I found Bob’s Arctic Ocean Heat Content graph quite interesting as it may explain why we are seeing a recovery in sea ice for the last two years. It also reminds me a lot of the graph seen of the Barents Sea water temperature plotted against the AMO which WUWT recently covered here.
Update of NODC (Levitus et al 2009) OHC Data Through June 2009
OK Leland Palmer, I told you on several occasions where you tried to steer threads towards Methane that you should wait until WUWT had a thread that was relevant – here you go, have at it. – Anthony
One of the indisputable facts in the field of global climate change is that the atmospheric build-up of methane (CH4) has been, over the past few decades, occurring much more slowly than all predictions as to its behavior (Figure 1). Since methane is a particularly potent greenhouse gas (thought to have about 25 times the warming power of CO2), emissions scenarios which fail to track methane will struggle to well-replicate the total climate forcing, likely erring on the high side—and feeding too much forcing into climate models leads to too much global warming coming out of them.
Figure 1. Atmospheric methane concentrations, 1985-2008, with the IPCC methane projections overlaid (adapted from: Dlugokencky et al., 2009)
Figure 2 shows the year-over-year change in the methane concentration of the atmosphere, and indicates not only that the growth rate of methane has been declining, but also that on several occasions during the past decade or so, it has dropped to very near zero (or even below) indicating that no increase in the atmospheric methane concentration (or a even a slight decline) occurred from one year to the next.
I thought I’d seen the end of this after we first saw it back on May 26th of this year. I wrote then:
How not to make a climate photo op
You have to wonder- what were these guys thinking? The only media visual they could have chosen that would send a worse message of forecast certainty was a dart board…or maybe something else?
MIT’s “wheel of climate” – image courtesy Donna Coveney/MIT
But no, they apparently didn’t get enough press the first time around. I mean, come on, it’s a table top roulette wheel in a science press release. Today we were treated to yet another new press release on the press mailing list I get. It is recycled science news right down to the same photo series above which you can see again in the press link below. The guy on the left looks slightly less irritated in the new photo at the link. Next, to get more mileage, I think we’ll see the online game version.
So what I think we need now is a caption contest for the photo above. Readers, start your word skills. I’ll post the best three captions from comments in a new post later.
Oh and if you want to read about the press release, here it is below:
From MIT Public Release: 2-Oct-2009
There’s still time to cut the risk of climate catastrophe, MIT study shows
A new analysis of climate risk, published by researchers at MIT and elsewhere, shows that even moderate carbon-reduction policies now can substantially lower the risk of future climate change. It also shows that quick, global emissions reductions would be required in order to provide a good chance of avoiding a temperature increase of more than 2 degrees Celsius above the pre-industrial level — a widely discussed target.
How to limit risk of climate catastrophe
A new analysis of climate risk, published by researchers at MIT and elsewhere, shows that even moderate carbon-reduction policies now can substantially lower the risk of future climate change. It also shows that quick, global emissions reductions would be required in order to provide a good chance of avoiding a temperature increase of more than 2 degrees Celsius above the pre-industrial level — a widely discussed target. But without prompt action, they found, extreme changes could soon become much more difficult, if not impossible, to control.
Ron Prinn, co-director of MIT’s Joint Program on the Science and Policy of Global Change and a co-author of the new study, says that “our results show we still have around a 50-50 chance of stabilizing the climate” at a level of no more than a few tenths above the 2 degree target. However, that will require global emissions, which are now growing, to start downward almost immediately. That result could be achieved if the aggressive emissions targets in current U.S. climate bills were met, and matched by other wealthy countries, and if China and other large developing countries followed suit with only a decade or two delay. That 2 degree C increase is a level that is considered likely to prevent some of the most catastrophic potential effects of climate change, such as major increases in global sea level and disruption of agriculture and natural ecosystems.
“The nature of the problem is one of minimizing risk,” explains Mort Webster, assistant professor of engineering systems, who was the lead author of the new report. That’s why looking at the probabilities of various outcomes, rather than focusing on the average outcome in a given climate model, “is both more scientifically correct, and a more useful way to think about it.”
Too often, he says, the public discussion over climate change policies gets framed as a debate between the most extreme views on each side, as “the world is ending tomorrow, versus it’s all a myth,” he says. “Neither of those is scientifically correct or socially useful.”
“It’s a tradeoff between risks,” he says. “There’s the risk of extreme climate change but there’s also a risk of higher costs. As scientists, we don’t choose what’s the right level of risk for society, but we show what the risks are either way.”
The new study, published online by the Joint Program in September, builds on one released earlier this year that looked at the probabilities of various climate outcomes in the event that no emissions-control policies at all were implemented — and found high odds of extreme temperature increases that could devastate human societies. This one examined the difference that would be made to those odds, under four different versions of possible emissions-reduction policies.
Both studies used the MIT Integrated Global Systems Model, a detailed computer simulation of global economic activity and climate processes that has been developed and refined by the Joint Program on the Science and Policy of Global Change since the early 1990s. The new research involved hundreds of runs of the model with each run using slight variations in input parameters, selected so that each run has about an equal probability of being correct based on present observations and knowledge. Other research groups have estimated the probabilities of various outcomes, based on variations in the physical response of the climate system itself. But the MIT model is the only one that interactively includes detailed treatment of possible changes in human activities as well — such as the degree of economic growth, with its associated energy use, in different countries.
Quantifying the odds
By taking a probabilistic approach, using many different runs of the climate model, this approach gives a more realistic assessment of the range of possible outcomes, Webster says. “One of the common mistakes in the [scientific] literature,” he says, “is to take several different climate models, each of which gives a ‘best guess’ of temperature outcomes, and take that as the uncertainty range. But that’s not right. The range of uncertainty is actually much wider.”
Because this study produced a direct estimate of probabilities by running 400 different probability-weighted simulations for each policy case, looking at the actual range of uncertainty for each of the many factors that go into the model, and how they interact. By doing so, it produced more realistic estimates of the likelihood of various outcomes than other procedures — and the resulting odds are often significantly worse. For example, an earlier study by Tom Wigley of the National Center for Atmospheric Research estimated that the Level 1 emissions control policy — the least-restrictive of the standards studied -would reduce by 50 percent the odds of a temperature increase of more than 2 degrees C, but the more detailed analysis in the new study finds only a 20 percent chance of avoiding such an increase.
One interesting finding the team made is that even relatively modest emissions-control policies can have a big impact on the odds of the most damaging climate outcomes. For any given climate model scenario, there is always a probability distribution of possible outcomes, and it turns out that in all the scenarios, the policy options have a much greater impact in reducing the most extreme outcomes than they do on the most likely outcomes.
For example, under the strongest of the four policy options, the average projected outcome was a 1.7 degrees C reduction of the expected temperature increase in 2100, but for the most extreme projected increase (with 5 percent probability of occurring) there was a 3.2 degree C reduction. And that’s especially significant, the authors say, because the most damaging effects of climate change increase drastically with higher temperature, in a very non-linear way.
“These results illustrate that even relatively loose constraints on emissions reduce greatly the chance of an extreme temperature increase, which is associated with the greatest damage,” the report concludes.
Webster emphasizes that “this is a problem of risk management,” and says that while the technical aspects of the models are complex, the results provide information that’s not much different from decisions that people face every day. People understand that by using their seat belts and having a car with airbags they are reducing the risks of driving, but that doesn’t mean they can’t still be injured or killed. “No, but the risk goes down. That’s the return on your decision. It’s not something that’s so unfamiliar to people. We may make sure to buy a car with airbags, but we don’t refuse to leave the house. That’s the nature of the kind of tradeoffs we have to make as a society.”
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UPDATE: WUWT commenter Deborah via Jim Watson implies in comments that she has too much time on her hands ;-)
La banquisa de hielo marino que rodea la Antártida desaparece casi por completo al final de los veranos australes pero alcanza una extensión de casi 20 millones de km2 (40 veces la de España) al final del invierno austral (es decir, ahora).
Un tema preferido de agitación propagandística suele ser en verano el deshielo del Artico. Este septiembre los medios se han exaltado y aparentan haberse escandalizado (veáse hoy mismo El País) porque dos mercantes noruegos de la compañía Beluga hubiesen podido navegar por la costa siberiana del Artico, desde Corea hasta Siberia, aprovechando el deshielo del final del verano. Acompañados, por si acaso, de dos rompehielos nucleares rusos, admitían y escribían algunos. Según una nota del presidente de la compañía naviera, Niels Stolberg, el tránsito por el paso del nordeste de dos cargueros de tal tamaño fue posible por la gran preparación y el magnífico trabajo de equipo de los capitanes y de su tripulación, así como de unas fiables predicciones meteorológicas. Pero si necesitaron del acompañamiento de dos formidables rompehielos rusos, aunque sólo fuese para hacerles compañía, no debió salirles barato el viaje.
Es verdad que, a diferencia del hielo marino invernal que rodea la Antártida, que tiende a aumentar, la tendencia en las dos últimas décadas del hielo veraniego en el Artico ha sido a disminuir. Es decir, que los mínimos han tendido a ser cada vez más bajos. Pero precisamente este año no ha ocurrido así. La publicación de la hazaña de los cargueros alemanes tapa lo que debería haber sido más noticiable: este verano del 2009 el hielo marino del Artico se ha encogido menos que el año pasado y el anterior. El Artico ha estado más blanco, menos azul. Arriba pongo los mapas del 19 de septiembre del 2007 y del 2009. Como se ve en la figura, en donde con colores morados se muestra la concentración del hielo, el paso del nordeste estuvo más impracticable entonces por una barrera entre Severnaya Zemlya y el continente, pero la extensión total del hielo marino era en la misma fecha bastante menor que la actual.
Ahora, a medida que se acorta el día y el Artico se sume en la oscuridad, las temperaturas de nuevo descienden muy por debajo de cero y los primeros metros de las aguas superficiales se congelan. La extensión de esta delgada cubierta de hielo marino, desde mediados de septiembre, aumenta. De hecho ha empezado ya a aumentar. Llegará a su máximo, de nuevo, a mediados de marzo, luego se reducirá y el ciclo, dirigido por el Sol, continuará.
ref. ArticoComparacion
From an Oregon State University Media Release (h/t to Leif Svalgaard)
Long debate ended over cause, demise of ice ages – may also help predict future
The above image shows how much the Earth’s orbit can vary in shape.
This process in a slow one, taking roughly 100,000 to cycle.
(Credit: Texas A&M University note: illustration is not to scale)
CORVALLIS, Ore. – A team of researchers says it has largely put to rest a long debate on the underlying mechanism that has caused periodic ice ages on Earth for the past 2.5 million years – they are ultimately linked to slight shifts in solar radiation caused by predictable changes in Earth’s rotation and axis.
In a publication to be released Friday in the journal Science, researchers from Oregon State University and other institutions conclude that the known wobbles in Earth’s rotation caused global ice levels to reach their peak about 26,000 years ago, stabilize for 7,000 years and then begin melting 19,000 years ago, eventually bringing to an end the last ice age.
The melting was first caused by more solar radiation, not changes in carbon dioxide levels or ocean temperatures, as some scientists have suggested in recent years.
www.newscientist.com : L'anomalia della circolazione atmosferica antartica, che prevede maggiore freddo sul Mare di Ross, e maggiore caldo attorno al Continente, in particolare sul Sud America e sulla Penisola Antartica Occidentale. Marco Rossi: 24-04-2009 ore 07:37
Possiamo seguirlo anche da soli, l'andamento di sviluppo dei ghiacci marini antartici, che sono in decisa crescita, contrastando così quella che è la teoria generalmente accettata riguardante il Global Warming.
Attualmente, l'estensione dei ghiacci antartici è superiore alla norma trentennale (1979-2009), di circa 1,2 milioni di kmq, ma quello che conta è anche il trend di crescita trentennale in costante aumento, al contrario di quanto stanno facendo i ghiacci artici.
A questo punto è d'uopo domandarsi il perché di questo andamento che si sta verificando in un momento nel quale le temperature di tutto il Mondo sono aumentate di alcuni decimi di grado nello stesso periodo (1979-2009).
Sulla rivista New Scientist è apparso uno studio di John Turner, del British Antartic Survey.
Secondo tale studio, i ghiacci marini antartici proseguiranno ad avanzare ancora per circa un decennio, prima di iniziare anch'essi a ritirarsi, tanto da attendersi una loro riduzione di circa un terzo entro la fine di questo Secolo.
La causa sarebbe il famoso "buco dell'Ozono", causato dalle emissioni di CFC, che avrebbe interferito sulla circolazione atmosferica polare meridionale.
In pratica, tale "buco" avrebbe portato ad un approfondimento di una circolazione depressionaria fredda sul Continente Antartico, con la caduta dei venti oceanici proprio in corrispondenza del Mare di Ross, dove massima è l'espansione dei ghiacci marini, e dove le temperature sono state in calo nell'ultimo trentennio.
Invece, tra il 40° ed il 60° parallelo sud, i venti oceanici avrebbero intensificato la loro velocità, causando così un forte riscaldamento sulla Penisola Antartica e sul Sud America, che, effettivamente, hanno registrato un impressionante trend termico in aumento.
Tuttavia, considerato che tale "buco" dovrebbe richiudersi entro 50 o 100 anni, anche la decrescita dei ghiacci antartici dovrebbe essere prevalente entro circa una decina di anni, fino a perdere un terzo circa della superficie totale entro la fine di questo Secolo.
Se questo è lo stato delle cose, dal punto di vista della circolazione, la spiegazione del "Buco dell'Ozono" quale causa principale presenta, dal nostro punto di vista, alcune contraddizioni.
Tale "buco", infatti, aumenterebbe la percentuale totale di radiazione solare in arrivo sull'Antartide, in quando la parte ultravioletta non verrebbe più filtrata dall'ozono, e giungerebbe ad incrementare il bilancio radiativo positivo.
Tutto ciò varrebbe soprattutto nei mesi estivi (ed infatti il mese di Gennaio è l'unico a non presentare significativi trend di crescita dei ghiacci), mentre nei mesi invernali, quando il Sole non c'è, il surplus di radiazione ultravioletta dovrebbe essere ininfluente sulla circolazione atmosferica polare.
Presentiamo comunque questa teoria come un tentativo di spiegazione di questa apparente anomalia nell'andamento del Global Warming.
