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Study Adds to Arctic Warming, Extreme Weather Debate

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A new study for the first time found links between the rapid loss of snow and sea ice cover in the Arctic and a recent spate of exceptional extreme heat events in North America, Europe, and Asia. The study adds to the evidence showing that the free-fall in summer sea ice extent and even sharper decline in spring snow cover in the Northern Hemisphere is reverberating throughout the atmosphere, making extreme events more likely to occur.

The study, published Sunday in the journal Nature Climate Change, is the first to find correlations between rapid Arctic warming and extreme summer weather events, since previous research had focused on the links between Arctic warming and fall and winter weather patterns.

A giant panda was playing with ice cubes in Chengdu, China to cool off from the summer heat in August 2011. 
Credit: Zhongjun Liu

While the study adds to the body of evidence pointing to the outsized role the Arctic is playing in shaping weather patterns, it won't end the debate within the scientific community over whether and how what is happening in the Far North could be having such far-reaching impacts.

There is virtually no controversy among climate scientists and meteorologists that massive changes have occurred in the Arctic environment during the past three decades, and that those changes are largely due to manmade greenhouse gas emissions.

Since the 1980s, Arctic sea ice extent has dropped at a rate of about 8 percent per decade during September, which is when the sea ice cover reaches its annual minimum. A record minimum was set in 2012. For a size comparison, consider that the area of summer sea ice lost since the 1980s would cover about 40 percent of the continental U.S., the study said.

Spring snow cover extent loss during June has dropped even more precipitously than sea ice cover, the study found, at a rate of about 18 percent per decade since 1979.

The reasons why the Arctic is warming so quickly — a phenomenon known as Arctic amplification — has to do with factors that are unique to the Arctic environment, involving feedbacks between sea ice, snow, water vapor and clouds. As the area warms in response to manmade greenhouse gases, melting ice and snow allow exposed land and water to absorb more of the Sun’s heat, which melts more ice and snow, and so on. A relatively small amount of initial warming can be greatly magnified in the Far North.

It is also widely agreed that the world has seen a spate of extreme heat events in recent years, such as the 2011 Texas heat wave and drought and the deadly 2010 heat wave in Russia, and that global warming made some of these events more likely to occur and more severe.

But scientific consensus breaks down when it comes to the issue of whether Arctic warming is altering weather patterns in the northern midlatitudes, stacking the deck in favor of extreme weather events.

On one side of the issue are some meteorologists and climate scientists who in their studies have found correlations between the vanishing Arctic sea ice and snow cover (collectively known as the cryosphere) and weather patterns that can lead to extreme weather events. 

On the other side are other climate scientists and meteorologists who, while convinced that manmade climate change is having profound impacts on the planet, don’t yet see clear physical science evidence showing that Arctic warming is changing the already chaotic nature of weather patterns, and leading to extreme weather events.

James Overland, a researcher at the National Oceanic and Atmospheric Administration (NOAA), said the split in the scientific community is an unusual one.

“The skeptics (of the link between Arctic warming and extreme weather events) actually tend to be some of the real top midlatitude dynamics climate scientists,” Overland said in an interview.  “They’re looking at the chaos of the long-wave atmospheric pattern and it’s really hard to see why modest additional forcing in the Arctic can overwhelm all the energy that’s in that chaotic pattern.”

It’s all in the jet stream

The case for a connection between Arctic warming and summertime extreme weather events rests on the Arctic’s crucial role as a pacesetter and shapemaker of the jet stream, the powerful ribbon of upper level winds that steer weather systems from west to east across the Northern Hemisphere.

Because the temperature contrast between the frigid Arctic and the milder mid-latitudes is what drives the powerful jet stream winds that guide weather systems, what happens in the Arctic is bound to have some sort of influence on the world’s weather.


NASA computer model animation showing the evolution of a large dip in the jet stream.

The new study, along with other previously published research, showed that the decline in sea ice and snow cover has slowed the west-to-easterly component of the jet stream, thereby enhancing the north-to-south waviness of the jet, which leads to the creation of more stagnant or “blocked” weather patterns. In addition, the new study found an association between sea ice and snow cover decline and a northward shift in the jet stream, which allows more warm air to move into the U.S. and Europe during the summer.

Paradoxically, other studies, including work by the same team of researchers, has shown that Arctic warming can actually enhance cold weather extremes in the U.S. and Europe during the winter.

Jennifer Francis, a meteorologist at Rutgers University, co-author of the new study, and the most prominent proponent of the hypothesis that Arctic warming is leading to more extreme weather events, told Climate Central that this study adds further evidence to the growing body of research supporting her team’s conclusions.

“While an observational study cannot pin down the mechanistic cause of the response, our results show a strong relationship between ice and snow losses during summer with heat waves in mid-latitude continents where billions of people are affected,” Francis said in an email conversation.

Observations show a northward shift in the jet stream is related to the smaller temperature difference between the equator and the poles.
Click image to enlarge. Credit: Climate Central.

But the lack of statistically significant results and, more important, the absence of evidence pointing to a smoking gun — a physical mechanism in the climate system that ties Arctic changes to extreme events — has left many top climate researchers unconvinced that rapid Arctic warming is a major player in causing extreme weather events outside of the Arctic itself.

The result, some of these scientists told Climate Central, is a series of hypotheses that have not yet been fully tested.

“I would have more confidence in the linkage being ‘real’ if there was a well-understood and proven mechanism to support the correlations,” James Screen, a climate researcher at the University of Exeter in the U.K., said in an email. “The arguments presented are plausible, but in my opinion the evidence presented is far from conclusive (to put it mildly)."

Kevin Trenberth, a senior scientist at the National Center for Atmospheric Research in Boulder, Colo., said the new study and others like it have failed to show statistically significant results. Additionally, he said they lack the physical evidence of what are known as “dynamical links,” — physical ties within elements of the Earth’s climate system, such as the upper oceans and lower atmosphere — between Arctic warming and extreme events.

“There is no plausible physical mechanism or analysis of how the atmosphere is forced to behave in this manner,” Trenberth said in an email.

Further adding to the divide within the climate science community is the fact that many of the climate models that Trenberth and others often use do not show the sorts of changes in the jet stream that the new study and others like it have pointed to, including the more frequently stagnated or “blocked” weather patterns that Francis cited. In fact, many of the newest generation of climate models show that atmospheric blocking will become less common in the North Atlantic than it is now.

“We need more case studies, and more direct dynamics studies rather than just correlation studies,” Overland said.

Arctic sea ice cover off Ellsmere Island in Canada.
Click image to enlarge. Credit: Michael D. Lemonick.

Overland pointed to the International Arctic Science Committee, which is making this a key focus of its research agenda during the next year. The International Arctic Science Committee is part of the World Meteorological Organization,

Judah Cohen, lead seasonal weather forecaster at AER, a weather and climate consulting firm, said the possibility that Arctic climate change is leading to more extreme weather patterns has initiated a flurry of new studies. “I can tell you that I am busier now reviewing journal papers than I have ever been in my career and they are all on sea ice” he said in an email. “I think this will be a dominant area of research and discourse for years to come.”

For her part, Francis is continuing to keep a wary eye on the weather map, convinced that the evidence for Arctic-induced weather extremes will continue to mount.

“As we continue to emit ever-increasing amounts of greenhouse gases into the atmosphere and as the Arctic continues to warm faster than mid-latitudes, we will see the case for the linkage strengthen,” Francis said. “I expect that with every year we will see a clearer response of weather patterns in all four seasons, and new modeling experiments will help elucidate the links in the chain, as well.”

Related Content
Hansen: Extreme Weather Tied to Climate Change
Arctic Warming May Not be Altering Jet Stream: Study

A Closer Look at Arctic Sea Ice Melt and Extreme Weather
Arctic Warming is Altering Jet Stream, Study Shows
Astonishing Ice Melt May Lead to More Extreme Winters
Warming Arctic Fueling Cold, Snowy Winters, Study Says
Video: Extreme Weather and Rapid Arctic Warming
Arctic Sea Ice Sets Record Low, And It's Not Over Yet
Climate Change and the Jet Stream

Comments

By Eric Peterson (Front Royal, VA 22630)
on December 8th, 2013

Like the rest of the planet, warming in the Arctic is starting to slow: http://images.remss.com/data/msu/graphics/TLT/plots/RSS_TS_channel_TLT_Northern Polar_Land_And_Sea_v03_3.png The lull in warming in the Arctic coincides with the slowdown in solar activity (since around 2008).  We would expect some lag in cooling since the Arctic ocean contains residual warmth, but the Arctic should cool in the near future.

The recent increases in waviness are likely to be part of a cycle and possibly a long term consequence of Arctic warming,and the there is seasonal evidence in favor of an Arctic connection.  Specifically the waviness has increased the most in summer when Arctic ice has decreased the most. Second most in fall when heat is released from refreezing of ice.  Waviness has not increased very much in the spring when melting ice tends to keep a lid on Arctic temperatures.

I think this is a reasonable debate to have, but we should not jump to conclusions about extreme weather since natural variation still far exceeds any possible manmade effects.

Reply to this comment

By john harkness
on December 9th, 2013

Thanks for this fascinating glance into the complexities of this kind of science and into some of the tensions and debate within it.

It sound to me as if developments in our massive, uncontrolled experiment on the climate system of the only planet we’ve got are moving faster than scientists can quite keep up with.

By the time we have all the statistically significant data we need to figure out what’s been going on up to now, the whole system will probably have already kicked into a radically different pattern that we will have even less of an idea about; and so on and on, with ever more chaotic and catastrophic results, ultimately threaten our ability to even even be able to study what is going on.

For example, at what point does the poleward drift of the mid-latitude jet streams force them to merge with the polar jet streams, essentially creating a two-cell rather than three-cell system in each hemisphere? Is this already starting to happen? What would be the consequences for global rain fall patterns and agricultural production? 

One small typo: You wrote “saud” instead of “said” for the Screen email.

Reply to this comment

By dan_in_illinois
on December 9th, 2013

It seems odd that there is still all this concern about Arctic warming.  There have been a number of articles talking about the Arctic ice actually being at a record high.  Here’s one example:

http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2013/09/23/antarctic-sea-ice-hit-35-year-record-high-saturday/

Reply to this comment

By Tyler (Kansas City)
on January 7th, 2014

The Arctic (North Pole) is what this article is discussing. The Post article is about the Antarctic (South Pole).
The Arctic is largely water, while the Antarctic has a large land mass with a large ice sheet covering it. Land is easier to cool then water ( i.e., more ice can form). We cannot expect these two vastly different, yet similar regions to react the same to climate change. Whether it is natural or manmade, the issue remaining is the fact that the climate is changing. Studies like these will help us survive the changes unlike other species that have become extinct over the last billions of years. We must use what nature or God gave us - our brains and superior intelligence.

Reply to this comment

By Neven (Austria)
on December 9th, 2013

This is a great article, Andrew. I’ll re-post the first half of it tomorrow on the Arctic Sea Ice Blog.

@ dan_in_illinois: Look at the link you posted. Does it say Arctic there?

Reply to this comment

By Terry (Cambridge Ont. N1R 3S2)
on December 9th, 2013

Dan
The Arctic is not the Antarctic.
As the article states there is consensus concerning the decline of Arctic Sea Ice, the debate is over how lower latitudes are being effected.
Yesterday Alaska temperature reached 39F while in Houston temperature reached 37F. Temperatures like these are indicative that the WACC (Warm Arctic Cold Continent) theory might be correct.
By the time we know positively it will be far too late to do anything about it.
Terry

Reply to this comment

By Andrew (NYC)
on December 9th, 2013

Thanks Neven, much appreciated.

Reply to this comment

By Spaniel (gakona/alaska/99586)
on December 9th, 2013

Maybe we’re in the never-ending inter-glacial period???
No more ice ages, yahoo!

Reply to this comment

By Magoo (Wellington.)
on December 10th, 2013

Without a tropospheric hot spot as empirical evidence of positive feedback from water vapour there is barely any evidence linking anthropogenic global warming with the warming temperature. CO2 can warm no more than 1.2C maximum per doubling of total (not just man’s) atmospheric CO2. This warming is supposed to be doubled/tripled by positives feedbacks of which the vast majority is supposed to come from water vapour. If the feedback from water vapour was positive it would result in a tropospheric hot spot that has not been found by either 2 satellites or over 30,000,000 radiosondes in more than 40 yrs of data. As a result it can warm no more than a maximum of 1.2C per doubling of total CO2, which at the current rate of 2.65 parts per million a year will take 148 years to warm 1.2C, and another 297 yrs to rise another 1.2C - i.e. 445 yrs to rise 2.4C. Without the positive feedback from water vapour the effects of CO2 alone are too small to make much of a difference to our climate.

No tropospheric hotspot = no positive feedback from water vapour = no AGW. This means that there is no empirical evidence that the thawing of the Arctic has anything to do with CO2, especially when the Antarctic has done the opposite. It’s true it had warmed until about 17 yrs ago, but the empirical evidence shows the link between CO2 and the rising temperature is very weak. For those who disagree then please explain how it can warm more than 1.2C maximum per doubling of total atmospheric CO2 without positive feedback from water vapour, and what empirical evidence is there of positive feedback from water vapour without the tropospheric hot spot.

The record Arctic ice loss of 2012 was a result of a storm which destroyed a large amount of sea ice as reported by NASA, not by warming temperatures, and that is why it has made a miraculous recovery in 2013:

http://www.nasa.gov/topics/earth/features/arctic-storm.html

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By Steven Blaisdell
on December 15th, 2013

Ho-kay. First, here’s the link to the IPCC AR5 summary:
http://www.climatechange2013.org/images/uploads/WGI_AR5_SPM_brochure.pdf

Now, from the text as written by the world’s leading climate scientists, with the contribution of over a thousand research papers on global warming:
“Warming of the climate system is unequivocal, and….many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased…The atmospheric concentrations of carbon dioxide, methane, and nitrous oxide have increased to levels unprecedented in at least the last 800,000 years. Carbon dioxide concentrations have increased by 40% since pre-industrial times, primarily from fossil fuel emissions and secondarily from net land use change emissions. The ocean has absorbed about 30% of the emitted anthropogenic carbon dioxide, causing ocean acidification….Total radiative forcing is positive, and has led to an uptake of energy by the climate system. [and, drum roll please….] The largest contribution to total radiative forcing is caused by the increase in the atmospheric concentration of CO2 since 1750”
Finally: “Human influence on the climate system is clear. This is evident from the increasing greenhouse gas concentrations in the atmosphere, positive radiative forcing, observed warming, and understanding of the climate system.”
I suspect your mistake is implicated in the last sentence, to wit: “understanding of the climate system.” If you truly feel you’ve discovered previously unnoticed phenomena that contradict the findings of thousands of deeply informed research papers and the IPCC, I strongly suggest you submit your research to the appropriate journals for consideration.
And just for the record, your “miraculous” recovery of the 2013 Arctic sea ice was the fourth lowest ice volume on record. those being 2013, 2012, 2011, and 2007. A more accurate look at the near future of the Arctic ice might be the 3,500 km3 drop from 1980-1981, given increasing positive feedback. Nice try, though.

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By Magoo
on December 18th, 2013

Here is my reply. I suggest you read it fully and very carefully, especially the parts from the Working Group 1 sections of the IPCC reports.

The IPCC are well aware of the phenomena (i.e. positive feedback from water vapour & a missing tropospheric hot spot) because they were the ones who predicted it in AR4 (Box 8.1, page 632). This may take a while to load:

http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter8.pdf

‘and the net effect of the combined water vapour/lapse rate feedback is to amplify the warming in response to forcing by around 50%’


This is what the IPCC predicted in AR4:

http://www.ipcc.ch/publications_and_data/ar4/wg1/en/figure-9-1.html


and this is what the empirical evidence showed (source shown in the graphic):

http://jonova.s3.amazonaws.com/graphs/hot-spot/hot-spot-model-predicted.gif


The IPCC shows how important the hot spot is in AR4 and then the empirical evidence shows how it is missing. They are fully aware of the failure of the AGW theory due to the missing hot spot.

Here is what the IPCC had to say about in the draft version of AR5, page 9-26 (capital letters are highlighting by me):

‘9.4.1.3.2 Upper tropospheric temperature trends
Most climate model simulations show a larger warming in the tropical troposphere than is found in observational datasets (e.g., (McKitrick et al., 2010) (Santer et al., 2012)). There has been an extensive and sometimes controversial debate in the published literature as to whether the difference between models and observations is statistically significant, once observational uncertainties and natural variability are taken into account (e.g., Douglass et al., 2008; Santer et al., 2008; Christy et al., 2010; McKitrick et al., 2010; Bengtsson and Hodges, 2011; Fu et al., 2011; Santer et al., 2012; Thorne et al., 2011). For the thirty-year period 1979 to 2009 (sometimes updated through 2010 or 2011), the various observational datasets find, in the tropical lower troposphere (LT, see Chapter 2 for definition), an average warming trend ranging from 0.07°C to 0.15°C per decade. In the tropical middle troposphere (MT, see Chapter 2 for definition) the average warming trend ranges from 0.02°C to 0.15°C per decade (e.g., Chapter 2, Figure 2.15; McKitrick et al., 2010). Uncertainty in these trend values arises from different methodological choices made by the groups deriving satellite products (Mears et al., 2011) and radiosonde compilations (Thorne et al., 2011), and from fitting a linear trend to a time series containing substantial interannual and decadal variability (Santer et al., 2008; McKitrick et al., 2010). Although there have been substantial methodological debates about the calculation of trends and their uncertainty, a 95% confidence interval of around ±0.1°C per decade has been obtained consistently for both LT and MT (e.g., Chapter 2; McKitrick et al., 2010). Hence, a trend of zero is, with 95% confidence, consistent with some observational trend estimates but not with others.

For the thirty-year period 1979 to 2009 (sometimes updated through 2010 or 2011), the CMIP3 models simulate a tropical warming trend ranging from 0.1°C to somewhat above 0.4°C per decade for both LT and MT (McKitrick et al., 2010), while the CMIP5 models simulate a tropical warming trend ranging from slightly below 0.15°C to somewhat above 0.4°C per decade for both LT and MT (Santer et al., 2012; see also Po-Chedley and Fu, 2012) who, however, considered the period 1979–2005). Both model ensembles show trends that are higher on average than the observational estimates, although both model ensembles overlap the observational ensemble. Because the differences between the various observational estimates are largely systematic and structural (Chapter 2; Mears et al., 2011), the uncertainty in the observed trends cannot be reduced by averaging the observations as if the differences between the datasets were purely random. Likewise, to properly represent internal variability, the full model ensemble spread must be used in a comparison against the observations, as is well known from ensemble weather forecasting (e.g., Raftery et al., 2005). The very high significance levels of model-observation discrepancies in LT and MT trends that were obtained in some studies (e.g., Douglass et al., 2008; McKitrick et al., 2010) thus arose to a substantial degree from using the standard error of the model ensemble mean as a measure of uncertainty, instead of the standard deviation or some other appropriate measure of ensemble spread. NEVERTHELESS, ALMOST ALL MODEL ENSEMBLE MEMBERS SHOW A WARMING TREND IN BOTH LT [lower troposphere] AND MT [mid troposphere] LARGER THAN OBSERVATIONAL ESTIMATES (McKitrick et al., 2010; Po-Chedley and Fu, 2012; Santer et al., 2012).

It is unclear whether the tropospheric model-trend bias is primarily related to internal atmospheric processes or to coupled ocean-atmosphere processes. The CMIP3 models show a 1979–2010 tropical SST trend of 0.19°C per decade in the multi-model mean, much larger than the various observational trend estimates ranging from 0.10°C to 0.14°C per decade (including the 95% confidence interval, (Fu et al., 2011)). This SST trend bias would cause a trend bias also in TL and TM even if the models’ atmospheric components were perfectly realistic. The influence of SST trend errors on the analysis can be reduced by considering changes in tropospheric static stability, measured either by the difference between MT and LT changes or by the amplification of MT changes against LT changes; another approach is to consider the amplification of tropospheric changes against SST changes. For month-to-month variations there is consistency between observations and CMIP3 models concerning amplification aloft against SST variations (Santer et al., 2005), and between observations and CMIP5 models concerning amplication of TM against TL variations (Po-Chedley and Fu, 2012). The 30-year trend in tropical static stability, however, is larger than in the observations for almost all ensemble members in both CMIP3 (Fu et al., 2011) and CMIP5 (Po-Chedley and Fu, 2012). For two CMIP3 models, ECHAM5/MPI-OM and GFDL-CM2.1, this trend bias in static stability lies outside each model’s internal variability and is hence highly statistically significant The bias persists even when the models are forced with the observed SST, as was found in the CMIP3 model ECHAM5 (Bengtsson and Hodges, 2011) and the CMIP5 ensemble (Po-Chedley and Fu, 2012).

IN SUMMARY, THERE IS HIGH CONFIDENCE (ROBUST EVIDENCE ALTHOUGH ONLY MEDIUM AGREEMENT) THAT MOST, THOUGH NOT ALL, CMIP3 AND CMIP5 MODELS OVERESTIMATE THE WARMING TREND IN THE TROPICAL TROPOSPHERE DURING THE SATELLITE PERIOD 1979-2011. THE CAUSE OF THIS BIAS REMAINS ELUSIVE.’

source:
http://www.stopgreensuicide.com/Ch9_models_WG1AR5_SOD_Ch09_All_Final.pdf


There you have it straight from the IPCC’s mouth. I don’t need to ‘submit [my] research to the appropriate journals for consideration’ because the IPCC has already published it, and they are fully aware of the failure of AGW as a consequence. The failure of the models to match the empirical evidence in the temperature records over the last 16-23 yrs is further evidence that the models rely on a positive feedback that isn’t there. As for your snide comment ‘I suspect your mistake is implicated in the last sentence, to wit: “understanding of the climate system.”’, it would seem that I’ve read a bit more of the IPCC’s reports than you have - weren’t you aware that CO2 was such a weak contributor to the temperature and the majority of the warming comes from the feedbacks?

No tropospheric hotspot = no evidence of positive feedback from water vapour = no amplification of CO2’s warming = no AGW. Either find the hotspot or explain how it can warm beyond 1.2C without positive feedback from water vapour. The IPCC has failed to do both, but as their models fail more & more as a result, at each of their reports their confidence in them rises. Doesn’t sound very scientific to me.

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By Magoo
on December 18th, 2013

Regarding your comment below:

‘And just for the record, your “miraculous” recovery of the 2013 Arctic sea ice was the fourth lowest ice volume on record. those being 2013, 2012, 2011, and 2007.’

I don’t think so as the records below show, and even if it was, without evidence of positive feedback from water vapour via a tropospheric hotspot there is no evidence that the ice loss is due to CO2 as it can’t warm enough on it’s own to have much of an effect (i.e. 1.2C max. per doubling of TOTAL atmospheric CO2):

http://www.ijis.iarc.uaf.edu/seaice/extent/AMSRE_Sea_Ice_Extent_L.png

http://arctic-roos.org/observations/satellite-data/sea-ice/observation_images/ssmi1_ice_ext.png

http://ocean.dmi.dk/arctic/plots/icecover/icecover_current_new.png

http://www.natice.noaa.gov/ims/images/sea_ice_only.jpg

http://www.natice.noaa.gov/ims/images/ims_data.jpg

http://arctic-roos.org/observations/satellite-data/sea-ice/observation_images/ssmi1_ice_area.png

Reply to this comment

By James (NA)
on December 10th, 2013

It’s not a coincidence. As carbon pollution warms the planet, Arctic ice is shrinking to record-lows. http://clmtr.lt/c/AyA0bZ0AU

Reply to this comment

By Leslie Graham
on December 10th, 2013

@ dan in illinois.

When you figure out where the Antarctic is you might also be interested to know that the long projected 1.4% per decade growth in temporary winter sea ice extent is itself a product of global warming.
Google is your friend.
You might also be interested to know that the Antarctic land ice (the part that matters) is losing mass at at the rate of 70,000,000,000 tonnes per year.

The Arctic has lost between 75% and 80% of it’s summer volume in the last 35 years.

Hope this helps.

Reply to this comment

By Eric Peterson (Front Royal, VA 22630)
on December 10th, 2013

“Yesterday Alaska temperature reached 39F while in Houston temperature reached 37F. Temperatures like these are indicative that the WACC (Warm Arctic Cold Continent) theory might be correct.  By the time we know positively it will be far too late to do anything about it.”

Alaska has been cooling for more than 10 years.  That cooling is indicative that the theory of solar cooling is correct since the rest of the Arctic has residual warmth from the ocean.  By the time we know positively, we may see drastic cooling worldwide with crop losses, etc.

Reply to this comment

By Sue (West Henrietta)
on December 11th, 2013

Re comments from John’s post (copied below)
“It sound to me as if developments in our massive, uncontrolled experiment on the climate system of the only planet we’ve got are moving faster than scientists can quite keep up with.

By the time we have all the statistically significant data we need to figure out what’s been going on up to now, the whole system will probably have already kicked into a radically different pattern that we will have even less of an idea about; and so on and on, with ever more chaotic and catastrophic results,...”

Very well stated - that’s exactly the situation we’re in.

Reply to this comment

By Robert
on December 11th, 2013

Eric, are you unaware that Alaska has been rapidly warming for the last ten years? As has the Arctic?

There is no global cooling, Eric. You are unfortunately illustrating why it is called climate “denial.”

Reply to this comment

By Eric Peterson (Front Royal, VA 22630)
on December 12th, 2013

Robert, here’s a report about Alaska: http://www.benthamscience.com/open/toascj/articles/V006/111TOASCJ.pdf (The First Decade of the New Century: A Cooling Trend for Most of Alaska)  The Arctic as a whole has been cooling since about 2007: http://images.remss.com/data/msu/graphics/TLT/plots/RSS_TS_channel_TLT_Northern Polar_Land_And_Sea_v03_3.png

Reply to this comment

By kermit
on December 11th, 2013

Magoo, climate science does not stand or fall on the identification of a long-term tropospheric hot spot. See here:
http://www.skepticalscience.com/tropospheric-hot-spot.htm

Also, it is not yet clear how much water vapor increase adds to warming. It is a green house gas, yes, but it also blocks the sunlight (e.g. clouds).  Can you provide a link indicating that “the vast majority” of global warming is supposed to be water vapor? Thanks, if so.

Eric, that link of yours shows a chart where the Arctic is “starting to cool”, yet the same chart shows it “starting to cool” at least 15 times over the last 33 years. Yet the overall trend is obviously rising. Climate trends need at least 30 years to make any sense of them. There is *no indication that global warming is slowing down.

Reply to this comment

By Magoo (Wellington)
on December 12th, 2013

Yes, I’ve read all that scepticalscience.con has to offer. They have failed to identify a tropospheric hotspot and have failed to explain how the initial warming attributable to CO2 can be amplified via water vapour without a hotspot. The issue about the hotspot is not about the so called ‘fingerprint’ of a warming upper troposphere & a cooling stratosphere (a red herring), but empirical evidence for positive feedback from water vapour - where is it?

Can you provide empirical evidence of positive feedback from water vapour please, if not can you please explain how it can warm more than 1.2C per doubling of total atmospehric CO2 without water vapour?

Here is an update to AR4 that shows how much water vapour is supposed to contribute to the warming. It’s plainly obvious that the vast amount of positive feedback comes from water vapour, so much in fact that it is almost all of the feedback:

http://jonova.s3.amazonaws.com/source/ipcc/5ar/draft/fig-9.44-ipcc-ar5.feedbacks-450.gif

‘Figure 9.44: a) Feedback parameters for CMIP3 and CMIP5 models (left and right columns of symbols) for water vapour (WV), clouds (C), albedo (A), lapse rate (LR), combination of water vapour and lapse rate (WV+LR), and sum of all feedbacks (ALL) updated from Soden and Held (2006). CMIP5 feedbacks are derived from CMIP5 simulations for abrupt four-fold increases in CO2 concentrations (4 × CO2).’

That’s right, water vapour also has a negative feedback when it manifests itself at lower altitudes as clouds, but it does not have a positive feedback at higher altitudes as predicted by the IPCC as there is no empirical evidence of it doing so (i.e. no tropospheric hotspot). AGW failed an empirical test when the hotspot failed to eventuate.

Reply to this comment

By Eric Peterson (Front Royal, VA 22630)
on December 12th, 2013

In case anyone is wondering why Alaska is cooling and the Arctic also seems to have started cooling, I would point to this chart of solar activity: http://www.leif.org/research/Ap-1844-now.png I don’t think anyone can really predict the level of solar activity 10 or especially 20 years from now, but if it continues to be weak, I would expect the cooling trends to continue both worldwide and in the Arctic.

Reply to this comment

By kermit
on December 12th, 2013

i haven’t heard of anybody in the science community wondering why Alaska is cooling, Eric, because there is no evidence indicating this. Are you thinking of somebody in the political blogosphere? Solar activity seems less and less relevant, considering how its effects are swamped by AGW.

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By Eric Peterson (Front Royal, VA 22630)
on December 12th, 2013

Kermit, cooling from low solar activity may not occur and if it does occur it may not last more than a decade or two.  But it seems to be a good bet for now.  In at least some of the 15 previous times you point to I said the warming is continuing despite a lull or short reversal.  It will still continue even this time, but only when the sun changes course which may take another cycle or two.

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By Steven Blaisdell
on December 15th, 2013

Eric, that’s not the case. Along with an extremely strong El Niño and persistent La Niña conditions, the ongoing deep and prolonged solar minimum has reduced overall warming only ~.04 C decadal:

http://www.realclimate.org/index.php/archives/2013/11/global-warming-since-1997-underestimated-by-half/

As noted in the link, warming has not ‘paused’ or slowed beyond expected variation. Corrections in measurement gaps fully account for the supposed ‘pause,’ which means the significant ocean warming (in particular mid-level) is above and beyond predicted. So - even with a “deep and prolonged solar minimum,” the planet is warming, quickly. 

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By eugene (Bemidji, MN 56601)
on December 13th, 2013

Let it go Eric.  I lived in Alaska for 20 yrs, spend time in Alaska every yr and it is not cooling. But if you want to ride the solar activity horse, far be it from me to stop you.  Expect all you like, reality will trump your expectations every time.  I figure as the Titanic slid beneath the waves, there was somebody screaming “but this ship can’t sink”.

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By Eric Peterson (Front Royal, VA 22630)
on December 13th, 2013

eugene, when did you leave Alaska? Do you only return in the summer?  If you left more than about 5 years ago you would not have noticed the winter and spring cooling.

The article explaining those details that I linked above: http://www.benthamscience.com/open/toascj/articles/V006/111TOASCJ.pdf

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By Steven Blaisdell
on December 15th, 2013

Eric, I’m sorry but that’s just wrong. Alaska is NOT cooling:

http://climate.gi.alaska.edu/ClimTrends/Change/TempChange.html

Period.  The Arctic is NOT cooling:

http://www.livescience.com/40676-arctic-temperatures-record-high.html

Period. And it’s disingenuous to switch from “Alaska” to “Alaska in the winter and spring.” Just a quick graf from the second link:
“New research shows that average summer temperatures in the Canadian Arctic over the last century are the highest in the last 44,000 years, and perhaps the highest in 120,000 years.” 
Cooling? Really?

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By William Hughes-Games (Waipara New Zealand)
on December 15th, 2013

If it is bad now, what will it be like when the Arctic is completely ice free for, say, a few months in the summer.  We ain’t seen nothing yet.
http://mtkass.blogspot.co.nz/2008/07/arctic-melting-no-problem.html

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By Dave Windship (Campbell River BC V0P1K0)
on January 4th, 2014

How does this wandering and erratic northern jet stream interact with the expanding Hadley Cells in the troposphere?

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