Every 120,000 years global temperatures and carbon dioxide levels fall quite dramatically. About a half million years ago it happened every 40,000 years. What caused it?
Every 120,000 years global temperatures and carbon dioxide levels fall quite dramatically. About a half million years ago it happened every 40,000 years. What caused it?God.
Every 120,000 years global temperatures and carbon dioxide levels fall quite dramatically. About a half million years ago it happened every 40,000 years. What caused it?Here you go. Rebuttals in comments section are priceless https://www.skepticalscience.com/climate-change-little-ice-age-medieval-warm-period.htm
Every 120,000 years global temperatures and carbon dioxide levels fall quite dramatically. About a half million years ago it happened every 40,000 years. What caused it?No way to answer that in a couple easy reading paragraphs. You have to put in some effort and do some serious studying if you really want to understand what's going on.
http://forecast.uchicago.edu Professor David Archer, PhD Global Warming: Understanding the Forecast is a comprehensive introduction to all aspects of global warming. Written in an accessible way, and assuming no specialist prior knowledge, this book examines the processes that control climate change and climate stability, from the distant past to the distant future. Second Edition now shipping. Thoroughly revised and updated but basically the same material. On-line interactive computer models allow you to play with the physics and chemistry behind the global warming forecast. Global Warming: The Science of Climate Change is running now on Coursera, a not-for-profit education company that partners with the top universities and organizations in the world to offer courses online for anyone to take, for free. The video lectures have been completely redone in a punchy 2-10 minute format, with revamped exercises using the updated online models interspersed throughout. Open Climate 101 brings the experience of University of Chicago class PHSC13400, part of our "core" science curriculum for non-science major undergraduates based on this text, to the internet at large. However, this class seems supplanted by the updated content in the Coursera class (above), so unless lots of people request otherwise, Open Climate 101 will shut down on or about Jan 1, 2014. Videos of lectures, both in ~45 minute classroom format (recorded Fall, 2009, University of Chicago), and in a 2-12 minute topical format intended for on-line learning (recorded Summer, 2013).Although SkepticalScience does do a great job of breaking it down for the busy lay-person.
Here you go. Rebuttals in comments section are priceless https://www.skepticalscience.com/climate-change-little-ice-age-medieval-warm-period.htm {also see http://www.skepticalscience.com/argument.php}They do a wonderful job of explaining
The little ice age occurred only 400 years ago accompanied by a temperature fall of less than 1 degree. I’m talking about events that happened more than 100,000 years ago and involved temperatures dropping 5 degrees. There doesn’t seem to be solid explanations why that happened.
The little ice age occurred only 400 years ago accompanied by a temperature fall of less than 1 degree. I'm talking about events that happened more than 100,000 years ago and involved temperatures dropping 5 degrees. There doesn't seem to be solid explanations why that happened.The hell there aren't, you just haven't tried finding anything and seriously learning about it. Plus you delude yourself into thinking you can skip the physics of greenhouse gases and still arrive at any satisfactory answers about paleoclimatology. Can't be done. That only works in the Alt-reality of politically passionate liars.
IPCC - 5th assessment - Climate Change 2013: The Physical Science Basis Information from Paleoclimate Archives http://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter05_FINAL.pdfThe Discovery of Global Warming A hypertext history of how scientists came to (partly)(that's science speak for there's always more to learn) understand what people are doing to cause climate change. https://history.aip.org/climate/index.htm
Then come the many circulation patterns that move the heat around our global and store some of it in our oceans
Ocean Currents and Climate Change Thermohaline Ocean Circulation - Stefan Rahmstorf http://www.pik-potsdam.de/~stefan/Publications/Book_chapters/rahmstorf_eqs_2006.pdf The thermohaline circulation is that part of the ocean circulation which is driven by fluxes of heat and freshwater across the sea surface and subsequent interior mixing of heat and salt. The term thus refers to a driving mechanism. Important features of the thermohaline circulation are deep water formation, spreading of deep waters partly through deep boundary currents, upwelling and near-surface currents, together leading to a large-scale deep overturning motion of the oceans. The large heat transport of the thermohaline circulation makes it important for climate, and its non-linear and potentially abrupt response to forcing have been invoked to explain abrupt glacial climate changes. Anthropogenic climate change is likely to weaken the thermohaline circulation in future, with some risk of triggering abrupt and/or irreversible changes. ..;.;This is dated but even then we knew plenty well what the main drivers of climate fluctuations were. But then I'm just an attentive witness, don't take my word for it:
Global Environmental Change: Research Pathways for the Next Decade (1999) Chapter: 6 Paleoclimate Overview https://www.nap.edu/read/5992/chapter/7 Paleoclimate Overview SUMMARY CASE STUDIES This report focuses on five case studies chosen to demonstrate the potential wealth of information available from the paleorecord. The first three are presented in specific time domains (the last glacial cycle to onset of the Holocene; the Holocene; the past 2,000 years of the Holocene). The last two focus on subject areas that draw on a wide range of Earth history—namely, climate-vegetation interactions and warm climates. The Last Glacial Cycle to the Onset of the Holocene (~11,500 years ago) The Holocene The Late Holocene (~2,000 years ago to present) Climate-Vegetation Interaction Warm Climates KEY SCIENTIFIC QUESTIONS AND ISSUES The key scientific questions facing paleoclimate researchers have been articulated in a series of international projects, including PAGES (Past Global Changes) of the International Geosphere-Biosphere Programme, CLIVAR (Climate Variability) of the World Climate Research Program, and GLOCHANT (Global Changes in the Antarctic) of the Scientific Committee on Antarctic Research. Through the integration of ice, ocean, and terrestrial paleorecords, these international efforts seek to develop a basis for understanding the characteristics of natural global environmental change, notably climate change. These paleodata are essential for assessing human influence on the global environment and for evaluating predictive climate models. Several questions and issues have evolved as foci for the paleocommunity. These consensus views have been expressed in several documents108 which form the basis for the specific scientific questions that follow.b Focus on the Past 2,000 Years Focus on the Past 250,000 Years RESEARCH IMPERATIVESThere's plenty more worthwhile stuff out there, just gotta poke around.
Guess cat got John’s tongue again. Or perhaps I simply intimidate him. I shouldn’t, I just happen to be someone who’s made learning about climate an active hobby since the early 1970s so he can’t bullshit me they way he can others. Still I’ve learned from the same information that’s been available to the public, he could have learned as much had he any interest in learning about how our planet functions. See I imagine his imagination doesn’t get past fighting for political and economic advantage. Tragically that type can’t conceive of people dedicated to and loving to learn about our planet.
But I don’t mean to be a jerk, just pointing out he’s a perfect example of the right-wing intellectual frauds running around polluting what should be a constructive public discourse. Still, that doesn’t mean I can’t try to communicate with him in a constructive (if not particularly diffident) manner. His last challenge is a wonderful example of what honestly learning about our planet’s climate had to offer to the HONESTLY CURIOUS.
The little ice age occurred only 400 years ago accompanied by a temperature fall of less than 1 degree. I'm talking about events that happened more than 100,000 years ago and involved temperatures dropping 5 degrees. There doesn't seem to be solid explanations why that happened.There is fascinating mounting evidence that the root of the so-called Little Ice Age (which was a tiny momentary dip, as opposed to today's relentlessly driven temperature increases.) can be traced to what happening in North America. 1492 Columbus sailed the ocean blue and discovered America while injecting the first doses of what would be a catastrophic invasion of microbes that more than decimated Indians. Most white folks don't realize that Indians had actually pretty much domesticated the Americas long before Columbus arrived. They used fire to suppress forests and increase grasslands and farmlands - then the flood of colonizers and slaves turned it all around.
... Yet it's increasingly clear that most of the carnage had nothing to do with European barbarism. The worst of the suffering was caused not by swords or guns but by germs."[9] By 1700, less than five thousand Native Americans remained in the southeastern coastal region.[4] In Florida alone, there were seven hundred thousand Native Americans in 1520, but by 1700 the number was around 2000.[4] In the summer of 1639, a smallpox epidemic struck the Huron natives in the St. Lawrence and Great Lakes regions. The disease had reached the Huron tribes through traders returning from Québec and remained in the region throughout the winter. When the epidemic was over, the Huron population had been reduced to roughly 9000 people, about half of what it had been before 1634.[10] The Iroquios people faced similar losses. [4] ... https://en.wikipedia.org/wiki/Native_American_disease_and_epidemicsWhen the Indians disappears, the forests rapidly resettled grasslands and farmlands, so much so that a significant amount of CO2 (atmospheric insulation !!!)was removed from the atmosphere. You see one thing the Alt-right and GOP kindergarteners refuse to appreciate is that our planet's climate system is on a feather balance, doesn't take much to nudge it one direction or another.
Stanford Report, December 17, 2008 Reforestation helped trigger Little Ice Age, researchers say BY LOUIS BERGERON http://news.stanford.edu/news/2009/january7/manvleaf-010709.html The power of viruses is well documented in human history. Swarms of little viral Davids have repeatedly laid low the great Goliaths of human civilization, most famously in the devastating pandemics that swept the New World during European conquest and settlement. In recent years, there has been growing evidence for the hypothesis that the effect of the pandemics in the Americas wasn't confined to killing indigenous peoples. Global climate appears to have been altered as well. Stanford University researchers have conducted a comprehensive analysis of data detailing the amount of charcoal contained in soils and lake sediments at the sites of both pre-Columbian population centers in the Americas and in sparsely populated surrounding regions. They concluded that reforestation of agricultural lands—abandoned as the population collapsed—pulled so much carbon out of the atmosphere that it helped trigger a period of global cooling, at its most intense from approximately 1500 to 1750, known as the Little Ice Age.
Columbus' arrival linked to carbon dioxide drop Depopulation of Americas may have cooled climate BY DEVIN POWELL 10:43AM, OCTOBER 13, 2011 Magazine issue: Vol. 180 #10, November 5, 2011, p. 12 https://www.sciencenews.org/article/columbus-arrival-linked-carbon-dioxide-dropIt really is amazing how well scientists understand the fundamentals and the details and it all fits a consistent narrative if you got the internal integrity to honestly review the evidence. JohnH, WHAT IS YOUR EXCUSE >:(
Guess cat got John's tongue again. Or perhaps I simply intimidate him. I shouldn't, I just happen to be someone who's made learning about climate an active hobby since the early 1970s so he can't bullshit me they way he can others. Still I've learned from the same information that's been available to the public, he could have learned as much had he any interest in learning about how our planet functions. See I imagine his imagination doesn't get past fighting for political and economic advantage. Tragically that type can't conceive of people dedicated to and loving to learn about our planet. But I don't mean to be a jerk, just pointing out he's a perfect example of the right-wing intellectual frauds running around polluting what should be a constructive public discourse. Still, that doesn't mean I can't try to communicate with him in a constructive (if not particularly diffident) manner. His last challenge is a wonderful example of what honestly learning about our planet's climate had to offer to the HONESTLY CURIOUS.He's a Trump supporter.The little ice age occurred only 400 years ago accompanied by a temperature fall of less than 1 degree. I'm talking about events that happened more than 100,000 years ago and involved temperatures dropping 5 degrees. There doesn't seem to be solid explanations why that happened.There is fascinating mounting evidence that the root of the so-called Little Ice Age (which was a tiny momentary dip, as opposed to today's relentlessly driven temperature increases.) can be traced to what happening in North America. 1492 Columbus sailed the ocean blue and discovered America while injecting the first doses of what would be a catastrophic invasion of microbes that more than decimated Indians. Most white folks don't realize that Indians had actually pretty much domesticated the Americas long before Columbus arrived. They used fire to suppress forests and increase grasslands and farmlands - then the flood of colonizers and slaves turned it all around.... Yet it's increasingly clear that most of the carnage had nothing to do with European barbarism. The worst of the suffering was caused not by swords or guns but by germs."[9] By 1700, less than five thousand Native Americans remained in the southeastern coastal region.[4] In Florida alone, there were seven hundred thousand Native Americans in 1520, but by 1700 the number was around 2000.[4] In the summer of 1639, a smallpox epidemic struck the Huron natives in the St. Lawrence and Great Lakes regions. The disease had reached the Huron tribes through traders returning from Québec and remained in the region throughout the winter. When the epidemic was over, the Huron population had been reduced to roughly 9000 people, about half of what it had been before 1634.[10] The Iroquios people faced similar losses. [4] ... https://en.wikipedia.org/wiki/Native_American_disease_and_epidemicsWhen the Indians disappears, the forests rapidly resettled grasslands and farmlands, so much so that a significant amount of CO2 (atmospheric insulation !!!)was removed from the atmosphere. You see one thing the Alt-right and GOP kindergarteners refuse to appreciate is that our planet's climate system is on a feather balance, doesn't take much to nudge it one direction or another.Stanford Report, December 17, 2008 Reforestation helped trigger Little Ice Age, researchers say BY LOUIS BERGERON http://news.stanford.edu/news/2009/january7/manvleaf-010709.html The power of viruses is well documented in human history. Swarms of little viral Davids have repeatedly laid low the great Goliaths of human civilization, most famously in the devastating pandemics that swept the New World during European conquest and settlement. In recent years, there has been growing evidence for the hypothesis that the effect of the pandemics in the Americas wasn't confined to killing indigenous peoples. Global climate appears to have been altered as well. Stanford University researchers have conducted a comprehensive analysis of data detailing the amount of charcoal contained in soils and lake sediments at the sites of both pre-Columbian population centers in the Americas and in sparsely populated surrounding regions. They concluded that reforestation of agricultural lands—abandoned as the population collapsed—pulled so much carbon out of the atmosphere that it helped trigger a period of global cooling, at its most intense from approximately 1500 to 1750, known as the Little Ice Age.Columbus' arrival linked to carbon dioxide drop Depopulation of Americas may have cooled climate BY DEVIN POWELL 10:43AM, OCTOBER 13, 2011 Magazine issue: Vol. 180 #10, November 5, 2011, p. 12 https://www.sciencenews.org/article/columbus-arrival-linked-carbon-dioxide-dropIt really is amazing how well scientists understand the fundamentals and the details and it all fits a consistent narrative if you got the internal integrity to honestly review the evidence. JohnH, WHAT IS YOUR EXCUSE >:(
He's a Trump supporter.Yea, and I bet he isn’t even a communist either. Is he lost? What’s he doing on this site!
Every 120,000 years global temperatures and carbon dioxide levels fall quite dramatically. About a half million years ago it happened every 40,000 years. What caused it?Weather climate cycle are caused by the path of the earth around the sun and the amount of sunlight reaching earth and the earth’s axis or tilt changing position. These cycles are known as the Milankovitch cycles and take 100,000 years to complete. www.sciencecourseware.org/eec/GlobalWarming/Tutorials/Milankovitch/ Most weather comes from the sun. What should we be looking at? When the earth goes around the sun it is following three cycles. The eccentricity cycle of 100,000 years, the obliquity cycle of 40,000 years and the precession cycle of 26,000 years.
Most weather comes from the sun.Here's yet another example of why no one should listen to you when it comes to manmade global warming driven climate change. The Sun provides the heat, the energy. The Earth provides the global heat and moisture distribution engine, which causes our weather. The two in intimate embrace, that's where the weather comes from. :cheese:
Most weather comes from the sun.Here's yet another example of why no one should listen to you when it comes to manmade global warming driven climate change. The Sun provides the heat, the energy. The Earth provides the global heat and moisture distribution engine, which causes our weather. The two in intimate embrace, that's where the weather comes from. :cheese: In one way or another, most of the energy on Earth originates from the sun. Heat from the sun "powers" all of the major processes in the atmosphere. The heat-trapping greenhouse properties of the Earth's atmosphere and the planet's tilt also play vital roles in weather dynamics and air circulation. Everything about Earth's weather, however, comes back to the sun. http://sciencing.com/nearly-earths-energy-atmosphere-come-from-12391.html
Every 120,000 years global temperatures and carbon dioxide levels fall quite dramatically. About a half million years ago it happened every 40,000 years. What caused it?Weather climate cycle are caused by the path of the earth around the sun and the amount of sunlight reaching earth and the earth’s axis or tilt changing position. These cycles are known as the Milankovitch cycles and take 100,000 years to complete. www.sciencecourseware.org/eec/GlobalWarming/Tutorials/Milankovitch/ Most weather comes from the sun. What should we be looking at? When the earth goes around the sun it is following three cycles. The eccentricity cycle of 100,000 years, the obliquity cycle of 40,000 years and the precession cycle of 26,000 years.Yes Mike, but efforts to reliably relate climate change to Milankovitch cycles haven't been particularly successful. How are they linked to fluctuations in atmospheric carbon dioxide? The worrisome issue to me isn't the accuracy of the simulated carbon dioxide effect but the recognition that past climate cycles resulted in global mean temperatures higher than current temperatures. That means maximum temperatures were even higher, though I haven't encountered estimates for maximum temperatures. Essentially, that means current concerns are over potential global temperatures that have been found to occur in the natural climate changes of the past. That history suggests that our efforts to "normalize" atmospheric carbon dioxide levels may not hold global temperatures below that which is currently considered to be problematic. That isn't to deny that current levels of anthropogenic greenhouse gas emissions may add an additional, perilous variable to climate dynamics and that it should be reversed but I worry that the challenge will turn out to be more complex than just greenhouse gases alone.
Most weather comes from the sun.Here's yet another example of why no one should listen to you when it comes to manmade global warming driven climate change. The Sun provides the heat, the energy. The Earth provides the global heat and moisture distribution engine, which causes our weather. The two in intimate embrace, that's where the weather comes from. :cheese: In one way or another, most of the energy on Earth originates from the sun. Heat from the sun "powers" all of the major processes in the atmosphere. The heat-trapping greenhouse properties of the Earth's atmosphere and the planet's tilt also play vital roles in weather dynamics and air circulation. Everything about Earth's weather, however, comes back to the sun. http://sciencing.com/nearly-earths-energy-atmosphere-come-from-12391.html I wasn't denying that - but you seem to try to take the Earth system out of the equation that to be polite is disconnected from the dynamics at work. The brain controls your body, but your heart better be doing it's job - the healthiest brain isn't enough. The Sun provides the heat, the Earth is doing the rest. Your problem is you think you can ignore fundamental components of our climate engine. NO, NO, NO, you got to understand the complete constantly evolving and changing system to understand these things. Ironically here JohnH wants to jump on the fool's bandwagon. John you should know better, you can ignore me but I got my eye on you buddy*. * or more accurately the disinformation about climate science you feel compelled to spread. { multiple edit due to too many distractions }
Yes Mike, but efforts to reliably relate climate change to Milankovitch cycles haven't been particularly successful. How are they linked to fluctuations in atmospheric carbon dioxide?That is utter bull shit. Scientists have a very clear understanding of how the Milankovitch cycles unfold and how that interacts with the state of the planet. On the most basic level it amounts to a very slight dimming and brightening of our Sun's insolation upon the Earth. After that heat is captured, Earth's atmospheric insulation dictates how much of the sun's insolation gets injected into the Earth's climate system Keep in mind our atmosphere has been an evolving entity - our Earth is also an evolving entity. Some crazy-makers like pointing out that at one time Earth's atmosphere was astronomically higher in CO2 compared to today - of course they also leave out that this was before life took hold in a big way roughly half a billion years ago. Think about it, before life there was nothing but rocks, weather, rain, wind, erosion, continents were smaller (but growing) and moving around, meaning the ocean circulation patterns were way different than today. A cornucopia of living things has sucked unimaginable amounts CO2 out of the atmosphere, with time geologic evolution enlarged and positioned the continents and oceans into their current position (though the migration continues - think earthquakes). Scientist have developed a keen understanding of the time line of Continental movement, life's development, and ecological processes that in turn developed - all of which influences the heat distribution on our planet and thus the weather and global temperatures. You may not ignore the evolving state of the planet if you want to understand paleoclimate.
The worrisome issue to me isn't the accuracy of the simulated carbon dioxide effect but the recognition that past climate cycles resulted in global mean temperatures higher than current temperatures.I don't suppose you'd be able to explain where your "simulated" comes from??? Did you totally ignore the information provided at http://www.centerforinquiry.net/forums/viewthread/19377/P30/#233645 courtesy of our US Air Force scientists. Of course there are many tests that simulate the carbon dioxide effect. But there are also mountains of direct evidence and details that have been provided by studying the actual atmosphere - done by many nations independently - all arriving at the same conclusion - THAT IS NOT A SIMULATION ! Oh and there is this interesting tidbit from a few years ago -
First direct observation of carbon dioxide's increasing greenhouse effect February 25, 2015 https://phys.org/news/2015-02-carbon-dioxide-greenhouse-effect.html ... The influence of atmospheric CO2 on the balance between incoming energy from the Sun and outgoing heat from the Earth (also called the planet's energy balance) is well established. But this effect has not been experimentally confirmed outside the laboratory until now. The research is reported Wednesday, Feb. 25, in the advance online publication of the journal Nature. The results agree with theoretical predictions of the greenhouse effect due to human activity. The research also provides further confirmation that the calculations used in today's climate models are on track when it comes to representing the impact of CO2. The scientists measured atmospheric carbon dioxide's contribution to radiative forcing at two sites, one in Oklahoma and one on the North Slope of Alaska, from 2000 to the end of 2010. Radiative forcing is a measure of how much the planet's energy balance is perturbed by atmospheric changes. Positive radiative forcing occurs when the Earth absorbs more energy from solar radiation than it emits as thermal radiation back to space. It can be measured at the Earth's surface or high in the atmosphere. In this research, the scientists focused on the surface. ...Hopefully you haven't embraced the contrarian meme that the so-called Medieval Warm Period was warmer than today. I would hope you know that's not true. But you know, that's the tough thing with folks like you and Mike, you're more into vague riddles, offer no references to better educate others on your position, then you ignore and sidestep all you find inconvenient, including every intellectual challenge you are handed. That's why it seems that trying to introduce doubt and confusion is all that type is about. How about working working on a constructive dialogue?
Yes Mike, but efforts to reliably relate climate change to Milankovitch cycles haven't been particularly successful.Good question. The answer is that we need the computer models to accomplish the task. Before the models can work we need to establish reliable data. That is where we are at now, building the system to collect reliable data. Just this week the news is that the energy coming from the sun to the earth was wrong. And new figures are now available for use. Basically, all past reports using the sun’s energy is now considered wrong. The point being, like CC stated that weather is the combination of earth’s reaction to the energy from the sun. That energy is constantly changing with the Milankovitch cycles, the sun’s eleven-year solar cycles and solar flares.
How are they linked to fluctuations in atmospheric carbon dioxide?The Ice Cores show that the Milankovitch cycles warms and cools the earth. The carbon dioxide follows the warm and cool cycles of the Global Warming. But, the Climate Change has broken the standard Global Warming cycle. We are in new territory with Climate Change caused by huge amounts of anthropogenic gases. //www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-6-1.html My choice is to choose factual science over consensual science. The problem is factual science takes time. Consensual science is what we have today. I have been backing the direction of the IPCC. The problem is that the IPCC is getting a lot more political pressures than it should.
The worrisome issue to me isn't the accuracy of the simulated carbon dioxide effect but the recognition that past climate cycles resulted in global mean temperatures higher than current temperatures. That means maximum temperatures were even higher, though I haven't encountered estimates for maximum temperatures. Essentially, that means current concerns are over potential global temperatures that have been found to occur in the natural climate changes of the past. That history suggests that our efforts to "normalize" atmospheric carbon dioxide levels may not hold global temperatures below that which is currently considered to be problematic. That isn't to deny that current levels of anthropogenic greenhouse gas emissions may add an additional, perilous variable to climate dynamics and that it should be reversed but I worry that the challenge will turn out to be more complex than just greenhouse gases alone.You’re not alone. I got the same worries.
CC, the reason I ignore you is that you approach debate in a hostile, obnoxious manner, responding more to your perceptions of disagreement rather than issues raised, presumably triggered by prejudices you cannot control. As a consequence, you have disrupted rather than contributed to substantive debate. Your debating style is contrary to forum rules (for example, personal attacks, suggesting I’ve joined the fools bandwagon or describing my comments as “bullshit” without any convincing explanation why. Even starting new threads in an effort to bait me.). So, yes, I choose for the most part to ignore you.
For anyone with a more level-headed interest here is an image relating several climate variables.
You may note that insolation is not well correlated with other changes. As far as I understand, attempts to incorporate Milankovitch cycles into climate simulations (climate models) have not provided a good fit with real data. If I am mistaken, references to reports of the success of such simulations will be much more convincing than simply characterizing my comments (possibly based on ignorance) as “bullshit” without any real evidence to back up the accusation. That is a violation of forum rules.
You may note that recent temperatures (the red line at the left side of the graph) have fluctuated within a 2 degree range for the last 10,000 years. About 20,000 years ago temperatures were 8 degrees cooler than those recent temperatures. The Little Ice Age occurred a few hundred years ago and isn’t even noticeable in the recent temperature fluctuations, so no, my focus isn’t the little ice age.
At least one of the temperature spikes at 125,000 240,000 and 320,000 years ago is higher that the IPCC projection for 2050. Other graphs show it more clearly, for example the Wikipedia paleoclimate entry. This is the source of my concern that natural climate changes may have the apparently unrecognized potential to add even more to our global warming problem. This isn’t denying or minimizing anthropogenic warming - it is a concern that we could be facing a double-whammy that we don’t seem to be prepared for.
You may also note the similarities between carbon dioxide and temperature changes in the last 4 temperature cycles. This means that carbon dioxide levels fell (naturally?) In previous climate cycles. The simple question in the OP to this thread was if anyone can point to what triggered this reversal. A further question may be what sources existing to support any explanations. By that I mean hard evidence along the lines of GCMs, not arm-waving generalities or opinion pieces by, for example a cognitive science graduate in a Department of Communication as is John Cook who runs the skeptical science website.
No problems with previews but spam when I post
CC, the reason I ignore you is that you approach debate in a hostile, obnoxious manner, responding more to your perceptions of disagreement rather than issues raised, presumably triggered by prejudices you cannot control. As a consequence, you have disrupted rather than contributed to substantive debate. Your debating style is contrary to forum rules (for example, personal attacks, suggesting I've joined the fools bandwagon or describing my comments as "bullshit" without any convincing explanation why. Even starting new threads in an effort to bait me.). So, yes, I choose for the most part to ignore you. For anyone with a more level-headed interest here is an image relating several climate variables.what response did you get when you when you posted your question on global warming scientific forums such as skeptical science because we can see how concerned on getting an educated answer.You may note that insolation is not well correlated with other changes. As far as I understand, attempts to incorporate Milankovitch cycles into climate simulations (climate models) have not provided a good fit with real data. If I am mistaken, references to reports of the success of such simulations will be much more convincing than simply characterizing my comments (possibly based on ignorance) as "bullshit" without any real evidence to back up the accusation. That is a violation of forum rules. You may note that recent temperatures (the red line at the left side of the graph) have fluctuated within a 2 degree range for the last 10,000 years. About 20,000 years ago temperatures were 8 degrees cooler than those recent temperatures. The Little Ice Age occurred a few hundred years ago and isn't even noticeable in the recent temperature fluctuations, so no, my focus isn't the little ice age. At least one of the temperature spikes at 125,000 240,000 and 320,000 years ago is higher that the IPCC projection for 2050. Other graphs show it more clearly, for example the Wikipedia paleoclimate entry. This is the source of my concern that natural climate changes may have the apparently unrecognized potential to add even more to our global warming problem. This isn't denying or minimizing anthropogenic warming - it is a concern that we could be facing a double-whammy that we don't seem to be prepared for. You may also note the similarities between carbon dioxide and temperature changes in the last 4 temperature cycles. This means that carbon dioxide levels fell (naturally?) In previous climate cycles. The simple question in the OP to this thread was if anyone can point to what triggered this reversal. A further question may be what sources existing to support any explanations. By that I mean hard evidence along the lines of GCMs, not arm-waving generalities or opinion pieces by, for example a cognitive science graduate in a Department of Communication as is John Cook who runs the skeptical science website. No problems with previews but spam when I post
JohnH, I don’t expect you to get an answer that is agreed upon by the consensual scientists. This question has been around for some time and there have been warnings from several scientists about how the lags and jumps work. But, no reaction or responses from the Global Warming movement. I have read that even Al Gore has taken the famous carbon following the heat details out if his charts he is using now. Point being, that if Al Gore can’t give an answer, then he doesn’t have the answer or the answer does not agree with his claims on how the CO2 works. A question that has not been answered is does the CO2 blanket only heat to a given point, no matter how much CO2 is in the air. During snowball earth, the C02 levels were said to be 300 times greater than today’s levels. Therefore, the computer models are the key to solving the questions of how and what we must do to make sure we save mankind.