through the iris
into space
be it gone
without a trace
Comment on What are the most controversial points in climate science? by KenW
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Comment on What are the most controversial points in climate science? by beththeserf
:)
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Comment on What are the most controversial points in climate science? by Hans Erren
The most controversial, but hardly recognised as such, point in climate science is the Bern Model which models a strong saturation n the Co2 uptake from the atmosphere in the coming decades. This alleged saturation is the corner stone of the hype and the key element of the RCP scenario set.
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Comment on What are the most controversial points in climate science? by Mike Jonas
What is the data that provides the greatest challenge to the dominant view of AGW?
1. The temperature and CO2 graphs in Al Gore’s “An Inconvenient Truth” are still a major problem. They show that in each cycle temperature decreases rapidly while CO2 is at maximum, and that temperatures rise while CO2 is at minimum. And for good measure, at intermediate concentrations of CO2 temperatures sometimes rise and sometimes fall. IOW that CO2 was absolutely not the dominant driver of climate back then, so it is highly questionable that it can be the dominant driver now.
2. The tropical troposphere had to warm more than the tropical surface during the ~1970-2000 period of global warming, if that warming was mainly caused by CO2. It didn’t. So something else was the main cause of the warming.
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Comment on What are the most controversial points in climate science? by ...and Then There's Physics
I would argue that you need to define controversial a bit more carefully. I don’t think that either of these are particularly scientifically controversial
Whether the warming since 1950 has been dominated by human causes
How much the planet will warm in the 21st century
As I understand it a vast majority of active climate scientists regard anthropogenic influences as having dominated since 1950 and, by and large, the IPCC warming projections are regarded as robust. Yes, there are some dissenting voices and, yes, there are some who are presenting results that suggest warming by 2100 may be less than the IPCC projections suggest, but the IPCC ranges are quite broad anyway and so the difference aren’t all that great. This doesn’t make these points controversial, though.
To me, these are controversial in the media and on blogs, but not all that controversial within the scientific community.
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Comment on What are the most controversial points in climate science? by Bob Tisdale
curryja asks, “What is the data that provides the greatest challenge to the dominant view of AGW?”
I just finished the chapter on TSI reconstructions for my latest book.
You may wish to consider the recent shift towards a reduced trend in TSI during the early part of the 20th Century.
The recommendation was that the CMIP5 models use the Lean reconstruction, which continues to show a substantial increase in trend through the 1940s, while the Dora, Krivova, Svalgaard and Wang reconstructions show much lower trends:
The Lean reconstruction is obviously now the outlier. Without that trend in the TSI data, the climate models would have even more trouble simulating the warming from the mid-1910s to the mid-1940s, which is comparable to the warming rate during the later warming period. And the models do a pretty bad job, as it is, simulating the early warming using the Lean reconstruction.
The data are from the Leif Svalgaard’s research page:
http://www.leif.org/research/
Specifically the spreadsheet here:
http://www.leif.org/research/TSI%20(Reconstructions).xls
One last note: The Svalgaard reconstruction in the above graph is outdated. Leif’s latest reconstruction (the blue curve identified as “Based on Corrected Sunspot Number”) shows an even smaller trend because he’s increased the solar maximums before the 1940s:
Cheers
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Comment on What are the most controversial points in climate science? by Jaime
This is very good, very to the point. We need to keep returning to the basic issues in climate science and re-iterate the requirement for climate science to provide us with hard physical, scientific evidence for the claims that man has significantly influenced the climate and probably will do so in the near and long term future.
The nexus of the entire debate is the IPCC AR5 attribution statement that it is ‘extremely likely’ humans have been responsible for ‘more than half’ of the observed warming over the period 1950-2010, with the best estimate being ‘similar to the observed warming’ over this period – meaning that the IPCC believes man has been the dominant cause of modern warming and that all other influences have tended to cancel one another out.
The ‘science’ on which this attribution statement is based is extremely shaky but it is taken as ‘fact’ by consensus climate science and a stepping off point for a whole host of ‘scientific’ claims by scientists, politicians and advocating bodies, whereas it is but an article of faith.
Tamsin Edwards has an article in the Guardian about lukewarmers:
http://www.theguardian.com/science/2015/may/03/climate-change-scepticism-denial-lukewarmers
Dr Edwards is perceived as an ‘honest broker’ in the climate debate, a conciliatory and reasonable voice who steers away from name-calling and is generally highly regarded by sceptics and warmists alike. This is true but alas, her categorisation of three types of people in the climate debate – sceptics, lukewarmers and mainstream climate scientists (and their trusting followers) is rooted firmly in the egregious IPCC AR5 attribution statement. hence she says of lukewarmers – whom she identifies as making up the majority of people opposing consensus climate science in the UK:
“They agree carbon dioxide is a greenhouse gas, that the world is warming, and that a significant fraction of this is down to humans.”
Sceptics – the non lukewarmers – she scathingly identifies as being “in denial”. Hence this ‘honest broker’ is using the AR5 attribution statement to attempt to reframe the climate debate – in the UK at least – as essentially a stand-off between lukewarmers who agree man has warmed the planet ‘significantly’ but don’t believe that climate change poses a future major threat to humanity and mainstream climate science and its advocates which does perceive a real threat from anthropogenic GHG warming. The nub of the disagreement according to Dr Edwards basically comes down to uncertainty over climate sensitivity and the current crop of generally lower estimates. Sceptics “in denial” about the basic ‘facts’ are then relegated to the sidelines.
In reality, there is no hard evidence to support the contention that more than half of post 1950 warming is due to CO2 emissions. With the combination of decreasing estimates for climate sensitivity and growing awareness of the role of natural climate forcings, the observed warming since 1950 directly attributable to AGW may be less than 50%, insignificant or even negligible.
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Comment on What are the most controversial points in climate science? by HAS
I guess the question to answer is “if the vast majority of active climate scientists regard anthropogenic influences as having dominated since 1950, what is the experimental evidence they would produce to justify that view”?
Looking at the question from a statistical POV (another part of the great tapestry that is science) the attribution is very difficult to sustain on any of the datasets currently available as far as I am aware. But I’m open to being shown otherwise.
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Comment on What are the most controversial points in climate science? by Fernando Leanme (@FernandoLeanme)
Ms. Pooh, I was wondering what is the impact of the UV variation on the atmosphere? Eyeballing that graph I would get about 0.1 watts/m2 for the visible spectrum, plus say another 0.1 watts per m2 for the UV spectrum? That’s a lot of variability when the heat uptake is 0.5 to 0.6 watts/m2.
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Comment on What are the most controversial points in climate science? by ...and Then There's Physics
HAS,
I’m not quite sure what you’re getting at, but you seem to be suggesting that we need some kind of observation (data) that convincingly shows that it’s anthropogenic, and that we don’t have that. Well, I don’t think that’s possible. Doing these attribution studies require models. There is no other way. In fact, the more than 50% anthropogenic attribution study actually works by trying to see if it is possible for more than 50% of the observed warming to be natural/non-anthropogenic. The result is that there is a less than 5% chance of this being the case, hence they reject the hypothesis that more than 50% of the warming since 1950 was non-anthropogenic.
Looking at the question from a statistical POV (another part of the great tapestry that is science) the attribution is very difficult to sustain on any of the datasets currently available as far as I am aware.
I’m not sure what you’re implying by this. Datasets tell us nothing of the physical processes that underly the system being observed. If you’re rejecting the idea that we can understand attribution using models, then you’re essentially arguing for a world in which we choose not to understand anything. Without a model you can make no statement about whether it is natural or anthropogenic.
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Comment on What are the most controversial points in climate science? by ulriclyons
“Nature and mechanisms of multi-decadal and century scale natural internal variability. How do these modes of internal variability interact with external forcing, and to what extent are these modes separable from externally forced climate change?”
I think that the AMO is driven by solar wind variability, and functions as an amplified negative feedback. With strong solar wind, particularly in the 1970’s, causing it to cool, and weaker solar wind since the mid 1990’s causing it to warm. With weaker solar wind conditions increasing negative NAO/AO states, which then affects the wind driven AMOC rates and increases AMO and Arctic warming.
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Comment on What are the most controversial points in climate science? by HAS
You start with data and then you build models, and you test those models independently against the data. I’m unaware of any attribution study that shows, under those criteria, that there is a less than 5% chance that more than 50% of the observed warming to be natural/non-anthropogenic.
But as I said I’m open to being shown otherwise.
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Comment on What are the most controversial points in climate science? by Peter Lang
Try Dr John Cook. I believe he gives on-line courses that are available through all the major universities around the world.
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Comment on Hearing: President’s UN climate pledge by Follow-up questions re my recent House testimony | Climate Etc.
[…] For reference, my previous blog post on the Hearing, along with my testimony, can be found [here]. […]
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Comment on What are the most controversial points in climate science? by mosomoso
Indeed, Great Cunn. We pay for scares at the expense of real need.
One would think that billions of poor incinerating whatever they can get hold of, and then inhaling, might be contributing to a problem or two. How much deforestation and how much domestic flame and smoke are prevented by having a nice coal power station burning away in the distance? Don’t ask Lew or Cook to quantify; their computational skills will suddenly desert them. Untaxable carbon is barely carbon at all for those guys.
Today I found myself e-shopping for a little power bank for a mobile phone. You see, I just don’t like it when the power goes off here, even for a matter of hours. I’m very first world in that way. Maybe it’s because I live in the scrub, but I tend to treat electricity as a recurring miracle, and I want to secure it. Living in timber country amid bloodwoods and other prime firewood timbers I get to enjoy the romance of my slow combustion every winter. But I can choose to burn, and choose to flick a switch when I choose not to burn. That’s still not the deal for most of the world, but it should be the deal.
We need to observe what happens immediately AFTER Earth Hour to see what all humans really want.
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Comment on What are the most controversial points in climate science? by mwgrant
Jim D,
At this point in time a person is going to see what a person wants to see. Quantitatively discerning a pause or lack of a pause is just beyond our means at this time. Frankly, as I noted earlier, I have reservation about any anomaly versus time calculation or plot as a practical predictor [corrections].
<i>...The hiatus or pause or leveling off is simple: it is what has been ‘observed’. [If one stretches the definition of ‘observe’. ] However, this back-and-forth on defining ranges is a very good segue. While we surely can make plots of [average] anomaly versus date/time, we seem to have lost sight of the fact the time-anomaly relationship is <b>[not]</b>(my bad--sigh) causal. <i>The implicit assumption is that at some level date/time serves as a proxy for the actual aggregated causative factors. This is really an extraordinary situation that merits discussion.</i> [Yes, I impose the requirement that for a relationship to be a physically useful predictive relationship it must be causal.] Now this opens the prospect of uncertainty in the ‘independent’ variable, here the date/time, and suggests application of other forms of regression. These may or may not make a differen[ce]. My point is that any realistic approach has to explore and document such matters–there are more.</i>
At this time both sides of the hiatus melee are straining at gnats.
(I apologize to anyone who has struggled with my multiple typos on this thread. It has been a tough day.)
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Comment on Follow-up questions re my recent House testimony by Peter Lang
5. The input to the models is the aggregate emissions, not the annual emissions. Do you have any estimate of the aggregate emissions of China, India, and Russia between 2005 and 2030?
A. How does this compare to the aggregate emissions REDUCTIONS claimed by the Obama Administration for the U.S.?
The Nordhaus RICE 2010 model can answer that question. A Denizen who can run the model, or interpret the outputs in the Excel version, could answer that question:
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Comment on Follow-up questions re my recent House testimony by Peter Lang
Download the RICE 2010 Baseline version from here: http://www.econ.yale.edu/~nordhaus/homepage/RICEmodels.htm
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Comment on Follow-up questions re my recent House testimony by Nick (@ledooze)
Judith, I’m curious about what you think about the EPA classifying CO2 as a pollutant. The change doesn’t get talked about much and doesn’t come up in the questions discussed in this post or your testimony. Regardless of whether one believes it contributes to warming or not, it seems that considering it a pollutant is a different issue. Can you provide your thoughts on the matter? I can’t recall a post on the issue.
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Comment on What are the most controversial points in climate science? by Vilka är de mest kontroversiella frågorna inom klimatvetenskapen? - Stockholmsinitiativet - Klimatupplysningen
[…] har jag inte arbetat alls utom genom att göra en översättning av ett inlägg på Judith Currys blogg. Jag har skrivit och frågat henne om hon har något att invända men hinner inte invänta ett […]
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