Better enjoy winter now...

[The_Global_Warmer]

I don't understand calling AGW a theory unless you are backing that increasing GHG does not warm the Earth. Because if human dumping GHGs into the atmosphere warms the Earth even slightly then AGW is not a theory.

So I guess those calling it a theory deny any human involvement in the warming or what?

[LakeEffectKing]

I don't understand calling AGW a theory unless you are backing that increasing GHG does not warm the Earth. Because if human dumping GHGs into the atmosphere warms the Earth even slightly then AGW is not a theory.

So I guess those calling it a theory deny any human involvement in the warming or what?

AGW HYPOTHESIS, includes feedbacks. This is what skeptics (most anyway) have the largest problem with, wrt having uncertainty about AGW. CO2 is a FORCING on the climate, and most agree on that. And if you have read the recently released emails, that uncertainty (as well as the DIRECT climate sensitivity) is not quite as much as a "consensus" opinion, as how they've purported it to the public as a "group/team" in the name of "The Cause".

But because our climate system is very complex.....we don't always have nice, clean direct correlations when changing any forcing variable.

[skierinvermont]

Right...the US , which has the best data available on the globe isn't warming as fast as the rest of the proxies.

No not at all...it was expected to warm twice as much and it didn't come close. And why is it divergining even further in recent years...is it because of ocean cycles that the last IPCC report said wasn't a major factor? (as evidenced in their temp progs)

You are cherry picking a starting point. The average starting point between 1880 and 1950 would give you about 25% greater winter U.S. warming than annual global warming. Only slightly less than the 50% GUESTIMATE I made for a theoretical long-term expectation.

And the IPCC does say natural cycles are a major factor globally and esp. regionally. Which is why the global projections have large confidence intervals in the short-term and regional projections would have even larger (much larger) confidence intervals in the short term. Even on a 100-yr timescale the confidence intervals would be fairly large for a small region like the U.S. because of natural climate variability. If the GHG trend is weak, these regional CIs may be larger than the GHG warming itself. If on the other hand the GHG trend is strong, as it will be over the coming century, the GHG warming will be much greater than the CIs.

[CoastalWx]

I'm saying it is possible on a REGIONAL basis over the last century but will not be true over the next century given the GHG forcing will be 2-3X greater.

And it's not as though the GHG signal was dwarfed.. the U.S. still warmed in winter dramatically. Just ever so slightly less than one might expect based on GHGs alone.

I just don't understand how people can sound so confident like they did back in the 90s about the doom and gloom predictions which aren't necessarily working out the way IPCC thought. The predictions about the excessive warming were made treating the globe as a test tube and applying the physical forcing behind GHGs. It doesn't work like that. What are people going to do when the AMO goes negative again and we see ice build up again in the North Pole? What do you think that will do to global temps? Will there be feedback with the increases albedo up there? What about this long lasting solar min? How and what will that do to temps? I just think there are so many variables, that it is impossible to make presumptions that bold, just because the computer model said so. I'm not a skeptic either about AGW...but I'm a skeptic of these bold predictions of the planet going up in flames. We are just beginning to understand the variability of our climate.

[WeatherRusty]

What is your longterm starting point? 1920? 1900? 1880? Because those do matter.

And you fail to address the overall lack of greater warming in the U.S. for all seasons, which IS expected based on AGW theory.

It really feels like you are just repeating a mantra here without actually examing the facts.

Very interesting dialog going on here, by folks who's motivation we can trust to be honest scientific inquiry.

taco...

Were do you get the idea that AGW theory states a uniform latitudinal warming on a global scale? To my understanding the spatial resolution of expected warming is very coarsely understood. That does not mean however that the real world acts with that kind of homogeneous pattern.

[WeatherRusty]

I agree with most of what you say here...but this does nothing to explain the lack of United States warming in winters over this period. Again, why should we believe that we will warm 3C over the next 90 years in winter when we have barely warmed at all since the 1920s?...around a half degree celcius.

Why do we have an actual cooling trend since 1986 if GHGs are supposed to be 2x that of the global warming in our latitude...this should dwarf any of our trends.

My theory (and many others) say that our winter weather is dominated by the multi-decadal oscillations and not GHGs.

That's 2x in the arctic.

Of course our winter weather is dominated by the oscillations, but the globe warms because of the GHG's. Over time the whole baseline temp. is lifting upward.

The globe should warm by 2C-3C over the next century due to the consequences of physical theory coupled with the our best estimate of equilibrium climate sensitivity. If during that period methane release accelerates from the melting arctic tundra, then we get the potential for the higher end projections.

[dabize]

I just don't understand how people can sound so confident like they did back in the 90s about the doom and gloom predictions which aren't necessarily working out the way IPCC thought. The predictions about the excessive warming were made treating the globe as a test tube and applying the physical forcing behind GHGs. It doesn't work like that. What are people going to do when the AMO goes negative again and we see ice build up again in the North Pole? What do you think that will do to global temps? Will there be feedback with the increases albedo up there? What about this long lasting solar min? How and what will that do to temps? I just think there are so many variables, that it is impossible to make presumptions that bold, just because the computer model said so. I'm not a skeptic either about AGW...but I'm a skeptic of these bold predictions of the planet going up in flames. We are just beginning to understand the variability of our climate.

The predictions of IPCC have been if anything too conservative if your outcome is based on global parameters (e.g. Arctic sea ice extent/volume).

This may have failed to translate on a regional basis in the case of CONUS; why this should be is a reasonable point for discussion and may inform us more about that variability that you mention.

But the confidence in the overall global trend is very well justified indeed.

[WeatherRusty]

Its kind of a much less obvious starting point than 1975 like your buddy Tamino loves to start at. You love to tell everyone who questions the science about Watts...your boy Tamino loves to start at 1975...I wonder why.

Any long term warming post 1970-75 is likely all anthropogenic with zero positive external forcing produced by the Sun.

[WeatherRusty]

This is a very short sighted opinion...and quite condescending. You still havent explained the lack of warming in the US in the time frame that we "should" have warmed by 2x than the global temps.

Maybe we don't know why? However, the hemisphere as a whole is warming and that is all current AGW really really addresses. Again 2x is occurring in the arctic, due to a longer duration of open water which puts more water vapor into the atmosphere and decreases the regional albedo.

[WeatherRusty]

So you are basically admitting that natural factors can completely dwarf the GHG backround in the future for US winters. Which is the way it always has been. GHG influence might be there if you try hard enough.

True, but has always been the case on a longer term basis, U.S. winters and indeed all seasons will fall in line with hemispheric and global trends.

[ORH_wxman]

Any long term warming post 1970-75 is likely all anthropogenic with zero positive external forcing produced by the Sun.

Yes we know where you stand...but we have peer reviewed papers that say 30-40% of the warming since 1975 was from multi-decadal oscillations

[ORH_wxman]

You are cherry picking a starting point. The average starting point between 1880 and 1950 would give you about 25% greater winter U.S. warming than annual global warming. Only slightly less than the 50% GUESTIMATE I made for a theoretical long-term expectation.

And the IPCC does say natural cycles are a major factor globally and esp. regionally. Which is why the global projections have large confidence intervals in the short-term and regional projections would have even larger (much larger) confidence intervals in the short term. Even on a 100-yr timescale the confidence intervals would be fairly large for a small region like the U.S. because of natural climate variability. If the GHG trend is weak, these regional CIs may be larger than the GHG warming itself. If on the other hand the GHG trend is strong, as it will be over the coming century, the GHG warming will be much greater than the CIs.

So are you when you start from 1880 or 1950. You love to say that we shouldn't start from an uneven point in ENSO history but that is exactly what the PDO multi-decadal oscillation is...a footprint of ENSO.

If the warming is so strong, then this shouldn't matter that much as many AGW people claim. You even claimed not too long ago that you thought the warming since 1975 would be the roughly the same if it wasn't for the multi-decadal oscillation...it was only after I had mentioned a paper off the top of my head that you changed your mind...and you looked it up and found a couple other papers too that showed the warming since then was likely enhanced by 0.05C+ per decade by multi-decadal oscillations.

The complete disregard for natural cycles in the AGW debate is what many skeptics contest.

[CoastalWx]

The predictions of IPCC have been if anything too conservative if your outcome is based on global parameters (e.g. Arctic sea ice extent/volume).

This may have failed to translate on a regional basis in the case of CONUS; why this should be is a reasonable point for discussion and may inform us more about that variability that you mention.

But the confidence in the overall global trend is very well justified indeed.

Well if you are using that as a proxy, we know some of that is explained from decadal cycles. I don't like seeing sea ice disappear either, but I don't see how you can pin that on AGW.

[dabize]

Well if you are using that as a proxy, we know some of that is explained from decadal cycles. I don't like seeing sea ice disappear either, but I don't see how you can pin that on AGW.

Uhhh............it hasn't happened since the Eemian, a period that includes the Holocene thermal maximum??

[ORH_wxman]

Uhhh............it hasn't happened since the Eemian, a period that includes the Holocene thermal maximum??

Supposedly, but the reconstructions aren't that accurate.

We had the same ice coverage in the 1950s as the late 1990s...and that was considered unprecedentedly low at the time until the 1950s reconstructions came out. Arctic temps are only marginally warmer relatively speaking than the 1940s right now...there are clearly natural cycles that go on...mostly the AMO WRT to arctic temps. The Atlantic is a very good transporter of heat to the arctic.

[WeatherRusty]

As I said before, we have just entered a -PDO phase and are moving towards a -AMO phase, both of which favor cooler winters nationally. The trend is higher now after a 30 year +PDO phase, but it is dropping now that it ended.

Aren't you guys mixing regional and global influence as if they respond equally to greenhouse warming? Of course ocean oscillations will affect regional areas, but they can not and will not affect the global trend long term. There will always be local and regional variation.

[ORH_wxman]

Aren't you guys mixing regional and global influence as if they respond equally to greenhouse warming? Of course ocean oscillations will affect regional areas, but they can not and will not affect the global trend long term. There will always be local and regional variation.

No they actually affect global temps on a decadal scale. At least most people believe that.

[WeatherRusty]

AGW HYPOTHESIS, includes feedbacks. This is what skeptics (most anyway) have the largest problem with, wrt having uncertainty about AGW. CO2 is a FORCING on the climate, and most agree on that. And if you have read the recently released emails, that uncertainty (as well as the DIRECT climate sensitivity) is not quite as much as a "consensus" opinion, as how they've purported it to the public as a "group/team" in the name of "The Cause".

But because our climate system is very complex.....we don't always have nice, clean direct correlations when changing any forcing variable.

The agreement is in accepting a climate sensitivity to a doubling of CO2 at 0.75C (+-0.25C) / watt of forcing. Another way to look at it is at radiative equilibrium you get a warming between 2C and 4.5C per doubling.

[dabize]

Supposedly, but the reconstructions aren't that accurate.

We had the same ice coverage in the 1950s as the late 1990s...and that was considered unprecedentedly low at the time until the 1950s reconstructions came out. Arctic temps are only marginally warmer relatively speaking than the 1940s right now...there are clearly natural cycles that go on...mostly the AMO WRT to arctic temps. The Atlantic is a very good transporter of heat to the arctic.

Yes but that "margin" may be very important. The loss of volume BTW, is much more dramatic than the loss of extent.

Also, the minimum extents in the '50s weren't as low in the 50s even if the means and maxima were similar.

And it seems that the demise of the thermohaline "conveyor" is overstated, and that there will be good transport of heat to the Arctic for a while.

I'm not disputing the presence of natural cycles. They clearly complicate the issue esp on a regional basis - I'd like to see a discussion on whether the resistance CONUS winter temps to the global pattern is due to a "threshold effect" based on either cycles or local circumstances (THC reduction, open Arctic increase in snow/cold etc.)

But the Keeling curve ain't natural, and keeping it and the well-correlated baseline increase in global temps out of the discussion in the name of cyclical/regional/UHI caused variation is a textbook example of "special pleading"

[CoastalWx]

Uhhh............it hasn't happened since the Eemian, a period that includes the Holocene thermal maximum??

What? We've had low sea ice as close by as the 1940s...real low.

[tacoman25]

You are cherry picking a starting point. The average starting point between 1880 and 1950 would give you about 25% greater winter U.S. warming than annual global warming. Only slightly less than the 50% GUESTIMATE I made for a theoretical long-term expectation.

Again, you fail to acknowledge how the ending point naturally influences this trend as well. Since most of the last 30 years were +PDO, and the last 15 +AMO, this favors a more positive longterm winter temperature trend for the U.S. If we were ending in a period where we had just decades of mostly -PDO/-AMO like the 1970s, the trend would not be as warm.

[WeatherRusty]

Yes we know where you stand...but we have peer reviewed papers that say 30-40% of the warming since 1975 was from multi-decadal oscillations

What peer-reviewed papers?

From a thermodynamic point of view, if 30%-40% of the warming came out of the deep oceans, then why has sea level continued to rise over that period? Why did OHC continue to rise? Makes no sense.

[tacoman25]

Very interesting dialog going on here, by folks who's motivation we can trust to be honest scientific inquiry.

taco...

Were do you get the idea that AGW theory states a uniform latitudinal warming on a global scale? To my understanding the spatial resolution of expected warming is very coarsely understood. That does not mean however that the real world acts with that kind of homogeneous pattern.

That's not my idea. I'm critical of those that would apply uniform warming math to a specific location. Like Milwaukee.

[tacoman25]

That's 2x in the arctic.

Of course our winter weather is dominated by the oscillations, but the globe warms because of the GHG's. Over time the whole baseline temp. is lifting upward.

The globe should warm by 2C-3C over the next century due to the consequences of physical theory coupled with the our best estimate of equilibrium climate sensitivity. If during that period methane release accelerates from the melting arctic tundra, then we get the potential for the higher end projections.

Did you read the conversation? It was skiier that brought up the 2x warming in the mid latitudes.

[Alpha5]

Again, you fail to acknowledge how the ending point naturally influences this trend as well. Since most of the last 30 years were +PDO, and the last 15 +AMO, this favors a more positive longterm winter temperature trend for the U.S. If we were ending in a period where we had just decades of mostly -PDO/-AMO like the 1970s, the trend would not be as warm.

Not to mention a relatively active sun

[The_Global_Warmer]

I just don't understand how people can sound so confident like they did back in the 90s about the doom and gloom predictions which aren't necessarily working out the way IPCC thought. The predictions about the excessive warming were made treating the globe as a test tube and applying the physical forcing behind GHGs. It doesn't work like that. What are people going to do when the AMO goes negative again and we see ice build up again in the North Pole? What do you think that will do to global temps? Will there be feedback with the increases albedo up there? What about this long lasting solar min? How and what will that do to temps? I just think there are so many variables, that it is impossible to make presumptions that bold, just because the computer model said so. I'm not a skeptic either about AGW...but I'm a skeptic of these bold predictions of the planet going up in flames. We are just beginning to understand the variability of our climate.

The AMO trended negative from 2005-2009 when the ice accelerated in it's overall melt, including glaciers, land ice, fastice, sea ice. Then the AMO spiked upwards again in 2010.

During the "Grand Solar Min". The ice continued on both sides of the arctic, well all sides. the CA region lost all of it's MYI, all of it. The only MYI there now is from compaction out of the arctic basin. And most of it melted in place. Part of that is from low snow cover in Spring helping get an early start to the melt. Another part is from build up of warm water that has been taking place for decades between 25-150 meters and from 200/300 meters below. This is not exclusive to any one part of the arctic but more so in places seeing increased surface warming over ice, land, water where ice and snow are thinner or gone.

People have come here time again saying the AMO is driving the arctic but the ice keeps melting out at an unprecedented rate. The 1990s ice extent, area, VOLUME is history. It should never be used as as a reference. The current ice levels are unprecedented. We have had incredible amounts of research up there the last decade, exp the last 5 years.

The extent of the melt season is far beyond any natural course, the amount of melt per season has far beyond what they used to believe. Bottom ice melt is in the 2-3 meter range over millions of kilometers when in the past it was no where to be seen over .50 meters.

the Laws of of Physics haven't changed. But the way the ice behaves has. Applying older causalities has proven to be fool hearty over and over as the ice decline slopes downward. Just the past two summers saw thousands of and tens of thousands of thickness measurements in the arctic all over. We have linked this here from many sources.

Have shown submarine, buoy, manned expeditions, boats with the only sole job to measure ice thickness in the arctic working together all over, Cryosat2 validation team which all lead to piomas validation. But it is still doubted in the face of that kind of effort up north., Even with the buoys showing 3-5 meters of ice melt per summer now in the CA Islands before buoys stop working because the 4 meter ice they lay on melted out which is confirmed with satellites, which mean the ice is fresher and thinner than ever and the water up there is warmer than ever(deeper than ever).

The glaciers are falling to pieces before our eyes with no stopping, actually melting out faster.

Skier posts papers that do not show the ice in the 1950s as low as the 1990s, I guess there is conflicting information out there. The sat records combined with records going back to 1962 by the Canadian Ice Service would suggest 1950s sea ice levels at 1990s levels would have had one hell of a rebound to go from 6-7km2 extent late summer back up to 8-9km2 extent by the early 60s. But the proxy data doesn't show that at all, neither do glacial melt patterns.

I would be very happy to see the ice not melt out completely in the next 5-20 years and go back up, but IMO that is not going to happen and so far nothing of that sort has started to happen by the sea ice or glaciers.

[tacoman25]

Any long term warming post 1970-75 is likely all anthropogenic with zero positive external forcing produced by the Sun.

What about going from -PDO to +PDO? The 1976-2006 period was +PDO, and therefore natural occilations favored warming if you start from the end of the last -PDO phase.

[tacoman25]

The AMO trended negative from 2005-2009 when the ice accelerated in it's overall melt, including glaciers, land ice, fastice, sea ice. Then the AMO spiked upwards again in 2010.

The AMO may have had a slight downward trend over those 4 years, but it has remained in an overall positive phase since the mid 1990s.

[The_Global_Warmer]

What? We've had low sea ice as close by as the 1940s...real low.

So even though glaciers and land ice was much more profound then the ice was real low like now then? or something close to now?

even though the proxies say otherwise?

Can you link me to the accepted peer reviewed work showing sea ice thickness, volume, extent, and area being so low in the 1940s.

[WeatherRusty]

Did you read the conversation? It was skiier that brought up the 2x warming in the mid latitudes.

Yes, but then he later stated that he "pulled it out of his ass"....