Arguments
Prudent Path Week
Posted on 21 February 2011 by dana1981
On 28 January 2011, 18 climate scientists sent a letter to US Congress urging them to "take a fresh look at climate change" and the threats that it poses to the USA and the world. In response, a group of "skeptic" scientists issued a "rebuttal" on 08 February 2011. The rebuttal letter referenced two documents - a report issued by co2science.org entitled 'Carbon Dioxide and Earth's Future: Pursuing the Prudent Path', and the NIPCC report. According to the letter, these two reports show a "profusion of actual observations of the workings of the real world showing little or no negative effects of the modest warming of the second half of the twentieth century", thus suggesting that the "prudent path" forward is to continue with business as usual.
Missing the Point
The key to this "rebuttal" - and where it misses the point entirely - is in its argument that the "modest warming" thus far has not resulted in terribly negative consequences. From this the "skeptics" infer that continued warming will also not result in terribly negative consequences, and this is where they go wrong.
It's true that the consequences of anthropogenic climate change so far have been manageable. It's also true that global surface air temperatures have only increased about 0.8°C over the past century. On a century timescale, this is actually quite a large and rapid warming, and let's not forget that based on the greenhouse gases we've emitted to this point, we've already committed the planet to an additional 0.6°C warming, nearly twice as much as the "modest warming" thus far.
But we're not particularly concerned about current temperatures or the current climate. In fact, if we could maintain the climate and average global temperature at today's levels, everybody would be thrilled. The consequences of climate change so far have probably been more bad than good, but compared to the warming and climate change to come, our current temperatures and climate are quite manageable.
However, a business-as-usual scenario will not maintain the current temperature or climate. Quite the opposite, in fact. While the planet has only warmed about 0.8°C over the past century, the IPCC projects that in a business-as-usual scenario, the planet will warm 2.5–4°C over the next century. That's a net warming in the ballpark of 3 to 5 times as much as over the 20th century. A major factor that the "skeptics" are missing is the massive amount of heat which is going into the oceans, which is slowing the warming of the surface air, for the time being. But eventually, after atmospheric greenhouse gas levels stabilize, the planet will reach equilibrium and that unrealized surface air warming "in the pipeline" will happen. And to eventually stop global warming, we have to stabilize atmospheric greenhouse gas levels first!
Stop Poking the Bear
Suggesting that we should continue in a business-as-usual scenario because climate change so far hasn't been bad is like saying that because lightly poking a sleeping bear with a stick didn't awaken it, we should try throwing rocks at it.
Even with the "modest warming" thus far, the signs of what's to come are not good. Arctic sea ice is declining rapidly, the Greenland and Antarctic ice sheets are losing ice much faster than expected, sea level is rising faster than expected, glaciers are declining worldwide, and overall, the negative effects of climate change are already outweighing the positives. The bear is stirring. We need to stop poking it.
A Little Graphical Perspective
Let's try to put what these "skeptics" are suggesting into perspective. In the figure below, the black line with blue error bars represents the instrumental temperature record, and surface air temperature change from 1900 to 2010. This is the warming thus far which hasn't had terribly bad consequences. The red line with yellow range represents the warming to come over the next 90 years in one of the more moderate IPCC business-as-usual emissions scenarios (A1B - rapid global economic growth with a balanced emphasis on all energy sources).
Figure 1: Global surface temperature record (black - NASA GISS) with one-sigma error bars (blue) and model runs for the IPCC A1B emissions scenario (red, yellow). Image courtesy of Robert Way.
We can also step back even further and compare the projected temperature change over the next century to reconstructions over the past 1,500 years:
Figure 2: Northern Hemisphere proxy temperature reconstruction (purple - Mann et al. 2008) vs. the instrumental temperature record (black) and projected 21st Century surface temperature changes in various IPCC emissions scenarios (red, yellow, green). Source: Copenhagen Diagnosis.
Note that even in Scenario B1, which involves "a high level of environmental and social consciousness combined with a globally coherent approach to a more sustainable development", warming in the 21st Century exceeds that of the 20th Century. In the business-as-usual Scenarios A1F1 and A2, global warming and climate change absolutely dwarf the changes over the past 1,500 years.
That is what we're concerned about. We're not worried about the relatively modest warming and climate change over the past century, we're worried about the dangerous change to come over the next century because of the rapid rise in global greenhouse gas emissions in the "skeptics" favored business as usual scenario.
Prudent Path Week
In light of the information discussed above, we believe the true "prudent path" is to attempt to significantly reduce global greenhouse gas emissions. In the USA, this will probably involve implementing some sort of carbon pricing mechanism. But the bottom line is that continuing on a business-as-usual path is not prudent, it is exceptionally risky. Arguing that future warming will not be dangerous because the warming thus far has not been significantly damaging, as the "skeptics" did in their letter to US Congress, is illogical and incorrect.
Over the next week we will examine some of the arguments made in the Prudent Path and NIPCC documents, some of the contradictions therein, and further illustrate why business-as-usual is actually a very imprudent path.
Second, GCM hindcasts and projections, have in peer review to be shown to be unreliable.
http://climate.nasa.gov/keyIndicators/
Actually this is a quite spectacular site for all the most recent measured data: ice extent, CO2 percent, global temperature, etc., presented on one screen.
Perhaps its easier for some to draw cartoons of drowning pet dogs than to study the science without political bias.
And has anyone answered my question on population growth ? If population doubles in the next 50 years then my efforts to walk to work to save the polar bears will have been in vain !
Climate scientists are well aware that ocean cycles affect climate. You make a good point - it's a very good idea to examine what's happening to the oceans as they have a much greater heat capacity than the atmosphere (in fact, over 90% of global warming is going into the oceans). So when we take a close look at the ocean, what do we see?
Firstly, we find globally, the oceans are building up heat. This cannot be explained by ocean cycles - it can only be explained by the planet being in energy imbalance. Our climate is accumulating heat:
The pattern of ocean warming provides much information also - we see heat penetrating from the surface into the deep waters in all the oceans of the world. Peer-reviewed research into this warming pattern found "the observed ocean heat-content changes are consistent with those expected from anthropogenic forcing, which broadens the basis for claims that an anthropogenic signal has been detected in the global climate system." (Barnett 2007).
The strength of your conviction is not sufficient to validate your claims. Please provide supporting references.
I reckon we'll stop using fossil fuels when there's none left.
"Funny how my taxes have gone up on the back of global warming."
Unless you're living in a mainland European country, I doubt very much that your claim is true-as Governments in every other industrialized Country are very much joined at the hip to the Coal/Oil Industry. Here in Australia, $10 billion per annum of tax-payers money is effectively shoveled into the pockets of the fossil fuel industry-in direct & indirect subsidies-but listen to the politicians *scream* if you suggest giving even 1% of that kind of money to the renewable energy industry.
Implications of "being on the payroll" as the basis for being a supporter are unwelcome here, regardless of the position being supported.
Back on topic - the rate of change projected by all the climate models is very high. A common skeptic argument is that there have been large changes in climate previously. Does anyone know of a chart which plots, say, the temp rise at the end of the last ice age (even just the steepest 1,000 years) against the temp profile as presented in Figure 2 above?
I should probably dig up the source data and chart it myself - I'd like to do the comparison for a presentation I'm putting together for work. CO2 & temp would be a useful pair of charts to illustrate how what's happening now differs from past episodes of climate change.
There's also an interesting post over at ClimateSight about the potential for mass extinction as a result of warming events.
http://www.informaworld.com/smpp/section?content=a928051726&fulltext=713240928
@mod response at 15: thanks, but I was mostly commenting on the fact that there doesn't appear to be a handy link to those graphics anywhere on the standard page layout - I've previously found it by searching for the blog posts that mention it.
We of course all know here that when a proper global analysis is being done, the models give quite accurate result. This is actually quite a remarkable achievement considering how crude the models are compared to the real Earth system. Models also do regionally rather well as can be seen in the link I gave. However, it is not expected that models should recreate the weather of every point of the Earth accurately. That would be expecting miracles.
Both because their ideology requires it, and because, in the US there is no scientific education and one political party is doing very well by denying any science whose outcomes it does not care for.
If you were comparing a local climate model, or even a regional one, you might have a bit of a case, but the broad-scale averaging required for the global models means you should only compare them with measurements averaged over wide areas.
Or so I understand it, not being a climate scientist myself.
By defining a grand check sum, the term "global warming" might actually mean something, regardless of whether climate was cooling or warming somewhere.
GISSTEMP is exactly NASAs best attempt at a "stable temperature measurement sampled around the globe". All an "anomaly" means is that the average value over some well defined baseline period has been subtracted. I has no effect whatsoever on trends etc, and I have no idea why skeptics have a problem with the data being presented as an anomaly (for instance the need to put it in quotes).
Do Spencer and Christy also need a second check sum, given that they also provide the UAH data as an anomaly?
Where can I find more detail and evidence about this claimed $10 billion subsidy to fossil fuel industries?
BTW, did you take into account the indirect subsidy that goes via the low electric prices for the aluminum smelting industry?
regards,
Stephen
Is there a particular reason why the data has to be tinkered with? Why not just publish a number? Whatever the number, it should be increasing slowly. Assuming the number is valid, it should just be a matter of dividing it by the number of samples, and the difference of this result every year should be some small number that jives with the anomaly curve in Figure 1.
This objection to a temperature anomaly seems to pop up every once in a while. I don't understand why it's an issue. The anomaly concept is simple enough: It's 'usually' some average M, now its +1 more than M; the anomaly is that difference.
But you touch on a more basic issue: Can skeptics be swayed? I suppose the answer depends on what the skeptic means when he or she self-identifies as a 'skeptic'. Those who are ideologically driven, have closed their minds to new ideas and/or are living in fear that 'they are all out to get us' do not sway. This seems to describe the majority of those who show up here calling themselves 'skeptics;' a few comments in and they show their true colors. Every once in a while, you run into a 'true skeptic' - one who has an open mind; it's a very refreshing change.
Wikipedia has it right (and I am usually very skeptical of Wikipedia):
Contemporary skepticism (or scepticism) is loosely used to denote any questioning attitude, or some degree of doubt regarding claims that are elsewhere taken for granted. Usually meaning those who follow the evidence, versus those who are skeptical of the evidence (see: Denier)
The subsidies on electricity to aluminium smelters are estimated to be worth $195-232 million per year (table p.17, discussion p.18), but the current figure may be $100m higher due to subsidies to the new(ish) Aldoga smelter near Gladstone.
If you want to have "the number", just add on the baseline offset for the particular record you are interested in, and you will have it. However, if you think measuring the Earths temperature is a straightforward matter, you are greatly mistaken, see e.g. Trewin (2010) for a very readable review of the need for homogenization etc.
Actually, those trends are 'the numbers' that should be the focus. Figure 1 in Monckton Myths#12 presents an excellent example: the number +6.3 degrees per century should be enough to sway even the most cold-hearted skeptic.
Or Table 1 in the same post, where 8 of the 10 warmest years in the Arctic temperature record occurred this decade. How do the so-called skeptics usually respond to that? With stories of uncomfortable seals from 1922 or a ship frozen in the ice from 1850.
I suppose its easier to laugh about how much those anecdotes 'prove' than actually think about the consequences of our actions.
See e.g. here for some graphs of current sea level rise (around 3 mm/yr) in historical context.
The post thereafter gives two graphs of sea level versus mean global temperature for different periods in earth' history. They may provide some useful perspective.
Dana,
In terms of how much warmign is still to come, there's the "unrealized" warming that still has to make its way out of the ocean as the planet equilibrates, but there's also the cooling effect of aerosols: They will most likely be cleaned up before we get rid of CO2 emissions. As aerosol pollution will be cleaned up, more and more of the "masked" warming will become apparent.
Gianfranco - yes, I essentially mean compared to what's to come. The consequences thus far have been bad, but they haven't had particularly horrific consequences yet.
I read your reference. The authors do not like global climate models. It is published in a relatively small journal and has not received much support from other scientists. Gavin Schmidt(who is published in high visibility journals) here comments on their methodology from their previous paper. The results you cited are certainly not the consensus of the field.
I find it difficult to determine what your objections are. If you specify what your objections are perhaps we can address those issues. Do you claim that all models are unreliable? Comparing for example Dr Hansens 1989 projections to what has been observed the projections are close to reality see models are unreliable.
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While off-topic, it seems an "edit post" feature for commenters would be extremely handy...
The earth is 4,5 billion years old and has had – some pretty extreme climates, to say the least. In the past the earth has been a giant snow ball with an average temperature of -50 degrees. It has also been a molten ball of lava, with a 1200 degrees surface temperature. So no matter how hot it is going to get on earth, it is never going to be “unprecedented”.
While your argumentation about the incompatibility of large temperature changes and low climate sensitivity is correct, I don’t think it addresses the underlying assumption of the “unprecedented” argument used by skeptics.
What is this “unprecedented” claim really about and why does it appear so often in skeptical arguments ? As far as I can tell, the implied argumentation behind it is: “If I can prove that in the past the earth was warmer than today due to natural causes, the present warming might be due to natural causes as well, and there is nothing to worry about.”
This is actually a valid reasoning if your understanding of the climate is zero. When lacking any other information, it is a crude way to determine if the current climate still falls within a range that can be considered as “normal”.
So it is a perfectly reasonable thing to do if you don’t have the information, but it is irrational behavior if you do have more detailed information at your disposal, which you choose to ignore.
Climate science takes into account all available information to explain all climate changes, past or present, warming or cooling. If we can explain and predict all climate changes of the past and the present, by means of all the known forcings (human and natural) and feedbacks, this means we understand the climate and also have a pretty good idea of how it is going to evolve.
Scientists have to fit the pieces of the puzzle together and check if there are any missing pieces, any holes in our understanding (e.g. warming or cooling that cannot be explained by the current theories). And as it appears the puzzle cannot be made complete without taking the role of CO2 into account.
No skeptical theory exists that is able to successfully explain and predict past and current climate changes, leaving CO2 out of the equation.
I’m sorry if this all sounds too obvious, but I think many people just don’t know these things.
Every now and then I'm struck by an observation one of our commenters makes. With regard to "skeptics", Ann makes this observation: Obviously Ann is not applying this to everyone posting here. Legitimate seekers of knowledge become obvious in short order; the obverse as well. It should be painfully obvious to readership which parties comes here in good faith to learn...and which do not (have any intentions to learn).
Thanks, Ann, for saying something more eloquently than I could.
The Yooper
Conversely, I have observed many posts that seem to ignore the most basic principles of physics as well as the many requests to look at data and citations presented to them.
Many contrarian arguments have been thoroughly debunked by addressing specific questions and providing scientifically supporting evidence only to have the originator of the argument to return and say their question was not addressed.
I know many posters here as well as I have become somewhat frustrated with the experience. For the past 24 hours I have only observed posts from the "Recent Comments" page and begin to look at this from a whole new prospective. No doubt it was difficult for me not to respond to some of the posts, but I begin to realize something very important.
Anyone coming to this site seeking information and understanding with an open mind can easily see what is happening in the climate debate. One side presents only science with supporting evidence and references from the scientific community. The other side continously ignores the information being presented and even refuses to read any of the many articles presented on this site already addressing their questions. Any open minded person visiting this site whether they post or not can easily see this and separate the wheat from the chaff. In my opinion, I think the contrarians are their own worst enemy, if by nothing else, the tone presented in their own posts. As someone said in the "Meet The Denominator" thread, "you are the gift that keeps on giving".
Understand my above comments apply only to those posters who have no intention of engaging in meaningful debate and not the true skeptics who wish to discuss and exchange ideas.
Thank you John, Moderators and everyone connected with SkS for following the "proper path", rather than the "prudent path", with such a high quality site for us all to learn and enjoy.