I would point you to IPCCs report on why predictions for 1988 to 2012 were off . Main reasons they claim are -
More volcanic activity leading to more aerosols.
Slump in Solar forcing from 2000 to 2009.
Inbuilt tendencies in some models to provide over estimations of the impact of green house gasses.
Possible cooling effect of water vapour in the stratosphere which was not considered.
The IPCC summarises the causes as below -
In summary, the observed recent warming hiatus, defined as the reduction in GMST trend during 1998â2012 as compared to the trend during 1951â2012, is attributable in roughly equal measure to a cooling contribution from internal variability and a reduced trend in
external forcing (expert judgment, medium confidence). The forcing trend reduction is primarily due to a negative forcing trend from
both volcanic eruptions and the downward phase of the solar cycle. However, there is low confidence in quantifying the role of forcing trend in causing the hiatus, because of uncertainty in the magnitude of the volcanic forcing trend and low confidence in the aerosol forcing trend.
See the words âlow confidenceâ in quantifying the effect of volcanoes and aerosols.
These are all reasons to keep watch on how accurate the predictions are. Itâs not just a matter of the physics being right or wrong.
In the past, this was the case. Long term climate changes in paleoclimates is due to the Milankovitch cycles which include changes in the elliptical shape of Earthâs orbit, wobbles in Earthâs tilt, and so on. These can combine to lower and raise temperature.
As the Milankovitch cycles warm the oceans they release carbon dioxide which amplifies the warming caused by the cycles.
This is not what we see in modern times. The increase in atmospheric carbon dioxide is 30% above any level seen in any paleoclimate record. This sudden increase is rich in 12C, a marker for fossil fuels. Carbon dioxide is increasing independently of temperature due to human activity.
Not on the basis of currently available evidence, no. If new evidence appears, Iâll re-assess. Thus far you look like a YEC who is trying not to look like a YEC.
I made these points.
The predictions have been accurate for a long more than 10-15 years.
I already said that uncertainties kick in as we go further into the future.
Our ability to predict into the short term future, especially in terms of a matter of decades, is extremely reliable.
The reliability of the models demonstrates we can trust them within their known margins of error. They are reliable for what we are using them for.
Youâre talking about the so-called âhiatusâ, which I already discussed in exhaustive detail. The fact was the models were correct; when the missing data was entered some years later, it was clear the models had been accurate. I explained all this previously.
No they werenât wrong for the period of 1998 to 2012 (you meant to write 1998-2012). You would know this if you had read anything more recent than the AR 5, which was published four years ago.
I note you have completely avoided addressing anything I wrote. This is a standard tactic you employ with others when they present you with information you canât deal with. So if you want anymore information on this topic, behold, go forth and educate yourself. I see no evidence that you are asking questions in good faith.
No I did not. I quoted your post and characterized your post as âclassic AGW denialiism on displayâ (even down to misrepresenting the activistsâ aims). Later I observed specifically that your language was the language of climate denialists. Bill Cole understood this, and so did Tim. I suspect you understood it too.
I agree with this but Ashwinâs point with the model is valid. If the model needs to be validated and its low accuracy base on past predictions is an issue.
You donât understand what an ad hominem is. You keep using this as a kind of trump card, when you donât understand what it is. What John wrote was not an ad hominem.
This is the complete opposite of the truth. The past prediction show the models have high accuracy.
This is typical behavior from you. I gave you a carefully argued position which started with facts established in the nineteenth century, and described decades of research, hypotheses, testing, predictions, and validation. You have deliberately avoided dealing with any of it.
Please educate me on what ad hominem is and why this is not ad hominem. You seem to use logical fallacies all the time I am not surprised that you would be in denial of what an hominem is
We are not on conflict on this⌠this is exactly the point⌠itâs getting the correct data to enter thatâs crucialâŚ
Which is why the models are better at predicting past events than future onesâŚ
This should be obvious by now.
I asked you some pretty simple questions and you did not answer them. It appears you really are not interested in a conversation on this subject.
Again
How much C02 is going to be emitted over the next 20 years?
How much is the US contributing to this number?
How much will this contribute to temperature elevation?
You have had this explained to you by other people in the past, such as Tim, so I donât expect youâll take any notice this time either. An ad hominem takes the form âPerson Aâs argument is wrong, because Person A has moral/character failings X, Y, and Zâ. John did not make an ad hominem argument. He said he doubts you noticed something on your own, when in the past youâve demonstrated an inability to comprehend graphs and figures.
I see you make this empty claim every time someone calls you out on your errors.
You asked me to present a hypothesis. I did. You ignored it. I presented you with several hypotheses, as well as details of how they were tested, and predictions and how they were validated. You ignored it. I presented you with carefully argued position which started with facts established in the nineteenth century, and described decades of research, hypotheses, testing, predictions, and validation. You have deliberately avoided dealing with any of it. Now you claim that I am not interested in a conversation on this subject. It is clear that you are not interested.
If you are genuinely interested, you will engage with what I wrote, and you will look for the answers to your questions in the place to which I directed you.
We are in conflict because you said the models were wrong for a given period. But they were right for the given period. Earlier scientists thought they didnât match the observations, but that turned out to be not because the models were wrong, but because the observation data set was incomplete. The models were correct. This is not a case of data being missing from the models. You still donât understand what happened.
Here is what the article you quoted says. This is exactly what IPCC also says in AR5⌠that the rate of warming was slower in this decade than earlier.
If there was an error on the part of the IPCC, it should have been published as an errata by now.
âThere was a natural slowdown in the rate of warming during roughly the decade of the 2000s due to a combination of volcanic influences and internal climate variability, but there was no actual âhiatusâ or âpauseâ in warming,â Michael Mann, director of the Earth System Science Center at Pennsylvania State University and an author of the climate modeling study, said.
You are confusing two separate issues. AR5 didnât talk about a slower rate of warming, AR5 talked about a hiatus, an actual pause in warming. Reading it, you can see they said what I already told you, that âthe 114 available climate-model simulations show a surface warming trend larger than the observationâ. In other words, the simulations showed more warming than the observations, so they assumed the observation were correct and the models were over-reaching. This turned out to be untrue. The models were accurate; there was no pause, and warming increased, though at a slower rate.
You have omitted the key part of the article, which is not what AR5 says, because they didnât even know this at the time AR5 was published. Here is the part you didnât quote.
Scientists know, for example, that the Arctic is warming at a faster rate than the planet as a whole, but there werenât enough temperature observations from the Arctic in the early 2000s to accurately measure the changes that were occurring there. As a result, data sets on global temperature tended to omit the Arctic until recently, when researchers came up with a better way to extrapolate data from the region. âWe simply didnât have all the information available at the time,â Stephan Lewandowsky, a researcher at the University of Bristol and lead author of the climate modeling report said.
So again, why are you trying to discredit the models based on this tiny fraction of a 140 year data set, while ignoring the overwhelming accuracy of the models? You are completely ignoring the fact that the IPCC AR5 specifically advised against making firm conclusions on the basis of tiny variability within a mere 15 years.
The point is that your ability to reflexively deny the obvious is fascinating. You wrote:
I provided a link to Orthodox Jewish terrorist (according to the Israeli government!) Baruch Goldstein.
Would you mind walking me through how my citing an Orthodox Jewish terrorist (Goldstein) from New York could have âlittle to do with Orthodox Jewish New Yorkersâ?
Arenât people from New York known as âNew Yorkersâ where youâre from?
