Bear in mind that the representation of clouds in climate models (and of water vapour, which is intimately involved with cloud formation) is such as to amplify the forecast warming from increasing atmospheric carbon dioxide—on average over most of the models—by a factor of about three. In other words, two-thirds of the forecast rise in temperature derives from this particular model characteristic. Despite what the models are telling us—and perhaps because it is models that are telling us—no scientist close to the problem and in his right mind, when asked the specific question, would say that he is 95 per cent sure that the effect of clouds is to amplify rather than to reduce the warming effect of increasing carbon dioxide. If he is not sure that clouds amplify global warming, he cannot be sure that most of the global warming is a result of increasing carbon dioxide.
All posts tagged climate change
Posted by Fred on January 28, 2014
A nice (English language) interview with Dr. Hans von Storch at Der Spiegel is well worth a read. It is nice to see climate scientists valuing the observational record, even if it is inconsistent with the predictions of climate models. Speaking of which, he seems to agree that we are well outside a 95% confidence level that the various climate models are wrong. That doesn’t mean we don’t have warming, or that there isn’t an anthropogenic component, or even that the earlier predictions of significant warming are mistaken. But it does lower the confidence rational people should have in the accuracy of the current climate models.
I also completely agree with this:
Unfortunately, some scientists behave like preachers, delivering sermons to people. What this approach ignores is the fact that there are many threats in our world that must be weighed against one another.
Anthropogenic Global Warming is “the global threat of our time,” as President Obama recently said, only until we detect an Earth intersecting asteroid, or a supervolcano goes off, or we get a 1918-style global pandemic, or a Carrington Event occurs, or a thousand other scary scenarios that could happen. We shouldn’t close our eyes to the very real dangers that could come our way.
Posted by Fred on June 25, 2013
The evidence for major climate change in the 17th century is both copious and unambiguous. Consider the year 1675. In July, the Paris socialite Madame de Sévigné complained to her daughter, who lived close to the Mediterranean: “It is horribly cold: We have the fires lit, just like you, which is very remarkable.” She added: “We think the behavior of the sun and of the seasons has changed.”
Judith Curry points us to a study of the 17th century climate in in The Inevitable Climate Catastrophe. She has extensive quotes from Geoffrey Parker’s new book “Global Crisis: War, Climate Change and Catastrophe in the Seventeenth Century.” It is well worth a read, for this lesson if nothing else:
Nevertheless, it took human stupidity to turn crisis into catastrophe.
The historical record is also a great cautionary tale that cooling is much, much worse than warming. And, since a static climate is as unrealistic as a static universe…
Posted by Fred on June 5, 2013
Judith Luber-Narod, a high-school science teacher at the Abby Kelley Foster Charter Public School in Worcester, Mass., has incorporated climate change into her environmental studies classes, even though she teaches in a somewhat conservative area.
“I hesitated a little bit talking about something controversial,” she said. “But then I thought, how can you teach the environment without talking about it?”
Her students, on the other hand, love topics some deem controversial, she said. She devised an experiment in which she set up two terrariums with thermometers and then increased the level of carbon dioxide, the main greenhouse gas, in one of them.
The students watched as that terrarium got several degrees hotter than the other.
“I say to them, ‘I’m here to show you the evidence,’ ” she said. “ ‘If you want to believe the evidence when we’re done, that’s up to you.’ ”
I’m still working on that Dark Energy post, but it is proving to be ‘interesting’ to write. In the meantime, I wanted to talk a little about the role of experiment and skepticism in Science. The quote above comes from a New York Times science article New Guidelines Call for Broad Changes in Science Education. I don’t mean to be hard on the teacher. I do mean to be a little hard on the author and editors. But mostly, I’d like to use this as a cautionary tale showing why Good Science is not easy to do.
So, what’s wrong with the little experiment designed to show students how the greenhouse gas carbon dioxide raises Earth’s temperature? Almost everything. In particular, it is a great example of how a little knowledge is a dangerous thing, and how the role of experiment is often misunderstood.
First, the greenhouse effect is not really how a greenhouse warms. The glass of a greenhouse will indeed absorb infrared radiation, reradiating some heat–which would otherwise escape to the outside–back into the greenhouse. But this effect is quite minor, and real greenhouses warm because the glass enclosure blocks convection, preventing hot air from rising and being replaced by cooler air flowing in to take its place. It is (relatively) easy to demonstrate this by replacing the glass panes of a greenhouse with panes made of rock salt. The rock salt is transparent to infrared radiation, and so does not stop radiative cooling. The salt panes do block the formation of convective air currents just as well as glass. A greenhouse with rock salt panes will warm like a glass greenhouse, so the real warming mechanism is the elimination of convective flow and not the reduction in radiative cooling.
Similarly, in almost all terrarium experiments like the ones mentioned above, the real warming mechanism at work is not the carbon dioxide keeping the infrared radiation from carrying off heat energy, but the carbon dioxide inhibiting the formation of convective currents of air. The carbon dioxide, being heavier than air, stays within the open top terrarium. It doesn’t get hot enough to rise over the rim of the terrarium and allow cooler outside air to flow in. This is (relatively) easy to demonstrate by using argon gas instead of carbon dioxide. Argon is heavier than air, and argon is transparent to infrared radiation (like the rock salt). A terrarium filled with argon gas will heat just as well as one filled with carbon dioxide. Ergo, the warming effect has very little to do with the carbon dioxide reducing radiative cooling of the objects in the terrarium.
So, what about “I’m here to show you the evidence. If you want to believe the evidence when we’re done, that’s up to you” that the teacher claims? The problem is the experimental result (the terrarium warming) has more than one explanation, and the experiment isn’t designed to eliminate effects other than greenhouse gas style radiative warming. Good science is really hard, because even if you see a predicted effect, it is necessary to rule out alternative explanations for the observed evidence. If your hypothesis predicts A, but evidence shows B, the hypothesis is wrong. But if the hypothesis predicts A and the evidence shows A, this doesn’t necessarily show the hypothesis is correct. Experiments must be designed to test all other explanations for A and rule them out before the evidence shows the hypothesis is correct.
Science requires skepticism. Science requires more than even a theory agreeing with the evidence. Sometimes, what you see isn’t quite what you (or your teacher) think it is. Don’t be hasty to agree with authority. Be skeptical.
Posted by Fred on April 25, 2013
[A]s an increasing body of research is suggesting, it may be that the climate is responding to higher concentrations of carbon dioxide in ways that had not been properly understood before. This possibility, if true, could have profound significance both for climate science and for environmental and social policy.
In Science, when theory meets observation, observation wins. No matter how elegant the theory, no matter how famous and intelligent the scientists who created the theory, if the theory’s predictions do not match up with observations, it is all just pretty math. Climate Science is having to come to grips with the fact that despite the sophistication of the computer models, despite the logical soundness of the underlying assumptions, the predicted warming is not being seen in the observed temperature measurements, both in the lower atmosphere and in all but the very top layer of the ocean. Real scientists will say “hey, there is more work to be done, clearly we do not yet understand the Earth’s climate well enough to predict its behavior.”
I’m a lukewarmer. I think it is clear the Earth has been warming for more than a century now, and I have no doubt that increasing CO2 levels play a part in that warming. But. There is so much we do not yet understand about the climate and the energy flows and feedback mechanisms in it. For example, cloud cover can have a significant effect on the energy flow in the lower atmosphere–white, fluffy clouds reflect solar energy back into space before it can strike the surface, be reradiated as infrared energy, and thereby trapped due to the greenhouse effect. But who has any detailed understanding about the effect of increasing CO2 and temperature on cloud cover? Without that understanding, climate models must guess at cloud cover changes. What are the effects of increasing thunderstorm activity over the oceans? Those huge heat engines transport lots of energy from the surface up to the stratosphere where it is radiated into space, bypassing the greenhouse driven delays in the lower atmosphere. In short, there are lots of questions which remain unanswered by current climate science. The answer to those questions, of which I have mentioned just two, has a great effect in the amount of negative feedback in the Earth’s climate. Without a model that accurately reflects all the important effects, we should take model results with a grain of salt. All models are wrong, but some models are useful.
So, what to do? First, we need to know more, to understand the behavior of the Earth’s climate in greater detail. More research is clearly necessary. Second, we shouldn’t be spending those resources on various social engineering schemes before the behavior of the climate itself is understood well enough to make predictions that are validated by observation. We may have a warming problem, but we may not, and until we have a deeper understanding, it is hubris to imagine we can ‘fix’ a problem which we do not understand and which may not even exist. And perhaps most importantly, climate science must be kept separate from political and social agendas. Science is never ‘settled’; Science is a process, and there is no area of scientific knowledge that is beyond questioning.
Posted by Fred on March 29, 2013
A mysterious warming of the climate was slowly manifesting itself in the Arctic, Dr. Ahlmann said, and, if the Antarctic ice regions and the major Greenland ice cap should reduce at the same rate as the present melting in the Arctic, oceanic surfaces would rise to catastrophic proportions and people living in the lowlands along their shores would be inundated.
He said that temperatures in the Arctic had increased 10deg. Fahrenheit since 1900—an “enormous” rise from a scientific standpoint. The waters in the Spitsbergen area in the same period had risen three to five degrees in temperature and one to one and a half millimeters yearly in level.
“The Arctic change is so serious that I hope an international agency can speedily be formed to study the conditions on a global basis,” he added. He pointed out that whereas in 1910 the navigable season along western Spitsbergen lasted three months it now lasted eight months.
Yowsa, sounds serious! We’d better… oh, wait. The quote is from May 30, 1947. You know, back when the CO2 concentration was around 316 ppm.
Posted by Fred on August 20, 2012
Russia has been flaring up to 50 billion cubic meters of natural gas a year. If a cubic meter of natural gas contains 37 Megajoules of energy and Russia is burning 50,000,000,000/365/24/3600 = 1,585 cu m/sec this is equal to 58,600 MW – six times the size of the nameplate Texas wind farms, recognizing that flaring goes on 24-7 while the wind turbines are much more intermittent. So it seems the topic has more validity than I might have thought, but is there an effect? If one looks at the global temperature maps that are issued by the Goddard Institute for Space Science (GISS) there is a consistent trend in those, which indicates the much higher temperatures that are found in Northern Russia and Siberia. These high temperatures are a significant contributor to the overall analysis that the average global temperature has been rising for the past 40-odd years.
No definitive answers to the climatic effects, but that is a stunning amount of natural gas being flared off. The World Bank and the Russian government are working to see that the gas is either captured and exported, or re-injected. Heading Out goes over the data to see what effect all these flares may be producing.
Posted by Fred on May 2, 2012