Moderated Global Warming Discussion

[lomiller]

What temperature increase is that exactly? According to the best studies I can find they show a .7C rise over the last 1000 years.

So a 0.3 deg drop over 900 years + a 1 deg increase over another 100 is “a 0.7 deg increase over 1000 years”



There is a statistically significant trend of 0.17 deg per decade since 1970. Whatever the trend was before this, that’s where the trend sits now.

There is no evidence for any change in this trend, rather you have listened to questionable sources who cherry picked starting and ending years to calculate a trend that turns out not to be statistically significant. Don’t just believe whatever random stuff you find on the internet, you need to apply some critical thinking or you will always end up falling for woo like this.

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

False. The Holocene maximum was comparable top today, possibly slightly warmer but the uncertainly is such that it’s not possible to conclusively say it was warmer (or cooler). It’s been ~125 000 years since the earth was warmer that 20th century norms, but that’s usually taken to mean circa 1950 and we’ve warmed since then.

BTW, information on the timing and magnitude of the Holocene optimum doesn’t come from “historians and archaeologists” it comes from climatologists, the same climatologists you conveniently ignore when they talk about current warming

"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

This is a local temperature proxy form a region that varies more greatly than global temperatures. It also specifies BP = before present which in climate papers typically refers to temperatures circa 1950. They later refer specifically to 1961-1990 average , but it’s not clear if this is how they are defining “present day”. Either way temperatures in 2010+ are already significantly greater than their comparison point, so it’s not at all clear that this area was warmer during the Holocene optimum.

 

[Mikemcc]

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.

Picking any time longer than approx 17 years will result in sufficient samples to determine statistical significance, by cherrry picking dates less than that you can show damned near anything because of the noise in the system. The only way that you can show 'little or no warming' is to pick a start date of 1998, a year either way shows clear warming trends. Foster and Rahmstorf have analysed some of the variations and show a clear warming trend:

Abstract
We analyze five prominent time series of global temperature (over land and ocean) for their common time interval since 1979: three surface temperature records (from NASA/GISS, NOAA/NCDC and HadCRU) and two lower-troposphere (LT) temperature records based on satellite microwave sensors (from RSS and UAH). All five series show consistent global warming trends ranging from 0.014 to 0.018 K yr^-1. When the data are adjusted to remove the estimated impact of known factors on short-term temperature variations (El Ni˜no/southern
oscillation, volcanic aerosols and solar variability), the global warming signal becomes even more evident as noise is reduced. Lower-troposphere temperature responds more strongly to El Ni˜no/southern oscillation and to volcanic forcing than surface temperature data. The adjusted data show warming at very similar rates to the unadjusted data, with smaller probable errors, and the warming rate is steady over the whole time interval. In all adjusted series, the two hottest years are 2009 and 2010.

http://iopscience.iop.org/1748-9326/6/4/044022/pdf/1748-9326_6_4_044022.pdf (my bold)

 

[Trakar]

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.

http://www.ipcc.ch/ipccreports/tar/wg1/figts-2.htm

looks similar, though the latest episode is more compressed than the 1910-1940 stretch. Of course, this is 2001 - WG1, I'll be interested to see what the upcoming report has to say as it includes the last decade's temps into this dataset. Ultimately, the problem is that prior to the late 20th sentury and satellites (that allow broad expanse consistently evaluated surface temp measurements in real-time) it is really difficult to attach much surety to temp changes in less than 50 year blocks of time.

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.

In addition to this, the sun was, and is, one of the most important climate drivers we know. The signature of the solar signal in the period qualified as the MWP (and even in the 1910-1940 period) seems to suggest that it may have played a large role in these warmings. This is a major misportrayal, by those who seek to distort climate science understandings. It has never been that there is a rejection of natural forcing elements, even now in the current episode of planetary climate change 10-20% (IIRC) of the warming is due to natural forcings and feedback effects. Likewise for the last several thousand years humans have had a small but significant climate impact as we cleared forests, diverted streams and rivers, drained swamps, etc.,. It has only been in the last couple centuries when we have started burning large amounts of fossil fuels releasing tens of millions of years (hundreds of billions of tons every few decades) worth of stored carbon into the atmosphere, that we have transitioned from being a relatively minor factor in our planet's climate, to being the primary climate forcing factor in this episode of change.

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.

And Lord help us if the sun does kick into a more active level anytime during the time while our atmospheric contributions are still dominating the climate trends.

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)...

is that a "best if used by" or "expiration" date?

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.

Story of my life,...check is in the mail!

 

[Trakar]

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.

Average Monthly Arctic Sea Ice Extent February 1979 - 2012
http://nsidc.org/arcticseaicenews/files/2012/03/Figure3.png

or

What’s in a number? Arctic sea ice and record lows
http://nsidc.org/icelights/2011/11/02/what’s-in-a-number-arctic-sea-ice-and-record-lows/

...Breaking records
If different satellite sensors can disagree on whether a record was reached, what does a record low really mean? “Whether this year was lowest or second-lowest isn’t important in the big picture of climate change,” said Meier. What does matter is the long-term trend. He said, “The long-term trend is becoming more and more clear: sea ice has declined by 12 percent per decade since 1979, and the last five years have still been the five lowest in the satellite record.”

So while new records can attract attention to declining sea ice extent, researchers say that focusing only on these milestones can be misleading. “Records are always an interesting marker,” said Meier, “They’re worth noting, but they only really have meaning in the context of the long-term trend.” Like record-breaking heat waves or snowstorms, sea ice extent is influenced by weather conditions in the Arctic that vary from year to year. So while researchers expect the decline to continue, nobody expects to see new records every single year. Stefan Rahmstorf from the Potsdam Institute for Climate Impact Research, pointed out in a recent article that the record or near-record ice extent this year reinforces the idea that the low ice extent in 2007 was not just an anomaly.

That downward trend means big changes for the Arctic Ocean—from increased shipping to changing wildlife habitats. Perhaps the biggest wildcard is the potential for even greater warming as the additional open water absorbs more heat from the sun...

or

Large Decadal Decline of the Arctic Multiyear Ice Cover
http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-11-00113.1

Discussion and Conclusions

Satellite observations of the perennial ice cover in the Arctic region have provided some of the most convincing evidence of a rapidly changing Arctic. The updated values for the trends in the extent and area of the perennial ice are -12.2% and -13.5 %/decade, respectively, revealing stronger negative trends than previously reported. The analysis of the thick component of the perennial ice, called multiyear ice, as detected by satellite data in winter, yielded an even more rapid rate of -15.1 and -17.2 % per decade for the multiyear ice extent and ice area, respectively. The much higher rate of decline of the multiyear ice than the perennial ice cover is clearly an indication that the average thickness of the Arctic ice cover is declining...

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.

History of sea ice in the Arctic
http://bprc.osu.edu/geo/publications/polyak_etal_seaice_QSR_10.pdf

...The current reduction in Arctic ice cover started in the late 19th century, consistent with the rapidly warming climate, and became very
pronounced over the last three decades. This ice loss appears to be unmatched over at least the last few thousand years and unexplainable by any of the known natural variabilities...

In geology we realise that Earth processes take decades or more to mature.

indeed we do.

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.

Unless you have some compelling published studies to present, your recollections sound about as reasonable as your prognostications. If you want to look at paleoclimate records, however, there are plenty of interesting datasets to examine. Nothing new under the sun.

Patterns, processes, and impacts of abrupt climate change in a warm world: the past 11,700 years - http://onlinelibrary.wiley.com/doi/10.1002/wcc.152/full

from conclusion -
...The examples demonstrate that impacts could depend upon the specific sequence of events or processes. In fact, climate changes need not be globally abrupt nor involve nonlinear processes to have important and abrupt consequences, but abrupt impacts could well increase in frequency as the rate of global change increases. The potential that higher rates of global change can result in more frequent abrupt impacts at local scales provides one of the strongest rationales for limiting the rate of future climate changes, especially if thresholds in some local systems can feedback to produce broad-scale consequences.

Northern Hemisphere temperature patterns in the last 12 centuries
http://www.clim-past.net/8/227/2012/cp-8-227-2012.pdf

...Our study also reveals that the 17th century was dominated by widespread and coherently cold anomalies representing the culmination of the LIA. Understandably, the centennial resolution of this study precludes direct comparison of past warmth to that of the last few decades. However, our results show the rate of warming from the 19th to the 20th century is clearly the largest between any two consecutive centuries in the past 1200 yr....

Insights from past millennia into climatic impacts on human health and survival
http://www.pnas.org/content/early/2012/02/03/1120177109.full.pdf+html

 

[Trakar]

Yes, it is sad that they must pay homage to the AGW elite to get a paper published...

If you mean that publications in mainstream scientific journals require compelling supporting evidences and sound derivative logic in the formulation of one's research and that one can't merely assert opinion as fact and expect publication, then I agree.

 

[Trakar]

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.

I would very much like to see the compelling evidence you have in support of this assertion, but it seems, to any proper examination of the available mainstream scientific considerations that your references and understandings are incorrect.

PALEOCLIMATOLOGICAL EVIDENCE FOR UNPRECEDENTED RECENT TEMPERATURE RISE AT THE EXTRATROPICAL PART OF THE NORTHERN HEMISPHERE - http://onlinelibrary.wiley.com/doi/10.1111/j.1468-0459.2011.00002.x/full

...All the nine temperature records, used in our work, agree that the twentieth century was the warmest throughout the last 500 years. Statistical analyses of eight out of nine palaeoclimatic reconstructions showed that in the extratropical part of the Northern Hemisphere the 1988 to 2008 time period was the warmest two decades throughout the last 1000 years with a probability of more than 0.70. However, the reconstruction of McIntyre and McKitrick (2003) showed that at the beginning of the fifteenth century the climate was warmer. In spite of some discrepancy between our and their results, which may be explained by different temperature reconstructions, those author's data in general suggest that the last two decades was a period of abnormally high temperatures and, hence, an abnormal period for the climatic system. This suggests that at the end of twentieth century the climatic system was additionally perturbed by some new forcing factor on a global scale...

Recent Warming Reverses Long-Term Arctic Cooling - http://denverclimatestudygroup.com/O...0909041236.pdf

...Orbitally driven summer insolation continued to decrease through the 20th century, implying that summer temperatures should have continued to cool. Instead, the shift to higher temperatures during the 20th century reversed the millennial-scale cooling trend. The warming during the 20th century (and first decade of the 21st century) contrasts sharply with the millennial-scale cooling, with the last half-century being the warmest of the past two millennia. Our synthesis, together with the instrumental record, suggests that the most recent 10-year interval (1999–2008) was the warmest
of the past 200 decades. Temperatures were about 1.4°C higher than the projected value based on the linear cooling trend and were even more anomalous than previously documented.

Growing Season Temperatures in Europe and Climate Forcings Over the Past 1400 Years - http://www.plosone.org/article/info:doi/10.1371/journal.pone.0009972

Conclusions -
We found that our results were accurate back to 750. Cold periods prior to the 20th century can be explained partly by low solar activity and/or high volcanic activity. The Medieval Warm Period (MWP) could be correlated to higher solar activity. During the 20th century, however only anthropogenic forcing can explain the exceptionally high temperature rise. Warm periods of the Middle Age were spatially more heterogeneous than last decades, and then locally it could have been warmer. However, at the continental scale, the last decades were clearly warmer than any period of the last 1400 years. The heterogeneity of MWP versus the homogeneity of the last decades is likely an argument that different forcings could have operated. These results support the fact that we are living a climate change in Europe never seen in the past 1400 years.

...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.

the "horrible things" have started, but it isn't so much about what has happened already. Equilibrium takes a while to filter through the climate system and we are still contributing to the imbalance at an ever increasing rate. If we look at the Holocene Maximum which the predominant, modern mainstream science perspectives and references hold as approximately equal to today. It isn't what gradually happened over 10's of thousands of years as the planet warmed up to that temperature through a set of gradual orbital shifts and CO2 feedbacks that we have to worry about, but rather the fact that we have warmed this much in the last century and a half, are far outpacing the lag of a CO2 driven warming (current temps are a flashing billboard along the sides of the track we are accelerating down) headed toward a future that is potentially only mirrored in the likes of the PETM, And we may reach those peaks in a few hundreds of years rather than the tens to hundreds of thousands it took for pre-PETM conditions to evolve.

Paleoclimate Implications for Human-Made Climate Change - http://arxiv.org/ftp/arxiv/papers/1105/1105.0968.pdf

...Consistent with our earlier study (Hansen et al., 2006), we conclude that, with the global surface warming of 0.7°C between 1880 and 2000 (Hansen et al., 2010), global temperature in year 2000 has reached at least the Holocene maximum...One conclusion deserving emphasis is that global mean temperatures in the Eemian and Holsteinian were less than 1°C warmer than peak Holocene global temperature. Therefore, these interglacial periods were also less than 1°C warmer than global temperature in year 2000.
Fig. 6 also suggests that global temperature in the early Pliocene, when sea level was about 25 m higher than today (Dowsett et al., 1994), was only about 1°C warmer than peak Holocene temperature, thus 1-2°C warmer than recent (pre-industrial) Holocene....

and we're approaching 10 gigatons of carbon emissions per year and still accelerating in our emission levels. It was the lagging CO2 levels in each of these previous episodes that pushed the golbal temperature to such high levels. We currently have more CO2 in our atmosphere than has existed since the late eocene when temps were 2.5-4.0º C higher and sealevels were 25 meters higher than present values.

 

[Trakar]

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.

No, and neither does climate science propose any such thing, but then, as this post (and the rest over the last few days) well illustrate, properly reading and understanding science doesn't seem to be a very high priority for you.
If all you wish to discuss are your personal opines regarding how you wish the world worked,...carry on! When you actually want to talk about mainstream science or public policy options given the best available science, we can have that talk.

So far you only seem to be presenting arguments that are a day late and a dollar short and were generally demonstrated to be erroneous back when they were fresh.

 

[temporalillusion]

http://scrippsnews.ucsd.edu/Releases/?releaseID=1258

A new study contrasting ocean temperature readings of the 1870s with temperatures of the modern seas reveals an upward trend of global ocean warming spanning at least 100 years.

The research led by Scripps Institution of Oceanography at UC San Diego physical oceanographer Dean Roemmich shows a .33-degree Celsius (.59-degree Fahrenheit) average increase in the upper portions of the ocean to 700 meters (2,300 feet) depth. The increase was largest at the ocean surface, .59-degree Celsius (1.1-degree Fahrenheit), decreasing to .12-degree Celsius (.22-degree Fahrenheit) at 900 meters (2,950 feet) depth.

"The significance of the study is not only that we see a temperature difference that indicates warming on a global scale, but that the magnitude of the temperature change since the 1870s is twice that observed over the past 50 years," said Roemmich, co-chairman of the International Argo Steering Team. "This implies that the time scale for the warming of the ocean is not just the last 50 years but at least the last 100 years."

I have a question about the portion in bold. This seems like something AGW deniers would pick up on right away. I guess my question would be how could AGW cause such changes in oceanic temperatures if atmospheric CO2 increases in the 1800's were comparatively low compared to the last 40 years?

TIA

 

[CapelDodger]

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.

I'd find it surprising if these "best studies" show recent temperatures to be 0.7C higher than in the MWP, which is what you're saying here. Do you have references?

It's not the statistical significance of warming which is of import, by the way, it's the physical manifestations which matter. Expansion of the tropics, for instance.

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.

3C warmer is a gross exaggeration, it may have been as much as 1C, or we may already have outstripped it.

What makes you think the tropics weren't more extensive in those days? Exactly what "horrible things" are you referring to? There was no flooding of coastal cities in the Stone Age, that's true. There was no major effect on agriculture from shifting rainfall patterns, since with a world population of a couple of million there was plenty of room to move.

Try going back to those conditions with seven billion people, very little room left, coastal cities galore, national boundaries and property-rights, and industrialised warfare - sounds potentially horrible. Things aren't too great in Mexico or Texas right now.

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

No, it wasn't. Agriculture didn't require "better weather", if that's what you're thinking, and settled living didn't require agriculture if that's what you're thinking.

"Nice" would be keeping things pretty much as they have been for the last two thousand years. Another Little Ice Age would be fine; been there, did that, came out firing on all cylinders with guns blazing. Another Holocene Maximum would be very nasty.

 

[Trakar]

Speaking of Public Policy discussions:

I recently reviewed this paper and though that it well laid out one aspect of the public policy discussion that will become ever more important in the coming years, and especially as the new IPCC report comes out next year and people begin to focus on it and the other (lessor known) reports the IPCC has produced over the last few years.

I suspect that this paper will begin to garner greater attention in the near future due not only to it's content, but also due to its authors, one who is a leading climate scientist at the University of Washington, Gerard Roe and the other who is a respected economist also teaching at the Foster business school at the University of Washington, Yoram Bauman.

Both of these researchers have a real speaking and teaching gift of taking complex subjects and making them easy to grasp, understand and remember. They accomplish this through real world connections and humor. In fact, professor Bauman is also known as the Standup Economist and has a blog by that name. He is a recognized stand-up comedian in addition to having his doctorate's in microeconomics, strong grounding in climate and environmental economics and has a new book out called "The Cartoon Introduction to Economics, Vol. 2",...but on to the paper.

Climate sensitivity: should the fat tail wag the policy dog?​

http://www.standupeconomist.com/wp-content/uploads/2012/03/FatTail_ClimaticChange_revise.pdf

...In this paper we focus on the role of two robust physical properties of the climate system: the enormous thermal inertia of the ocean, and the long timescales associated with high climate sensitivity. Economic models that include a climate component, and particularly those that focus on the tails of the probability distributions, should properly represent the physics of this slow response to high climate sensitivity, including the correlated uncertainty between present forcing and climate sensitivity, and the global energetics of the present climate state. If climate sensitivity in fact proves to be high, these considerations prevent the high temperatures in the fat tail from being reached for many centuries. A failure to include these factors risks distorting the resulting economic analyses. For example, we conclude that fat-tail considerations will not strongly influence economic analyses when these analyses follow the common|albeit controversial|practices of assigning large damages only to outcomes with very high temperature changes and of assuming a signicant baseline level of economic growth...

 

[Trakar]

http://scrippsnews.ucsd.edu/Releases/?releaseID=1258

I have a question about the portion in bold. This seems like something AGW deniers would pick up on right away. I guess my question would be how could AGW cause such changes in oceanic temperatures if atmospheric CO2 increases in the 1800's were comparatively low compared to the last 40 years?

TIA

The wording seems a bit awkward, but it looks like they are saying that the ocean temperature over the last ~150 years (2010 - 1870 = 140) is almost twice the ocean temperature rise of the last 50 years. To me this says that ocean temperatures over the last 50 years have risen twice as fast as they did over the 100 year period before then. As they are averaging over long periods of time, I don't find this particularly unusual or unexpected.

(press releases aren't noted for their clarity or accuracy regarding scientific research subject matter.)

 

[lomiller]

http://scrippsnews.ucsd.edu/Releases/?releaseID=1258





I have a question about the portion in bold. This seems like something AGW deniers would pick up on right away. I guess my question would be how could AGW cause such changes in oceanic temperatures if atmospheric CO2 increases in the 1800's were comparatively low compared to the last 40 years?

TIA

Couple of points.

First, climate response to CO2 is not linear, at lower concentrations less CO2 is required to cause the same amount of warming. The generally accepted range is that every time atmospheric CO2 doubles the earth will warm 2-4.5 deg C, with 3 deg C being the most likely. In absolute terms less CO2 was required to warm the planet 100 years ago than would be needed to cause the same warming today.

Second, there are more than one climate forcing acting on the earth. In the first half of the 20th century in addition to anthropogenic forcing there were 2 other warming influences increased solar activity and reduced volcanic activity.

About 20% of the warming in the first half of the 20th century was due to reduced volcanic activity, 40% was due to increasing solar activity at the time and the last 40% was due to various anthropogenic forcing. In the second half of the 20th century volcanic activity returned to normal and solar activity stabilized so pretty much 100% of the warming in that period can be attributed to human activity.


Third, there isn't just one component to anthropogenic forcing, there are three or 4. Co2 you know of, but Methane is a big warming factor as well, accounting for maybe 1/2 as much warming as CO2.

There is also a big cooling effect from aerosols (not the spray can type ) that is about as big as the warming from Methane, but this is the most difficult to estimate accurately.

The last is Ozone, which is is also a greenhouse gas. It's effects are smaller than the other three but not entirely negligible, especially in the Antarctic. Since Ozone is a greenhouse gas, damage to the ozone layer creates a cooling effect and it one of a number of reasons central Antarctica hasn't warmed much but as it slowly regenerates it will actually cause warming. IOW it's "built in" warming that has yet to be felt.


Overall 2-4 roughly cancel each other out and there is no current warming/cooling from solar or volcanic activity which leaves CO2 as the main driver of current changes but in reality it's the sum of all the above that cause the climate to change. It's worth noting, however that the effects of CO2 are much longer lived than the others, meaning it will be around strongly form hundreds of years and in some amounts form hundreds of thousands, while the others would be gone in a few decades if we stopped messing with them.

 

[Warmer1]

From the BBC
http://www.bbc.co.uk/news/science-environment-17611404

CO2 'drove end to last ice age'

"A new, detailed record of past climate change provides compelling evidence that the last ice age was ended by a rise in temperature driven by an increase in atmospheric carbon dioxide."

""At the end of the last ice age, CO2 rose from about 180 parts per million (ppm) in the atmosphere to about 260; and today we're at 392," explained lead author Dr Jeremy Shakun."

"So, in the last 100 years we've gone up about 100 ppm - about the same as at the end of the last ice age, which I think puts it into perspective because it's not a small amount. Rising CO2 at the end of the ice age had a huge effect on global climate."

As you can see in the graph I posted earlier, linked again below, CO2 concentrations have fluctuated between around 180 ppm and 260 ppm for the last 800,000 years driven by the Milankovich wobbles, so once again the increase of 100 ppm in the last 100 years is absolutely unprecedented over the last 800,000 years. Look at the right side of the graph and you see uprecedented beyond belief.

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

"The key result from the new study is that it shows the carbon dioxide rise during this major transition ran slightly ahead of increases in global temperature."

Now imagine how temperature will follow the unprecedented CO2 increases on the right side of the graph and one can well imgine we will have a very rapidly changing world. We are recording and witnessing the changes.

"It looks as though whatever kicked off this whole sequence of events to get out of the ice age was something really, in global terms, rather minor and regional, and yet it led to a sequence of events that led to a complete change in the way the surface of the Earth looked, with ice sheets disappearing.

And as one famous palaeoclimatologist put it: 'we poke it at our peril'."

However, when one looks at the climate over the last 200 years this is much ado about nothing.

I see in your posts that you mention subjects you studied many years ago and that may be why you are not as up to date as others here. We can now look back 800,000 years based on a lot of very recent core samples and climate studies.

I may be wrong though so please post the links to the science that is the basis for your conclusions and statements.

 

[CapelDodger]

I have a question about the portion in bold. This seems like something AGW deniers would pick up on right away. I guess my question would be how could AGW cause such changes in oceanic temperatures if atmospheric CO2 increases in the 1800's were comparatively low compared to the last 40 years?

TIA

Note that it's from the 1870's, not the 1800's generally. Prior to that emissions were pretty slight but from then the rate really started to pick up as oil came into the picture, initially for lighting. Then there was electricity generation (mostly from coal), and, gradually, internal combustion.

That, and what lomiller said .

 

[CapelDodger]

From the BBC
http://www.bbc.co.uk/news/science-environment-17611404

CO2 'drove end to last ice age'

[snip]

"The key result from the new study is that it shows the carbon dioxide rise during this major transition ran slightly ahead of increases in global temperature."

That's going to stir things up. I trust Shakun et al are ready for what's likely to come at them and their institutions after this.

It coincides remarkably with http://www.sciencedaily.com/releases/2012/04/120404133801.htm , also in Nature, about the PETM and subsequent climate excursions :

"In a new study reported in Nature, climate scientist Rob DeConto of the University of Massachusetts Amherst and colleagues elsewhere propose a simple new mechanism to explain the source of carbon that fed a series of extreme warming events about 55 million years ago, the Paleocene-Eocene Thermal Maximum (PETM), and a sequence of similar, smaller warming events afterward."

That mechanism being permafrost melting in response to Milankovich cycles (" changes in Earth's tilt and orbit").

The amounts and distributions of permafrost were very different at those transitions to what they are today, and the process was relatively slow, so we can't predict a significant fast positive feedback during the current transition. The slow feedback is likely to be significant, though.

 

[CapelDodger]

The wording seems a bit awkward, but it looks like they are saying that the ocean temperature over the last ~150 years (2010 - 1870 = 140) is almost twice the ocean temperature rise of the last 50 years. To me this says that ocean temperatures over the last 50 years have risen twice as fast as they did over the 100 year period before then. As they are averaging over long periods of time, I don't find this particularly unusual or unexpected.

My response was much the same. Featuring a snapshot of the Challenger measurements looks to me, frankly, like an attempt to piggy-back on James Cameron's recent publicity.

I take a pride in my cynicism .

 

[Trakar]

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.

Please quote where I have stated what you assert.

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

Have you actually read this paper, or are you pulling it off of some blog listing?

El Niño variability off Peru during the last 20,000 years
http://www.agu.org/pubs/crossref/2005/2004PA001099.shtml

...Within the medieval period of extraordinarily weak El Nin˜o activity NH temperatures peaked; the period as a whole and secular temperature and El Nin˜o activity variations are anticorrelated. Dating uncertainties could easily be held responsible for the secular anticorrelation within the medieval anomaly but even so, that would leave a broad medieval El Nin˜o weakening during the NH medieval thermal optimum...During the last millennium, El Nin˜o activity resembles the global temperature (or vice versa). Thus a major Holocene El Nin˜o weakness during the late medieval period that must have cooled down large parts of the lower latitudes implies that the climate in medieval times can only be of limited use as an analogy in the recent
discussion of climate change.

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

You do realize that this is the same Antarctic peninsula discussed earlier, correct? and these authors don't seem to be in any rush to support your argument and make comments more in accord with the more recent researchers:

...Regardless of the exact cause for the LIA, MWP, and earlier climatic events, these events most likely reflect climate change on the regional or hemispheric scale, considering intensity and duration (decades to centuries) of the LIA and MWP. Therefore, the high-frequencyMS fluctuations observed in the eastern Bransfield Basin as a proxy for late Holocene climate are important for separating natural variability from anthropogenic effects in potential global warming.

Weren't we just talking about the distinctions between correlation and causation?

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

Another decade old paper dealing with a small island off the coast of the same penninsula discussed in the other two papers. Dare we check to see if the author's believe their work supports your assertions?

...enhanced 18O values occur during more arid, warmer conditions with longer periods of open water in summer. This isotope record can be used to determine century-scale to decadal variability in air circulation and moisture origin. Strong similarities with other Holo cene proxy records from the Weddell Sea and Antarctic Peninsula Region are apparent, including the mid-Holocene climate optimum followed by the Neoglacial and, most recently, late twentieth-century climatic warming...

The abstract doesn't seem very supportive, but despite the region, I'll withold full assessment until I can look at the actual paper.

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

A nearly 35-year old paper using a single stalagmite, from a single cave in New Zealand referencing papers from ~50 years ago. Not that there is anything fundementally wrong with the papers given the state of understandings at the time, but there is nothing in them that I can see which either compellingly supports your assertions, or that refutes any of the things I have said.

 

[temporalillusion]

Thanks Trakar and lomiller

 

[Haig]

Indeed, that does about say it all for poor Piers.

Nope, he's doing better than ever (No I'm not back , just passing, too busy these days)

Increasingly popular - WeatherAction USA "10/10 Brilliant consistent long range skilled extremes forecasts"

All the key weather scenarios and major events USA in each of the last ten forecast time periods have been basically confirmed in a recent check from late February:-
For samples and links see below. For full forecasts see http://www.weatheraction.com/wactmember5.asp USA Maps

Feb28-March 1st
"Snow in NE USA ~29Feb and major tornado activity MidWest & S/E USA at start of March were driven by our Top Red (R5) Solar Factor predicted 30 days ahead for weather effect around Feb 28-March 1 (with uncertainties/extensions ~1day) which triggered these events”, says Piers Corbyn Astrophysicist WeatherAction.com confirmed http://www.weatheraction.com/docs/WANews12No11.pdf

MARCH 1-3
(COMMENT ON TV WEATHER FORECAST MAPS OF THE TIME rather than forecast) Solar Factors: R5 ends after ~March 1st. =~2-3rd becomes NSF/Q. "The very significant intense activity across USA in period ~28th-1st {last weather period in Feb forecast} was/is driven by the top level "R5” solar influences predicted. After 1st Mar although the general motion of systems West to East continues the intensity of activity will drop generally later. Confirmed see eg Mar2nd http://www.hpc.ncep.noaa.gov/dailywxmap/index_20120302.html

MAR 4-8 Solar Factors: R3, 6-7 March
Deep thundery low pressure over East of Great Lakes and NE USA with cool showery weather around West part of Great Lakes. Confirmed http://www.hpc.ncep.noaa.gov/dailywxmap/index_20120305.html

MAR 9-12 Solar Factors: NSF/Q then R2 11-12th.
High pressure (N-S) tendency persists in central parts and Low pressure Mexico gives very warm South winds in SW USA. Moderately active Low (moving East)over Great Lakes / East of Great Lakes…See http://www.hpc.ncep.noaa.gov/dailywxmap/index_20120313.html for Temp increase(ing)(ed) early 13th

March 13-15 Solar Factors: R4 13-15
Heavy thundery attack NW USA confirmed http://www.weatheraction.com/docs/WANews12No14.pdf
Massive thunderstorms, giant hail and tornado activity lower mid-west confirmed: http://www.weatheraction.com/docs/WANews12No16.pdf

MAR 16-20 Solar Factors: NSF/Q then R3 19-20th.
The unseasonal heat in central and SE USA in 3rd week of March was accurately predicted 3 weeks ahead
http://climaterealists.com/attachments/ftp/WA News 17 2012.pdf (WANews17)

MAR 21-23 Solar Factors: NSF/Q
Texas Heat warned "Spot-on” by WeatherAction 24 days ahead
http://climaterealists.com/attachments/ftp/WA News 18 2012.pdf (WANews18).
The WeatherAction forecast maps for these periods 16-20th and 21-23rd clearly distinguish between the different heat distributions and were both confirmed.

MAR 24-28 Solar Factors: NSF/Q then R4 26-28th
… Frontal activity increases dramatically 26-28th. ……. Widespread intense tornadic developments 26-28th including much of mid west and especially in South and midparts of ‘tornado alley’ Low pressure Mexico, Hot/very warm in SW. High pressure SouthWest coast
Powerful active Low attacks Vancouver/NW from around 26th giving major thunderstorms. Confirmed, see http://www.hpc.ncep.noaa.gov/dailywxmap/index_20120327.html for powerful Active thundery low ~mid-west, heat ~SW and Powerful attack NW

MAR 29-31 Solar Factors: NSF/Q
High pressure persists over Great Lakes and Low pressure over Mexico. SW parts are very warm or hot…. Generally confirmed http://www.hpc.ncep.noaa.gov/dailywxmap/index_20120331.html

APRIL 1-4 Solar factors R2 (later R3) 2-3rd
Generally mobile, with weather systems moving west to east. Thunder/tornado developments in central parts. Confirmed (eg) across the ArkLaTex http://www.ksla.com/story/17316320/strong-winds-cause-several-fallen-trees-across-the-arklatex

Joe Bastardi: Kudos to NBC for blaming heat on Jet Stream!
http://climaterealists.com/index.php?id=9316&linkbox=true&position=1

Comments

"I posted on the ABC article site:
(Piers Corbyn says: March 21, 2012 at 7:54 pm))

Claims that this weather is 'new' and/or something to do with mankind's CO2 are delusional nonsense for which there is no evidence.
Some points to note:

1. As has been pointed out the world anyway is not now warming but cooling - see:
http://climaterealists.com/index.php?id=9316&linkbox=true&position=1

2. In terms of world averages this warmth in center and east USA (NOT West) is more than offset by the prolonged cruel deadly cold over a much wider area - Europe + Asia + Middle East and North Africa over late Jan and most of Feb.

3. A long period of continuing extreme weather situations driven by jet stream shifts which are driven by predictable solar-magnetic and lunar effects were warned of by us (WeatherAction) two years ago.

4. The specific continuing heat in parts of USA and contrasting cold in the West for a time as well as the giant hail + tornado events in the lower mid-West in mid March were specifically predicted 3 weeks ahead by our Solar-Lunar Action Technique (SLAT) - see
http://climaterealists.com/index.php?id=9306

5. All the major extremes in USA in 2011 including the tornado swarm which destroyed Joplin and the Tropical storm which became named Irene were predicted in long-range by our Solar-Lunar Technique and all based on things that have happened before.
There is NOTHING NEW going on.

CO2 delusionism is holding back the advance of Science and the application of scientific forecasts which can save suffering, money and lives.

Piers Corbyn,
WeatherAction.com long range forecasters"

Just Out 26 March MUST SEE YOUTUBE: "Piers Corbyn knocks them dead at the Internationale Klima- und Energiekonferenz in München, Nov 2011
http://www.youtube.com/watch?v=tbGWLgpylKc&feature=youtu.be
.
.

 

[Trakar]

Couple of points.

First, climate response to CO2 is not linear, at lower concentrations less CO2 is required to cause the same amount of warming. The generally accepted range is that every time atmospheric CO2 doubles the earth will warm 2-4.5 deg C, with 3 deg C being the most likely. In absolute terms less CO2 was required to warm the planet 100 years ago than would be needed to cause the same warming today.

Second, there are more than one climate forcing acting on the earth. In the first half of the 20th century in addition to anthropogenic forcing there were 2 other warming influences increased solar activity and reduced volcanic activity...

Don't forget land usage. And I'm not just talking 19th and 20th centuries, though there has been a greatly magnified acceleration of land usage changes in the last couple of centuries. Pre-columbian americans cleared vast tracts of south, central and north american forests and jungles; many of these jungles and forests regrew after climate and foriegn/domestic pestilences took their toll on populations that we are only now coming to fully appreciate in regards to size and inter-connected complexities. Noble or not, they lacked the tools to appropriately appreciate what was happening to them or why (other than that the Gods must be punishing them for their failings and weaknesses - hopefully our understandings are sufficient to yield more rational reactions.). Land use means more than just forests, it can refer to swamps and wetlands that are drained or reclaimed, streams and rivers that are diverted or dammed, lakes that are drained, paving and concrete expanses, etc.,. According to some research, human climate influences may stretch back to the holocene optimum period when human agricultural efforts first went large-scale, predominantly in the lower latitudes, at or shortly before the birth of "Great Civilizations."