Moderated Global Warming Discussion

[Trakar]

Yes, we go back to the MWP, the RWP, the 6th Century Climate Catastrophe and the LIA bvecause they OCCURED. The AGW supporters try their darndest to disappear them from the historical record but they really did occur and they really were global.

The primary AGW claim is the current warming is unprecedented. If the historical record is indeed accurate, then "unprecedented" isn't accurate, is it.

Please reference and support your allegations of AGW claims, your iteration seems much broader and more unqualified than any scientific claim I have ever heard with regards to modern Anthropogenic Climate Change proposals. In general, we don't assess the current global warming event to be of anthropogenic origins because it is "unprecedented," we identify it as anthropogenic because of well-established physics and accurate industrial records.

The claims I have heard, more closely resemble those presented in the IPCC reports which state:

"Climate has changed on all time scales throughout Earth’s history. Some aspects of the current climate change are not unusual, but others are. The concentration of CO2 in the atmosphere has reached a record high relative to more than the past half-million years, and has done so at an exceptionally fast rate. Current global temperatures are warmer than they have ever been during at least the past five centuries, probably even for more than a millennium. If warming continues unabated, the resulting climate change within this century would be extremely unusual in geological terms. Another unusual aspect of recent climate change is its cause: past climate changes were natural in origin (see FAQ 6.1), whereas most of the warming of the past 50 years is attributable to human activities."

Section titled - Frequently Asked Question 6.2
Is the Current Climate Change Unusual Compared to Earlier Changes in Earth’s History? - http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-6-2.html

 

[Trakar]

srex

Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX) - http://srren.ipcc-wg3.de/

This latest report has been mentioned before but its been given a bit better web presence since the last time I mentioned it.

RENEWABLE ENERGY SOURCES AND CLIMATE CHANGE MITIGATION SPECIAL REPORT OF THE INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE
SUMMARY FOR POLICYMAKERS AND TECHNICAL SUMMARY
http://www.ipcc.ch/pdf/special-reports/srren/SRREN_FD_SPM_final.pdf

A lot of meat for policy discussions.

 

[Mikemcc]

Has it? Most temperature records don't say that. Most temp series show the global temp flatlining for the last 10 to 12 years.

Citation? Picking 1998 as your statrt point is not good science

 

[Reality Check]

The primary AGW claim is the current warming is unprecedented. If the historical record is indeed accurate, then "unprecedented" isn't accurate, is it.

That is wrong.
The climate science measurements are that the rate of increase of global temperatures is unprecedented in the historical record.
It is only in the last few years that current global temperature became unprecedented in that it exceeded the MWP temperature.

 

[CapelDodger]

That "when" is now. Try looking at the Arctic. The Northwest Passage is becoming ice-free enough to be considered navigable, a huge change from the 1800s when it could be completely ice bound for two or three years at a time.

That's causing political tensions between Canada and the US. Canada says the Passage is territorial waters and has the right to patrol it; the US says it's international waters and they have the right to send through any ship as they please.

There's been quite a bout of flag-waving in the Arctic recently; even the Vikings (aka Danes; Greenland's still theirs) have got involved. In geopolitical terms an open Arctic is a game-changer. Imagine how differently history would have unfolded had it always been that way.

No less than three companies are planning to run fibre optic cables from London to Tokyo through the Northwest Passage. You couldn't do that twenty years ago; there was just too much ice.

That's interesting. What are the odds that BP drills through at least one of them ?

 

[lomiller]

Has it? Most temperature records don't say that. Most temp series show the global temp flatlining for the last 10 to 12 years.

They show nothing of the sort. There is absolutely zero evidence in any of the major temperature records suggesting the warming trend of ~0.17 deg per decade has stopped or changed in any way.

 

[lomiller]

Yes, we go back to the MWP, the RWP, the 6th Century Climate Catastrophe and the LIA bvecause they OCCURED. The AGW supporters try their darndest to disappear them from the historical record but they really did occur and they really were global.

No one has said they didn't. They were very small and slow changes in comparison to what's going on now, but no one has said they didn't occur.

The AGW supporters try their darndest to disappear them from the historical record but they really did occur and they really were global.

False. You just don't like the fact that they were so minor in comparison to what's currently occurring. In the end though the science is the science, and how large you would like these events to be change nothing about how large they really were.

 

[lomiller]

The primary AGW claim is the current warming is unprecedented. If the historical record is indeed accurate, then "unprecedented" isn't accurate, is it.

Yes, it is accurate. The temperature record shows cooling of ~0.5 - 0.8 Deg C from the height of the MWP to the depth of the LIA. That's about 10X slower than the globe is currently warming.

 

[CapelDodger]

That is wrong.
The climate science measurements are that the rate of increase of global temperatures is unprecedented in the historical record.
It is only in the last few years that current global temperature became unprecedented in that it exceeded the MWP temperature.

I'm not sure that the rate of increase is unprecedented on the scale of three decades. It's certain that the absolute temperature is greater now than in the MWP (if only because things are emerging from ice after at least 5000 years and permafrost has developed timeline gaps which are not evident around 1000CE), and there's no sign of an end to warming. The rate of warming was not that different between ~1910-40, and the rate of warming leading up to the Medieval Warm Peak is not well-determined. There's good reason to think it wasn't significantly more rapid, of course. People would have noticed, and written about it.

The MWP coincides (roughly) with a low-point in vulcanism, and so is something of a benchmark for not having that negative forcing. The ~1910-40 period is a similar benchmark. Vulcanism in the 20thCE has remained low, but of course that's not a positive forcing. It's just the absence of a negative one. It's (forgive me) recovery from the Little Ice Age. Anthropogenic aerosols then introduced a confounding factor which the Vikings simply weren't capable of, hence cooling.

It was still arguable in the 1980's that the world was no warmer than in the MWP but that's simply untenable now (although some people cling to it desperately). Now we're warming from the already-warm, and if China and India get into clean air the way developed nations did in the 70's the rate can only increase.

Half of the CO₂ increase has occurred since the mid-70's (that's probably out-of-date by now, but so am I in some ways) so we've yet to see just what it has in store for us since, of course, the rate of AGW lags behind the rate of CO₂ increase.

 

[CapelDodger]

Yes, we go back to the MWP, the RWP, the 6th Century Climate Catastrophe and the LIA bvecause they OCCURED. The AGW supporters try their darndest to disappear them from the historical record but they really did occur and they really were global.

Nobody (except the ignorant) tries to deny them. What people try to do is put them in context, and explain them.

The 6thCE Catastrophe had a climatic impact of no more than a decade, and was caused by a massive explosive eruption in Indonesia. It had huge and long-lasting historical impacts on human societies that were already unstable, but that's a completely different issue.

You thing that these must have been serious climatic episodes and assume that they're being concealed when the data shows them to be less pronounced than you expect. The fact is that human societies are easily disrupted; another fact is that climate change is less of an influence than many people assume.

The primary AGW claim is the current warming is unprecedented. If the historical record is indeed accurate, then "unprecedented" isn't accurate, is it.

Current warming is unprecedented. We are warming from a warm situation. There's only one explanation for that, and it's the explanation that predicted it beforehand. This warming is pre-explained. Your hope of cooling any time now is just that, hope. According to the hopeful we've been in a long-term cooling phase since at least 2005, and look how that's worked out. Not as badly for them as you might expect, but for some people being wrong for ever really isn't a problem.

It may not be a problem for you in twenty years. The world will be warmer and the effects will be more obvious but you'll still have the Gleick du jour to distract you. I've watched the sequence Gore, Hansen, Mann, Phil Jones, Gleick, and I've no doubt there are more to add. Gleick is the first I'd never heard of, which may be a harbinger of things to come.

 

[Westwall]

That "when" is now. Try looking at the Arctic. The Northwest Passage is becoming ice-free enough to be considered navigable, a huge change from the 1800s when it could be completely ice bound for two or three years at a time.

That's causing political tensions between Canada and the US. Canada says the Passage is territorial waters and has the right to patrol it; the US says it's international waters and they have the right to send through any ship as they please.

No less than three companies are planning to run fibre optic cables from London to Tokyo through the Northwest Passage. You couldn't do that twenty years ago; there was just too much ice.

The Artctic is at the highest level in years and probably going to continue that way as the multi year ice is increasing as is the thickness of the old ice.
This according to NSIDC.

As far as the Northwest passage goes, I agree 20 years ago it would have been impossible. However, there have been 2 times in the last 150 years where it would have been possible.

When you limit yourself to the last 30 years for your data set you can make all kinds of dire predictions. However, when one looks at the climate over the last 200 years this is much ado about nothing.

In geology we realise that Earth processes take decades or more to mature. I suggest you take a look at the historical record going back 1000 years and you will see many cycles in play. It's been 30 years or so since I looked at them but my recollection was there is a 100 year cycle with seperate 50 and 30 year cycles within. When all of those cycles match up you have extremes of climate.

That's why the Farmers Almanac can give a pretty good weather prediction for the coming year...based entirely upon those well known cycles.
http://nsidc.org/data/seaice_index/images/daily_images/N_timeseries.png

 

[Westwall]

The scientist who wrote that abstract also has had this to say:

http://www.skepticalscience.com/scientist-sets-record-straight-on-mwp-research.html#commenthead

Yes, it is sad that they must pay homage to the AGW elite to get a paper published. However, I made no such assertions. I merely stated that the paper established a good foundation for the MWP being global. There are at least 100 other peer reviewed studies I will be happy to post that state the same thing if you so desire.

 

[CapelDodger]

It's been measurable for quite a while now.

Breaking away from global surface temperature (which denialists used to dismiss as a meaningless concept) the physical impacts of AGW are more than obvious and have arrived rather sooner than predicted. So much for "alarmism".

A straight line drawn from 1997 to 2012 (so far) does show no surface warming for 15 years, but naturally ignores the fact that 2011 was the warmest La Nina year on record. The next neutral ENSO year, let alone a sustained El Nino, will resurrect the "global temperature is a meaningless concept" theme. That's my latest prediction, anyway .

I long ago predicted that the MWP would warm without limit to remain warmer than today, and I've not yet been proved wrong about that.

 

[Westwall]

It started more than a century ago, and by best current evidences will continue in impact for the next several tens of thousands of years at a minimum.



Upon what empiric evidences do you base this assessment and more importantly, please reference the actively working and publishing climate researchers who concur with your opinions.

Thank-you, however, for keeping the sub-thread alive, it is the appropriate venue to continue discussing the topic that OP introduced, namely the "Planet Under Pressure" conference held in London this last week.

http://www.planetunderpressure2012.net/

STATE OF THE PLANET DECLARATION
International scientific community issues first
“State of the Planet Declaration”​

http://www.planetunderpressure2012.net/pdf/State_of_the_Planet_Declaration.pdf


(rest at above link)

What temperature increase is that exactly? According to the best studies I can find they show a .7C rise over the last 1000 years. That is within the error bars of most of those studies. Pardon me for not panicking, but according to the last statistics class I took 50 odd years ago, that was not statistically significant.

Couple that fact with the well known (at least to historians and archaeologists) warming and cooling periods where the temps were correspondingly higher and then lower and now rising again and you have a wonderfully stable period. This last 10,000 years has been truly remarkable for its consistency. The holocene thermal maximum was a minimum 3C warmer than today and all of the horrible things the AGW supporters claim will occur.....didn't.

All evidence shows that it was actually pretty darned nice. It is responsible for the first major spurt on mans long trip to advancement.

"Abstract
The magnitude and timing of Holocene maximum warmth in the Arctic and sub-Arctic has been the subject of considerable recent interest, particularly in the context of future climate change. Although lying at a crucial location in the North Atlantic close to significant atmospheric and oceanic boundaries, terrestrial Holocene climatic data from Iceland are few and predominantly derive from glacial and palaeoecological evidence. Here we present new datasets from Tröllaskagi, based on chironomid-inferred temperatures (CI-T), using sub-fossil chironomids from the same lake sediments supplemented by pollen data. July air temperatures have been derived using an Icelandic training set, and the data suggest optimal temperatures at sea level up to 1.5 °C above current levels around 8 k cal. yr BP, a time when birch woodland was well developed in Tröllaskagi, but when woodland had still not fully developed in the more isolated NW peninsula. Our data thus suggest that optimal summer warmth did not occur in Iceland until 8 kcal. yr BP at the earliest, possibly lasting until 6.7 kcal. yr BP. The amount of warming for July was therefore at least 1.5 °C, but possibly up to 2-3 °C higher than the 1961-1990 average on the basis of the tree-line data. Comparison with data from elsewhere in adjacent Arctic regions, Greenland and Eastern Arctic Canada show peak warmth to be later in Iceland, and less pronounced. It also appears that there were enhanced temperature gradients during the first half of the Holocene between the two study areas Tröllaskagi and the NW Peninsula and that they influenced patterns of vegetation colonisation, with current spatial temperature patterns only developing as Holocene climate deteriorated after around 6 kcal. yr BP."


http://ff.org/centers/csspp/library/co2weekly/20060823/20060823_13.html

 

[Westwall]

Potential impacts of human-induced land cover change on East Asia monsoon
http://g01.cnitc.cn/uploadfile/file/资源/链接与文献/2003/2012010716254421.pdf

FROST FOLLOWED THE PLOW: IMPACTS OF DEFORESTATION ON THE CLIMATE OF THE UNITED STATES
http://www.esajournals.org/doi/abs/10.1890/1051-0761(1999)009[1305:FFTPIO]2.0.CO;2?journalCode=ecap

The Role of Human Activities in Past Environmental Change
http://www.ak-geomorphologie.de/data/pgcf/chapter7.pdf

Climate-human-environment interactions: resolving our past
http://hal.archives-ouvertes.fr/docs/00/29/81/43/PDF/cpd-2-563-2006.pdf


Many, many more such references available. Human induced climate change is not new, it has accompanied our species in its spread from its african cradle, and if we aren't careful it may guide us into a premature grave.

Yes, it is well established that farm practices can increase the devestation wrought by weather disasters. Witness the Dust Bowl of the 30's, however, man had nothing to do with the weather event. Climatology is the only science I have ever witnessed that seems to believe correlation equals causation.

It doesn't.

 

[Westwall]

Not at all, of course we were discussing the LIA not your MWP fantasies. If you wish to discuss those in a rational and supported fashion, that is an ussue we can take up.



I'm not sure what you are referring to with regards to ignoring "the scientific method," but if you mean ignoring empiric evidences and demonstrable facts, I wouldn't dream of such behavior.



First, and foremost, nothing in this paper repudiates or contradicts my statement that: "Among mainstream working and publishing climate scientists, there is very little controversy. Global effects and impacts were minimal, barely registering above the noise of normality. Northern hemisphere effects approached significance but with a lot of varience depending upon which region you focus upon, and North Atlantic region effects were of significance. That position covers about two standard deviations (perhaps a bit more) of the population of working and publishing climate scientists."

Secondly, as the authors of this very paper state:

http://asnews.syr.edu/newsevents_2012/releases/ikaite_crystals_climate_STATEMENT.html

Edited by Gaspode: 

Edited for moderated thread.

Here are a FEW peer reviewed stydies that show thge MWP was warmer than the current day and global in scope....I've concentrated on papers that deal only withe the southern hemisphere to make a point.

The temp increase is variable from area to area (as would be expected) but it is constant and global. That is the point. It clearly was not a regional event as you all claim and that is born out by over 100 peer reviewed studies from areas all over the globe.



http://www.agu.org/pubs/crossref/2005/2004PA001099.shtml

http://www.sciencedirect.com/science/article/pii/S0033589402923719

http://hol.sagepub.com/content/13/2/251.abstract

http://www.nature.com/nature/journal/v279/n5711/abs/279315a0.html

 

[Westwall]

Citation? Picking 1998 as your statrt point is not good science

Neither is picking 1972! And please note I am not claiming anything other than what we are seeing is simply natural variability. All I have to do is show historical evidence to support that viewpoint. You have made extraordinary claims. Now it's up to you to prove them. It is my job to poke holes in your theories THAT IS THE ESSENCE OF THE SCIENTIFIC METHOD. Something you seem to have forgotten.

 

[Warmer1]

Yes, we go back to the MWP, the RWP, the 6th Century Climate Catastrophe and the LIA bvecause they OCCURED.

Yes they did occur and are included in the graph that I posted (post #4704) which was an early core which presents the temperature record from 420,00 years until present. Once again there are many cores that have been done since then.

once again the same graph http://en.wikipedia.org/wiki/File:Vostok_Petit_data.svg

The AGW supporters try their darndest to disappear them from the historical record but they really did occur and they really were global.

Please post an example to support your claim. I posted the entire temperature record and will post more below.

The primary AGW claim is the current warming is unprecedented. If the historical record is indeed accurate, then "unprecedented" isn't accurate, is it.

Yes, it is unprecedented as show in the graph below, Can you please post your science or evidence that disproves that the following graph is correct.

http://www1.ncdc.noaa.gov/pub/data/cmb/images/indicators/800k-year-co2-concentration.gif

The graph above is provided by The National Oceans and Atmosphere Association (NOAA) and linked to on this page, which you might want to read if you are interested.

http://www.ncdc.noaa.gov/indicators/

the subjects include;

-How do we know the Earth's climate is warming?
-The Global Surface Temperature is Rising
-U.S. Surface Temperature is also Rising
-Sea Level is Rising
-Global Upper Ocean Heat Content is Rising
-Northern Hemisphere Snow Cover is Retreating
-Glacier Volume is Shrinking

I really don't think I am doing a very good job hiding the graphs created from the data.

If you have evidence that proves the above climate records to be wrong please post it because I would love for all of this not to be true, and accelerating rapidly.

 

[Warmer1]

Oops! I only posted the CO2 concentration record which are unprecedented but obviously temperature and CO2 are mostly in sync over thousands of years as shown in this graph.

http://en.wikipedia.org/wiki/File:Co2-temperature-plot.svg

 

[lomiller]

I'm not sure that the rate of increase is unprecedented on the scale of three decades. It's certain that the absolute temperature is greater now than in the MWP (if only because things are emerging from ice after at least 5000 years and permafrost has developed timeline gaps which are not evident around 1000CE), and there's no sign of an end to warming. The rate of warming was not that different between ~1910-40, and the rate of warming leading up to the Medieval Warm Peak is not well-determined. There's good reason to think it wasn't significantly more rapid, of course. People would have noticed, and written about it.

The MWP coincides (roughly) with a low-point in vulcanism, and so is something of a benchmark for not having that negative forcing. The ~1910-40 period is a similar benchmark. Vulcanism in the 20thCE has remained low, but of course that's not a positive forcing. It's just the absence of a negative one. It's (forgive me) recovery from the Little Ice Age. Anthropogenic aerosols then introduced a confounding factor which the Vikings simply weren't capable of, hence cooling.

It was still arguable in the 1980's that the world was no warmer than in the MWP but that's simply untenable now (although some people cling to it desperately). Now we're warming from the already-warm, and if China and India get into clean air the way developed nations did in the 70's the rate can only increase.

Half of the CO₂ increase has occurred since the mid-70's (that's probably out-of-date by now, but so am I in some ways) so we've yet to see just what it has in store for us since, of course, the rate of AGW lags behind the rate of CO₂ increase.

Pretty much.

Because the error bands get wider as you go farther back in time you can’t say with certainly that current temperatures are warmer than the Roman period, even though it’s likely that they are. Conversely you can’t say the Roman period is warmer than today, and it’s unlikely that it was. Even though the actual number is currently higher than it was in the Roman period the uncertainty is still less than 1 sigma.

As you say there is evidence from specific sites that temperatures have not been this high in 5000 – 8000 years, which basically takes us back to the Holocene optimum. This dispute the fact the orbital conditions that created the Holocene optimum have long since passed and have been in an 8000 year cooling pattern, which has revered in a matter of decades.