From Penn State , another Mann paper with proxy sets, and a divergence problem. At least they are talking about the MWP, or as they call it, the Medieval Climate Anomaly which had been erased in previous papers Mann had been involved with. The attempt to link paleo data to the PDO is interesting too. Mann was not lead author, and hopefully none of the flawed PCA math he’s used to mess up other papers made it into this one. I’m hopeful, as the SI contains some equations/code.
The gist of the paper is this: they wanted to determine patterns of drought in the Pacific Northwest, so the authors used proxy data obtained both from tree rings and from oxygen isotopes related to lake sediments.
According to lead author Byron Steinman.“The data matched up on a short-term, decadal scale, however, on a longer-term, century scale, the records diverged. The tree-ring data suggests dry conditions during the Medieval Climate Anomaly summers while the isotope data suggest wetter-than-expected winters.”
New methods help scientists shed light on ancient climates
Tree ring and oxygen isotope data from the U.S. Pacific Northwest do not provide the same information on past precipitation, but rather than causing a problem, the differing results are a good thing, according to a team of geologists.
The researchers are trying to understand the larger spatial patterns and timing of drought in the arid and semiarid areas of the American West.
“We generally understand that the Medieval Climate Anomaly, a warm period in much of the northern hemisphere that occurred about 950 to 1250 was a dry period in the American West,” said Byron A. Steinman, postdoctoral researcher in meteorology, Penn State. “But there is complexity to the patterns of drought and it may not have been dry in winter in the Pacific Northwest.”
East of the Cascade Mountains, the Pacific Northwest is dry and hot in the summer and wet in the winter now.
Estimates of past precipitation are made from proxies like tree rings, which can record amounts of precipitation and temperature. But tree rings are better at recording what happens during the spring and summer, when the tree is growing, than in the winter when the tree is not.
Steinman, who worked with Mark B. Abbott, professor of geology and planetary science, University of Pittsburgh, his Ph.D. advisor, looked at oxygen isotopes found in 1,500 years of sediment at the bottom of lakes. The isotopic composition of these sediments can reflect the amount of water that enters the lake, especially during the wet season.
The analyzed lake sediments contain calcium carbonate in the form of calcite. The oxygen isotope ratios in this mineral relate directly to the isotope ratio of water in the lake. The researchers looked at sediment from two small lakes in Washington state. Castor Lake is on a plateau and water inflow is only from precipitation and groundwater. This lake has no outflow, so most water loss is through evaporation. Lime Lake, on the other hand, loses the majority of water through a permanent outflow stream, although all water enters in the same manner as for Castor Lake. By comparing the two lakes, the researchers could determine the water balance between evaporation and precipitation.
The researchers looked at two stable isotopes of oxygen — oxygen 16 and oxygen 18 — in the sediments. Oxygen 16 is lighter than oxygen 18, so during evaporation and lake draw down, more oxygen 16 evaporates out and the calcite in the sediments contain more oxygen 18. If the lakes are full of water, then there will be more oxygen 16 in the calcite. The layers of sediment that are laid down each year can be dated either by using carbon 14 dating of organic material or by locating layers of tephra — volcanic ash, that signifies known — dated volcanic eruptions. In this way, the researchers could pinpoint when drought occurred.
“The tree ring data and isotope data match up on a short term, decadal scale,” said Steinman. “On a longer term, century scale, the records diverge.”
While the decadal ups and down remain the same for both proxies, when viewed on a 100-year or longer scale, the proxies show differences. The tree ring data suggest dry conditions during the Medieval Climate Anomaly summers, while the isotope data suggests wetter than expected winters.
Comparing the lake sediment records to existing records of the Pacific Decadal Oscillation, a warming or cooling of the coastal waters off the Pacific Northwest, the researchers report in the current online issue of the Proceedings of the National Academy of Sciences “a strong centennial timescale relationship over the past 1,500 years between winter precipitation amounts in eastern Washington and Pacific Decadal Oscillation temperature anomalies.”
The PDO is linked to the El Nino Southern Oscillation, a tropical phenomenon that influences global weather patterns. During and before the Medieval Climate Anomaly, the North Pacific Ocean was warmer and Washington had greater precipitation than during the Little Ice Age, which occurred from about 1450 to 1850, when there was less precipitation.
Steinman used a previously published and validated model based on established lake physics and modern recorded precipitation and temperature to determine the amounts of rainfall indicated by the isotopic record
“The best thing we could do now is to produce additional quantitative precipitation records, this time with different lake systems,” said Steinman.
Other researchers on this project were Michael E. Mann, professor of meteorology and geosciences and director of the Penn State Earth System Science Center; Nathan D. Stansell, former Ph.D. student at the University of Pittsburgh, now a research fellow, Byrd Polar Research Center, Ohio State University and Bruce Finney, professor of biological sciences, Idaho State University.
The National Science Foundation funded this research.
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Paper: 1500 year quantitative reconstruction of winter precipitation in the Pacific Northwest, by Byron A. Steinman, Mark B. Abbott, Michael E. Mann, Nathan D. Stansell, and Bruce P. Finney, PNAS, 2012.
Abstract
Multiple paleoclimate proxies are required for robust assessment of past hydroclimatic conditions. Currently, estimates of drought variability over the past several thousand years are based largely on tree-ring records. We produced a 1,500-y record of winter precipitation in the Pacific Northwest using a physical model-based analysis of lake sediment oxygen isotope data. Our results indicate that during the Medieval Climate Anomaly (MCA) (900–1300 AD) the Pacific Northwest experienced exceptional wetness in winter and that during the Little Ice Age (LIA) (1450–1850 AD) conditions were drier, contrasting with hydroclimatic anomalies in the desert Southwest and consistent with climate dynamics related to the El Niño Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO). These findings are somewhat discordant with drought records from tree rings, suggesting that differences in seasonal sensitivity between the two proxies allow a more compete understanding of the climate system and likely explain disparities in inferred climate trends over centennial timescales.
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Data deposition: Precipitation reconstruction data are available for download at the NCDC/NOAA Paleoclimate data archive website (www.ncdc.noaa.gov/paleo).
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This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1201083109/-/DCSupplemental.
bill tuttle, lower solar activity means a cooler planet under natural conditions. how can less energy coming from the sun mean anything else ? though there are other forcing agents besides the sun eg albedo, volcanic and of course greenhouse effect .prove that c02 changes climate? well c02 certainly effects the temperature and that has been known for well over a century. . the greenhouse effect is basic physics. how do you explain the planet warming [ and empirical measurements prove that it is ] when the sun is cooling? explain the physics of that .? i did not say increase in temp is responsible for weather. increase in temp intensifies weather. eg more evaporation means more rainfall which means flooding is intensified. and the stratosphere is cooling because less heat is escaping from the” troposphere”. as i said the hot spot is not missing. i suggest you look at nasa satelite images. the hotspot is a sign of ”any ” warming. it is not specific to agw. so why would the scientists be desperate to find it ? flooding heat waves etc happened in the past because it was warmer. but it was naturally occurring warming. it was not warming caused by an energy imbalance as is the case now. it can take 5000 years for c02 levels to rise 100 ppm under natural conditions. we have experience a 100ppm increase in less than 200 years now. that cannot be normal. it is ”unprecedented ”. i will not check the links you sent because i have heard it all before. and i have my own peer reviewed links to draw on. maybe you should go over to ”the other side” and see things from a more scientific perspective?
bill tuttle, i know climate and global temp has changed in the past. and all of those changes can be explained eg, increasing or decreasing solar activity, a change in the earths orbit, volcanic activity etc. however please explain present warming giving an example of what forcing agents are at work. and i know what a solar minimum is.[ a decrease of energy coming from the sun.] its a little like the decreasing credibility coming from your argument. you do not understand the hotspot, the cooling of the stratosphere, the properties of c02, the difference between climate and weather, the difference between natural and unnatural. and you claim to be more of an authority on global temp than the world met? it hardly inspires confidence in the links you gave me. i prefer to get my info from nasa, the world met, the csiro, the royal society, the american geophysical union and the american academy of science. because they do not endorse your position at all.
Solar irradiance changes have been measured reliably by satellites for only 30 years. These precise observations show changes of a few tenths of a percent that depend on the level of activity in the 11-year solar cycle. Changes over longer periods must be inferred from other sources. Estimates of earlier variations are important for calibrating the climate models. While a component of recent global climate change may have been caused by the increased solar activity of the last solar cycle, that component was very small compared to the effects of additional greenhouse gases. According to a NASA Goddard Institute for Space Studies (GISS) press release, “…the solar increases do not have the ability to cause large global temperature increases…greenhouse gases are indeed playing the dominant role…” The effects of global climate change are apparent (see section below) despite the fact that the Sun is once again less bright during the present solar minimum. Since the last solar minimum of 1996, the Sun’s brightness has decreased by 0.02% at visible wavelengths, and 6% at extreme UV wavelengths, representing a 12-year low in solar irradiance, according to this NASA news article (April 1, 2009). Also, be sure to read this more recent article: 2009: Second Warmest Year on Record; End of Warmest Decade.
john day, you frog analogy is a very poor one. is there any scientific evidence or even a theory that frogs come from raindrops? there is however empirical observations that the planet is warming and that the sun is cooling. there is even a law in relation to the greenhouse effect. is there any scientific groups actively pursuing the study of frogs and rain drops? it sounds very silly doesn’t it? but that is only because the premise of your argument is
brian h. i bet the americans are really enjoying their massive heat wave and the russians their recently flooding, where so far 87 people have died?
david brown says:
July 7, 2012 at 5:30 am
bill tuttle, lower solar activity means a cooler planet under natural conditions. how can less energy coming from the sun mean anything else ?
First of all, you claimed that “we have been in a solar minimum for 40 years. so there is no natural explanation for present warming” — where did you hear that? There have been *four* solar cycles in the last forty years, which means that there have been four solar *maxima* to give plenty of natural warming — the following graph shows them all quite nicely:
http://wattsupwiththat.files.wordpress.com/2009/01/ap-index-1932-2008.png
So where did you get that 40-year solar minimum? There hasn’t been one that long since the Maunder Minimum ended in 1715.
though there are other forcing agents besides the sun
The sun is not a “forcing agent” — the sun is the *source*.
eg albedo, volcanic and of course greenhouse effect .prove that c02 changes climate? well c02 certainly effects the temperature and that has been known for well over a century. . the greenhouse effect is basic physics.
You list only a very few of the many things that affect climate and temperature and then conclude that CO2 must be causing warming, which is a non-sequitur — and if CO2 causes warming, why did the Earth undergo a cooling spell between 1940 and 1965, which is the time frame that worldwide industrialization was pouring increasing amounts of CO2 into the atmosphere?
how do you explain the planet warming [ and empirical measurements prove that it is ] when the sun is cooling? explain the physics of that .?
Empirical measurements prove that the planet hasn’t warmed since 1998 — in fact, the temperature has decreased and the trend is slightly negative:
http://www.c3headlines.com/global-cooling-dataevidencetrends/
david brown,
Where I live in the U.S. temperatures are much cooler than normal. What you are describing is simply regional weather, nothing more. Global temperatures have not risen for the past 15 years.
You posted five comments in a row. If you are trying to convince the rest of us that anything unusual or unnatural is occurring, you have failed. Get up to speed on the climate null hypothesis, then you will be able to understand that everything being observed is well within past parameters, when CO2 was very low. Until then, you’re just scaring yourself for no good reason.
Okay, the coding on that one (7:45am) was really ugly — this should clarify things a bit:
david brown says:
July 7, 2012 at 5:30 am
bill tuttle, lower solar activity means a cooler planet under natural conditions. how can less energy coming from the sun mean anything else ?
First of all, you claimed that “we have been in a solar minimum for 40 years. so there is no natural explanation for present warming” — where did you hear that? There have been *four* solar cycles in the last forty years, which means that there have been four solar *maxima* to give plenty of natural warming — the following graph shows them all quite nicely:
http://wattsupwiththat.files.wordpress.com/2009/01/ap-index-1932-2008.png
So where did you get that 40-year solar minimum? There hasn’t been one that long since the Maunder Minimum ended in 1715.
though there are other forcing agents besides the sun
The sun is not a “forcing agent” — the sun is the *source*.
%$#@ur momisugly! — coffeeeee…
the sun is source of energy and a forcing agent bill . increased solar activity can ”force ” climate to change. that means it is a forcing agent. we are in a solar minimum. i suggest you check with the relevant scientific groups to confirm this . [ NASA ] solar cycles still take place during solar minimums. you are badly misinformed . american temp is not global temp. global temp is the entire heat content of the planet. global temp is not cooling. it has been an upward trend for the last 15 years. with natural variability eg volcanic activity having a temporary cooling effect. cooling from 1940 to 1965 was caused by industrial aerosols . they over rode the c02 effects. however when aerosols were limited, temp began to rise again. aerosols industrial or natural [ volcanos ] have a cooling effect global temp wise . your sources have been telling you that we are not in a solar minimum or that global temp is not increasing.? i very much doubt that that position is from peer reviewed published sources. it certainly is not endorsed by one major science group on earth. can you name me one that supports your position? [ is that the sound of silence i hear ? ] i would reread that posting of mine . it comes direct from nasa. it destroys you argument about global temp cooling over the last decade and your reluctance to accept the fact of a solar minimum. now who should we believe, Bill Tuttle or NASA? i think the answer is obvious don’t you? enjoy your coffee but i think you need something stronger to wake you up
smokey. what i am saying is the global warming effects weather. it intensifies it. the things i mention were weather . however if you read my posts you will see that i know the difference between climate and weather. please read my post which is cut and pasted from NASA. the planet is not cooling mate. you are very badly misinformed. even skeptics agree that its warming though they do not accept AGW as the reason
bill i mentioned the main forcing agents. there is not an infinite number. solar activity, albedo, greenhouse gases, volcanic activity. industrial aerosols, are the main ones. now can you show me what forcing agents are at work presently, warming the planet. [ or even cooling it ]. on one hand you say the planet is cooling and then say the sun is not in a minimum . how does the planet cool when the sun is increasing in activity as you say it is ?, that completely contradicts your argument .. and please note how i dealt with your argument about cooling from 1940 to 1965? i explained it logically and with information that you did not have. eg industrial aerosols cause cooling. the year 1940 is important. it was the beginning of the war when industry was in full swing. then you ban aerosols and voila, temp starts to rise again. it is so logical and obvious.
The radiation balance can be altered by factors such as intensity of solar energy, reflection by clouds or gases, absorption by various gases or surfaces, emission of heat by various materials, and other factors related to climate change. Any such alteration is a radiative forcing, and causes a new balance to be reached. In the real world this happens continuously as sunlight hits the surface, clouds and aerosols form, the concentrations of atmospheric gases vary, and seasons alter the ground cover.
[edit]
please take note bill.” intensity of solar energy” is named as a forcing agent.
david brown says:
July 7, 2012 at 10:15 am
the sun is source of energy and a forcing agent bill .
Something cannot be both a source and a forcing agent. For example, ocean water is the source of a wave, but the “forcings” which create waves on a beach are wind, tidal effects, subsurface terrain, currents — even passing boats. The water is the source of the wave, but it doesn’t create the wave.
now can you show me what forcing agents are at work presently, warming the planet. [ or even cooling it ]. on one hand you say the planet is cooling and then say the sun is not in a minimum . how does the planet cool when the sun is increasing in activity as you say it is ?,
Putting words in my mouth will not win you any points. I said we’ve had four complete solar cycles, minima and maxima, where you insisted we’ve been in a solar minimum for the past forty years. I gave you a graph, which you obviously ignored.
that completely contradicts your argument .. and please note how i dealt with your argument about cooling from 1940 to 1965? i explained it logically and with information that you did not have. eg industrial aerosols cause cooling. the year 1940 is important. it was the beginning of the war when industry was in full swing. then you ban aerosols and voila, temp starts to rise again. it is so logical and obvious.
Logic FAIL. US industry did not go onto a war footing until 1942 and the EPA didn’t undertake any actions on aerosols until after it’s 1978 study — a decade *after* temperatures began to rise again.
Solar minimums and maximums are the two extremes of the sun’s 11-year activity cycle.[1
see bill. the eleven year cycle is actually part of the solar minimum. you still have solar cycles even during a minimum. and the sun is both an energy source” and a forcing agent”. why cant it be both? a forcing agent is anything that ”forces ” climate to change. hence the name. and increased or decreased solar activity forces climate to change. i suggest you ask a friend who knows more than you what a forcing agent is. or better still. read a basic science book. europe went to war in 1939 by the way. and american industry was contributing to the war effort well before 1942. industrial aerosols cool, just as aerosols from volcanos cool. that is an established fact. the increase or decrease in aerosols will effect the climate. if warming increased ten years before action was taken on aerosols, that could have been for a number of reasons. less aerosols due to better technology. less manufacturing or increased solar activity. . the final nail in your coffin is on one hand you say the sun is not in a minimum. meaning it is increasing in activity. but then you say the global temp is cooling.. that my friend, contradicts and destroys your argument
“Medieval Climate Anomaly”
Well, hopefully they are easing into it, given that there were earlier warm periods so the MWP as not an anomaly.
During 2008-2009 NASA scientists noted that the Sun is undergoing a “deep solar minimum,” stating: “There were no sunspots observed on 266 of [2008’s] 366 days (73%). Prompted by these numbers, some observers suggested that the solar cycle had hit bottom in 2008. Sunspot counts for 2009 dropped even lower. As of September 14, 2009 there were no sunspots on 206 of the year’s 257 days (80%). It adds up to one inescapable conclusion: “We’re experiencing a very deep solar minimum,” says solar physicist Dean Pesnell of the Goddard Space Flight Center. “This is the quietest sun we’ve seen in almost a century,” agrees sunspot expert David Hathaway of the National Space Science and Technology Center NASA/Marshall Space Flight Center.[6] It’s a natural part of the sunspot cycle, discovered by German astronomer Heinrich Schwabe in the mid-19th century.[6] A “clockwork pattern” that has held true for more than 200 years.[7]
See bill. this is from NASA. it states clearly that we are in a solar minimum. and yet global temperature still rises. please explain?
bill, you missed the moon as an integral point of ocean behaviour. i think your comparisons between the sun and the ocean is rather silly.. it has nothing to do with the fact that solar activity effects climate. and that by definition means it is a forcing agent
david brown says:
“Global temp is not cooling. it has been an upward trend for the last 15 years.”
Wrong.
Brown continues: “what i am saying is the global warming effects (sic) weather. it intensifies it. ”
That misrepresents the situation. Temperature itself has no effect on weather. What matters is the temperature gradient. Furthermore, extreme weather events have been declining, not increasing.
Brown says: “the planet is not cooling mate. you are very badly misinformed.”
Pay attention. I have never said there has been no global warming. The planet has been warming along the same long term trend line since the Little Ice Age.
The problem climate alarmists have is the fact that the long term natural rising temperature trend has not accelerated. [The green line is the trend. Note that it is decelerating.] You can see here that in eight large cities around the globe, the rising temperature trend since the LIA is not accelerating, thus falsifying the claim that CO2 will cause runaway global warming. Following a 40% increase in harmless, beneficial CO2, the long term trend has not accelerated. CO2 may have an effect, but it is too small to measure.
CO2 does not have the effect claimed by the alarmist crowd, otherwise the 40% rise in CO2 would have caused the warming trend to accelerate, no? But that has not happened. Even Phil Jones admits that what we have observed recently has happened repeatedly in the past, before CO2 was an issue.
Finally, global temperatures over the past three years continue to decline
So relax. Nothing unusual is happening. Instead of worrying yourself silly over tenths of a degree natural fluctuations, look at the big picture.
smokey i am not saying anything. i am merely repeating what NASA, the world met and every major scientific group on earth is saying. saying ”Wrong ” is not a counter argument. and the sources you give are not peer reviewed or published in the appropriate science journals. your arguments are pretty much of a cliche. it is the same misinformation eg it is not warming, it is natural, c02 is a harmless trace gas. temp has no effect on weather. it is warming after an ice age etc? you say that rather emphatically. the truth is you do not know and your position is not endorsed by a major science group. so you may well be wrong. extreme weather events are on the increase. you would have to be blind not to see it. heat waves, floods , drought etc are not in decline. please give sources and figures for that claim. temp effects evaporation [ simple physics ] which must influence rainfall. storms feed of heat. thats why the southern hemisphere, the warmest hemisphere has the more intense storms. warm water feeds the energy of a storm. what 40% increase in c02? what are you talking about? what have large cities got to do with anything. urban island heat effect is nonsense, temp rises in rural areas as well. we are talking global temp not regional. the LIA is not effecting present global temp. the LIA was not a major ice age.and is certainly not responsible for present warming. you contradict yourself. firstly you say it is warming a result of the LIA . and then you say its cooling. which is it? if its cooling, that destroys your LIA argument. if its warming i win. i would suggest you study the NASA temp data or the world met. they say that temp is accelerating. melting glaciers and ice caps seem to indicate that as well. i am not interested in non peer reviewed studies that are not endorsed by a major science group/ that they are ”definitely ” wrong. but there is a huge possibility they are
smokey, what causes the warming after an ice age. what is the forcing agent? is it solar activity increase? what causes the warming? or do you think climate change happens by magic? i look forward to your response.
Anecdotal evidence that the world’s weather is getting wilder now has a solid scientific basis in fact following a dramatic global assessment from the World Meteorological Organization.
A study released Wednesday by the WMO — a specialized climate science agency of the United Nations — says the world is experiencing record numbers of extreme weather events, such as droughts and tornadoes.
Laying the blame firmly at the feet of global warming, the agency warned that the number and intensity of extreme weather events could continue to increase.
they are the findings of the world met smokey. excuse me if i accept their word over yours.
smokey , when thinking in terms of trends three years indicates nothing. what is the trend for the last decade? it is increased warming. what is the trend for the last century? it is warming and more warming. taking phil jones out of context is cherry picking. what did phil jones say in the entire statement? did he reject AGW? no. the trend line over the last century is upward. the LIA ice age has nothing to do with present warming. scientists would have considered LIA and rejected it
nothing unusual is happening smokey? scientists and most people disagree. it is not ”natural fluctuations” there is nothing natural about it. the sun is in minimum the globe is warming. that is not natural. it is not ”natural ” for c02 levels to increase 100 ppm in 200 years. a natural increase of that much takes thousands of years. ”c02 has had an effect but it is too small to measure?” no it isnt. it is being measured and the results should cause humanity to worry. pardon me me if i accept what most scientists and every major science group on earth thinks as opposed to what you and your non peer reviewed sources think. put it down to commonsense