# Leaked IPCC report: 90% confidence in AGW is now 95% -- and sea level will rise! **URL:** \ **Category:** Great Debates\ **Created:** [August 23, 2013, 8:36pm UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002 "2013-08-23T20:36:49Z")\ **Posts on this page:** 20\ **Page:** 24
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [September 28, 2013, 9:55pm UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002/461 "2013-09-28T21:55:25Z")
> [@FXMastermind](#): > > Sea levels change, that is one of those things we know for sure. Exactly how much and how fast is still a question. > > [http://www.pnas.org/content/early/2011/06/13/1015619108.full.pdf](http://www.pnas.org/content/early/2011/06/13/1015619108.full.pdf) > **Sea level then increased for 400 y at a rate of 0.6 mm/y** = a rise of 2 and a half meters, during what is known as the MWP, another thing warmists don’t like to admit is real. Strawman, what the scientists say is that the MWP is not as warm as today. As for the implication that seas rises fast in the past with no human intervention, it has to be pointed that the paper you cites agree that the warming is happening. And the current warming and ocean rise have other reasons for happening now. > **[Predicting future sea level rise](https://skepticalscience.com/Predicting-future-sea-level-rise.html)** > > The two main contributors to sea level rise are thermal expansion of water and melting ice. Predicting the future contribution from melting ice is problematic. Most sea level rise from ice melt actually comes from chunks of ice breaking off into the... > [@](#): > > Response: These are fundamental and well established issues. Every climate scientist will agree that: > > 1. Temperature has changed naturally in the past (before humans). > 2. As sea level is directly affected by sea level (as established in Vermeer 2009) then sea level has changed naturally in the past > > Do not fall into the logical fallacy that past natural climate change means humans can’t influence climate now. On the contrary, past climate change shows us that climate is sensitive to radiative forcing - to energy imbalance. As we are currently imposing an energy imbalance through an enhanced greenhouse effect, past climate change is actually evidence for our climate’s sensitivity to CO2. > > Is it likely that cyclical ice ages will occur in the future? In the short term (geologically speaking), the peer reviewed science says no. The radiative forcing from CO2 far outstrips the radiative forcing from orbital changes that initiate cyclical ice-ages. I touch on this tangentially on We’re heading into a new Little Ice Age although that page is talking more about the forcing from falling solar levels, not orbital forcing. However, orbital forcing is even less than solar forcing so the argument stands. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [September 28, 2013, 10:17pm UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002/462 "2013-09-28T22:17:30Z")
> [@FXMastermind](#): > > Long before the current global warming suckfest began, there was a lot of research into the sun, climate, changes, and all kinds of theories and musings about it. The sun doesn’t seem to change it’s visible output enough to cause large changes, but our actual science about this is so short you can’t really know. Argument from ignorance. > [@FXMastermind](#): > > Certainly the recent findings about how much the UV changes, how they effects the upper layers of the atmosphere, how those layers influence weather and climate down below, and of course the cloud issue, it doesn’t seem to be anywhere close to settled. As pointed before, Richard Lindsen proposed the Iris effect as a mechanism that would lead the clouds to increase and be mostly a negative feedback, it failed to show up. > **[Lindzen's Clouded Vision, Part 1: Science](https://skepticalscience.com/lindzens-clouded-vision-part1.html)** > > When it comes to global climate change, there are two critical and intertwined, but distinct issues: science, and policy.  We generally focus on the science, because that is what dictates the appropriate policy response, or at least what our climate... > [@](#): > > Lindzen’s Cloudy Iris > > In Gillis’ Times article, Lindzen brings up his Iris hypothesis. Back in 2001, Lindzen proposed that in response to global warming, increased sea surface temperature in the tropics would result in reduced cirrus cloud formation and thus more infrared radiation leakage from Earth’s atmosphere. This radiation leakage in turn would have a cooling effect, dampening global warming as a negative feedback (like the iris in a human eye contracting to allow less light to pass through the pupil in a brightly lit environment - hence the term ‘iris effect’). > > However, within a year of the publication of Lindzen’s iris paper, there was one study published concluding that Lindzen had significantly overestimated the iris effect, a second concluding that if the iris effect existed, it would lead to increased warming, and a third and fourth papers finding no evidence for the iris effect. The vast majority of subsequent research has simply not substantiated Lindzen’s iris hypothesis - it has not withstood the test of time. > [@FXMastermind](#): > > Certainly the hydrological cycle is connected to the sun, and we suspect strongly the maunder Minimum was due to the sun (even with the volcanic effect, volcanoes don’t influence climate for that long). > > I don’t trust the people who act like they know it all when it comes to nature. They are usually dead wrong. Like how right now we were supposed to be in this grand solar maximum, extreme danger from solar storms, the powwer grids at risk, and this prediction was from 2005. Dead wrong. [http://solarscience.msfc.nasa.gov/predict.shtml](http://solarscience.msfc.nasa.gov/predict.shtml) > [@](#): > > Predicting the behavior of a sunspot cycle is fairly reliable once the cycle is well underway (about 3 years after the minimum in sunspot number occurs [see Hathaway, Wilson, and Reichmann Solar Physics; 151, 177 (1994)]). Prior to that time the predictions are less reliable but nonetheless equally as important. Planning for satellite orbits and space missions often require knowledge of solar activity levels years in advance. BTW this slowdown on the activity by the sun is one of the reasons the contributing scientists to the IPCC to be more confident that the sun is not the main driver of the current warming. > **[Why is the IPCC AR5 so much more confident in human-caused global warming?](https://skepticalscience.com/ipcc-ar5-human-caused-global-warming-confidence.html)** > > Skeptical Science has launched a new feature, a collection of debunkings of the most popular myths about the IPCC. This post has been adapted into a rebuttal of the myth 'IPCC human-caused global warming attribution confidence is unfounded'. The... > [@](#): > > The IPCC elaborates further. > > What’s causing global warming: human greenhouse gas emissions. > > > [@](#): > > > > ``` > > "The best estimate of the human-induced contribution to warming is similar to the observed warming over this period ... The observed warming since 1951 can be attributed to the different natural and anthropogenic drivers and their contributions can now be quantified. Greenhouse gases contributed a global mean surface warming likely to be in the range of 0.5°C to 1.3 °C over the period 1951−2010, with the contributions from other anthropogenic forcings, including the cooling effect of aerosols, likely to be in the range of −0.6°C to 0.1°C." > > > > ``` > > What’s not causing global warming: natural external factors like solar activity, and natural internal factors like ocean cycles. > > > [@](#): > > > > ``` > > "The contribution from natural forcings is likely to be in the range of −0.1°C to 0.1°C, and from internal variability is likely to be in the range of −0.1°C to 0.1°C. > > > > ``` > > " > > We’ve observed about 0.6°C average global surface warming over the past 60 years. During that time, the IPCC best estimate is that greenhouse gases have caused about 0.9°C warming, which was partially offset by about 0.3°C cooling from human aerosol emissions. During that time, natural external factors had no net influence on global temperatures. For example, solar activity has been flat since 1950. ---
**Author:** ![Aji\_de\_Gallina](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aji_de_gallina/32/260_2.png) [@Aji\_de\_Gallina](https://boards.straightdope.com/u/Aji_de_Gallina)\ **Post date:** [September 28, 2013, 10:46pm UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002/463 "2013-09-28T22:46:07Z")
I’ll ammend my question once more to see if any AGWers finally commit or simply say nothing or simply do a wall-of-text or chain of links. Since it’s been mentioned several times in several AGW threads that **1998** is an evil, oil-industry-shill,denier-of-death, puppy-kicking cherry-picked year to show the pause, I wonder, for the fourth time on this thread I ask: What’s the non-Niña, non-big-volcano year that is OK? (i.e., the year that would show that temperatures have not increased or have decreased from THAT year to now and that would not be considered cherry-picked and that could be considered that start of a scientifically and statistically significant long-term trend) (BTW, the answer is a four-digit number, not unrelated quotes or even fully-related ones) ---
**Author:** ![Aji\_de\_Gallina](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aji_de_gallina/32/260_2.png) [@Aji\_de\_Gallina](https://boards.straightdope.com/u/Aji_de_Gallina)\ **Post date:** [September 28, 2013, 10:54pm UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002/464 "2013-09-28T22:54:14Z")
> [@Trinopus](#): > > One of the denialist arguments is an objection to spending billions of dollars to combat the effects of global warming. Now, as you say, sure, we can deal… It only costs the same billions of dollars they don’t want to spend. > > Do you figure sea-gates to preserve Venice are going to be cheap? > > Look at the costs of the proposed installations in New York City after the recent flooding. Not cheap. > > And, in any case, the fact that we can (at huge expense) deal with sea level rising cannot meaningfully be used as an argument that it isn’t happening. Venice is sinking, tht effect is much greater than sea-level rise. NYC was flooded by a particularly strong storm, not sea-level rise. The barriers you built to protect against normal, snail-speed sea-level rise are different from storm gates. Maybe it’s a case of TL,DR but I seem to unable to find anyone on this thread saying that seas weren’t rising ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [September 28, 2013, 11:07pm UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002/465 "2013-09-28T23:07:27Z")
> [@Aji\_de\_Gallina](#): > > I’ll ammend my question once more to see if any AGWers finally commit or simply say nothing or simply do a wall-of-text or chain of links. > > Since it’s been mentioned several times in several AGW threads that **1998** is an evil, oil-industry-shill,denier-of-death, puppy-kicking cherry-picked year to show the pause, I wonder, for the fourth time on this thread I ask: > > What’s the non-Niña, non-big-volcano year that is OK? (i.e., the year that would show that temperatures have not increased or have decreased from THAT year to now and that would not be considered cherry-picked and that could be considered that start of a scientifically and statistically significant long-term trend) > > (BTW, the answer is a four-digit number, not unrelated quotes or even fully-related ones) The walls of text are important, suffice to say, you are looking for a simple answer for a complex item; sucks, but you have to read. Stop looking for the red herring. ---
**Author:** ![Aji\_de\_Gallina](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aji_de_gallina/32/260_2.png) [@Aji\_de\_Gallina](https://boards.straightdope.com/u/Aji_de_Gallina)\ **Post date:** [September 28, 2013, 11:08pm UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002/466 "2013-09-28T23:08:18Z")
Triple post, but I don’t care. This phrase is the worst possible one in the actual IPPC AR5 SPM. “No best estimate for equilibrium climate sensitivity can now be given becuase of a lack of agreement on values across assessed lines of evidence and studies.” While I aplaud the honesty, if you can’t give \*\*the most important number \*\*of the whole AGW debate because you can’t agree on the number, then, sorry, it ain’t settled. It also states, “As one example, the rate of warming over the past 15 years (1998–2012;\*\* 0.05 \*\*[–0.05 to +0.15] °C per decade), which begins with a strong El Niño, is smaller than the rate calculated since 1951 (1951–2012; \*\*0.12 \*\*[0.08 to 0.14] °C per decade)”. (my bolding) Finally admiting some pause even if they say that it starts at a particularly warm point. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [September 28, 2013, 11:11pm UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002/467 "2013-09-28T23:11:17Z")
> [@Aji\_de\_Gallina](#): > > Triple post, but I don’t care. > > This phrase is the worst possible one in the actual IPPC AR5 SPM. > > “No best estimate for equilibrium climate sensitivity can now be given becuase of a lack of agreement on values across assessed lines of evidence and studies.” > > While I aplaud the honesty, if you can’t give \*\*the most important number \*\*of the whole AGW debate because you can’t agree on the number, then, sorry, it ain’t settled. Exactly the point made before by other researchers, so stop going for the strawmen. Yet in the body of the report, they do indicate a likely range. Again, not settled; but once again, the confidence on the most likely outcome is still reported. ---
**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\ **Post date:** [September 28, 2013, 11:44pm UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002/468 "2013-09-28T23:44:48Z")
> [@Aji\_de\_Gallina](#): > > . . . What’s the non-Niña, non-big-volcano year that is OK? (i.e., the year that would show that temperatures have not increased or have decreased from THAT year to now and that would not be considered cherry-picked and that could be considered that start of a scientifically and statistically significant long-term trend) . . . Every year is part of the overall data set. No one in their right mind is going to say, “1956 is the cut off: we can ignore all data prior to that.” We can assign greater weight to more recent years, as measurement techniques have improved, but if we found a list of temperatures in a set of Dead Sea Scrolls, we wouldn’t simply dismiss it. > [@Aji\_de\_Gallina](#): > > Venice is sinking, tht effect is much greater than sea-level rise. > > NYC was flooded by a particularly strong storm, not sea-level rise. The barriers you built to protect against normal, snail-speed sea-level rise are different from storm gates. > > Maybe it’s a case of TL,DR but I seem to unable to find anyone on this thread saying that seas weren’t rising Yet, in your very own post, you seek to belittle it, comparing other things to it as larger. You may not be denying it (although others certainly have, not in this thread, but in others) but you seem to be de-emphasizing it, minimizing it, and sidelining it. Venice is sinking and sea levels are rising. The combination is worse than either effect alone. ---
**Author:** ![Aji\_de\_Gallina](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aji_de_gallina/32/260_2.png) [@Aji\_de\_Gallina](https://boards.straightdope.com/u/Aji_de_Gallina)\ **Post date:** [September 29, 2013, 1:22am UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002/469 "2013-09-29T01:22:33Z")
I’ll ammend my question once more to see if any AGWers finally commit or simply say nothing or simply do a wall-of-text or chain of links. Since it’s been mentioned several times in several AGW threads that 1998 is an evil, oil-industry-shill,denier-of-death, puppy-kicking cherry-picked year to show the pause, I wonder, for the fifth time on this thread I ask: What’s the non-Niña, non-big-volcano year that is OK? (i.e., the year that would show that temperatures have not increased or have decreased from THAT year to now and that would not be considered cherry-picked and that could be considered that start of a scientifically and statistically significant long-term trend, not a cutoff point but the start of the trend. It’s really, really basic) (BTW, the answer is a four-digit number, not unrelated quotes or even fully-related ones) * * * And the ECS is? * * * > [@Trinopus](#): > > Yet, in your very own post, you seek to belittle it, comparing other things to it as larger. You may not be denying it (although others certainly have, not in this thread, but in others) but you seem to be de-emphasizing it, minimizing it, and sidelining it. Venice is sinking and sea levels are rising. The combination is worse than either effect alone. I’d love you to find one person on the whole SDMB that has denied even once, that sea levels are not rising. In the case of Venice, AGW-derived changes in the speed of the sea level rise, are a minimal part of the problem. Aqua Alta is a tide-related event, not a sea-level rise one. ---
**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\ **Post date:** [September 29, 2013, 2:15am UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002/470 "2013-09-29T02:15:11Z")
> [@Aji\_de\_Gallina](#): > > . . . I’d love you to find one person on the whole SDMB that has denied even once, that sea levels are not rising. . . . I didn’t specify the Straight Dope. [There are people denying sea level rise.](http://www.telegraph.co.uk/comment/columnists/christopherbooker/5067351/Rise-of-sea-levels-is-the-greatest-lie-ever-told.html) ---
**Author:** ![Aji\_de\_Gallina](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aji_de_gallina/32/260_2.png) [@Aji\_de\_Gallina](https://boards.straightdope.com/u/Aji_de_Gallina)\ **Post date:** [September 29, 2013, 2:32am UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002/471 "2013-09-29T02:32:06Z")
> [@Trinopus](#): > > I didn’t specify the Straight Dope. > > [There are people denying sea level rise.](http://www.telegraph.co.uk/comment/columnists/christopherbooker/5067351/Rise-of-sea-levels-is-the-greatest-lie-ever-told.html) There’s always someone somewhere saying something. ---
**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\ **Post date:** [September 29, 2013, 4:00am UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002/472 "2013-09-29T04:00:40Z")
> [@Aji\_de\_Gallina](#): > > There’s always someone somewhere saying something. It’s worth rebutting. ---
**Author:** ![FXMastermind](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fxmastermind/32/7289_2.png) [@FXMastermind](https://boards.straightdope.com/u/FXMastermind)\ **Post date:** [September 29, 2013, 4:01am UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002/473 "2013-09-29T04:01:19Z")
> [@Aji\_de\_Gallina](#): > > There’s always someone somewhere saying something. And somewhere someone disagreeing with them. ---
**Author:** ![FXMastermind](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fxmastermind/32/7289_2.png) [@FXMastermind](https://boards.straightdope.com/u/FXMastermind)\ **Post date:** [September 29, 2013, 4:10am UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002/474 "2013-09-29T04:10:00Z")
> [@Trinopus](#): > > You may not be denying it (although others certainly have, not in this thread, but in others) > [@Aji\_de\_Gallina](#): > > I’d love you to find one person on the whole SDMB that has denied even once, that sea levels are not rising. > [@Trinopus](#): > > I didn’t specify the Straight Dope. It just “seemed” like you did. ---
**Author:** ![brazil84](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@brazil84](https://boards.straightdope.com/u/brazil84)\ **Post date:** [September 29, 2013, 9:11am UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002/475 "2013-09-29T09:11:02Z")
> [@Trinopus](#): > > Every year is part of the overall data set. No one in their right mind is going to say, “1956 is the cut off: we can ignore all data prior to that.” We can assign greater weight to more recent years, as measurement techniques have improved, but if we found a list of temperatures in a set of Dead Sea Scrolls, we wouldn’t simply dismiss it. If I understand you correctly, it follows from your reasoning that it’s essentially impossible for global warming to pause. Even if global surface temperatures stay the same for the next 50 years, one can still say that they have risen, on average, since 1950. Even if global surface temperatures drop to the levels they were at in the 1970s and stay there for 100 years, that’s still warmer than temperatures in 1900. So by your reasoning, one still cannot say that global warming has paused. Basically, according to your reasoning, we would need to re-enter a Little Ice Age type condition for you to even consider the possibility that global warming has paused. > [@](#): > > Venice is sinking and sea levels are rising. The combination is worse than either effect alone. Do you agree that sea levels have been steadily rising since at least 1900? If so, do you happen to know what caused the sea level rise between 1900 and 1950? And did that cause go away or is it still having effects today? ---
**Author:** ![brazil84](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@brazil84](https://boards.straightdope.com/u/brazil84)\ **Post date:** [September 29, 2013, 2:51pm UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002/476 "2013-09-29T14:51:14Z")
> [@Aji\_de\_Gallina](#): > > I’ll ammend my question once more to see if any AGWers finally commit or simply say nothing or simply do a wall-of-text or chain of links. > > Since it’s been mentioned several times in several AGW threads that 1998 is an evil, oil-industry-shill,denier-of-death, puppy-kicking cherry-picked year to show the pause, I wonder, for the fifth time on this thread I ask: > > What’s the non-Niña, non-big-volcano year that is OK? By the way, if the question on the table is whether global warming has paused, it is completely reasonable to look at how many years have passed since there has been a record high global surface temperature for the year. In fact, there was a post at Realclimate about 5 years ago called [What the IPCC Models Really Say](http://www.realclimate.org/index.php/archives/2008/05/what-the-ipcc-models-really-say/). The post calculated predicted wait times for a new temperature record based on IPCC Models. Just eyeballing the chart, the chances of waiting 15 years or more for a new temperature record are less than 1%. So based on one of the most prominent warmist web sites, it’s totally reasonable to use 1998 as a reference point. At least going by what they were saying 5 years ago. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [September 29, 2013, 3:14pm UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002/477 "2013-09-29T15:14:32Z")
> [@brazil84](#): > > If I understand you correctly, it follows from your reasoning that it’s essentially impossible for global warming to pause. Even if global surface temperatures stay the same for the next 50 years, one can still say that they have risen, on average, since 1950. > > Even if global surface temperatures drop to the levels they were at in the 1970s and stay there for 100 years, that’s still warmer than temperatures in 1900. So by your reasoning, one still cannot say that global warming has paused. > > Basically, according to your reasoning, we would need to re-enter a Little Ice Age type condition for you to even consider the possibility that global warming has paused. Basically this is ignoring was was reported back in 2008 What it is demanded is less than a complete falsification, but it does apply also to the so called pause. (BRW contrarians continue to ignore the oceans to get a misleading point going on.) [http://www.realclimate.org/index.php...ls-really-say/](http://www.realclimate.org/index.php...ls-really-say/) > [@](#): > > What the IPCC models really say > > Over the last couple of months there has been much blog-viating about what the models used in the IPCC 4th Assessment Report (AR4) do and do not predict about natural variability in the presence of a long-term greenhouse gas related trend. Unfortunately, much of the discussion has been based on graphics, energy-balance models and descriptions of what the forced component is, rather than the full ensemble from the coupled models. That has lead to some rather excitable but ill-informed buzz about very short time scale tendencies. We have already discussed how short term analysis of the data can be misleading, and we have previously commented on the use of the uncertainty in the ensemble mean being confused with the envelope of possible trajectories (here). The actual model outputs have been available for a long time, and it is somewhat surprising that no-one has looked specifically at it given the attention the subject has garnered. So in this post we will examine directly what the individual model simulations actually show. > First, what does the spread of simulations look like? The following figure plots the global mean temperature anomaly for 55 individual realizations of the 20th Century and their continuation for the 21st Century following the SRES A1B scenario. For our purposes this scenario is close enough to the actual forcings over recent years for it to be a valid approximation to the simulations up to the present and probable future. The equal weighted ensemble mean is plotted on top. This isn’t quite what IPCC plots (since they average over single model ensembles before averaging across models) but in this case the difference is minor. > > It should be clear from the above the plot that the long term trend (the global warming signal) is robust, but it is equally obvious that the short term behaviour of any individual realisation is not. This is the impact of the uncorrelated stochastic variability (weather!) in the models that is associated with interannual and interdecadal modes in the models – these can be associated with tropical Pacific variability or fluctuations in the ocean circulation for instance. > [@](#): > > Over the short 8 year period, the regressions range from -0.23ºC/dec to 0.61ºC/dec. Note that this is over a period with no volcanoes, and so the variation is predominantly internal (some models have solar cycle variability included which will make a small difference). The model with the largest trend has a range of -0.21 to 0.61ºC/dec in 4 different realisations, confirming the role of internal variability. 9 simulations out of 55 have negative trends over the period. > > Over the longer period, the distribution becomes tighter, and the range is reduced to -0.04 to 0.42ºC/dec. Note that even for a 20 year period, there is one realisation that has a negative trend. For that model, the 5 different realisations give a range of trends of -0.04 to 0.19ºC/dec. > > Therefore: > > ``` > [ul] > > ``` > > [li]Claims that GCMs project monotonic rises in temperature with increasing greenhouse gases are not valid. Natural variability does not disappear because there is a long term trend. The ensemble mean is monotonically increasing in the absence of large volcanoes, but this is the forced component of climate change, not a single realisation or anything that could happen in the real world.[/li][li] Claims that a negative observed trend over the last 8 years would be inconsistent with the models cannot be supported. Similar claims that the IPCC projection of about 0.2ºC/dec over the next few decades would be falsified with such an observation are equally bogus.[/li][li] Over a twenty year period, you would be on stronger ground in arguing that a negative trend would be outside the 95% confidence limits of the expected trend (the one model run in the above ensemble suggests that would only happen ~2% of the time)[/li][/ul] That made a commenter mention how to falsify this, and it applies also to what a real pause that would give pause 🙂 to the climatologists would look like: > [@](#): > > So, to give one possibility, if the global mean temperature from 2050 to 2070 would end up being lower than the 1950 to 1970 global mean temperature, would that be enough to falsify the IPCC projections, assuming no volcanic eruptions, cometary impacts, etc.? > > [Response: …and that the trajectories of the GHGs and aerosols looked something like this scenario. Yes. - gavin] Essentially, if there had been a real pause from the warming part caused by human activities, temperatures like the 50s-70s need to be seen and then remain there for 20 years or so to get a trend. The reason why this chase of a single year to start counting is a red herring is that the observed temperatures have not reached the previous temperatures when nature was the one doing warming or cooling, indeed more than one factor is needed to begin to start to claim that the temperature record is showing a pause or that our contributions to the warming should be dismissed. As pointed before, it takes more than a single cherry picked year, the influence of other forcings and feedbacks needs to continuously be looked at. The increase in temperature caused by human emissions began to clearly overwhelm the natural ones (on the surface temperatures) from the 50’s-60’s. But the human activities began to influence the system early on. > [@brazil84](#): > > Do you agree that sea levels have been steadily rising since at least 1900? If so, do you happen to know what caused the sea level rise between 1900 and 1950? And did that cause go away or is it still having effects today? [http://planetearth.nerc.ac.uk/news/story.aspx?id=551](http://planetearth.nerc.ac.uk/news/story.aspx?id=551) > [@](#): > > And during the twentieth century, only four centimetres of the observed 18 centimetre sea-level rise is down to natural variation. The remaining 14 centimetres is a direct result of human activities. > > They also found that before 1800 any change in sea level can be explained by natural variation, caused by phenomena like changes in the amount of heat reaching the Earth from the Sun or the cooling effects of volcanic eruptions. > > The researchers report that a large part of sea-level rise after 1800 is a result of an increase in atmospheric carbon dioxide (CO2) from deforestation and then later, burning fossil fuels from the start of the Industrial Revolution. > Shocking > > ‘It’s shocking that so much of the sea-level rise we saw in the twentieth century is because of what we’re doing. What’s surprising is if we hadn’t put carbon dioxide (CO2) into the atmosphere, sea level would have risen by only four centimetres last century,’ says Dr Svetlana Jevrejeva from the Proudman Oceanographic Laboratory in Liverpool. No, the cause has not gone away, it is mostly us. ---
**Author:** ![doorhinge](https://avatars.discourse-cdn.com/v4/letter/d/a5b964/32.png) [@doorhinge](https://boards.straightdope.com/u/doorhinge)\ **Post date:** [September 29, 2013, 3:24pm UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002/478 "2013-09-29T15:24:36Z")
> [@brazil84](#): > > By the way, if the question on the table is whether global warming has paused, it is completely reasonable to look at how many years have passed since there has been a record high global surface temperature for the year. (I shortened your post) It’s also totally and completely reasonable to wait for the new-and-as-of-yet-unvetted IPCC report to be officially released AND vetted by ANY independent group that is given access to the man-made inputs and software used for the IPCC Modeling. Or the IPCC can refuse to share it’s data and processes with those it deems unworthy of questioning MMCO2GW, in which case, the doubts about the validity of the IPCC “claims” will continue. ---
**Author:** ![brazil84](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@brazil84](https://boards.straightdope.com/u/brazil84)\ **Post date:** [September 29, 2013, 3:36pm UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002/479 "2013-09-29T15:36:08Z")
> [@doorhinge](#): > > (I shortened your post) > > It’s also totally and completely reasonable to wait for the new-and-as-of-yet-unvetted IPCC report to be officially released AND vetted by ANY independent group that is given access to the man-made inputs and software used for the IPCC Modeling. Yes, I have made similar points in the past. Every last paper relied on by the IPCC; every last scrap of data; every last computer program; etc. should be made 100% open to public scrutiny, including hostile scrutiny. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [September 29, 2013, 3:37pm UTC](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002/480 "2013-09-29T15:37:15Z")
> [@brazil84](#): > > By the way, if the question on the table is whether global warming has paused, it is completely reasonable to look at how many years have passed since there has been a record high global surface temperature for the year. > > In fact, there was a post at Realclimate about 5 years ago called [What the IPCC Models Really Say](http://www.realclimate.org/index.php/archives/2008/05/what-the-ipcc-models-really-say/). > > The post calculated predicted wait times for a new temperature record based on IPCC Models. Just eyeballing the chart, the chances of waiting 15 years or more for a new temperature record are less than 1%. Why we should eye ball it when the cite explains? > [@](#): > > A related question that comes up is how often we should expect a global mean temperature record to be broken. This too is a function of the natural variability (the smaller it is, the sooner you expect a new record). We can examine the individual model runs to look at the distribution. There is one wrinkle here though which relates to the uncertainty in the observations. For instance, while the GISTEMP series has 2005 being slightly warmer than 1998, that is not the case in the HadCRU data. So what we are really interested in is the waiting time to the next unambiguous record i.e. a record that is at least 0.1ºC warmer than the previous one (so that it would be clear in all observational datasets). That is obviously going to take a longer time. > > This figure shows the cumulative distribution of waiting times for new records in the models starting from 1990 and going to 2030. The curves should be read as the percentage of new records that you would see if you waited X years. The two curves are for a new record of any size (black) and for an unambiguous record (\> 0.1ºC above the previous, red). The main result is that 95% of the time, a new record will be seen within 8 years, but that for an unambiguous record, you need to wait for 18 years to have a similar confidence. As I mentioned above, this result is dependent on the magnitude of natural variability which varies over the different models. Thus the real world expectation would not be exactly what is seen here, but this is probably reasonably indicative. > [@brazil84](#): > > So based on one of the most prominent warmist web sites, it’s totally reasonable to use 1998 as a reference point. At least going by what they were saying 5 years ago. No, as the commentary by the author explained you also need to see the warming added by human activities to go away and observe temperatures to remain like the ones seen in the 50s-70s for a significant amount of time. One could go farther back than that, but to keep it simple it is easier to understand that the sun activity and the surface temperatures did go to in different directions around that period and now we are mostly driving the increase in temperature. [Previous page](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002.md?page=23) [Next page](https://boards.straightdope.com/t/leaked-ipcc-report-90-confidence-in-agw-is-now-95-and-sea-level-will-rise/667002.md?page=25)