Climate Change Banter

[GaWx]

Then 1884-1885 was one of the coldest winters on record. You could also to a lesser extent throw in 1881-1882 for an extreme warm winter...not quite as widespread as the warmth in 1877-1878, but still exceptional. Another extreme cold winter in 1887-1888.

 

 

 I meant to add some more things about ENSO. 1884-5 was at/near a low end weak Nino, which has a number of times been associated with the E US as a whole having very cold winters. 1887-8 had similar ENSO.

 

 The two warmest ATL winters of all time, 1879-80/1889-90, were during mod/very strong La Nina's. ATL's winters have been warmest on average during La Nina.

 

 My point is that regardless of AGW, the sun and other factors, the natural ENSO often has ruled and still rules the roost quite often when looking at individual winters. I assume you agree.

 

 I still wonder about the overall degree of extremes of US wx in the late 1800's. I don't know how they couldn't have been way up there.

[ORH_wxman]

Unfortunately, the CEI index doesn't go back to that era to make a comparison. But other recent studies have

shown an increase in swings or extremes as the climate warms. 

 

Swings In North Atlantic Oscillation Variability Linked To Climate Warming

 

http://www.sciencedaily.com/releases/2009/01/090113101200.htm

 

 

The research team found the variability of the NAO decade-to-decade (multi-decadal scale) has been larger, swinging more wildly, during the late twentieth century than in the early 1800s, suggesting that variability is linked to the mean temperature of the Northern Hemisphere. This confirms variability previously reported in past terrestrial reconstructions.

“When the Industrial Revolution begins and atmospheric temperature becomes warmer, the NAO takes on a much stronger pattern in longer-term behavior,” said Goodkin. “That was suspected before in the instrumental records, but this is the first time it has been documented in records from both the ocean and the atmosphere.

 

http://www.livescience.com/14176-tree-ring-el-nino-records-climate-change.html

 

 

Many of the El Niño and La Niña events of the last millennium were more intense than the ones scientists have direct data on. Overall, the world has seen a trend of increasing swings to extremes over the past millennium, researchers said.

These changes in the intensity of ENSO appear to be linked to the tropical Pacific climate. Samples taken from lake sediments in the Galapagos Islands, the northern Yucatan in Mexico and the Pacific Northwest suggest that the eastern-central tropical Pacific climate swings between warm and cool phases, each lasting from 50 to 90 years. During warm phases, El Niño and La Niña events were more intense than usual, and during cool ones, they deviated little from the long-term average.

 

 

The thing about the CEI is that if you remove the temperature from it, then you get no trend. It's almost entirely weighted by an increase in temperature...which is already a known bellcurve shift to the right.

 

The other components are essentially flat.

[tamarack]

One data set I've used as a proxy for extreme events is the state records for hottest and coldest days, and wettest/driest years, 200 records in all.  Two caveats:  First, the smaller number of recording locations prior to 1900 will bias against representation from that time.  Second, some of the temperature extremes note "also on earlier dates", which may also bias against earlier years.  (Or not - Maine's hottest temp is one of the ties, but the earlier date occurred during the same week and location.) 

 

There are only 10 records set prior to 1890 and only one of those was for temperature.  Then the 1890s, 1900s, and 1910s averaged 9 per decade.  The 1920s set only 3 extremes.  Then came the 1930s, with 23 record highs, 10 lows, 2 wettest, 17 driest, 52 extremes in all and top decade for all but wettest year.  The next six decades averaged 17 each, ranging from 12 to 26.  Extremes have been less common during the new millenium, with only 7 for 2000 on, though there may be updated records of which I'm not aware.  The two most recent are both cold extremes, 2009 in Maine and 2011 in OK.

[bluewave]

The thing about the CEI is that if you remove the temperature from it, then you get no trend. It's almost entirely weighted by an increase in temperature...which is already a known bellcurve shift to the right.

 

The other components are essentially flat.

 

You get a strong signal both from temperature and precip extremes which is stronger in some regions than others.

[GaWx]

One data set I've used as a proxy for extreme events is the state records for hottest and coldest days, and wettest/driest years, 200 records in all.  Two caveats:  First, the smaller number of recording locations prior to 1900 will bias against representation from that time.  Second, some of the temperature extremes note "also on earlier dates", which may also bias against earlier years.  (Or not - Maine's hottest temp is one of the ties, but the earlier date occurred during the same week and location.) 

 

There are only 10 records set prior to 1890 and only one of those was for temperature.  Then the 1890s, 1900s, and 1910s averaged 9 per decade.  The 1920s set only 3 extremes.  Then came the 1930s, with 23 record highs, 10 lows, 2 wettest, 17 driest, 52 extremes in all and top decade for all but wettest year.  The next six decades averaged 17 each, ranging from 12 to 26.  Extremes have been less common during the new millenium, with only 7 for 2000 on, though there may be updated records of which I'm not aware.  The two most recent are both cold extremes, 2009 in Maine and 2011 in OK.

 

Tam,

 Thanks for this data.

 

 To be fair (and assuming a near steady background avg. temp.), the # of records of any kind will be biased higher in earlier periods. Example: An all-time record low or high on any date at most any station in, say 1915, was much easier to attain than it would be in 2015 simply because the record is now 100 years longer.

[ORH_wxman]

You get a strong signal both from temperature and precip extremes which is stronger in some regions than others.

 

I don't see a strong signal on the precip component of their index...maybe if you start in the 1960s-1970s

 

[ORH_wxman]

Actually nevermind bluewave, I missed their 4th component which is "extreme precip"

 

That one does have a good trend upward...which makes sense too since higher precip events have shown to be increasing in the U.S.

 

 

But the rest of them are definitely flat

[nflwxman]

The hurricane stuff quieted down somewhat after Chris Landsea's paper in 2010-2011. I'm sure the major hurricane landfall drought since 2005 has also helped. But I'd bet the hyperbole will start up again when we finally get a major hurricane landfall.

Attribution studies are very uncertain by nature. The problem is you need to understand the inherent extremes of meteorology first before making a connection to AGW on whether it increases or decreases the probability. About the only robust one globally is shifting the probability of heat waves and decreasing probability of cold waves...which of course makes sense in an overall warmer world.

 

See, if the physical basis makes sense, I'm willing to give many of attribution theories the benefit of the doubt.  To be honest, higher SSTs and more water vapor intuitively would fuel stronger hurricanes.  Yes, shear could increase and it could counteract much of that. Unlike temperature data, we just don't have the dataset frequency to statistically attribute more extreme events to AGW.  HOWEVER, the fact that there is physical backing should give many pause.  The truth is we probably won't have a hurricane dataset large enough to definitively say anything until 2050.  At that point, it's too late.

 

Until then, we are just going to have physical studies suggesting one thing and statistical studies throwing a bucket of cold uncertainty on the whole issue.

 

Anyone who thinks that AGW absolutely had no influence whatsoever on the intensity of Katrina or Sandy is missing the point.  The truth is we don't know for sure and pointing to similar storms in the past doesn't really change that. 

[bluewave]

Actually nevermind bluewave, I missed their 4th component which is "extreme precip"

 

That one does have a good trend upward...which makes sense too since higher precip events have shown to be increasing in the U.S.

 

 

But the rest of them are definitely flat

 

You can also see peaks in the temp extremes if you choose that option.

[ORH_wxman]

See, if the physical basis makes sense, I'm willing to give many of attribution theories the benefit of the doubt.  To be honest, higher SSTs and more water vapor intuitively would fuel stronger hurricanes.  Yes, shear could increase and it could counteract much of that. Unlike temperature data, we just don't have the dataset frequency to statistically attribute more extreme events to AGW.  HOWEVER, the fact that there is physical backing should give many pause.  The truth is we probably won't have a hurricane dataset large enough to definitively say anything until 2050.  At that point, it's too late.

 

Until then, we are just going to have physical studies suggesting one thing and statistical studies throwing a bucket of cold uncertainty on the whole issue.

 

Anyone who thinks that AGW absolutely had no influence whatsoever on the intensity of Katrina or Sandy is missing the point.  The truth is we don't know for sure and pointing to similar storms in the past doesn't really change that. 

 

If anything hurricanes have shown to be decreasing through time...albeit the trend is insignificant.

 

Blaming Katrina on AGW is just not well supported by the science.

[nflwxman]

If anything hurricanes have shown to be decreasing through time...albeit the trend is insignificant.

 

Blaming Katrina on AGW is just not well supported by the science.

 

Blaming the hurricane formation, I agree.  It almost certainly would have been a tropical cyclone in the absence of AGW.  Suggesting they were stronger and more damaging than the otherwise would be?  I disagree.  I think there is a physical basis there that one can't overlook.  In fact, to write off a potential correlation is very foolhardy given the small amount of data we have.  As I said before, whether or not it's actually occurring in practicality can not be proven given the small dataset we have in many of these basins.

 

This is just about hurricanes though.  As other extremes have been statistically proven to have increased.

 

http://www.pbs.org/wgbh/nova/earth/climate-change-sandy.html

[StudentOfClimatology]

How about the theory that the extremes have been increasing recently like we saw from the 1910's into the 1930's due to warmer Arctic temperatures relative to the rest of the Northern Hemisphere? You can also see the extremes decreasing as the Arctic cooled again after the 1930's into the 1970's. I guess you could say correlation doesn't equal causation, but I would like to see a study that focuses on the last 100 years or so rather the last 30 to get some clarity on this issue.

It's a chicken/egg question. It could very well be that the relatively warmer Arctic was a result of the increased meridional mass transport responsible for the mid-latitude extremes. A stable, zonal circulation reduces poleward heat transport and eddy flux, allowing an overall cooling of the Arctic atmosphere, which is in a yearly radiative deficit.

Naturally, the two variables are tied together.

Given the strong influence tropical forcing has on poleward AAM transport and wave size/spacing, I believe that's where the source of these extremes lies, not the Arctic, which contains only a fraction of the energy in direct exchange. Believing the Arctic is responsible, IMO, is analogous to the tail wagging the dog.

[AvantHiatus]

The idea of a climate system dominated by negative feedbacks is laughable, as is the idea of a stable, unchanging ESC/TCR. As the ENSO system proves, it only takes a shift in global circulation to dramatically alter global temperatures...that's all ENSO is.

As ORH alluded to, the paleo data not only reveals the the existence of positive feedback loops, but also the fact that they appear to be highly non-linear in nature. Both the TCR and ESC can vary significantly over time.

[ORH_wxman]

Blaming the hurricane formation, I agree.  It almost certainly would have been a tropical cyclone in the absence of AGW.  Suggesting they were stronger and more damaging than the otherwise would be?  I disagree.  I think there is a physical basis there that one can't overlook.  In fact, to write off a potential correlation is very foolhardy given the small amount of data we have.  As I said before, whether or not it's actually occurring in practicality can not be proven given the small dataset we have in many of these basins.

 

This is just about hurricanes though.  As other extremes have been statistically proven to have increased.

 

http://www.pbs.org/wgbh/nova/earth/climate-change-sandy.html

 

 

You linked me to an article that discusses blocking and Sandy....yet there's papers that refute that.

 

The evidence isn't robust.

 

 

 

As for strength....cliamte models show that hurricanes on average will increase their maximum sustained winds by about 1-3% in the future toward the middle 21st centruy...and perhaps to 2-10% by 2100. Again, blaming the strength on AGW is a stretch if we are talking significant attribution...maybe Katrina would have been a 106 knot hurricane at landfall instead of 110 knots if it werent for AGW. But lets be intellectually honest on the subject...the biggest reason for Katrina's strength was the loop current that season extending further north than usual and some very favorable upper level winds as it exited Florida and into the gulf.

 

By far the biggest impact of AGW on Katrina was sea level being about 6-7 inches higher...so it made the storm surge 6 to 7 inches higher.

[GaWx]

Blaming the hurricane formation, I agree.  It almost certainly would have been a tropical cyclone in the absence of AGW.  Suggesting they were stronger and more damaging than the otherwise would be?  I disagree.  I think there is a physical basis there that one can't overlook.  In fact, to write off a potential correlation is very foolhardy given the small amount of data we have.  As I said before, whether or not it's actually occurring in practicality can not be proven given the small dataset we have in many of these basins.

 

This is just about hurricanes though.  As other extremes have been statistically proven to have increased.

 

http://www.pbs.org/wgbh/nova/earth/climate-change-sandy.html

 

 How do you explain that GA hasn't had a single H hit nearly as bad as the multiple major hits throughout the 1800's in over 100 years and not near the frequency? I could just as easily say there's some significance to that but I won't because there's no way to know the reason. It could just as easily be due mainly to randomness. 

[AvantHiatus]

Keep in mind, the AGW signal grows with time and the energy imbalance has not declined to where it should reside. Using past attribution will make you more inaccurate the larger your temporal arrangement becomes.

[StudentOfClimatology]

Your two most recent papers on the wavy jet split up into Arctic and Tropical origins. So perhaps it's better to take

a more holistic approach. But it's human nature to use your own area of expertise to try and explain an individual

phenomena.

I don't believe I linked any "wavy-jet" literature here, and I certainly wouldn't read any study that treats the tropics and high latitudes as separate entities. That flies in the face of every long-range forecasting advancement we've made since the 1990s.

A lot of what we're observing, extremes-wise, can be explained by changes to the dominant tropical circulations (Walker/Hadleys), which govern the manner in which the mid latitude wave train interacts with both the polar domains and the tropical domains.

[nflwxman]

You linked me to an article that discusses blocking and Sandy....yet there's papers that refute that.

 

The evidence isn't robust.

 

 

 

As for strength....cliamte models show that hurricanes on average will increase their maximum sustained winds by about 1-3% in the future toward the middle 21st centruy...and perhaps to 2-10% by 2100. Again, blaming the strength on AGW is a stretch if we are talking significant attribution...maybe Katrina would have been a 106 knot hurricane at landfall instead of 110 knots if it werent for AGW. But lets be intellectually honest on the subject...the biggest reason for Katrina's strength was the loop current that season extending further north than usual and some very favorable upper level winds as it exited Florida and into the gulf.

 

By far the biggest impact of AGW on Katrina was sea level being about 6-7 inches higher...so it made the storm surge 6 to 7 inches higher.

 

I agree, but that's simply because its very hard to statistically prove it as this juncture at time.  Unlike the idea of surface temperature forcing (which has it's own uncertainties), hurricanes are inherently complex issues that require quite a few variables to drive track, strength, and formation.  Those variables can't be isolated statistically right now.  I'm not so sure why you would be so quick dismiss a potential physical basis because the lack of sample size.

 

Most of the papers you site as refuting attribution are statistically derived analysis with uncertainty bands that reach on both sides of the moon.  We are not going to solve this question anytime soon on the statistical side.  But that doesn't mean it's not a possibility.

[nflwxman]

 How do you explain that GA hasn't had a single H hit nearly as bad as the multiple major hits throughout the 1800's in over 100 years and not near the frequency? I could just as easily say there's some significance to that but I won't because there's no way to know the reason. It could just as easily be due mainly to randomness. 

Yeah, that's probably weather.  But we don't know for sure.

 

That's really my sole statement here.  There are physical reasons why extremes could increase, but too little of a sample size to prove it (for hurricanes, tornadoes, severe storms) at this juncture. 

[ORH_wxman]

Keep in mind, the AGW signal grows with time and the energy imbalance has not declined to where it should reside. Using past attribution will make you more inaccurate the larger your temporal arrangement becomes.

 

 

We've already seen a drastic increase in heat content and surface temperature since the late 1800s...so obvious trends in TCs should be detectable if AGW impacted them so much....there aren't obvious trends. You can argue a very weak increase in the absolute strongest storms, which is consistent with the literature, but it's still quite small (orders of magnitude lower) in comparison to the way storms are classified themselves.

 

There is not expected to be a detectable trend in major hurricanes of cat 4/5 until the 2nd half of the 21st century and even those trends aren't expected to be strong.

[Jonger]

You linked me to an article that discusses blocking and Sandy....yet there's papers that refute that.

 

The evidence isn't robust.

 

 

 

As for strength....cliamte models show that hurricanes on average will increase their maximum sustained winds by about 1-3% in the future toward the middle 21st centruy...and perhaps to 2-10% by 2100. Again, blaming the strength on AGW is a stretch if we are talking significant attribution...maybe Katrina would have been a 106 knot hurricane at landfall instead of 110 knots if it werent for AGW. But lets be intellectually honest on the subject...the biggest reason for Katrina's strength was the loop current that season extending further north than usual and some very favorable upper level winds as it exited Florida and into the gulf.

 

By far the biggest impact of AGW on Katrina was sea level being about 6-7 inches higher...so it made the storm surge 6 to 7 inches higher.

 

When boarding up your windows in 2050... use one extra nail per window to counter this wind speed increase.

[ORH_wxman]

Yeah, that's probably weather.  But we don't know for sure.

 

That's really my sole statement here.  There are physical reasons why extremes could increase, but too little of a sample size to prove it (for hurricanes, tornadoes, severe storms) at this juncture. 

 

 

I don't think anyone is "Writing them off" so to speak...more just criticizing a lot of the stories we read on these events being blamed by AGW. There are certainly some extremes that are supported by both empirical evidence and theoretical physical arguments...obvious being shifting the bell curve to the right on temperature extremes.

 

That doesn't mean we need to start blaming other events on them when the evidence is either inconclusive or even against the claim.

[nflwxman]

We've already seen a drastic increase in heat content and surface temperature since the late 1800s...so obvious trends in TCs should be detectable if AGW impacted them so much....there aren't obvious trends. You can argue a very weak increase in the absolute strongest storms, which is consistent with the literature, but it's still quite small (orders of magnitude lower) in comparison to the way storms are classified themselves.

 

There is not expected to be a detectable trend in major hurricanes of cat 4/5 until the 2nd half of the 21st century and even those trends aren't expected to be strong.

 

Another point ORH is that the climate models show a 1-3% increase in intensity globally.  That does not mean some basins or storms with not get disproportionately affected by climate change.  It may not be as easy as saying Katrina would have been 4 weaker without AGW.  We just don't know.

 

Remember how many global surface temperature models were tuned to account for arctic amplification observed?  That will likely be the future of regional and extreme climate models. 

[nflwxman]

I don't think anyone is "Writing them off" so to speak...more just criticizing a lot of the stories we read on these events being blamed by AGW. There are certainly some extremes that are supported by both empirical evidence and theoretical physical arguments...obvious being shifting the bell curve to the right on temperature extremes.

 

That doesn't mean we need to start blaming other events on them when the evidence is either inconclusive or even against the claim.

 

Yeah, I strongly agree with that.  The media is generally to blame on poor AGW reporting.  I don't blame the media and public asking those questions post-Sandy, but the scientists should be intellectually honest and just say the truth: We just don't know.

[ORH_wxman]

Another point ORH is that the climate models show a 1-3% increase in intensity globally.  That does not mean some basins or storms with not get disproportionately affected by climate change.  It may not be as easy as saying Katrina would have been 4 weaker without AGW.  We just don't know.

 

Remember how many global surface temperature models were tuned to account for arctic amplification observed?  That will likely be the future of regional and extreme climate models. 

 

 

Well the tropics are expected to warm the least, so it makes sense not to expect a massive jump in storm strength there. The biggest impact is expected to be how far north the TCs can sustain.

 

Obviously there is no way to know for sure until we actually go out in time and observe for ourselves...but Gulf of Mexico SST anomalies have shown a flat trend going back to the 1800s. This actually matches well with the southeast U.S. "warming hole" that shows up on land data too.

[tamarack]

Tam,

 Thanks for this data.

 

 To be fair (and assuming a near steady background avg. temp.), the # of records of any kind will be biased higher in earlier periods. Example: An all-time record low or high on any date at most any station in, say 1915, was much easier to attain than it would be in 2015 simply because the record is now 100 years longer.

 

Easier to set at that time, but with 100 years to be broken at a later date.  IMO, the size of the observational network would be the strongest bias, with fewer stations in the 19th and early 20th century (and, unfortunately, in recent years.  I've noted a number of very long term sites having ceased reporting during the past 5 years.)  I've found many sites with records beginning August 1, 1948, perhaps a postwar effort to add robustness, and a small but interesting number for which records begin Jan. 1, 1893.  The more places being observed, the greater the chances of catching an extreme.  The -50 in 2009 which reset Maine's cold extreme came, IMO, because there was finally a station recording in the far NW part of the state.  There are a number of anecdotal accounts of sub-minus 50 temps from that area, -52 at Estcourt Station, -54 at Nine-Mile Bridge on the St. John (recounted in the book of that name) and others.  And now both Clayton Lake and Allagash have winked out, leaving that cold quadrant with nothing except Big Black.

[Sophisticated Skeptic]

a little strange how so many of these anomalies are so close to land. 

 

I'd be interested to see if these warm currents (west)can provide a rare / favorable pattern for rain temporarily out there...or at-least until summer kicks in, 

[AvantHiatus]

The eastern NA anomalies are driven by their proximity to the world's primary poleward heat currents (and OHC is rising). GOM loop current is way warmer than average as well.

 

These things have implications going forward, which was why I made it clear that people should not let their guard down anymore during hurricane season, despite forecasts. The warm coastal water also provides fuel for extratropical winter storms and was a factor in dumping snow on Boston.

[AvantHiatus]

Amazing Temperature Change Over The Mid-Atlantic Friday

[downeastnc]

Amazing Temperature Change Over The Mid-Atlantic Friday

 

This is so silly I cant even tell if your just being a troll here.......or you are somehow implying this has something to do with AGW.  There was 34 degree of temp rise in 12 hrs that isn't exactly unheard of this time of year... , the entire article is totally stupid and written by someone with no understanding of the normal climate in this part of the world apparently because it wasn't amazing....unless he just means how changeable the weather is the April on the east coast.