#trends
Lewis (#154),
Your question is imprecise.
The 40 year figure quoted by Hank (which is undertain and may for all I know not be representative of the views of most experts) has a precise meaning. It seems to be the time at which approximately 60% of the warming would be realized. Like all such figures, it’s based on an arbitrary choice.
The reason you need an arbitrary choice is that the total intertia of the oceans is huge. You’d need thousands of years to get the to the full effect of a given stable forcing. Refer to IPCC WG1 AR4 for the consensusual take on this kind of stuff.
But no forcing is going to be that stable so it’s kind of a moot point. The inertia for the top of the oceans is more relevant to our concerns but where do you draw the line?
Dan H., Just curious. Do you really think it is a profitable use of time to challenge physics that has been known for more than a century (Arrhenius predicted anthropogenic climate change from fossil fuel burning in 1896)?
Do you also think we should revisit whether atoms exist? How about investigating the nature of the luminiferous aether? And that pesky quantization–hasn’t that always bugged you? Relativity? The atomic nucleus? So, tell us, Dan, what else, in your opinion, should we toss out along with all of climate theory?
> 40 year figure quoted
That’s the number from the HTML link to a headline; it’s the author’s rounded-off approximation of the overly precise “midpoint” of the paper’s estimate of a range. Don’t put much weight on it, you’ll fall through.
It’s explained in the linked article.
Re Ray 161
Hmmm. I guess what I thought I understood by the “natural” warming trend is based on the concept that the last ice age is still in “retreat” – i.e. “natural” warming must be the result of the rebalancing of “natural” events that caused cooling, for instance volcanoes or large asteroid stikes or something – rather than being “warmed” by the sun because the sun is is somehow generating more energy.
Andreas @167
Are we are talking about the same ‘document’? I am not entirely sure any more!
This is because you say “He doesn’t use GISTEMP as an estimate for global temperature nor for its anomalies. ” Yet the Whitehouse nonsense linked at the top of this post (& thus what I am referring to) discusses “NasaGiss” using words like “…running mean global temperature…” and “Average Temperature Anomaly”
On the off-chance that we are referring to the same ‘document’ and that you wish to defend it further (I cannot for the life of me think why you would. Even Whitehouse would probably here call it a day.), let me give you my honest opinion of it.
First off, it says GWPF at the top. I never can remember what that stands for (Is it Grand Words Pure Flimflam?) but I know GWPF is used to prepare the reader for some of the most bizarre comments and analysis on AGW that they are ever likely to encounter.
In this GWPF paper Whitehouse describes the recent global temperature record in a manner akin to a blind man’s description of the anatomy of an elephant based solely on a chance overheard elephant-keepers’ conversation on the top deck of a London omnibus.
Whitehouse notes that the strongest period of warming was in the mid 1990s yet fails to mention either the rather significant eruption of Pinatuba or the strongest El Nino event on record which, goodness, may be the reason for this short period of strong warming. Clever Whitehouse! He’s discovered volcanoes & ENSO cause wobbles in global temperature. If we hang on a few more centuries he might just be able to add the solar infulence onto that and work out why the recent global temperatures aren’t surging up as rapidly as they might (or as he calls it the “no increase in temperature”).
Then all Whitehouse needs to do is work out how to write his message using a tenth the words he does at present and he may then find his errors are better received.
Dr Nick Bone @168
Hey. I think it is not the likes of Hansen that “wildly extrapolates.”
Hansen & Sato 2010 (now on line to refresh my memory) do talk of the mechanisms for a potential increasing rate of sea level rise. In this they point to the floating ice actually cooling the planet by significant amounts (& for a significant period, not doubt).
I am inclined to the view that the main message of Hansen & Sato 2010 of long term multi-metre sea level rise from quite modest temperature rises is well founded. The exponential increase in sea level rise by 2100 surely requires more glacier study (& less extrapolation) to be seen as more than speculative.
I was careful @145 to talk of “melting” ice caps & the reference you link to talks of “collapsing ice sheets” which I take to mean unmelted ice pouring into the oceans. (There is something odd about the numbers in that Scientific American article. The crucial Blanchon quote says clearly ’20cm in 50 years’ when elsewhere the rate is given as ten times that.) The ” 2m jump” mentioned is also in the referenced Nature article (what can be seen of it) – “2-3m jump in sea level.” – again suggesting collapsing ice sheets. The stated rate of rise (50mm pa) would require some 6 zJ pa to melt the ice which is about what the annual rise in Ocean Heat Content is presently measured at. So warming would be greatly restrained while such levels of ice melted & if rates were higher than 50mm as Hansen’s 10 year doubling would bring, the result would be those cooling temperatures during the melt
Dan,
Where are you getting the idea that warming since the 1970s can be explained by natural causes alone, or is ignoring the effects of CO2? If this information is coming from the media, talk show hosts, or extremist websites, then perhaps, it is time to switch to more scientific outlets. Check out what is printed in the scientific literature.
There you can find details of both natural and manmade causes of warming and cooling, not just of the past 40 years, but throughout history. Condescending attitudes and implying that your opponents are ignorant does not lend your post much credence. In fact, it implies that you are in denial of the science.
Not all scientists agree as to the effect of each of these causes, and I am curious as to your explanations for the variations in the warming and cooling of the past 40 years.
I confess that I’ve never thought about our Sisyphean task of enlightenment in just these terms before. The idea of “cohort replacement” cheers me greatly although it implies gratification postponed. Read all about it HERE.
#178–
“I guess what I thought I understood by the “natural” warming trend is based on the concept that the last ice age is still in “retreat” – i.e. “natural” warming must be the result of the rebalancing of “natural” events that caused cooling. . .”
Many people seem to hold the intuitive view that there is some sort of equilibrium to which temperatures ‘automatically’ return, like a default setting. Thus, take away a source of cooling, and things return to ‘normal,’ like a spring relaxing.
Unfortunately, that perception appears not to be accurate. Cooling or warming occurs in response to specific forcings and the feedbacks following therefrom.
And WRT the current situation, the climate has generally been cooling, not warming, since the height of the current interglacial–the peak temperatures of the Holocene (until just recently, that is) appear to have been roughly 10,000 years ago. So from this perspective, the current warming isn’t a continuation, but a reversal of a trend.
@176
Ah, I would submit that the “skeptic for skepticism’s sake” doesn’t want to toss anything out. They just want to start each day fresh, surprised that the sun has risen again, that apples still fall from trees, and glad that they have yet another opportunity to reinvent the wheel, rediscover first principles, and generally float in a timeless adolescent fog of perpetual cafe debate.
James, when you posit a “natural” cause for warming, you need to keep in mind its mechanism. Volcanism modulates climate by decreasing the sunlight that reaches the planet. It acts on a timescale of years. Likewise an asteroid impact. There is zero evidence that the current warming is being driven by such a cause.
The temperature of the planet is determined by the energy absorbed from the sun and the energy that escapes Earth as outgoing infrared radiation. If the temperature is rising, then either energy in must be increasing or energy out must be decreasing. Energy in does not look to be increasing–solar irradiance hasn’t been increasing. Accordingto Milankovich cycles, we ought to be cooling.
That leaves energy out decreasing. Every indication is that this decrease is due to greenhouse gasses. There is no credible competing hypothesis.
Frankly, the whole “natural warming” argument is unscientific. It sounds like a teenager standing over a broken vase saying, “It just happened!!!”
Ray Ladbury wrote: “Dan H., Just curious. Do you really think it is a profitable use of time to challenge physics that has been known for more than a century …”
It has become abundantly obvious that Dan H. thinks that a profitable use of his time is wasting other people’s time with disingenuous nonsense.
The distortions from “Dan H.” are getting pretty blatant.
Above, “Dan” replies to “Dan H.” who posted a big bundle of denial at 156.
173 Dan says: 8 Feb 2012 at 6:42 PM
> … We are talking about
> the warming that has occurred
> since the 1970s which can not be
> explained by natural causes alone.
and Dan H. says: 9 Feb 2012 at 9:15 AM
> Dan,
> Where are you getting the idea that
> warming since the 1970s can be
> explained by natural causes alone …
The forces of anti-science descend on Amazon.com: Michael Mann and the Climate Wars
#Ray 185
Ray, you started well and went all grumpy SOB at the end! – likening my thought processes to those of a teenager.
Please try and understand that not everyone has the knowledge that you, and other contributers, have and try and understand how, and where, reasonably intelligent lay people get their “knowledge”.
Throughout the whole of my education I was taught that the planet has experienced various major clamatic events. I believe, because that was what I was taught, that dinosaurs probably became extinct because of an asteroid stike which sent plumes of matter into the skies – which darkened (cooled) the planet and wiped out much natural life.
I believe, this event, or others, lead to an ice age such that my country (England) was once frozen over for many years.
I was then lead to believe that as the dust settled (literally) the planet started to warm (naturally) and the ice started to retreat (and still does).
You went on to say:
…………………….
If the temperature is rising, then either energy in must be increasing or energy out must be decreasing.
………………………..
At the risk of incurring your ire, is this really correct?
It is surely not suggested that the sun was getting “hotter” after the ice age – only that more of the sun’s energy was getting through because the dust settled.
It seems logical to me (although this may be a big mistake) that the earth would actually have an equilibrium point that the average temperature would hold at, or return to, – if volcanoes and asteroid stikes didn’t occur and man was not affecting the atmosphere (and that changes in the sun was not affecting temps)- and subject to anolomolies caused by weather sytems around the world in any year.
If there is no “equilibrium point” then the alternative is that momentum takes things to a tipping point one way or t’other over time and man’s efforts to affect this would probably be in vain.
As I hit the “say it” button …. I am diving under the table.
More on the declining costs of solar power, this time in Germany: http://cleantechnica.com/2012/02/09/solar-pv-reducing-price-of-electricity-in-germany/
James – Ray is normally a “grumpy SOB”. While your “thought processes” may have progressed beyond those of a teenager, your knowledge of the processes of the physics of climate haven’t . . . click the “Start Here” button at the top of the site and you might improve your understanding of why those changes you were taught of have occured – it isn’t as simple as dust settling and what “seems logical”. ;)
James,
The Earth does have an “equlibrium” temperature per se. Rather the temperature of the Earth is dependant on the energy in and energy out, as mentioned by Ray. During the recent ice ages and interglacials, the temperature of this planet has swing wildly from a cold, dry planet of expanding glaciers to the mild (by our standards) temperatures of today. Prior to that, the climate was even hotter and wetter.
Do not think of it as a single temperature about which the Earth swings like a pendulum. But rather, as a constantly changing tempperature, influenced by both external and internal forces. Changes in these forces will cause the most recent “equilibrium” to move to a new equilibrium state. Momentum will not take over and cause temperatures to rise or fall in a runaway fashion.
James, I was not trying to imply that you were thinking like a teenager–rather that the whole “natural cycle…” argument is unscientific. Sorry for the misunderstanding.
Unfortunately, popular culture is full of sciencey sounding myths. Yes, the at least some dinosaurs probably died out due to a mass extinction event resulting from a large impact. No, this had nothing to do with the ice ages. Rather, the glacial/interglacial periods seem to be modulated by subtle changes in solar irradiation resulting form minor changes in Earth’s orbital distance, orientation, orbital phase, etc. Collectively, these changes go under the heading Milankovich cycles. What happens is that small changes in solar radiation absorbed (note, that’s energy in) give rise to changes in ice cover and greenhouse gasses, etc. (modifying energy out). Then the planet swings the other way and the process is reversed.
The planet does have an equilibrium for a given amount of solar energy absorbed and a given state–at which point energy in equals energy out. Now let’s say we change the state of the planet by adding 40% more of a powerful greenhouse gas. That takes a big bite out of the outgoing infrared spectrum (decreasing energy out). That’s got to heat things up, right? However, as things heat up, the planet emits more infrared radiation across the spectrum, so eventually, the energy leaving the planet (integrated over the entire curve) is again equal to energy in, despite the big bite taken out.
Generally, what saves us from reaching a tipping point is that the changes in both energy in and out are pretty small as a proportion of the total.
Aw, come on. I’m not that mean!
You know, every once in a while, I will go peruse the Borehole. I always think with a shudder what would happen if the containment on that vessel gave way and unleashed so much weapons-grade stupidity on the world at once.
Re: 180. The abstract from Blanchon’s Nature article describes the 2-3 meter rise as happening on an “ecological” timescale; the supplementary info (which is available for download) gives the argumentation for this, and the interpretation as “the lifespan of one or two generations of coral”. Also, if you look at Blanchon’s comments to the SA article, then he says the rates were the same as at the end of the last glaciation. So Blanchon is indeed claiming several meters per century.
Further, note that the SA article links to an earlier Nature letter by Rohling et al which found average rates of 1.6 meters per century rise during the Eemian. Link here: http://www.nature.com/ngeo/journal/v1/n1/full/ngeo.2007.28.html .
I agree fast rise does not require actual melting of an icesheet: it could just mean large amounts of ice are being floated off the ground, or sudden collapse of a shelf into the sea. But couldn’t a shelf collapse in the next century as well (e.g. part of WAIS), much faster than it would take to melt out?
> the temperature of this planet has swing wildly
“wildly” is bogus misdirection.
Look up the rate of global change for natural variation.
Compare that to the current rate of global change.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2234160/
Rates of change in natural and anthropogenic radiative forcing over the past 20,000 years
“global climate change, which is anthropogenic in origin, is progressing at a speed that is unprecedented at least during the last 22,000 years.
Dan H. keeps trying to pose as a knowledgeable commentator, while slipping in bogus ‘information’. He’s become quite a clever mimic. Watch him.
Damn, I miss killfile. I’m getting snippy.
Here, picture this:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2234160/bin/zpq0030891370002.jpg
Proc Natl Acad Sci U S A. 2008 February 5; 105(5): 1425–1430.
doi: 10.1073/pnas.0707386105
James,
You might be interested in this blog post that I wrote where I outlined why climate changes on a number of different timescales, ranging from years to billions of years (Note that the asteroid impact was some 65 million years ago, completely irrelevant to us today), and I give some more developed examples in Earth’s history.
Actually, it’s a self-advertisement to all.
It seems to me that something was not cleared up in the discussion between James and Ray.
The statement James questioned makes an unstated assumption: “If the temperature is rising, then either energy in must be increasing or energy out must be decreasing.”
If you assume radiative equilibrium, then that’s of course true. But, given a pre-existing disequilibrium, it’s not: it doesn’t take any increase or decrease to cause a change in temperatures.
I think that James’ conjecture was about (in other words) a pre-existing disequilibrium such as would have been caused by a drop in global ice cover. The early Holocene must have had a sustained disequilibrium of this sort for instance.
It doesn’t seem that there actually was a pre-existing disequilibrium large enough to cause anything like the increase in temperatures during the last third of the 20th century. The erratic recovery from the LIA or the more vigorous recovery from the 19th century chill (itself partly caused by changes in GHGs) don’t have the required magnitude and there’s no evidence of a catastrophic feedback that could have amplified them (like a large ice sheet giving way or something).
But you can’t rule out something like that a priori with a theoretical argument.
AC, if there is a disequilibrium, then by definition energy in is not equal to energy out.