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Post by steve on Jan 6, 2010 11:01:17 GMT
If one throws out the climate reconstructions of the Mann, Briffa faction, the older - and newer - scientific body clearly supports a worldwide MWP. I realize this is a very broad statement but suggest those skeptical of it simply start reading. Start for example with latitudinal and altitudinal tree-line studies (note tree lines not tree rings). These invariably show that on all continents, tree lines extended higher- latitudinally and altitudinally - during the MWP than today. The highest recorded tree line elevations occured during the holocene thermal maximum a few thousand years ago. So, historically speaking, today's climate is well within recent and slightly older historical ranges. Climactically speaking, tree lines seem to me to be much more honest climate proxies than tree rings - being influenced primarily by temperatures rather than temperatures, precipitation, soil conditions and surrounding flora. Their limitation is that they don't offer proxies on annual time scales. Its also worthy of note that many of the high latitude tree ring proxies used by Mann and Briffa came from preserved dead trees extracted from the permafrost. An interesting irony. The northern latitudes of the northern hemisphere received more summer sunlight 1000 years ago. Evidence here is not evidence of global warmth. If you *continue* reading, you will tend to find that *any* evidence of possible warmth or dryness or anomalous climate in any period between 900 and 1350 is often ascribed to "the MWP". But that the same studies often show evidence in the opposited direction at other periods during the 900-1350 period. And a lot of them aren't necessarily temperature proxies. That is why when you average them out, they may suggest a warmer climate than the LIA, but be more equivocal about whether it is as warm as now.
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Post by spaceman on Jan 9, 2010 0:15:10 GMT
If you *continue* reading,
Continue reading what Steve? The Holy Book of AGW? Maybe you missed the record lows in south Florida. Which direction do you think orange juice and produce are headed? Which way did food prices go during the LIA in Dutch guilders? (assuming in your book there was a LIA) They closed the schools in Louisiana due to record cold. I saw a beautiful picture of England from space completely covered in snow. Tell me again that there has not been a variation in climate now or in the past.
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Post by aj1983 on Jan 9, 2010 0:39:20 GMT
Whoo, you have found some records (weather.gov only states near record cold). I think if you compare ALL records worldwide from the last decade you'll find 10x more warm than cold records. But, maybe you are right and we will experience a very cold second decade of the 21st century. One or two cold winters do not make an ice age . I'm STILL waiting for a below average year here. It's really weird that we haven't had one (not even close) since 1996... so please excuse me for being a AGW proponent.
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Post by nautonnier on Jan 9, 2010 1:10:49 GMT
Whoo, you have found some records (weather.gov only states near record cold). I think if you compare ALL records worldwide from the last decade you'll find 10x more warm than cold records. But, maybe you are right and we will experience a very cold second decade of the 21st century. One or two cold winters do not make an ice age . I'm STILL waiting for a below average year here. It's really weird that we haven't had one (not even close) since 1996... so please excuse me for being a AGW proponent. There was warming in the last decades of the twentieth century - either as a step in 1998 or as a trend. After ~2003 there has been no warming - we are on a plateau or slowly cooling. So rather obviously these years on the plateau or in slow cool will be warmer than the average of the warming years from 1980 onward. BUT there has been no significant warming even with the ARGO float 'adjustments'. The heat content of the Earth oceans and atmosphere has NOT increased. Tell us how heat content can stop rising with CO 2 continuing to rise to levels that Hansen claimed would prove to be a tipping point into runaway warming. Don't point at the Sun as we have been told by the AGW proponents that the Sun's TSI varies far too little to have ANY effect. See: www.ingentaconnect.com/content/mscp/ene/2009/00000020/F0020001/art00008;jsessionid=1k9alnlpdhr7c.alice"Ocean heat content data from 2003 to 2008 (4.5 years) were evaluated for trend. A trend plus periodic (annual cycle) model fit with R2 = 0.85. The linear component of the model showed a trend of −0.35 (±0.2) × 1022 Joules per year. The result is consistent with other data showing a lack of warming over the past few years."and pielkeclimatesci.wordpress.com/2009/03/24/new-paper-on-ocean-heat-content-changes-by-craig-loehle/"While the analysis presented in my paper, that was completed by Josh Willis, indicates the uncertainties are too large to definitively conclude that there has been cooling, the lack of warming in both papers are in conflict with the predictions of the global climate models as reported, for example, in the Climate Science weblog"and icecap.us/images/uploads/05-loehleNEW.pdf"Global satellite data is analyzed for temperature trends for the period January 1979 through June 2009. Beginning and ending segments show a cooling trend, while the middle segment evinces a warming trend. The past 12 to 13 years show cooling using both satellite data sets, with lower confidence limits that do not exclude a negative trend until 16 years. It is shown that several published studies have predicted cooling in this time frame. One of these models is extrapolated from its 2000 calibration end date and shows a good match to the satellite data, with a projection of continued cooling for several more decades."I needn't point out to you that changes in ocean heat content take orders of magnitude more energy than transient atmospheric warming. So there has been a considerable reduction of heat IN the Earth systems. All we hear are statements like ' heat is in the pipeline' and ' it will get really hot when its stopped getting cold' or even less logical - ' you can expect periods of cooling when more heat is trapped in the system by CO2"Perhaps its time to 'adjust' the ARGO float readings again?
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Post by sigurdur on Jan 9, 2010 1:22:04 GMT
As with most trends, there is a plateau when one changes directions in said trend.
If climate sensativity to co2 results in a 0.3C increase in normal temps, that 0.3C will buffer a cooling trend as well.
The main thing in all of this is to find out WHY we are cooling. It is obvious that when we find what changed to switch to cooling, that we will also find out what changes to cause the warming.
Physically, co2 is an atribute, but not a driver of climate. Methane is also an atribute of climate. We have had increased levels of methane and co2, however, it does appear that we have not had the response indicated to these increased levels.
The thrust of science should be to understand what has changed. Climate science has many unkowns. The questions are all with merit, the answers will be found.
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Post by spaceman on Jan 9, 2010 13:21:10 GMT
Somehow, sitting in a nice warm office playing with numbers talking about how warm it is going to be is different than seeing your orange trees covered in ice. As Ive said, I believe that there has been a warming trend, I don't know that for sure. A cooling trend does not mean that ice sheets will start covering the earth. What it does mean is that co2 has not been the main driver of climate change. It also means that there has been no planning for declining temps. A retreating grow line in Canada has implications for all crops. The zones where different crops can be grown will move accordingly. When temps drop, it takes out food producing areas. There are a lot more people to feed now than in the 1950's. A change back to colder weather will have devastating results without planning. It is irresponsible to think that this one thing is driving the climate, co2.
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Post by steve on Jan 9, 2010 14:23:13 GMT
If you *continue* reading, Continue reading what Steve? The Holy Book of AGW? Maybe you missed the record lows in south Florida. Which direction do you think orange juice and produce are headed? Which way did food prices go during the LIA in Dutch guilders? (assuming in your book there was a LIA) They closed the schools in Louisiana due to record cold. I saw a beautiful picture of England from space completely covered in snow. Tell me again that there has not been a variation in climate now or in the past. "If you *continue* reading" refers to what brian said about starting reading about treelines. Over the last thousand years, the northern latitudes have been gradually receiving less summer sunshine. Maybe that could be an explanation for treeline changes. Why would I tell you again that there has not been a variation in the climate since I never told you in the first place. And you have to stop confusing weather with climate. Temperatures have risen about half a degree on average in the last 50 years. How is that going to stop Florida frosts, or snowy Britain?
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Post by hairball on Jan 9, 2010 16:20:17 GMT
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Post by crakar24 on Jan 10, 2010 14:11:12 GMT
Nautonnier,
I have always enjoyed reading your posts your last is no exception. Logic and common sense will always prevail, well done.
crakar
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Post by AstroMet on Jan 10, 2010 14:24:35 GMT
Somehow, sitting in a nice warm office playing with numbers talking about how warm it is going to be is different than seeing your orange trees covered in ice. As Ive said, I believe that there has been a warming trend, I don't know that for sure. A cooling trend does not mean that ice sheets will start covering the earth. What it does mean is that co2 has not been the main driver of climate change. It also means that there has been no planning for declining temps. A retreating grow line in Canada has implications for all crops. The zones where different crops can be grown will move accordingly. When temps drop, it takes out food producing areas. There are a lot more people to feed now than in the 1950's. A change back to colder weather will have devastating results without planning. It is irresponsible to think that this one thing is driving the climate, co2. Great point Spaceman. This is something I feel strongly about, and is one of the major reasons why I am a long-range forecaster. Unless we all get off the ideological train, and get back to real science, with results, there is going to be a major series of climate-related disasters that will seriously affect agriculture and food production in the near future.
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jtom
Level 3 Rank
Posts: 248
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Post by jtom on Jan 10, 2010 23:28:59 GMT
The trouble is the mixed messages the average joe is getting from the experts. For example, vast amounts of croplands have been classified as disaster areas because of these weather-related events. At the same time, forecasters are predicting bumper-year crop-yields. People won't - and given this you can't expect them to - realize the disaster of ideological-based 'science' until the grocery store shelves are bare.
Which is it going to be for this year's crops, feast or famine?
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Post by sigurdur on Jan 11, 2010 0:36:27 GMT
If the long range forcasts are right, it is going to be famine.
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Post by stranger on Jan 11, 2010 1:05:20 GMT
Indeed, Sigurdur, the long term forecasters with the best record predict continuing cooling with shorter growing seasons. Of course, the firm of Jones and Mann disputes that.
However, let me put forth a slight quibble. Timberline and "treeline" need the disambiguation treatment, lest the discussion turn into a comparison of watermelons and grapes.
"Timberline" should be reserved for how far up a mountain - at what altitude - even the most cold hardy trees can no longer survive. When you see a mountain top naturally devoid of timber, the highest trees are at the timber line. Within known limits the Earth's precession does not affect timberline below 60 degrees north or south latitude. At this moment, timberline is generally "coming down the mountain," indicating a cooler climate at present.
In the context of climate, "Treeline" properly refers to the latitude the most hardy trees can no longer survive. This depends on many factors, including atmospheric and oceanic currents and the Earth's precession. Since precessional changes have been infinitesimal for as far back as we can measure it with any accuracy, and timberline has changed appreciably in places it would be best to examine the evidence without conjecture. From personal conversation with Arctic dwellers it appears the tree line is edging south as well. Also indicating a cooling trend.
Whether that trend is short or long term remains to be seen. But it would be a delicious irony if the most prominent exponent of "ice age now" gave up on his thesis just 22 years too early.
Stranger
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Post by aj1983 on Jan 11, 2010 12:23:27 GMT
If I understand it correctly, nearly? all natural variations are in a cooling phase, that's why many AGW skeptics and even some AGW proponents forecasts global cooling which will peak in 2030. Is it true that ALL major variations (will) show cooling?
I'm wondering which variations are in a negative phase? I've heard:
solar activity NAO/AO (NH only) PDO ...
~maybe ENSO tending toward more La Nina.
Any others I've forgot? What is the average period for these oscillations to stay negative, and is anything known on how large the temperature anomaly is for these phases? What will be the temperature drop around 2030? I think if you don't consider AGW (but even if you do), this very important to know for the coming decades. Maybe we should start a topic "what will the global average temperature (anomaly) be around 2030?"
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Post by aj1983 on Jan 11, 2010 12:24:33 GMT
If the long range forcasts are right, it is going to be famine. Even if they are wrong there is going to be famine.
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