Climate Change Banter

[HailMan06]

I'm curious about those peer-reviewed papers refuting Marcott et al. 2013, SOC.

[StudentOfClimatology]

This is the mistake you guys are making..PhillipS did not correctly interpret Marcott's smoothing algorithm.

Read Marcott's FAQ if you're having trouble interpreting it statistically.

http://www.realclimate.org/index.php/archives/2013/03/response-by-marcott-et-al/comment-page-1

Statement by Marcott et al:

Holocene Temperature Distribution: Based on comparison of the instrumental record of global temperature change with the distribution of Holocene global average temperatures from our paleo-reconstruction, we find that the decade 2000-2009 has probably not exceeded the warmest temperatures of the early Holocene, but is warmer than ~75% of all temperatures during the Holocene. In contrast, the decade 1900-1909 was cooler than~95% of the Holocene. Therefore, we conclude that global temperature has risen from near the coldest to the warmest levels of the Holocene in the past century. Further, we compare the Holocene paleotemperature distribution with published temperature projections for 2100 CE, and find that these projections exceed the range of Holocene global average temperatures under all plausible emissions scenarios.

Anyone arguing that today's temperatures are warmer than those observed during the Holocene climate optimum would be laughed at in any academic setting.

I can link more recent papers, but they basically reiterate what the former were saying, as this is basically settled science.

[Polar Vortex 2014]

Did you even read my post? That's exactly what I said.

 

No, it isn't. You said, and I quote, "[Current global temperature is] nowhere near the levels seen during the Holocene climate optimum (yet)." The paper I linked to says the exact opposite.

[StudentOfClimatology]

No, it isn't. You said, and I quote, "[Current global temperature is] nowhere near the levels seen during the Holocene climate optimum (yet)." The paper I linked to says the exact opposite.

I thought you were referring to the quote about the Pliocene.

Regarding the Holocene climate optimum, your study is in the scientific minority, sorry. I just linked about 30 papers, including the beloved Marcott et al 2013, highlighting the consensus that current temperatures have not exceeded those observed during the Holocene climate optimum. The majority of the evidence points in this direction.

This is basically settled science, at this point. If I'd argued that we were currently warmer than the HCO in any academic thesis or presentation, I'd flunk unless I were to provide original research of my own. That's seriously way "out there".

[PhillipS]

http://www.pages-igbp.org/calendar/127-pages/904-holocene-climate-change

 

 

Pages magazine is not peer-reviewed, it's an open publication not  a scientific journal.  None of the articles provide publication history (date submitted, date accepted, and so forth).  And when I tried to find some of the articles using Google Scholar they didn't turn up in the search results.  Try for yourself and see if you get the same results.

 

Another thing - when I read over the list of papers I saw very few familiar names among those cited, and most of the prominent researchers in the paleoclimate research community were conspicuously absent.  Interesting.

 

SOC this was definitely a swing and a miss for you.

[StudentOfClimatology]

Pages magazine is not peer-reviewed, it's an open publication not a scientific journal. None of the articles provide publication history (date submitted, date accepted, and so forth). And when I tried to find some of the articles using Google Scholar they didn't turn up in the search results. Try for yourself and see if you get the same results.

Another thing - when I read over the list of papers I saw very few familiar names among those cited, and most of the prominent researchers in the paleoclimate research community were conspicuously absent. Interesting.

SOC this was definitely a swing and a miss for you.

Well, at least now I know you're pretty stupid. Not only is every paper fully documented and reachable via Google Scholar (do I really have to demonstrate this?), but you misinterpreted the conclusions of the Marcott et al 2013 study that you linked. Marcott et al 2013 agrees with the scientific consensus, which is that the HCO was clearly warmer than today, globally.

I'm sick of having to rehash the basics of paleoclimatology here. This research is easy to do. Use your brain.

[StudentOfClimatology]

Here, I'll do your research for you. Gosh.

Tell me which papers you "can't find", and I'll link them for you. Call it a personal favor.

First, I'll quote Marcott et al directly, because you obviously did not read the paper. Even though their proxies are aggregated on a 200-300yr resolution and do not show the variability that most reconstructions present, they state:

Based on comparison of the instrumental record of global temperature change with the distribution of Holocene global average temperatures from our paleo-reconstruction, we find that the decade 2000-2009 has probably not exceeded the warmest temperatures of the early Holocene, but is warmer than ~75% of all temperatures during the Holocene

http://www.realclimate.org/index.php/archives/2013/03/response-by-marcott-et-al/comment-page-1

Again, this is basically settled science.

[AvantHiatus]

 

All the endless ranting about how we post garbage from the blogosphere...

[StudentOfClimatology]

All the endless ranting about how we post garbage from the blogosphere...

No such ranting exists.

I'm just tired of rehashing what is largely settled science.

[AvantHiatus]

No such ranting exists.

That was fast, you should get out more.

 

Relax my friend.

[StudentOfClimatology]

That was fast, you should get out more.

Relax my friend.

Yeah, I'd actually just clicked on the cc-forum when you posted.

[PhillipS]

Here, I'll do your research for you. Gosh.

Tell me which papers you "can't find", and I'll link them for you. Call it a personal favor.

First, I'll quote Marcott et al directly, because you obviously did not read the paper. Even though their proxies are aggregated on a 200-300yr resolution and do not show the variability that most reconstructions present, they state:

http://www.realclimate.org/index.php/archives/2013/03/response-by-marcott-et-al/comment-page-1

Again, this is basically settled science.

 

Well, at least now I know you're pretty stupid. Not only is every paper fully documented and reachable via Google Scholar (do I really have to demonstrate this?), but you misinterpreted the conclusions of the Marcott et al 2013 study that you linked. Marcott et al 2013 agrees with the scientific consensus, which is that the HCO was clearly warmer than today, globally.

I'm sick of having to rehash the basics of paleoclimatology here. This research is easy to do. Use your brain.

 

 

It's fun to watch you try to avoid accepting responsibility when you're caught, shall we say, 'embroidering' the facts.  In this case you started off by claiming:

 

That Marcott et al study depicting Holocene climate variability is at odds with ~80% of the peer reviewed literature in the paleoclimate arena. The consensus is the globe was at least 1 degree centigrade warmer during the Holocene climate optimum than it is now.

 

But when asked to share a link to four peer-reviewed studies that support your claim you failed to even link to one.  Instead you went for the unsupported bluff:

 

Yes, we'll eventually surpass the Holocene climate optimum. We'll need to warm at least 1 - 1.5 degrees centigrade, though.

 

Followed by:

 

Three of the last five interglacials peaked at or above 1.5 degrees centigrade warmer than post-modern era. This is undisputed in the literature. The Holocene optimum wasn't quite as warm, but still peaked early in both the borehole data and the ice core data, well above current/post-modern era temperatures. 

 

But of course you know as well as the rest of us that borehole and ice core proxies are regional, not global, so even if 1.5C number were true this was just a bit of misdirection.  Then you started moving the goal posts until you ended with:

 

Marcott et al 2013 agrees with the scientific consensus, which is that the HCO was clearly warmer than today, globally.

 

So what happened to your 80% that disagree with Marcott et al 2013?  And why haven't  you shared even the four peer-reviewed papers you claimed you would?

 

But the more serious issue is that you try to misrepresent Marcott's work to prop up your disingenuous position.  As SOC quoted, Marcott wrote:

 

Our results indicate that global mean temperature for the decade 2000–2009 (34) has not yet exceeded the warmest temperatures of the early Holocene (5000 to 10,000 yr B.P.).

 

But that's hardly definitive as to whether today's global temperature is equal or greater than that of the early Holocene.  After all, the Earth has continued to warm, and 2014 was the warmest year on record according to NASA..  So let's look a bit deeper into Marcott et al 2013.  Below is Fig 3, and its caption, from the paper.  The right hand vertical line is the mean for 2000 - 2009, and the anomaly is around 0.45 C from the 1961 - 1990 baseline.  The lowest  horizontal lozenge is the Holocene temperature spread (roughly -0.2 C - 0.51 C).  Note that the Holocene max is only 0.06 C above the 2000 - 2009 mean, so if today's global temps have risen 0.06 C in recent years then we're tied with the HCO max, and if they've risen more than 0.06 C then we've exceeded the HCO.  Turns out the answer depends on which global temperature set and which warming trend value you give credence to.  But clearly, the Earth does not need to warm much more to exceed the HCO maximum beyond doubt.

 

[StudentOfClimatology]

It's fun to watch you try to avoid accepting responsibility when you're caught, shall we say, 'embroidering' the facts. In this case you started off by claiming:

But when asked to share a link to four peer-reviewed studies that support your claim you failed to even link to one. Instead you went for the unsupported bluff:

You're full of it.

I linked you to 28 peer reviewed studies, all in unanimous agreement regarding the magnitude of the HCO relative to today's climate. I'm only aware of four studies in existence that argue otherwise.

If you don't want to read them, that's your choice. But I'm not going to do your research for you.

But of course you know as well as the rest of us that borehole and ice core proxies are regional, not global, so even if 1.5C number were true this was just a bit of misdirection.

Ice core proxies are not regional, they're hemispheric. The O^16/O^18 isotope ratios are determined primarily by temperatures at 300-1000mb over the sea surface between 10N/S and 60N/S latitude bands, where the heavier isotopes are circulated and subsequently rained out at higher latitudes due to the decease in macroscale buoyancy. The ratio between the variously isotopes is then calculated.

The ratio of concentrations of two isotopes of oxygen in the water molecules in ice serves as a proxy indicator of global temperatures. Oxygen has two commonly occurring natural isotopes, the usual 16O (which makes up more than 99% of naturally occurring oxygen on Earth) and the less abundant 18O. The two extra neutrons in 18O cause water molecules containing this isotope to be heavier than normal water molecules. These heavier water molecules cannot escape from ocean water to become water vapor in the atmosphere via evaporation as readily as lighter water molecules. This tendency for preferential evaporation of 18O varies, however, as a result of the ocean temperature. Through a rather complex chain of events involving the global water cycle, this disparity between concentrations of oxygen-18 and oxygen-16 shows up in the snow that falls in polar regions, and thus in the ice formed from this snow. The net result is that the ratio of 18O to 16O in ice samples provides clues about global ocean temperatures and the extent of the polar ice caps at a given time in Earth's history.

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

But the more serious issue is that you try to misrepresent Marcott's work to prop up your disingenuous position. As SOC quoted, Marcott wrote: Our results indicate that global mean temperature for the decade 2000–2009 has not yet exceeded the warmest temperatures of the early Holocene.

But that's hardly definitive as to whether today's global temperature is equal or greater than that of the early Holocene.

After all, the Earth has continued to warm, and 2014 was the warmest year on record according to NASA.

So let's look a bit deeper into Marcott et al 2013. Below is Fig 3, and its caption, from the paper. The right hand vertical line is the mean for 2000 - 2009, and the anomaly is around 0.45 C from the 1961 - 1990 baseline. The lowest horizontal lozenge is the Holocene temperature spread (roughly -0.2 C - 0.51 C). Note that the Holocene max is only 0.06 C above the 2000 - 2009 mean, so if today's global temps have risen 0.06 C in recent years then we're tied with the HCO max, and if they've risen more than 0.06 C then we've exceeded the HCO.

Once again, you are not accounting for the resolution change between the paleoclimate reconstruction and the observational data. If you want to determine the HCO/modern day differential with any certainty, you need to tune the observational data to the proxy resolution, or statistically account for the smoothing process in the proxy data itself. Do you understand why this is?

Marcott explains this in the FAQ of the paper. If you'd actually have read it, you wouldn't be posting this nonsense..

[PhillipS]

Not one of the dusty aged studies you shared is relevant to your claim that 80% of climate scientists reject Marcott et al 2013.  Your claim was simply fiction, you know it and, more importantly, we all know it too.

 

But carry on with posting your nonsense - it only hurts your credibility and is immensely entertainingl

[FloridaJohn]

Thanks, Phillip.

[StudentOfClimatology]

Not one of the dusty aged studies you shared is relevant to your claim that 80% of climate scientists reject Marcott et al 2013. Your claim was simply fiction, you know it and, more importantly, we all know it too.

But carry on with posting your nonsense - it only hurts your credibility and is immensely entertainingl

You'd honestly be laughed at by anyone with education in paleoclimate if you pulled crap in an academic setting. I mean, you were treating just aggregated proxy data as if it were analogous to yearly changes in the instrumental data..talk about hall-of-fame caliber nonsense.

Also, I added a *~* symbol before the number 80. I don't know what the exact number is but the point stands..the vast majority of work in the database suggests the HCO was significantly warmer than present, including Marcott et al 2013, as a matter of fact.

[nflwxman]

SoC, you seems to get in one major nasty debate a day with someone here.  Often someone on the realist/alarmist side.  Why?

[Polar Vortex 2014]

This is the mistake you guys are making..PhillipS did not correctly interpret Marcott's smoothing algorithm.

Read Marcott's FAQ if you're having trouble interpreting it statistically.

http://www.realclimate.org/index.php/archives/2013/03/response-by-marcott-et-al/comment-page-1

Statement by Marcott et al:

Anyone arguing that today's temperatures are warmer than those observed during the Holocene climate optimum would be laughed at in any academic setting.

I can link more recent papers, but they basically reiterate what the former were saying, as this is basically settled science.

 

I have to say I'm rather skeptical myself at the conclusion in Marcott et al. that 1900-1909 was cooler than 95% of all Holocene decades. It's at odds with the limited instrumental records we have (BEST) showing a gradual warming trend from the mid 1700s into the early 20th century. It's also at odds with our understanding of the Little Ice Age, which is believed to have lasted from around 1300 C.E. to 1850 C.E. It's known to a great deal of certainty from temperature records, historic observations, glacial melt that the turn of the 20th century was warmer than the several hundred preceding years. So this claim would basically say the LIA is the only time since the dawn of the Holocene, where temperatures were lower than the early 20th century average. Color me skeptical.

[ORH_wxman]

I have to say I'm rather skeptical myself at the conclusion in Marcott et al. that 1900-1909 was cooler than 95% of all Holocene decades. It's at odds with the limited instrumental records we have (BEST) showing a gradual warming trend from the mid 1700s into the early 20th century. It's also at odds with our understanding of the Little Ice Age, which is believed to have lasted from around 1300 C.E. to 1850 C.E. It's known to a great deal of certainty from temperature records, historic observations, glacial melt that the turn of the 20th century was warmer than the several hundred preceding years. So this claim would basically say the LIA is the only time since the dawn of the Holocene, where temperatures were lower than the early 20th century average. Color me skeptical.

 

 

Actually, the instrumental record shows the first decade of the 20th century as colder than what we know of the 2nd half of the 19th century...there was a pretty signficiant cooling that occurred during the AMO drop and solar minimum:

 

 

 

 

 

 

That said, I agree it's a questionable claim that it would be colder than much of the LIA between the 14th and 18th centuries.

[Polar Vortex 2014]

Actually, the instrumental record shows the first decade of the 20th century as colder than what we know of the 2nd half of the 19th century...there was a pretty signficiant cooling that occurred during the AMO drop and solar minimum:

 

 

 

 

 

 

That said, I agree it's a questionable claim that it would be colder than much of the LIA between the 14th and 18th centuries.

 

Well, I was looking at the BEST reconstruction, which is somewhat at odds with Hadley in the early years (generally shows it a bit colder).

 

[ORH_wxman]

Well, I was looking at the BEST reconstruction, which is somewhat at odds with Hadley in the early years (generally shows it a bit colder).

 

decadal-land-surface-average-temperature-berkeley-earth.jpg

 

 

BEST only measures land temps though....granted their land temps are colder than Hadley's land temps, but if you include SST in there, then the decline from the late 1800s becomes more prominent.

[StudentOfClimatology]

SoC, you seems to get in one major nasty debate a day with someone here. Often someone on the realist/alarmist side. Why?

It's definitely seemed that way recently, I admit. I'll try to tone it down. I'm just a bit frustrated because we had this exact debate ~ 6 months ago and I thought it had run its course. Denying that the HCO was the warmest period since the Eemian maximum is almost like denying AGW.

[StudentOfClimatology]

I have to say I'm rather skeptical myself at the conclusion in Marcott et al. that 1900-1909 was cooler than 95% of all Holocene decades. It's at odds with the limited instrumental records we have (BEST) showing a gradual warming trend from the mid 1700s into the early 20th century. It's also at odds with our understanding of the Little Ice Age, which is believed to have lasted from around 1300 C.E. to 1850 C.E. It's known to a great deal of certainty from temperature records, historic observations, glacial melt that the turn of the 20th century was warmer than the several hundred preceding years. So this claim would basically say the LIA is the only time since the dawn of the Holocene, where temperatures were lower than the early 20th century average. Color me skeptical.

I agree with you here. It's generally viewed that the 8200kyr event marked the coldest excursion within the Holocene, followed by the LIA and the DACP.

[forkyfork]

You'd honestly be laughed at by anyone with education in paleoclimate if you pulled crap in an academic setting. I mean, you were treating just aggregated proxy data as if it were analogous to yearly changes in the instrumental data..talk about hall-of-fame caliber nonsense.

Also, I added a *~* symbol before the number 80. I don't know what the exact number is but the point stands..the vast majority of work in the database suggests the HCO was significantly warmer than present, including Marcott et al 2013, as a matter of fact.

what's your degree program and at what school? i can't find any climatology programs near md

[A-L-E-K]

what's your degree program and at what school? i can't find any climatology programs near md

 

 

[GaWx]

Actually, the instrumental record shows the first decade of the 20th century as colder than what we know of the 2nd half of the 19th century...there was a pretty signficiant cooling that occurred during the AMO drop and solar minimum:

This late 19th century and early 20th century cooling during that solar minimum with what could be some lag then getting started combined with the idea that the 2nd half of the 20th century had the most active sun of any 50 year period in at least 350 years (which coincided well with the strong warming during that period) has been telling me to at least be open-minded about the potential amount of cooling effect from the likely upcoming grand solar minimum. However, the longer we go over just the next few years without at least a sign of any cooldown, the less likely in my mind that we'll ever get much cooling from any grand solar minimum. It is getting close to put up or shut up time IMO as regards the sun.

[ORH_wxman]

This late 19th century and early 20th century cooling during that solar minimum with what could be some lag in getting started combined with the idea that the 2nd half of the 20th century had the most active sun of any 50 year period in at least 350 years (which coincided well with the strong warming during that period) has been telling me to at least be open-minded about the potential amount of cooling effect from the likely upcoming grand solar minimum. However, the longer we go over just the next few years without at least a sign of any cooldown, the less likely in my mind that we'll ever get much cooling from any grand solar minimum. It is getting close to put up or shut up time IMO.

 

We'd have to see a noticeable cooling by 2017-2018 or so because by that point, we'd be more than 3 years beyond the weak solar max we had in cycle 24. It's been argued by some that the weak solar maxes are more important than the mins during decreased acitivty...so you can pretty much discard the theory if by 2018 the effects of the weak max and subsequent min have not been felt to a significant degree. I'm fairly skeptical though on it having a large impact. We may see a muted effect like we did from 2008-2012...we'll find out soon enough.

[GaWx]

We'd have to see a noticeable cooling by 2017-2018 or so because by that point, we'd be more than 3 years beyond the weak solar max we had in cycle 24. It's been argued by some that the weak solar maxes are more important than the mins during decreased acitivty...so you can pretty much discard the theory if by 2018 the effects of the weak max and subsequent min have not been felt to a significant degree. I'm fairly skeptical though on it having a large impact. We may see a muted effect like we did from 2008-2012...we'll find out soon enough.

I agree with about a 2018 deadline to finally see some cooling impact from a solar minimum. That's been near my put up or shut up time for a few years in this forum.

[The_Global_Warmer]

what's your degree program and at what school? i can't find any climatology programs near md

Bump

[StudentOfClimatology]

what's your degree program and at what school? i can't find any climatology programs near md

http://www.atmos.umd.edu