Denying the Climate Catastrophe: 3. Feedbacks
This is the third chapter of an ongoing series. Other parts of the series are here:
- Introduction
- Greenhouse Gas Theory
- Feedbacks (this article)
- A) Actual Temperature Data; B) Problems with the Surface Temperature Record
- Attribution of Past Warming: A) Arguments for it being Man-Made; B) Natural Attribution
- Climate Models vs. Actual Temperatures
- Are We Already Seeing Climate Change
- The Lukewarmer Middle Ground
- A Low-Cost Insurance Policy
We ended the last chapter on the greenhouse gas theory with this:
So whence comes the catastrophe? As mentioned in the introduction, the catastrophe comes from a second, independent theory that the Earth's climate system is dominated by strong positive feedbacks that multiply greenhouse warming many times into a catastrophe.
In this chapter, we will discuss this second, independent theory: that the Earth's climate system is dominated by positive feedbacks. I suppose the first question is, "What do we mean by feedback?"
In a strict sense, feedback is the connection of the output of a system to its input, creating a process that is circular: A system creates an output based on some initial input, that output changes the system's input, which then changes its output, which then in turn changes its input, etc.
Typically, there are two types of feedback: negative and positive. Negative feedback is a bit like the ball in the trough in the illustration above. If we tap the ball, it moves, but that movement creates new forces (e.g. gravity and the walls of the trough) that tend to send the ball back where it started. Negative feedback tends to attenuate any input to a system -- meaning that for any given push on the system, the output will end up being less than one might have expected from the push.
Positive feedback is more like the ball sitting on top of the hill. Even a small tap will send it rolling very far away, because the shape of the hill and gravity tend to push the ball even further in the direction of the tap. Positive feedback amplifies or multiplies any input to a system, meaning that even small pushes can lead to very large results.
The climate temperature system has a mix of positive and negative feedbacks.
For example, consider cumulus clouds. If the Earth warms, more water tends to evaporate from the oceans, and some of that water will form big fluffy white clouds. These clouds act as an umbrella for the Earth, reflecting heat back into space. So as more clouds form due to warming, there is a net new cooling effect that offsets some of the original warming. The amount of warming we might have expected is smaller due to the negative feedback of cloud formation.
On the other side, consider ice and snow. Ice and snow reflect sunlight back into space and keep the Earth cooler than it would be without the ice and snow cover. As the world warms, ice and snow will melt and thus reflect less sunlight back into space, having the effect of warming the Earth even more. So an initial warming leads to more warming, amplifying the effect of the initial warming.
Since we know both types of feedback exist, what we care about is the net effect -- does negative or positive feedback dominate? In every catastrophic forecast you have seen for global warming, in nearly every climate model the IPCC uses, the authors have assumed that the climate is dominated by strong positive feedbacks that multiply incremental warming from greenhouse gasses many times.
This is the result:
As a reminder, the green line is the warming from increases in atmospheric CO2 concentration solely from the greenhouse gas effect, without any feedbacks taken into account. It is generally agreed to be a warming rate of about 1.2C per doubling of CO2 concentrations, with which I and many (or most) science-based skeptics agree. The other lines, then, are a variety of forecasts for warming after feedbacks are taken into account. You can see that all these forecasts assume positive feedback, as the effect is multiplicative of the initial greenhouse gas warming (the pink, purple, and orange lines are approximately 3x, 5x, and 10x the green line, implying very high levels of positive feedback).
The pink line is the mean forecast from the 4th IPCC, implying a temperature sensitivity to CO2 of about 3C. The purple line is the high end of the IPCC forecast band, implying a temperature sensitivity of 5C. And the highest is not from a mathematical model per se, but from the mouth of Bill McKibben (sorry for the misspelling in the chart) who has on several occasions threatened that we could see as much as 10C of warming from CO2 by the end of the century.
Skeptics have pointed out a myriad of issues with the climate computer models that develop these forecasts, but I will leave those aside for now. Suffice it to say that the models exclude many important aspects of the climate and are subject to hand tuning that allows modellers to produce pretty much any output they like.
But I do want to say a few words about computer models and scientific proof. Despite what you will hear from the media, and even from the mouths of prominent alarmist scientists, computer models do not and cannot constitute "proof" of any sort. Computer models are merely tools we use to derive the predicted values of physical parameters from complex hypotheses. They are no different than the pen and paper computations an 18th century researcher might have made for the position of Saturn from Newton's celestial mechanics equations. The "proof" comes when we take these predicted values and compare them against actual measurements over time and find that they are or are not accurate predictions. Newton's laws were proved as his equations' outputs for Saturn's position were compared to Saturn's actual measured position (and in fact they were disproved, to a small extent, when Mercury's position did not accurately match and Einstein has to fix things a bit). Similarly, hypotheses about global warming will be proved or disproved when the predictions of various models are compared to actual temperatures.
So we can't really get much further until we get to actual observations of the climate, which we will address in the next several chapters. But I want to make sure that the two-part theory that leads to catastrophic global warming is clear.
This is the portion of the warming due to greenhouse gas theory:
As you can see, the portion due to greenhouse gas theory is relatively small and likely not catastrophic. The catastrophe comes from the second independent theory that the Earth's climate system is dominated by strong (very strong!) positive feedbacks.
It is the positive feedback that causes the catastrophe, not greenhouse gas theory. So in debating catastrophic man-made global warming theory, we should be spending most of our time debating the theory that the climate is dominated by strong positive feedbacks, rather than debating the greenhouse gas theory.
But in fact, this does not happen in the mainstream media. If you are an average consumer of climate news, I will be you have never heard a discussion in the media about this second theory.
And this second theory is far from settled. If on the "settled" scale from 1-10, greenhouse gas theory is an 8 or 9, this theory of strong positive feedbacks dominating the climate is about a 2. In fact, there is plenty of evidence that not only are scientists estimating feedbacks incorrectly, but that they don't even have the sign right and that net feedbacks may be negative.
This is a bit hard to communicate to a layman, but the positive feedbacks assumed by the most alarmist and catastrophic climate forecasts are very, very high. Way higher than one might expect in advance upon encountering a new system. This assumption of strong positive feedbacks is one that might even offend the sensibilities of the natural scientist. Natural systems that are long-term stable (and certainly for all its variation the climate system has remained in a pretty narrow range for millions and millions of years) are typically not dominated by positive feedbacks, they are dominated by negative feedbacks.
If in fact our climate temperature system is dominated by negative feedbacks, the future warming forecast would actually be below the green line:
OK, without getting in and criticizing the details of these models (which would by the way be a pointless wack-a-mole game because there are dozens of them) the best way to assess the validity of these various forecasts is to now consult actual observations. Which we will begin to do in our next chapter, part 4a on actual temperature measurements.
In 1821, a hurricane flooded Manhattan about as badly as Sandy did. And it hit at low tide! If there had been subways then, they would have been flooded.
For there to be 2 meters of sea level rise by 2100, the rate would have to be 25 mm/year on average, a 10-fold increase over the present. If the acceleration is constant, by the end of the century the rate would have to be 50 mm/year. Seriously?
Even the high-end IPCC projections would require significant acceleration from present rates.
And what level of tropical storms hit when you were there? Sandy was just shy of hurricane status when she hit and was actually two tropical storms merged into one superstorm (one faster and one slower).
Manhattan is is also populated by the very poor and everywhere else in between. The rich don't generally use subways.
The sea level would be rising in Florida and Bangladesh and everywhere else no matter what we do or did or don't do. Our actions *may* have increased the rate to some extent. Adaptations would have had to be made no matter what. That's what we do. It's normal. You may not like change, but change happens whether you like it or not.
I am certainly not an expert in this area. The IPCC is a conservative organization when it comes to sea level rise projections. The paper featured in my link to the WaPo, is based on using climate models focussed on the Antarctic region as inputs to model the detailed dynamics of the calving of glacial ice as a result of migration of glaciers downward from the land toward the ocean. They do this for the 3 emissions scenarios used by the IPCC.
http://www.nature.com/articles/nature17145.epdf?referrer_access_token=kOTO6_e1oumbgbGGMXYs1tRgN0jAjWel9jnR3ZoTv0M-pvJMg7VLINRa2mnTNsvXE_walr5kLcSaXAbIeg24vmaYSI-ipyMZIWWW8iRbXSFGwdsR0z9mNSsspZkxzAvKv2HuxbP4dxskvZHqJjyMcJod7NLP4XQUD9WFmxsIs1GTwHJTWDAUclZcfNkolDBGdApsb4SwD08kqvkvWS1BpX0OeD_Bj9lfy7Oz7NfVPixVWk9S7OZ8S9G4BesomSHqaBd-Dnxh5K3GRNMQyS7C42kcS9485UmAsvx0Vbr9PkMbBBer9id5VOfVSGFDvqlp&tracking_referr2.er=www.washingtonpost.com
The ability to model this is rather recent. It involves modelling the reduction of friction due to melt water running under the ice, and effect of rising temperatures in the water supporting the extensions of the glaciers protruding over the ocean, on the formation of cracks on the mechanics of calving. The support of the sea underneath these extensions retards the motion of the glaciers toward the sea. If global warming cause an increased rate of fracture and calving, the support is lost, and the motion of glaciers toward the sea is accelerated. They claim to have tested and calibrated their model on the progress of glacial decline during the ice age recovery periods. The authors have done previous estimates of this phenomenon and claim that their current estimate matches the data better.
The mechanism they are talking about is clearly realistic. It is a peer reviewed paper. The abstract says Antarctica has the potential to provide more than a meter of sea level rise by 2100. If you look at figure 5 you can see a mean value of 1.05+/-.25 for the highest IPCC emissions scenario.
I doubt that either of us knows enough about this subject to evaluate the accuracy of this paper's calculations, to either refute it or support it. It would be interesting to know if the same method has been applied to Greenland, and what the outcome of the simulation is.
Isostatic land changes *increase* the height of the land as it bounces back from removal of glacial weight. That would be a counter to overall sea level rise.
Catastrophic is what happens when you wake up in the morning and find your back yard has fallen into a sinkhole. It's not what happens when you know that the land is slowly sinking and somewhere in the next twenty or thirty or fifty years you may need to bring in some landfill or maybe consider moving.
IPCC projections have been consistently high when compared to actual measurements. Reality has almost fallen below the lower edge of their most conservative projection.
Let's see, 2 meters in 84 years would be an average rate of about 24 mm/yr. In the past 150 years it's increased, at most, from 1.8 to 3.1 mm/yr. For an average of 24mm/yr from our current 3.1, we would have to have a rate of 50mm/yr or more by the end of the century.
The glaciers have been melting and the sea level has been rising, both from that and thermal expansion, for tens of thousands of years. Sometimes faster, sometimes slower. It's nothing new. We adapt.
You seem to be claiming the rate of sea level rise makes no difference in the level of damage and climate change makes no difference. The scientific literature says that global temperature increases can have enormous effects on sea level rise.
One recent peer reviewed paper says that the sea level rise contribution from calving of Antarctic glaciers by 2100 varies from 0.11M to 1.05M depending on whether IPCC emissions scenario 2.5 or 8.5 is followed.
http://www.nature.com/articles/nature17145.epdf?referrer_access_token=kOTO6_e1oumbgbGGMXYs1tRgN0jAjWel9jnR3ZoTv0M-pvJMg7VLINRa2mnTNsvXE_walr5kLcSaXAbIeg24vmaYSI-ipyMZIWWW8iRbXSFGwdsR0z9mNSsspZkxzAvKv2HuxbP4dxskvZHqJjyMcJod7NLP4XQUD9WFmxsIs1GTwHJTWDAUclZcfNkolDBGdApsb4SwD08kqvkvWS1BpX0OeD_Bj9lfy7Oz7NfVPixVWk9S7OZ8S9G4BesomSHqaBd-Dnxh5K3GRNMQyS7C42kcS9485UmAsvx0Vbr9PkMbBBer9id5VOfVSGFDvqlp&tracking_referrer=www.washingtonpost.com
Are you that much of an expert that you can produce a rebuttal of this paper?
Have you ever looked at a map of Antarctica? There's this one peninsular area called West Antarctica. It makes up maybe 10% of the continent. That is the region that glaciers are moving so fast in. The rest of the continent is actually *gaining* land ice mass. More than West Antarctica is losing. Somehow that little fact gets left out.
There are also two reasons for part, if not most, of the accelerated glacial flow that have nothing to do with us and are nothing we can control. There is new volcanic activity under the ice that is melting it from below. There's also an underwater ridge that had been acting as a brake which crumbled. Neither of those has anything to do with human activity.
No. What I'm saying is that it isn't an immediate catastrophe and we have time to adapt and in most cases it will be cheaper to adapt than to disrupt the economy of the world by trying to ban fossil fuels.
What I'm also saying is that we're not the cause of all of it or even most of it. Natural changes are going on all the time.
Peer review is meaning less and less all the time. Some college students decided to have fun a few years ago and programmed a computer to write random papers which they then submitted. A lot of them got accepted.
30 years ago I was a member of AAAS. I was reading through Science one month and hit a paper that stopped me in my tracks. Written just like every other one, full of numbers and projections based on data. Their data? They had two, yes, just two, data points and used the straight line between them as their projection for everything else. I never renewed my membership after that.
The paper I linked to is of high quality. The authors have previously published a lot of work on this subject. In my opinion their paper is worth more than your opinion, and the mindless meme that you quote, that "Natural changes are going on all the time."
There is very little likelihood that your opinion is more valid than their paper. If they are right, your claim, "we have time to adapt and in most cases it will be cheaper to adapt than to disrupt the economy of the world by trying to ban fossil fuels.". Also your opinion is not shared by the leaders of the 195 countries who did their "homework" and signed up to reduce their emissions in order to reduce the impact of climate change. Do you have more knowledge of the economics of the policy options than they do?
"Isostatic land changes *increase* the height of the land as it bounces back from removal of glacial weight. That would be a counter to overall sea level rise."
This is true if the change is uniform across the globe. It is not. Recovery of land height from glaciation is concentrated near the polar regions. The regions where there is no recovery will see an increase in sea levels.
https://en.wikipedia.org/wiki/Post-glacial_rebound
"Since the glacial isostatic adjustment process causes the land to move relative to the sea, ancient shorelines are found to lie above present day sea level in areas that were once glaciated. On the other hand, places in the peripheral bulge area which was uplifted during glaciation now begins to subside. Therefore, ancient beaches are found below present day sea level in the bulge area. The "relative sea level data", which consists of height and age measurements of the ancient beaches around the world, tells us that glacial isostatic adjustment proceeded at a higher rate near the end of deglaciation than today."
This paper shows that with the IPCC scenario 8.5, sea level
http://www.nature.com/articles/nature17145.epdf?referrer_access_token=kOTO6_e1oumbgbGGMXYs1tRgN0jAjWel9jnR3ZoTv0M-pvJMg7VLINRa2mnTNsvXE_walr5kLcSaXAbIeg24vmaYSI-ipyMZIWWW8iRbXSFGwdsR0z9mNSsspZkxzAvKv2HuxbP4dxskvZHqJjyMcJod7NLP4XQUD9WFmxsIs1GTwHJTWDAUclZcfNkolDBGdApsb4SwD08kqvkvWS1BpX0OeD_Bj9lfy7Oz7NfVPixVWk9S7OZ8S9G4BesomSHqaBd-Dnxh5K3GRNMQyS7C42kcS9485UmAsvx0Vbr9PkMbBBer9id5VOfVSGFDvqlp&tracking_referrer=www.washingtonpost.com
I am sure the authors have looked at a map and are aware of the meltwater created by these volcanoes. It is has certainly been in the news.
http://www.livescience.com/46194-volcanoes-melt-antarctic-glaciers.html
Volcanoes may be a factor in the current and past rate of flow of glaciers toward the sea. We do not know how much of a factor. .
What the authors have done is to look at the effect of the impact of future global warming and sea surface temperatures on the rate of flow. They are not attempting to model the effect of volcanoes, which they assume is constant. Here is a link which claims that volcanoes are not an important factor in the melt of Antarctic ice, contrary to your claim.
http://www.livescience.com/45571-antarctic-melting-myths.html
"West Antarctica, where the ice is melting fastest, is also home to a number of active volcanoes. Could they be melting the ice, instead of climate change?
Several lines of evidence say the answer is a resounding NO.
First is Iceland. The land mass has many very active volcanoes, but glaciers still cover its surface. And Iceland is just one of several examples showing that fire and ice can coexist at volcanoes without widespread melting occurring. Second, volcanoes called tuyas erupted through ice sheets during past Ice Ages, and there is little evidence they caused rapid, catastrophic melting. Third, the volcanic activity beneath West Antarctica hasn't significantly changed in the past few decades, which is when the glaciers there started their galloping retreat. Finally, a super-eruption the size of Yellowstone's biggest blast would be needed to melt through the miles of ice that cloak the volcanoes, scientists have calculated. [Fire and Ice: Images of Volcano-Ice Encounters]"
There is also this answer to the question about the importance of volcanic activity in melting Antarctic glaciers, from a site dedicated to explaining Antarctic Glaciers.
http://www.antarcticglaciers.org/question/volcanic-activity-contributing-melting-west-antarctic-ice-sheet/
"The West Antarctic Ice Sheet has many subglacial lakes beneath it; geothermal heating is thought to contribute to the melting of the base of the West Antarctic Ice Sheet. However, the extent of this, and the rate, is very poorly known and currently not included in glaciological numerical models."
It makes sense to me to say we don't know enough about the impact of glacial activity to claim that it nullifies the importance of global warming on the rate of glacial calving in Antarctica and its contribution to sea level, as calculated in the recent paper I linked to.
Some places go up and other places go down, although since the water weight that was in the glaciers is now in the oceans, that also increases ocean depths and more of the ocean is deep than shallow. Things change. We adapt.
As to the article ... Actual measured data is below the RCP 2.6 projection lines (which even their simulations shows little or no appreciable effect on MSL), yet you're worrying using their worst case RCP 8.5 projections?
You keep trying to simplify my statements. I didn't say volcanos were the only cause, just that they were one of the causes of the increased glacial flow rate in West Antarctica. I also said the crumbling of a submarine ridge was also contributing to it. I also said increased temperature is contributing to it. Only the latter cause can have *any* element of human causation in it and the actual magnitude of that amount is still highly uncertain. More than 0%, probably more than 10%, maybe even 20 or 30%. Unlikely to be much more than that.
They may have published a lot of work. They probably know a lot more about the precise mechanics of glacial flow than I do. But in reading the paper, I saw that the numbers you were using came from their simulation (not even projections, simulations - much different methodologies) run using worst case IPCC projections. From the article ... "The RCP scenarios (Fig. 4) produce a wide range of future Antarctic contributions to sea level, with RCP2.6 producing almost no net change by 2100"
Comparing actual measurements to the IPCC projections, shows at or below the bottom of the RCP2.6 projections.
I know a lot more about both economics and science than almost every politician I've ever heard pontificate on the subjects.
"Actual measured data is below the RCP 2.6 projection lines (which even their simulations shows little or no appreciable effect on MSL), yet you're worrying using their worst case RCP 8.5 projections"
I assume you are referring to figure 3a in the paper. The figure is a little confusing, because you have to read the figure caption carefully to understand what is shown.
Fig 3 a) Change in GMSL based on simulations starting from modern glacial conditions in blue, and 130K BFP conditions in red.
The black simulation is the estimated CONTRIBUTION of ANTARCTICA'S CONTRIBUTION to GMSL changes.
So this graph compares modelled total GMSL to estimate contribution to GMSL from melting of the Antarctic Ice sheet. We should expect the black curve to be less than the red and blue curves. . What we see is a delay in the melting of Antarctic ice relative to the start of global sea level increases due to climate change and that t freezing of the Antarctic Ice sheet is the leading edge of the reduction of sea level as a new glacial period starts
This pattern is reproduced on a much smaller scale in the future simulation as current total contributions to sea level rise from Antarctic glaciers are negative, because accumulation of ice due to snowfall currently exceed melting. This is shown in the simulated future graphs of figure 5, where there is a negative slope to the contribution of Antarctica before the graphs turn up.
" Only the latter cause can have *any* element of human causation in it and the actual magnitude of that amount is still highly uncertain. More than 0%, probably more than 10%, maybe even 20 or 30%. Unlikely to be much more than that."
"
If you really know this, you need to publish a paper. The consensus in the published literature, which is reflected in the IPCC statement, is that about 1/2 of current sea level rise is due to warming of the ocean, and about 1/2 is due to glacial melting. The rest of the contributions are very small. They also say that all of the temperature increase since 1950 can be ascribed to warming resulting from human caused GHG increases in the atmosphere. This is the reverse of what you say. Do you have any research that backs you up?
Your objection to the paper is nonsense. What I saw was that past glacial contributions came from simulations. They need to use paleoclimate proxies to get the simulations of Antarctic glacier volume changes 11100-11400 years ago. . What is bad about that? Can you suggest a better way to do that? Did we have satellites to measure glacial volume in those days.
You also say,
"Comparing actual measurements to the IPCC projections, shows at or below the bottom of the RCP2.6 projections."
The text on page 593 states that graphs in fig 4 show the contributions of the Antarctic melting to sea level rise, not the total sea level rise. From page 593,
"The RCP scenarios Fig(4) produce a wide range of future Antarctic contributions to sea level, .."
In fact for scenario RCP2.6, the snowfall on Antarctica exceeds the mass loss for a long time, just as it does currently.
"I know a lot more about both economics and science than almost every politician I've ever heard pontificate on the subjects."
I realize that you believe that. It may be true, but most politicians would consult climate scientists and economists to make their decisions. You have shown that you suffer from Dunning Kruger syndrome in the process that you use to form your opinions, ignoring the work of published scientists in favor of what you think you know.
I put this one off 'til today because I wanted to have more time to write it.
My background is in engineering. I made my own energy engineering degree (which wasn't a recognized major) by doing a concurrent double major in electrical and mechanical engineering. My first love was actually nuclear physics, which I still followed up to quantum mechanics as electives, but I'm also a hands on kind of person which doesn't really track with a career in that field :)
Skipped to the end of your comment and found and downloaded the book. Looks interesting, but it will take a bit to read through. Short fun side story on units brought to mind as I was reading through the preface ... I was working on a major HVAC project for a senior paper and my husband (PhD in Catalytic Chemistry) decided he wanted a go at it. He kept getting more and more frustrated and finally let me follow through what he was figuring. He got to a section using lbm and plugged in a totally weird number. He was reading lbm as pound mol, whereas in HVAC, lbm is pound mass. Big difference and a good example of where assumptions can go awry, even with the best of intentions. :)
So, on to the current discussion ...
Most of the atmosphere (78% Nitrogen, 21% Oxygen, 0.9% argon - H2O isn't included in that figure and varies up to about 4%) is transparent to radiation in both the IR and visible light spectrum. Of the major components, only water vapor is a significant greenhouse gas. That is what I meant about only a fraction being involved in GHGs and radiation.
Yes, without GHGs the earth would be a frozen planet and yes, physical motion between molecules is what we measure as temperature, not radiation absorption and re-emission so we're batting 1000 so far.
Ultimately, almost all of Earth's heat balance comes from the sun. Internal heat contributes a very small fraction of the total. Energy out and energy in are pretty close to a net balance. Any cumulative differences are what changes the total heat energy and therefore measured temperature up or down.
I should have said up to 90% of the effect for water vapor, since it varies with location and time specific concentrations and conditions. Really exact numbers are hard to come by because of overlap, saturations, interactions and just plain lack of knowledge. Then you have to be careful to see that water vapor is even being included in the numbers (some studies try to totally ignore it since it's so transient, but transient or not it's real and *really* major - if I see a paper that ignores it, I ignore the paper, as a general rule). Water also has major negative feedback effects - clouds, snow and ice and the changes they make to the albedo.
I've seen water vapor given as anything from 36% to 95% (where it's included at all and including or ignoring the many ways water in its various forms affects the climate) and CO2 from 9% to 85% (depending on how they consider water and other GHGs)
On the linear coefficients, for example, stratospheric cloud effects are taken to be simply 0.3 of the methane contribution. Other simplifications are used throughout and the IPCC readily admits (at least in the scientific report, not the political summaries) that the total effect of water vapor in all its forms, and especially as clouds, is not well understood. If you look at the errors bars on the effects for various energy balance components, the largest by far is for the negative forcing of the cloud albedo effect
http://www.realclimate.org/images/ipcc_rad_forc_ar5.jpg
I think you're using the term chaotic in a different, non-mathematical sense :). Chaotic systems are dynamic and highly sensitive to initial conditions, colloquially called the "Butterfly Effect." As the IPCC itself says, "The climate system is a coupled non-linear chaotic system, and therefore the long-term prediction of future climate states is not possible."
https://www.ipcc.ch/ipccreports/tar/wg1/501.htm
The Stefan–Boltzmann law states that the total energy radiated per unit surface area of a black body across all wavelengths per unit time (also known as the black-body radiant exitance or emissive power) is directly proportional to the fourth power of the black body's thermodynamic temperature T
It's simply a physical, ideal situation truism. How would it be a limiting factor? Is there some newer corollary to it I don't know?
As to climate always changing, it does. There have been periods in the current interglacial that were warmer than today (MWP, Roman maximum, Minoan, etc.) and others that were colder. In fact, the Little Ice Age which "officially" ended in the mid 1800s, was the coldest period since the start of this interglacial. We don't know what started them or what ended them.
Natural systems are almost always stabilized by net negative feedback. Positive feedback makes systems oscillate out of control. Where, in the global warming arguments, are those limiting negative feedbacks discussed? What are they? At what point do they kick in? What are the assumptions being made? What do we actually know for sure and what don't we know and how important is it?
I would love an actual scientific discussion of a lot of it, and I will be reading that book you recommended. But I keep finding myself arguing with idiots like one who seems to follows me everywhere who thinks, for example, that the temperature on the surface of Venus is totally due to the greenhouse effect. He doesn't know the Ideal Gas Law (or much of any other science, for that matter), doesn't want to know it and doesn't care that he doesn't know it. But he's absolutely positive that he's right and I'm wrong. How can you argue with someone like that? Facts don't matter. Logic doesn't matter. And he's just an annoyingly persistent example of the vast majority of people who seem to populate these threads.
Look, I'm not saying that the climate hasn't warmed in the last 150 years. It has, no question. Nor am I saying that our actions haven't contributed to the warming. They have.
What I object to is using worst case scenarios created by computer models with high levels of uncertainty that have already been proven to not accurately predict the subsequently measured data as scare tactics to massively change the entire economic and technological landscape of the entire Earth via greatly increased government control.
I object to the politicalization of science, to poor science being presented as fact and to using the heavy hand of government to stop any questioning of it.
I know I'm sounding like I'm laying it on you, and I'm not. I just get so frustrated with it sometimes and have to vent.
I didn't object to the paper, I objected to your use of it, pulling out only the worst case scenario and ignoring the most likely case based on empirical comparisons to the IPCC projections.
Politicians consult the experts who tell them what they want to hear. Normal human nature.
The UN created IPCC is one group of scientists. Their whole purpose for existing is to validate the proposition that human action is a major cause of recent changes in the climate. That is their official mandate. Those responsible for the final report pick and choose what goes into it. Many scientists have quit because they wouldn't hew to the pre-determined conclusions. There have even been scientists who want their name taken off the reports because their work has been misrepresented.
Those responsible for writing the summary that is used by politicians and the media aren't even scientists themselves. It's a political document, not a scientific one.
The consensus idea is quite made up. There is no consensus beyond the fact that yes, temperatures have increased in the last 150 and 50 years and yes, that human action has been a significant (with no numbers being assigned to the word significant - scientifically that can be as little as 5%) part of it.
As to your statement that *all* of the warming since 1950 is due to human action, even the IPCC doesn't go that far.
No, I'm referring to the text which reads: "The RCP scenarios (Fig. 4) produce a wide range of future Antarctic contributions to sea level, with RCP2.6 producing almost no net change by 2100, and only 20 cm by 2500."
In addition to the cooling due to clouds (during the day, but warming at night), and perhaps more important, the rain cycle moves large amounts of heat from the surface to the upper atmosphere. A very small change in this cycle can (and apparently does) offset a fairly large increase in CO2.
This is a negative feedback. I would call it obvious, but I've studied thermodynamics. I guess it's not as obvious as a cloud.
"Large positive feedbacks" lead to monostable systems. Not bistable systems.
Actually, feedback is not a response to an input, it is a response to a condition. For example, the room gets hot (condition), the AC turns on (response). And in the case cited, the condition is heat, and the response is radiation. Radiation is also a mechanism, a mechanism of heat transfer, but so what? That does not preclude its being a feedback.
Ok. I tend to think in mechanistic and systemic terms, but I can see where that definition could make sense.
I'm loving this book. Thank you so much for recommending it. I'm only about 2/3 of the way through the first chapter, but his writing style and the way he separates out what we know and don't know is great. And the range ... Earth to other parts of the solar system to exoplanetology and back to Earth. What is that small land mass just below Asia in figure 1.8 at the end of the Cretaceous? The Himalayas before they got smushed between Asia and India? I didn't know Madagascar split off *that* early. Explains why there's so many unique species there.
No, it is based on a model of the atmosphere. What is known and repeatable is the absorption spectrum of CO2. To calculate the effect of that absorption on a planetary atmosphere, you need a model of that atmosphere. And there is no way to even attempt to experimentally validate such a model.
No. It's based on repeatable laboratory experiment. Experiments that were first done well over 100 years ago. The specific mechanisms of how it works took longer to discover, but the empirical facts haven't changed.
When a quanta of radiation is absorbed by a gas (at the spectrum that corresponds to the molecular bonds for that molecule) it is translated into movement between the atoms that make up the molecule. CO2 is a linear molecule so there is only one sort of movement, in and out. For H2O there are more modes because it's an angular bonding. That's why it's an even stronger greenhouse gas.
That absorbed energy is either re-emitted as IR radiation which can go in any random direction or transferred as kinetic energy via collision with other molecules. Temperature is a measure of the movement of molecules, so if there is more movement, there is a higher temperature.
For CO2 it is a logarithmic relationship between concentration and additional increases in temperature, meaning each additional amount of CO2 has less effect than the one before. All else being the same, for each doubling of the CO2 concentration it will cause an increase in temperature of about 1.1°C.
That's not what the debate about Catastrophic Human Caused Global Warming is about. The debate is about what happens overall in a climactic system. What are the secondary and tertiary effects? Do those effects constitute a net positive or net negative feedback system and what the magnitude of those feedbacks are.
Some people say that it's a net negative and so, where in the lab, a doubling would cause an increase of 1.1°C in the total system it might only be 0.5°C. Others go in the other direction and say that what in the lab would cause a 1.1°C change will create a 2° or 3° or even greater change when in the total climactic system.
The fact is, even according to the IPCC (although you have to dig to find it), "The climate system is a coupled non-linear chaotic system, and therefore the long-term prediction of future climate states is not possible."
Increased CO2 will make the temperature go up. Fact. Period. End of statement. How much is the question no one can answer for certain. If you compare IPCC projections to actual measured temperatures, it's at or below the lowest of their projection ranges. But there's still an increase. That, there is no argument about.
"Politicians consult the experts who tell them what they want to hear. Normal human nature."
Look in the mirror carefully when you say that.
It is normal human nature to ignore a problem that may cost you money, change your lifestyle but will happen far in the future, with little present evidence, and mainly understood well by scientists.
"pulling out only the worst case scenario and ignoring the most likely case based on empirical comparisons to the IPCC projections."
The Antarctic is mentioned in the IPCC report as a region that is not well understood. The paper I brought to your attention was not included in the IPCC AR5 report because it was published after it was completed. I mention it because it seems like a thorough and well done piece of work by experts in the field. We have to wait for the next iPCC report to see how it will be rated. The IPCC has been conservative about sea levle projections, and there are a lot of papers out there projecting higher rates of future rise than the ranges shown in their report.
" Many scientists have quit because they wouldn't hew to the pre-determined conclusions. There have even been scientists who want their name taken off the reports because their work has been misrepresented."
You can always find some iconoclasts and egotists among scientists. The fact that some have been dissatisfied and quit should not be surprising. A number of independent surveys of climate scientists and their publications show the ones you are talking about represent a small minority.
"As to your statement that *all* of the warming since 1950 is due to human action, even the IPCC doesn't go that far."
Once again you are caught making up facts. The following link shows a bar graph published in the IPCC attribution section, figure 10.5.
http://www.realclimate.org/index.php/archives/2014/08/ipcc-attribution-statements-redux-a-response-to-judith-curry/
"The best estimate of the warming due to anthropogenic forcings (ANT) is the orange bar (noting the 1? uncertainties). Reading off the graph, it is 0.7±0.2ºC (5-95%) with the observed warming 0.65±0.06 (5-95%). The attribution then follows as having a mean of ~110%, with a 5-95% range of 80–130%. This easily justifies the IPCC claims of having a mean near 100%, and a very low likelihood of the attribution being less than 50% (p < 0.0001!). "
The IPCC and the paper you object to are in agreement about the changes in sea level resulting from RCP2.6. The paper shows almost no net change. Look at the graph of the sea level rise contributed by Antarctic ice in figure 4 of the paper.
You are objecting to the paper without even understanding what is in it, and when I point this out to you, you refuse to accept it. You should quit commenting so often and do a little more careful thinking.
You don't understand what you are reading and are floundering.
You are using terminology from electronics. Explain what you mean by a bistable system in terms of climate.
Once again, I am not objecting to the paper, I am objecting to your initial selective use of it.
You then said I must be referring to one thing in the paper (that I wasn't) and when I gave the exact text I was actually referring to you once again claim I am objecting to the paper that I took the exact text from. What kind of logic are you operating on?
Try going to the IPCC directly. From the AR5 text itself:
"The evidence for human influence on the climate system has grown since the IPCC Fourth Assessment Report (AR4). It is extremely likely that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic increase in GHG concentrations and other anthropogenic forcings together."
Or this:
"Anthropogenic forcings have likely made a substantial contribution to surface temperature increases since the mid-20th century over every continental region except Antarctica. Anthropogenic influences have likely affected the global water cycle since 1960 and contributed to the retreat of glaciers since the 1960s and to the increased surface melting of the Greenland ice sheet since 1993. Anthropogenic influences have very likely contributed to Arctic sea-ice loss since 1979 and have very likely made a substantial contribution to increases in global upper ocean heat content (0–700 m) and to global mean sea level rise observed since the 1970s."
"More than half" and "substantial" is a long way from all of it.
To a new topic ... probability
Here are their definitions for the terms as they use them ...
Likelihood scale used in the IPCC AR5 report:
Virtually certain 99+% probability
Very likely 90+% probability
Likely 66+% probability
About as likely as not 33 to 66% probability
Unlikely 33-% probability
Very unlikely 10-% probability
Exceptionally unlikely 1-% probability
The standard definition for minimum statistical significance is two standard deviations, or about about 95% confidence, so they're even fudging the words and numbers there.
What you would be saying if you claim that all observed warming was due to human action is that if we had not put the extra CO2 into the atmosphere, the temperature would not have changed at all. Can you find ANY period of history in which that is true? You can't.
So the actual question is trying to sort out the signal (changes due solely to human action) from the noise (completely natural changes that would have happened if we hadn't done anything). Somehow this necessary part of the analysis is left out or glossed over.
Why? Because we don't know what causes natural changes in the climate in anything but the broadest terms. There are no definable alternative hypotheses or even a null hypothesis to test against. That's why they can't use standard statistical tests and terms.
Their "probabilities" are not based on any sort of mathematical analysis because no actual analysis can be made. At best they are made on "gut" estimates. Plugging one set of numbers into a computer model vs another set or model doesn't prove anything mathematically.
Again, going to the IPCC itself, "The climate system is a coupled non-linear chaotic system, and therefore the long-term prediction of future climate states is not possible."
Yes, it is normal human nature. Myself and you included.
Once again, I am not objecting to the report. I objected to your selective use of it, pulling out just the numbers that you wanted to use instead of all sides, especially when the actual measured readings of data vs projections strongly indicate using a different scenario which is also covered in the report.
Diane, all you need to do is look at the graph that was taken from the IPCC AR4. . It says there is a 50% likelyhood that 110% or more of the temperature increase since 1950 is due to human emissions of GHG's, just as the Realclimate I posted said. This is not inconsistent with the other statements you have included. That would mean it is more likely than not that 100% of the temperature increase is due to human emissions of GHGs. No matter how hard you twist and squirm that is what the graph says.
Nothing is ever proven conclusively in a mathematical sense in science Scientists look at alternative theories and choose the one that best represents what is observed i.e. is consistent with all the data available. In the case of climate these data include the pattern of warming on land versus oceans, lattitude and height variations in the atmosphere, as well as the availabe data on radiative forcings due to the drivers of the earth's climate. There are a lot of measurements and theoretical papers written on this subject.
I wouldn't call these gut estimates, they are way more sophisticated than that. Many sets of numbers and many different models are used. Asking for mathematical conclusive proof is scientifically incorrect, and is not appropriate for making policy decisions either. No decision will ever be made if that is the criterion required.
Your objection is not clear to me. I pointed out to you that the simulation of the Antarctic Glacial contribution to sea level in the paper actual was consistent with what was said in the IPCC report. In addition, this is a new paper not considered by the IPCC, so if the results were different from what the IPCC said previously about Antarctica it doesn't detract from the credibility of the paper.
Your comments are not specific enough for me to understand what you are objecting to an why.
50% likelihood, in statistical terms, is meaningless. The standard minimum for statistical significance is 95%.
The quotes I gave came directly from AR5. Look at the words ... "extremely likely that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic increase in GHG concentrations and other anthropogenic forcings together."
Their definition of extremely likely is at the 99%, the only one of their ranges that is actually and definitely statistically significant and at that level of confidence they're only saying more than half.
The second quote, also from AR5:
"Anthropogenic forcings have likely made a substantial contribution to surface temperature increases since the mid-20th century over every continental region except Antarctica. Anthropogenic influences have likely affected the global water cycle since 1960 and contributed to the retreat of glaciers since the 1960s and to the increased surface melting of the Greenland ice sheet since 1993. Anthropogenic influences have very likely contributed to Arctic sea-ice loss since 1979 and have very likely made a substantial contribution to increases in global upper ocean heat content (0–700 m) and to global mean sea level rise observed since the 1970s."
"likely made a substantial contribution to" and "likely affected" and "contributed to" and "very likely contributed to" and "very likely made a substantial contribution to"
How can you read any of those as "all of?" Especially if you compare their definitions to statistical standards.
Somebody made a very vague graph with numbers on it without any attribution as to where the numbers come from. Designed for public consumption, not actual analysis.
I went to the source.
The exact descriptive text from AR5 of chapter 10 (you can get it here: http://www.ipcc.ch/report/ar5/wg1/), where the "original" data for that graph came from is as follows: “More than half of the observed increase in global mean surface temperature (GMST) from 1951 to 2010 is very likely due to the observed anthropogenic increase in greenhouse gas concentrations.”
The figure that they used to pull from to make that graph, Fig 10.5, has a 0 level of natural contribution and a 0 level of internal variability. For this specific chart, they left that part out. Plus, look at the size of the error bars on both the GHGs and OAs. Error bars don't cancel each other out. (the orange ANT bar is a combination of the two)
http://www.climatechange2013.org/images/figures/WGI_AR5_Fig10-5.jpg
Now let's take it a step further. I mentioned the need for a null hypothesis in another reply. Also from AR5 Chapter 10, is Fig FAQ10.1-1. I pulled the model they're using for "natural" comparison and used green to put trends in observed temperatures on it and marked 1950. The red and blue lines (blue is mostly behind the red) are what they say would have happened normally. 1950 is when they say human action started actually showing up.
Their models don't track the observations before 1950, nor do they show any effect of the major El Nino events since, one of the two specific natural forcings they mention in the text. The other one is volcanic eruptions. Those show up just fine in their models. What does that tell you about the accuracy of the models? The further back you run the models, the less they agree with observed and recorded reality. Again, what does that tell you about the accuracy of the models?
Then let's look at their combined graph (they never do actually give a graph for just the human "contributions," so I can't put it up). In this one I marked 1950 and 1998 in green. Between those two lines, their models miraculously track observation almost perfectly. Not before and not after. Once again, what does that tell you about the accuracy of their models?
50% likelihood, in statistical terms, is meaningless. The standard minimum for statistical significance is 95%.
The quotes I gave came directly from AR5. Look at the words ... "extremely likely that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic increase in GHG concentrations and other anthropogenic forcings together."
Their definition of extremely likely is at the 99%, the only one of their ranges that is actually and definitely statistically significant and at that level of confidence they're only saying more than half.
The second quote, also from AR5:
"Anthropogenic forcings have likely made a substantial contribution to surface temperature increases since the mid-20th century over every continental region except Antarctica. Anthropogenic influences have likely affected the global water cycle since 1960 and contributed to the retreat of glaciers since the 1960s and to the increased surface melting of the Greenland ice sheet since 1993. Anthropogenic influences have very likely contributed to Arctic sea-ice loss since 1979 and have very likely made a substantial contribution to increases in global upper ocean heat content (0–700 m) and to global mean sea level rise observed since the 1970s."
"likely made a substantial contribution to" and "likely affected" and "contributed to" and "very likely contributed to" and "very likely made a substantial contribution to"
How can you read any of those as "all of?" Especially if you compare their definitions to statistical standards.
Somebody made a very vague graph with numbers on it without any attribution as to where the numbers come from. Designed for public consumption, not actual analysis.
I went to the source.
The exact descriptive text from AR5 of chapter 10 (you can get it here: http://www.ipcc.ch/report/ar5/..., where the "original" data for that graph came from is as follows: “More than half of the observed increase in global mean surface temperature (GMST) from 1951 to 2010 is very likely due to the observed anthropogenic increase in greenhouse gas concentrations.”
The figure that they used to pull from to make that graph, Fig 10.5, has a 0 level of natural contribution and a 0 level of internal variability. For this specific chart, they left that part out. Plus, look at the size of the error bars on both the GHGs and OAs. Error bars don't cancel each other out. (the orange ANT bar is a combination of the two)
http://DianeMerriam.com/img/MyGauntlet/Fig10-05sm.jpg
Now let's take it a step further. I mentioned the need for a null hypothesis in another reply. Also from AR5 Chapter 10, is Fig FAQ10.1-1. I pulled the model they're using for "natural" comparison and used green to put trends in observed temperatures on it and marked 1950. The red and blue lines (blue is mostly behind the red) are what they say would have happened normally. 1950 is when they say human action started actually showing up.
http://DianeMerriam.com/img/MyGauntlet/IPCCNatural.jpg
Their models don't track the observations before 1950, nor do they show any effect of the major El Nino events since, one of the two specific natural forcings they mention in the text. The other one is volcanic eruptions. Those show up just fine in their models. What does that tell you about the accuracy of the models? The further back you run the models, the less they agree with observed and recorded reality. Again, what does that tell you about the accuracy of the models?
Then let's look at their combined graph (they never do actually give a graph for just the human "contributions," so I can't put it up). In this one I marked 1950 and 1998 in green. Between those two lines, their models miraculously track observation almost perfectly. Not before and not after. Once again, what does that tell you about the accuracy of their models?
http://DianeMerriam.com/img/MyGauntlet/IPCC Combined.jpg
You are confoosid again.
50% likelihood, in statistical terms, is meaningless. The standard minimum for statistical significance is 95%.
The quotes I gave came directly from AR5. Look at the words ... "extremely likely that more than half
You have the likelihood and amount mixed up. Look up the definition of IPCC's 'extremely likely", it is more than 50%.
You are also confoosid on radiative forcing and the CMIPs graph. There is a slight decline of natural forcings. That is why the planet was cooling before we warmed it. The heating from ~1800s comes from anthropogenic forcings. They've been quantified over and over so not sure why you'd pretend otherwise, and not show them.
/basics
Best,
D
The rest of the continent is actually *gaining* land ice mass. More than West Antarctica is losing. Somehow that little fact gets left out.
Not at all certain. Not at all.
Best,
D
Maybe they aren't so obvious!
There isn't a single example in Earth's history of polar ice sheets withstanding CO₂ as high as we have right now.
That tells me scientists are missing some rather major feedbacks.
Funny how some people's "skepticism" only seems to run one way...
I think that there is no inconsistency between our claims of what the IPCC said.
See figure 10.5 on page 884 of chapter 10 of the AR5:
http://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter10_FINAL.pdf
The figure caption is:
" Assessed likely ranges (whiskers) and their mid-points (bars) for attributable warming trends over the 1951–2010 period due to well-mixed greenhouse gases, other
anthropogenic forcings (OA), natural forcings (NAT), combined anthropogenic forcings (ANT) and internal variability. "
Look at the extent of the midpoints of the attributed components of the temperature increase. The human GHG attribution is 0.9C, the green bar.
The human aerosal is the -2.5C, the yellow bar.
The observed change in temperature is 0.65C.
The colored bar represents the best estimate. So the best estimate of the human GHG contribution is 0.15C greater than the observed temperature increase of 0.65C, just as the quote from my Realclimate web page said.
Since what I said regarding the IPCC assessment was correct, based on their bar graph, which you kndly showed in your post, you are now disputing the correctness of the bar graph and the IPCC statement.
At end of your post, You asked the following question:
". Between those two lines, their models miraculously track observation almost perfectly. Not before and not after. Once again, what does that tell you about the accuracy of their models?"
You are asking the wrong question. Some of the discrepancy could be due to the data. According to your reference, the graphs which you got from AR5 show the HADCRUT4 temperatures. These temperatures do not include large parts of the Arctic region which is warming more rapidly than the rest of the globe and could be underestimating the increase in temperature. In addition, corrections for the substitution of buoys for ships intakes have artificially cooled sea surface temperatures in recent years. Hadcrut4 is underestimating the recent increases in global average temperature. Papers on these subjects have been published by Karl et. al and Cowtan et. al, in 2015, since the IPCC AR5 was prepared. Scientists see these discrepancies and look for the answers. This is how science progresses.
What I said about the attribution previously is clearly correct, whether you like it or not. .You may prefer a different sort of statement, but it doesn't make what I said incorrect.
I didn't know about that event. Doing some research, I found it seems to have been more powerful than Sandy.
http://www.livescience.com/40865-sandy-damage-development-historic-marshes.html
"For example, comparing sand deposits left by New York City's 1821 hurricane to those left by Hurricane Sandy reveals the 1821 storm produced a much larger storm surge, said Christine Brandon, a graduate student at the University of Massachusetts at Amherst. "This was a much-faster-moving storm [than Sandy]," Brandon said.
Brandon analyzed sediment pulled from ponds and lakes on Staten Island's southern coast. Her research confirms a newspaper account of the 1821 storm that reports a 13-foot (4 meters) water-level rise in the East River. Though the report said the flooding raced through New York in only an hour, Brandon's model shows the East River storm surge probably took two hours, she told LiveScience. And it hit at low tide, so the flooding could have been worse. (Hurricane Sandy's storm surge was boosted by a high tide.)"
- See more at: http://www.livescience.com/40865-sandy-damage-development-historic-marshes.html#sthash.lPlLpV5Q.dpuf
They have?
berkeleyearth.org/wp-content/uploads/2016/01/2015-Hottest-Year-BE-Press-Release-v1.0.pdf
Error bars do not cancel out. Nor does the climate go 60 years with no natural changes.
It seems there's a new explanation for the lack of measured heating since the El Nino of 1998 every few months after each previous one is discarded. Shoot, the El Ninos themselves don't show up in their models, only the volcanos. I don't know what the third major drop in the "natural" projections is. There were only two volcanic eruptions big enough to make any significant difference in global climate - El Chichon (Mexico in 1982) and Pinatubo (Indonesia in 1991).
Nor do you address the major inconsistencies before 1950. The major warming trend of the 30's and 40's is almost non-existent in their models. So is the cooling of the late 1800's and the cooling after 1940. The models don't even hindcast well, at least not before their picked starting point of 1950. There was no significant spike in the type or amount of data available until the late 1970's when satellite data really started becoming available.
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Wow!! Curiosity let me to do a search on how levels of likelihood and certainty by the IPCC were assigned. It's not mathematically in most cases. The authors themselves decided what label to put on it due to agreements, modelling and even just personal "expert" (which they are all expected to be) judgement, not just scientifically. Plus statistics significance only needed a 90% instead of the 95+% that is normally accepted as the minimum for any statistical validity.
Search "ipcc how are confidence levels assigned." First two results:
https://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch1s1-6.html for AR4 and
https://www.ipcc.ch/pdf/supporting-material/uncertainty-guidance-note.pdf for AR5
It also said they are *supposed* to concentrate on the probabilistic tails (low actual probability) for possible major consequence findings. I knew they did that, but I didn't know they were *instructed* to do it.
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Back to looking for what they include as natural forcings ...
http://www.climatechange2013.org/images/report/WG1AR5_Chapter08_FINAL.pdf
Natural Forcing Section 8.4
Summary: "Satellite observations of total solar irradiance (TSI) changes
from 1978 to 2011 show that the most recent solar cycle minimum
was lower than the prior two. This very likely led to a small
negative RF of –0.04 (–0.08 to 0.00) W m–2 between 1986 and 2008.
The best estimate of RF due to TSI changes representative for the 1750
to 2011 period is 0.05 (to 0.10) W m–2. This is substantially smaller
than the AR4 estimate due to the addition of the latest solar cycle
and inconsistencies in how solar RF has been estimated in earlier IPCC
assessments. There is very low confidence concerning future solar forcing
estimates, but there is high confidence that the TSI RF variations
will be much smaller than the projected increased forcing due to GHG
during the forthcoming decades. {8.4.1, Figures 8.10, 8.11}
The RF of volcanic aerosols is well understood and is greatest
for a short period (~2 years) following volcanic eruptions. There
have been no major volcanic eruptions since Mt Pinatubo in 1991, but
several smaller eruptions have caused a RF for the years 2008–2011 of
–0.11 (–0.15 to –0.08) W m–2 as compared to 1750 and –0.06 (–0.08
to –0.04) W m–2 as compared to 1999–2002. Emissions of CO2 from
volcanic eruptions since 1750 have been at least 100 times smaller
than anthropogenic emissions. {8.4.2, 8.5.2, Figures 8.12, 8.13, 8.18}
There is very high confidence that industrial-era natural forcing
is a small fraction of the anthropogenic forcing except for brief
periods following large volcanic eruptions. In particular, robust
evidence from satellite observations of the solar irradiance and volcanic
aerosols demonstrates a near-zero (–0.1 to +0.1 W m–2) change in
the natural forcing compared to the anthropogenic ERF increase of 1.0
(0.7 to 1.3) W m–2 from 1980 to 2011. The natural forcing over the last
15 years has likely offset a substantial fraction (at least 30%) of the
anthropogenic forcing. {8.5.2; Figures 8.18, 8.19, 8.20}"
--You can't have it both ways. Either "natural forcings are small fractions other than volcanoes" or "the natural forcings over the last 15 years has likely offset a substantial fraction." Not both.--
Specifics:
"This section discusses solar and volcanic forcings, the two dominant natural contributors of climate change since the pre-industrial time."
--What?!! There are a lot of past changes that don't coincide with either of these. It's not even agreed that the Maunder Minimum triggered the Little Ice Age, much less any other solar changes and even if it did (which seems likely, from what I've read) it doesn't account for it continuing for over 400 years.--
"Volcanic eruptions that inject substantial amounts of SO2 gas into the stratosphere are the dominant natural cause of externally forced climate change on the annual and multi-decadal time scales, both because of the multi-decadal variability of eruptions and the time scale of the climate system response, and can explain much of the pre-industrial climate change of the last millennium"
--What?!! Volcanic effects only last for a few years at most. so they can't drive overall changes either. They even explicitly stated that in the chapter summary. Nor have there been many eruptions that can change climate on any significant scale globally. Laki, Tamboura and Krakatoa if you go back a couple hundred years more.--
There seems to be very little work done on the natural drivers of climate changes, certainly little done at the IPCC level. Without knowing the natural causes, there's no way to compare differences between natural and man made. There's no background to test against. What started and ended the MWP, the LIA, the warming in the 30's and 40's, all the other temperature excursions in the records? You have to be able to model the past in a way that matches actual data before you can even start to make a useful model of the future. Then you have to test that model against future data and it has to match as well before it's useful for making any projections, especially projections that are being used to promote disrupting the entire economy of the world and therefore condemn millions or even billions to continued poverty and high mortality.
Another basic error: the lack of measured heating since the El Nino of 1998
And arguments from incredulity: rarely compelling.
But wait, let me guess: you have a manuscript in press pointing out these errors from professionals not in your field, amirite?
Best,
D
"Error bars do not cancel out. Nor does the climate go 60 years with no natural changes."
The climate can go 60 years with no natural changes. Short term natural changes are noise in the system without some kind of radiatonal forcing. The prinicipal natural forcing is solar irradiance which was quite stable on average during the time period. There were a few negative bursts of forcing due to volcanoes. What is the basis for your claim? Who is claiming that error bars "cancel out"?
The models don't predict ENSO reliably. That is why short term and detailed year by year predictions should not be expected from them. Since the effects of ENSO cancels over the long term, this is not a problem for use of models for long term trend projections.
"--You can't have it both ways. Either "natural forcings are small fractions other than volcanoes" or "the natural forcings over the last 15 years has likely offset a substantial fraction." Not both.--"
Your objection is nonsense. Natural forcings could have been net positive for 18 years, 1980 to 1999 and negative for the next 10 years, and cancel out. There is no law saying that volcanoes and ENSO can't do that. The burden of proof is on you, if you maintain it didn't happen. Or maybe you would prefer the AGW denier argument that it is all a hoax on the part of money grubbing scientists.
"There seems to be very little work done on the natural drivers of climate changes, certainly little done at the IPCC level. "
What evidence do you have of this.
The search on climate volcanic forcing on Google Scholar got 93,000 results..
The search on climate Solar Irradiance got 307,000 results
It seems like a lot of work to me.
" especially projections that are being used to promote disrupting the entire economy of the world and therefore condemn millions or even billions to continued poverty and high mortality."
Where is the evidence for this claim? Solar and wind technology are currently being installed in South Africa and are cheaper than the alternatives and together are able to provide base load power.
http://mainstreamrp.com/analysis-shows-south-africas-wind-and-solar-power-generation-demand-profile/
So it's coincidence that everything just happened to balance exactly out over the course of their 65+ year span?
ENSO varies quite a lot from cycle to cycle and they are basing their projections on time spans that aren't much more than one and a half typical cycle length. If they can't model them, then how can they say they're not a factor in their "studied" time span?
Volcanoes have no long term effect on climate. The aerosols precipitate out over the course of just a few years even in the largest eruptions. They state that natural forcings are minor, yet they can't explain or model long term major shifts (and I'm not talking glaciation cycles) in the past. They happened. No question.
I said work in the IPCC. Section 8.4 of AR5 is all there is that concentrates on natural factors and it only talks about solar and volcanoes and then discounts those as being any significant (or according to their chart, any level) factors.
This is quoted verbatim from the summary of Section 8.
"There is very high confidence that industrial-era natural forcing
is a small fraction of the anthropogenic forcing except for brief
periods following large volcanic eruptions. In particular, robust
evidence from satellite observations of the solar irradiance and volcanic
aerosols demonstrates a near-zero (–0.1 to +0.1 W m–2) change in
the natural forcing compared to the anthropogenic ERF increase of 1.0
(0.7 to 1.3) W m–2 from 1980 to 2011. The natural forcing over the last
15 years has likely offset a substantial fraction (at least 30%) of the
anthropogenic forcing. {8.5.2; Figures 8.18, 8.19, 8.20}"
To which I commented:
--You can't have it both ways. Either "natural forcings are small fractions other than volcanoes" or "the natural forcings over the last 15 years has likely offset a substantial fraction." Not both.--
There were no major volcanic eruptions in the last 15 years. It says there was a near zero change in natural forcings from 1980 to 2011 but then in the very next sentence says that natural forcings compensated at least 30% of the anthropogenic forcings. AR5 cutoff date was March of 2013, so the reference to the previous 15 years would have been from 1998 to 2013, when the measured data started really diverging widely from their projections. That would have required a large heating effect previously to balance it out. But there is no heating in their natural projection chart that shows that. In fact, the only deviations from flat their natural model shows are negative.
http://DianeMerriam.com/img/MyGauntlet/IPCCNatural.jpg
I repeat, you can't have it both ways.
At this point, I can't remember if it was you I replied to on questions of the economics of alternate energy, but I said that there are undoubtedly places in which solar or wind might be the best economic choice even without government subsidies.
That's backed up by what the article says: “The analysis also shows something which gives South Africa significant competitive advantage in that the combined wind and solar resources match the average demand profile for electricity. This is significant because the wind blows and the sun shines when electricity is most needed, AND THIS IS NOT SOMETHING THAT OCCURS WITH SUCH REGULARITY IN OTHER GLOBAL MARKETS.”
The modernization of most of the third world cannot be driven with expensive alternate energy sources. That modernization is what has allowed over a billion people to rise out of absolute poverty in the last 16 years alone.
Look, I'm not saying that global warming is a hoax. It isn't. Nor am I saying that we haven't contributed to it with our GHG emissions. We have.
What I am saying is that the fears are being stoked with bad science passed off as good, concentrating on worst case, and often totally unrealistic, scenarios, even as empirical observations correspond with far less worrisome ones.
I am saying that proposed mitigations are not economically sound, that the costs of them often far outweigh the benefits to the average person, but do often greatly benefit crony crapitalists. Run through government programs and studies, it could hardly be any other way.
"They have"
Yes. 2015 setting the hottest year on record and the majority of climate models running hot are not mutually exclusive.