chubbs

According to Citicorp reducing GHG is the low cost option. Clicking through to the underlying report provides a wealth of information on energy and climate economics.

http://www.theguardian.com/environment/climate-consensus-97-per-cent/2015/aug/31/citi-report-slowing-global-warming-would-save-tens-of-trillions-of-dollars

April 2015 snowpack in the Sierra Nevada was 5% of normal - unprecedented in snowpack record and 500 year tree-ring proxy.

http://www.nature.com/articles/nclimate2809.epdf?referrer_access_token=8U88K0Q

However, there are shorter periods, throughout the data record, where the two diverge due to the varying regional nature of climate change. Due to RATPAC's lack of spatial coverage over much of the Pacific and Southern Oceans, it may fail to pick up these regional warming differentials. Notice how the MSU/AMSU data reveals reduced warming in the very areas where RATPAC lacks coverage.

That is why they grid the radiosonde data. The radiosonde data lines up very well with the re-analysis data even over short time periods. You wouldn't get such close agreement if the radiosondes were missing important regional temperature trends.

Here is a chart from Christy's upper-air section in the 2014 BAMS state-of-the-climate. He uses RATPAC data and shows that it agrees very well with other upper-air datasets.

http://www.ncdc.noaa.gov/bams-state-of-the-climate/

Here is a comment on the recent Jakobshavn glacier at Nevins.  

 

And a Washington Post article that includes quotes from Jason Box and Richard Alley

 

And last, but certainly not least, is the NASA Earth Observatory post.

 

There is a lot of uncertainty in the estimates of the size of the calving event, but this size of event will have a big impact on the net mass balance analysis for the 2015 melt season.  Many estimates put it at around 125 km2 in area, so if the glacier is 1,000 meters thick at the calving site, that would mean a loss of roughly 125 Gtons of mass in four days.  And the calving goes on all year, unlike the surface melt.

Nevins blog corrected their initial estimate to 12.5km2 down an order of magnitude from the original. Still a very significant event. With the calving, the glacier has retreated roughly 600m since last years max retreat (max retreat is usually in September) indicating that net mass losses continue in the glacier drainage.

2012 - 2019/20, 2013 - not in our lifetime - but I would have taken 2016-2020 if it was offered. Just eyeballing the trend line, looks like 2013 is more likely to occur than 2012 up until roughly 2018.

That's still hyperbole....

 

1. Why would CO2 double in 40 years?

 

2. Even if it did, the claim is still outlandish. The West Side Highway isn't going to be underwater by the time CO2 is doubled even a few more decades beyond that.

 

The semanatics game distracts from the general point...a point where I was also blaming media for taking these talking points and promoting them to the public.

See the interviewers summary of the discussion below. It was a very informal discussion. I don't sense a desire to mislead or exaggerate on Hanson's part.  We have had posts alleging that Hanson was to blame for climate denial by overstating climate impacts. After a little investigation we haven't found too many examples of exaggeration - just some bad reporting perhaps. On the other hand Anthony Watts  plays fast and loose with the truth about Hanson and this becomes an internet myth. This gets repeated over and over again in the denier blogosphere. Our posters pick it up and there you are.  

Bob Reiss reports the conversation as follows:

 "When I interviewe­­d James Hansen I asked him to speculate on what the view outside his office window could look like in 40 years with doubled CO2. I'd been trying to think of a way to discuss the greenhouse effect in a way that would make sense to average readers. I wasn't asking for hard scientific studies. It wasn't an academic interview. It was a discussion with a kind and thoughtful man who answered the question. You can find the descriptio­­n in two of my books, most recently The Coming Storm."

The misquote was for the year...some though he meant 2008...but it was really more like 40 years beyond that time (of 1988), which would be closer to 2030 (the year I reported in my post).

 

Regardless, it is still that type of hyperbole which was being criticized.

According to skeptical science this is an internet myth that has been propagated by Anthony Watts. Hanson's original statement needs to be placed in the proper context. He was asked to speculate in a 1988 interview what the view from his office might look like in 40 years if CO2 doubled. The interviewer published Hanson's  response in a book 10 years later, but in a subsequent interview for Salon the interviewer left out the doubled CO2 and shortened the time to 20 years. A key learning over the past few days - don't believe what you read on the internet about climate scientists.

http://www.skepticalscience.com/Examining-Hansens-prediction-about-the-West-Side-Highway.html

There are some extremely alarming things well within the threshold of scientific possibility with climate change.  While abrupt methane feedback or sudden sea level rise is not likely in the next 100 years, there is some evidence to suggest there is a modest possibility either could actually occur.  Even if that possibility is 2%, should climate scientists just sweep it under the rug?  I just don't understand that logic.  Why bury earth changing consequences of climate change because they are unlikely or cause "scary" PR?  Look at the WAIS.  No more than 10 years ago scientists that suggested inevitable collapse were heavily mocked and now that thought is becoming mainstream in literature.

 

Some on this board treat many of these scientifically feasible CAGW events as alarmist propaganda while other treat them like an absolute certainty.  Both are wrong, IMO.

Yes its silly to blame scientists for their communication limitations - that is what politicians and PR experts are for. Climate change happens over very long time frames and there is large uncertainty. Scientists who have a little clearer vision into the future have a huge communication challenge that they are not prepared for. The potential WAIS collapse is a good example.The impact is so large that it is difficult for most to fathom and our current science cannot provide any timing estimate. So messaging is difficult. No matter what is said most people find it too alarming to contemplate or far enough in the future to ignore.

The flip side is effective communication by deniers/skeptics. Their job is much easier since they mainly aim to confuse and discredit.  The key components are a few simple talking points repeated in a consistent and reinforcing manner combined with villains that many can identify with (liberals, lying scientists, big government etc).

I agree, but his hyperbolic tone with the media is not without consequences. The discussion was hinging on the connection between denialism and alarmist rhetoric. While saying Hansen is to blame is surely hyperbolic in it's own right, exonerating failed alarmist predictions is also not completely accurate IMHO.

 

You are still trying to tie in his peer reviewed official work, which is generally good. If you read most of his testimonies they are pretty good too...but again, where do you think the media and headliners get those 2-4C predictions from 1986 or the 10 meter SLR? They get it from his testimony. His west side highway under water while talking to the author of a book. That is all stuff the media grabs and the public hears about.

 

As mentioned above, I think the media is more to blame than hyperbole from Hansen. However, I generally still think that scientists participating in activism can compromise the objective image of the science they represent.

I can see where it would be misleading if snippets were taken out of context. These posts stimulated me to read portions of his 1981 paper. While portions are dated and missed the mark, many of his 1981 predictions are  very accurate. His discussion of WAIS could have been written today but was way ahead of his time. It would be the height of irony if his warning of a WAIS collapse turns out to be correct - and yet leads to inaction per the theory outlined above

Hansen's peer reviewed stuff is mostly good. (as are most other scientist's peer reviewed work)

 

It is his public activism and his hyperbole in outlets such as senate testimony or just to the media in general are what has been counterproductive IMHO. An example was his 1986 testimony where he warned of a 2 to 4 degree rise in temps in the next 20 years. Or his more recent claims of 5-10 meter SLR by 2100 (even suggesting up to 25m to senate in 2007)...while the latter isn't verifiable yet of course, it is an outlandish claim given the rest of the literature. His account of NYC's west side highway being underwater due to SLR by 2030. His predictions for strong or super el Ninos (one was as recently as 2011 when everyone else was predicting a La Nina).

 

All of that is stuff the public/media hears and latches onto. It's unfortunate it has to be that way, but only climate hobbyists and other scientists actually read the literature. The rest only read the media headlines or the hyperbole directly from the scientist's mouth. Hansen has been an activist and while I don't doubt his sincerity in his cause, it does create a less than objective image for the science he represents. People like us who follow climate rigorously can just say "well ignore that junk and focus on the literature"....but that can't be said of most of the population.

 

I don't blame all of it on Hansen of course...I think the media has been the worst offender.

I wasn't familiar with Hanson's testimony so I googled and came up with the document linked below based on his 2007 testimony. Its not nearly as bad as you suggest. Its very scientific in tone - unlikely to cause a reaction in anyone except those already of a skeptical bent. His temperature projections are close to consensus. Some of his effect projections are high end but I wouldn't call them outlandish. He says SLR could be 2 meters in 100 years due to mainly to WAIS.. At the time this was quite aggressive.Since then however much more has been published on ice sheet instability and WAIS in particular. His projection is still high end but it is moving into the range of possible outcomes.

Blaming Hanson for climate denial/skepticism is a big exaggeration. I discuss climate with many skeptics. They mainly stick close to the denier talking points:: the data is fudged, the scientists are in cahoots to get grant money,  temperatures haven't increased in 18 years, climate has always varied etc.. No one ever mentions Jim Hanson. For the most part people believe the story lines that fit in with their preconceived views.

http://arxiv.org/abs/0706.3720

James Hansen has done more harm to climate science's public perception in the U.S. more than any other person. His exaggerated predictions throughout the years that have not come true has contributed to the high % of denialism in this country.

For that reason the harm he has done heavily outways the good. And he has done some good things.

Dr. Hansen is one of the reasons I've become so outspoken about cool, objective thought & language centered around climate change. When discussing concerns & dangers excited, hyped, exaggerated language (when unknown) only creates damage when there is no fruition.

Remember that perception is reality to the public.

That is a ridiculous assertion.  These predictions made by Hanson in a 1981 paper before global warming was even an issue have proven to be quite accurate. Unfortunately we didn't make much use of them.

Hansen, J., D. Johnson, A. Lacis, S. Lebedeff, P. Lee, D. Rind, and G. Russell, 1981:

Climate impact of increasing atmospheric carbon dioxide.

Science, 213, 957-966, doi:10.1126/science.213.4511.957.

The global temperature rose 0.2°C between the middle 1960s and 1980, yielding a warming of 0.4°C in the past century. This temperature increase is consistent with the calculated effect due to measured increases of atmospheric carbon dioxide. Variations of volcanic aerosols and possibly solar luminosity appear to be primary causes of observed fluctuations about the mean trend of increasing temperature. It is shown that the anthropogenic carbon dioxide warming should emerge from the noise level of natural climate variability by the end of the century, and there is a high probability of warming in the 1980s. Potential effects on climate in the 21st century include the creation of drought-prone regions in North America and central Asia as part of a shifting of climatic zones, erosion of the West Antarctic ice sheet with a consequent worldwide rise in sea level, and opening of the fabled Northwest Passage.

You can argue it if you can prove that as much as half of the warming since that time was not anthropogenic.

 

I don't find those arguments very convincing, mostly due to empirical energy budget papers....but you can certainly believe the temperature record and also believe an ECS under 1.5C.

That's the rub though no one can identify a natural factor that fits the long-term pattern of warming as well as AGW.

No. Rather than debate / engage the science presented in the papers, you / others immediately rushed to attack the credibility of a journal which hosted one of the studies I posted. It's apparent that many here are not willing to even entertain scientific papers that deviate from their current mindset. That mindset is further evidenced in your reply above: you assume that low sensitivity papers are of low quality without having thoroughly examined the studies. It's pointless to post studies if no one intends to actually critique/address them for the science.

I looked at the abstracts and didn't see anything that makes me want to read further.  Why should I go to the trouble of reading and critiquing obscure papers. Would be much easier if you summarized the key science in the papers that supports low sensitivity.

The final report summarizing the recent Ringberg ECS workshop has been posted. The report is not earthshaking. The main recommendation is to focus research on the science needed to justify ECS below 2C and above 4C. The unstated implication is that ECS between 2 and 4C are reasonable in the absence of new science..

 http://www.mpimet.mpg.de/en/science/the-atmosphere-in-the-earth-system/ringberg-workshop/ringberg-2014.html

Well you can easily move that number by 25% in either direction when you use the method you just did depending on your starting and end points.

 Sure I just used 1979 because the NASA GHG forcing series starts then on the website. However we've been locked into a relatively steady T increase since around 1970. The rate of temperature increase per unit of forcing was lower before 1970 and particularly before 1900. That is one reason the energy balance ECS estimates that go back that far are lower.

This also ignores any potential rapidly ampliying feedbacks such as albedo, methane, etc.  We can't assume that these feedbacks will be increasing linearly since the paleoclimatic evidence suggests otherwise.  I agree a hybrid approach should be taken when determining ECS, but I think several here have incorrectly dismissed ECS amounts of >3C due to static boundary condition empirical studies.

Yes.I do not advocate estimating ECS or even TCR this way. It is just useful in producing mileposts to check progress. If temperature trends diverge from recent history then there is evidence for a change in behavior.

It's a bit dangerous to estimate TCR that way unless you use an energy budget equation with it....because you are using relatively short time scales that can be affected by internal variability (an energy budget equation can offset some of that problem). The 1979-2015 period also includes two major volcanic eruptions in the first 12 years, so even an energy budget equation would be difficult since you'd have to account for those somehow.

 Sure it could be off, but the longer we maintain a relatively steady warming the more likely the the middle estimates are correct.

Agreed.  And for the most part they still fall in the 2.2-3C range for ECS.

 

The whole debate about ECS becomes a bit more muddied when one considers increasing feedbacks ala methane, albedo drops.  To date these feedbacks have been likely muted, but tipping points will make a generally linear temperature rise more exponential in the future.

GHG forcing has increased by 0.66% per year since 1979, this rate of increase produces a doubling in a little over 100 years.This makes it easy to do the math when relating temperature to forcing.  Surface temperature has increased by 0.0158 per year on GISS in the same period. Ignoring aerosals, other non-GHG forcings and natural variability, this gives a very rough TCR estimate of 1.6C, which is consistent with a mid-range ECS.

GHG forcing from here: http://www.esrl.noaa.gov/gmd/aggi/aggi.html

The bold is where you make a leap...that's only half of what determines the weight of the ratio. Remember that the temperature at which evaporation occurs determines the initial O^16/O^18 ratio before the precipitation process occurs..polar SSTs are usually too cold to sufficiently evaporate O^18 at the ratio observed in the cores. A good portion of the O^18 that precipitates over the poles has a tropical/subtropical source. These isotopes are subsequently rained out during the condensation process and relatively few are transported to the poles. So, warmer tropical/mid-latitude oceans will lead to more O^18 being transported poleward.

For all intents and purposes, ice cores are hemispheric SST proxies.

You are underestimating the importance of condensation vs evaporation. Here is a plot of current mean annual temperature vs isotope ratio for samples collected at different locations in Antarctica and Greenland. Note the Antarctic data is Deuterium and Greenland is O18. There is a very good correlation between isotope ratio in current snow samples and the local mean annual temperature.  O18 is removed preferentially over the  lowest and warmest portions of the ice sheet so by the time water vapor reaches the highest and coldest locations it has been significantly depleted in O18.

Lets go back to the original point. The lines in this plot, or similar, are used to convert the measured isotope ratio in the ice core to a local temperature value. So when the paper that started this discussion reports ice core temperature variation of 0.97C it doesn't mean that the mean global temperature has varied by 0.97C.  Similarly when an ice core shows a temperature change of 10C in a short period of time during the Younger Dryas it doesn't mean that the mean global temperature varied by 10C - obviously the oceans can't warm or cool that quickly.

However I do agree that ice cores are good proxies for temperature change over broad regions. There had to be large changes in NH jet stream configuration and climate during the Younger Dryas and similar periods with rapid variation in ice core temperature.

I think 2 different concepts are being argued over, especially the second point:

 

1.) O^18 / O^16 ratio is indicative of changes in global SST / change in global ice volume --> relate to global surface Temps, although not directly 

2.) O^18 / O^16 ratio corresponds to temperature of snow when the snow fell, which isn't necessarily where the snow fell .. 

 Yes The ice core records are broadly indicative of  regional and hemispheric temperatures but are most closely related to cloud temperatures when snow condenses. The measured oxygen isotope ratios in the core are usually converted to temperatures by collecting current ice sheet snow and temperature data  and correlating the local isotope ratios and temperatures

I'm sick of rehashing preschool science to you. Arguing that the O^18/^16 ratios are regionally representative is analogous to arguing that CO^2 is not well mixed, or that the dust concentration in the ice pack is regional.

http://www.econ.yale.edu/~nordhaus/homepage/documents/icecore_review.pdf

http://eo.ucar.edu/staff/rrussell/climate/paleoclimate/ice_core_proxy_records.html

 

Quotes from p6 of your first reference below. It is very clear that the ice core temperatures are regional.

 "As these water molecules are evaporated, primarily from the oceans, the lighter molecules, those having fewer neutrons, are preferentially evaporated over the heavier ones, due to a slight difference in vapor pressure caused by the extra neutrons. This causes the vapor to be depleted in heavy molecules but enriched in lighter ones. As the air mass cools and condensation occurs, the heavier molecules preferentially condense due to the same principle The condensation is then assumed to fall out of the cloud as precipitation. Thus, the oxygen isotopic ratio of rain and snow is strongly related to condensatIf the temperature of the air mass should continue to fall, the condensation will contain decreasing concentrations of the heavy molecules, resulting in a depletion of 18O relative to precipitation that condensed in a warmer environmention temperature. . ....In the context of ice cores, this technique allows scientists to estimate the actual air temperature of condensation when the snow fell".

I agree that the paper is fatally flawed, but too many people misunderstand what ice core proxies are actually measuring. The isotope ratios used to reconstruct temperature are governed by processes over the tropical, subtropical, and extratropical oceans, not over the Arctic. The heavier O^3 isotopes are mostly rained out by 50-60N, in fact.

The isotope ratios within ice cores are, for all intents and purposes, hemispheric SST proxies. The Arctic cores depict SSTs over the Northern Hemisphere, while the Antarctic cores depict SSTs over the Southern Hemisphere.

No the temperatures are regional. Changes in isotope ratio during vapor transport are more important than changes at the source. The heavier isotopes are preferentially removed as water vapor is transported, lifted, cooled and percipitated. A local calibration is performed to relate isotope concentration to temperature on the ice sheet. Note that a part of the variation in the isotope record is due to changes in moisture transport to the ice sheet and not temperature.

The article is rubbish research.  It's published in Energy & Environment, the pal-reviewed denialist journal, and it's methodology is fatally flawed.  The author used a cherry-picked portion of ice core records, performed a number of questionable statistical operations, and conflates his finding to represent the entire globe.  

 

The Denier Choir has posted this on various forums, and will certainly continue to do so, but the kindest review one can make of this paper is that it represents the views of one of the 3%ers.

You can tell by reading the abstract that the paper is junk science which that journal has a habit of producing. The abstract  equates ice core variability to global variability. There are several problems with that.  First variation in the arctic is much larger than the tropics. Second variability in one region is not the same as global variability. . Regional variability can arise from variation in mean wind or ocean circulation. However circulation variability balances out over the globe. Large variation in global mean temperature requires a change in forcing or a major change in ocean circulation and there is no evidence for that in the holocene. Secondly the paper doesn't identify any natural cause for the global warming over the past 150 years. Natural variability can be warm or cool. To conclude that natural variability has been a major factor in warming a natural warming effect or combination of effects comparable in magnitude to the over 2.5 W/m2 of man-made GHG forcing would have to be identified.

Even if climate change ranked higher on the list of concerns for the general public, the technology problem would still

be there. It's going to take a much more concerted effort on the part of the global community to find a viable replacement

for fossil fuels as our primary energy source. There is just nothing in the near term which can meet the majority of

the worlds energy needs and significantly reduce emissions. People relate to money so a serious push in R&D 

spending would have to be marketed to the public as a way that it's going to save them money in some tangible manner.

You are right there is no short-term easy fix. However today's actions will determine whether we can make a significant move away from fossil fuels in the longer term. The best way of reducing the cost of renewable energy sources is to increase deployment to benefit from cost learning curve and economies of scale. A carbon tax or carbon credits would move us in the right direction.