So much for the global-warming induced, permanent drought that had afflicted California. Population in California has doubled since 1979 but water resources infrastructure has not changed much. Ground water is being consumed and depleted at an increasing pace. Yet normal weather variations are taken to be man-made global warming.
An index of precipitation at eight sensors showed that just under 90 inches of rain and snow have fallen this winter in the northern Sierra Nevada. The previous record of 88.5 inches was set in the winter of 1982-1983. The average for the region is 50 inches a year, according to the state Department of Water Resources.
The record was surpassed less than a week after Gov. Jerry Brown officially declared an end to California’s drought emergency — a largely symbolic pronouncement that left in place some water-conservation rules for the 40 million residents of the nation’s most populous state.
More snow and rain is likely to pad the record before the wet season ends.
This new paper finds that CO2 concentration in the atmosphere has risen by 110 ppm since 1750, but of this the human contribution is just 17 ppm. With the concentration now at 400 ppm, the human contribution is just 4.3%. The results indicate that almost all of the observed change of CO2 during the Industrial Era comes, not from anthropogenic emissions, but from changes of natural emission.
The general assumption by IPCC and the global warming fraternity that natural carbon dioxide absorption and emissions are miraculously in balance and, therefore that man-made emissions are solely responsible for the increase in carbon dioxide concentration is deeply flawed (if not plain stupid).
Clearly this paper is not at all to the liking of the religious zealots of the “global warming brigade” and is causing much heartburn among the faithful.
•An alternative carbon cycle is presented in agreement with the carbon 14 decay.
•The CO2 uptake rate scales proportional to the CO2 concentration.
•Temperature dependent natural emission and absorption rates are considered.
•The average residence time of CO2 in the atmosphere is found to be 4 years.
•Paleoclimatic CO2 variations and the actual CO2 growth rate are well-reproduced.
•The anthropogenic fraction of CO2 in the atmosphere is only 4.3%.
•Human emissions only contribute 15% to the CO2 increase over the Industrial Era.
Abstract: Climate scientists presume that the carbon cycle has come out of balance due to the increasing anthropogenic emissions from fossil fuel combustion and land use change. This is made responsible for the rapidly increasing atmospheric CO2 concentrations over recent years, and it is estimated that the removal of the additional emissions from the atmosphere will take a few hundred thousand years. Since this goes along with an increasing greenhouse effect and a further global warming, a better understanding of the carbon cycle is of great importance for all future climate change predictions. We have critically scrutinized this cycle and present an alternative concept, for which the uptake of CO2 by natural sinks scales proportional with the CO2 concentration. In addition, we consider temperature dependent natural emission and absorption rates, by which the paleoclimatic CO2 variations and the actual CO2 growth rate can well be explained. The anthropogenic contribution to the actual CO2 concentration is found to be 4.3%, its fraction to the CO2 increase over the Industrial Era is 15% and the average residence time 4 years.
Climate scientists assume that a disturbed carbon cycle, which has come out of balance by the increasing anthropogenic emissions from fossil fuel combustion and land use change, is responsible for the rapidly increasing atmospheric CO2 concentrations over recent years. While over the whole Holocene up to the entrance of the Industrial Era (1750) natural emissions by heterotrophic processes and fire were supposed to be in equilibrium with the uptake by photosynthesis and the net oceanatmosphere gas exchange, with the onset of the Industrial Era the IPCC estimates that about 15 – 40 % of the additional emissions cannot further be absorbed by the natural sinks and are accumulating in the atmosphere.
The IPCC further argues that CO2 emitted until 2100 will remain in the atmosphere longer than 1000 years, and in the same context it is even mentioned that the removal of human-emitted CO2 from the atmosphere by natural processes will take a few hundred thousand years (high confidence) (see AR5-Chap.6-Executive-Summary).
Since the rising CO2 concentrations go along with an increasing greenhouse effect and, thus, a further global warming, a better understanding of the carbon cycle is a necessary prerequisite for all future climate change predictions. In their accounting schemes and models of the carbon cycle the IPCC uses many new and detailed data which are primarily focussing on fossil fuel emission, cement fabrication or net land use change (see AR5-WG1-Chap.6.3.2), but it largely neglects any changes of the natural emissions, which contribute to more than 95 % to the total emissions and by far cannot be assumed to be constant over longer periods (see, e.g.: variations over the last 800,000 years (Jouzel et al., 2007); the last glacial termination (Monnin et al., 2001); or the younger Holocene (Monnin et al., 2004; Wagner et al., 2004)).
Since our own estimates of the average CO2 residence time in the atmosphere differ by several orders of magnitude from the announced IPCC values, and on the other hand actual investigations of Humlum et al. (2013) or Salby (2013, 2016) show a strong relation between the natural CO2 emission rate and the surface temperature, this was motivation enough to scrutinize the IPCC accounting scheme in more detail and to contrast this to our own calculations.
Different to the IPCC we start with a rate equation for the emission and absorption processes, where the uptake is not assumed to be saturated but scales proportional with the actual CO2 concentration in the atmosphere (see also Essenhigh, 2009; Salby, 2016). This is justified by the observation of an exponential decay of 14C. A fractional saturation, as assumed by the IPCC, can directly be expressed by a larger residence time of CO2 in the atmosphere and makes a distinction between a turnover time and adjustment time needless. Based on this approach and as solution of the rate equation we derive a concentration at steady state, which is only determined by the product of the total emission rate and the residence time. Under present conditions the natural emissions contribute 373 ppm and anthropogenic emissions 17 ppm to the total concentration of 390 ppm (2012). For the average residence time we only find 4 years.
The stronger increase of the concentration over the Industrial Era up to present times can be explained by introducing a temperature dependent natural emission rate as well as a temperature affected residence time. With this approach not only the exponential increase with the onset of the Industrial Era but also the concentrations at glacial and cooler interglacial times can well be reproduced in full agreement with all observations. So, different to the IPCC’s interpretation the steep increase of the concentration since 1850 finds its natural explanation in the self accelerating processes on the one hand by stronger degassing of the oceans as well as a faster plant growth and decomposition, on the other hand by an increasing residence time at reduced solubility of CO2 in oceans.
Together this results in a dominating temperature controlled natural gain, which contributes about 85 % to the 110 ppm CO2 increase over the Industrial Era, whereas the actual anthropogenic emissions of 4.3 % only donate 15 %. These results indicate that almost all of the observed change of CO2 during the Industrial Era followed, not from anthropogenic emission, but from changes of natural emission.
The results are consistent with the observed lag of CO2 changes behind temperature changes (Humlum et al., 2013; Salby, 2013), a signature of cause and effect. Our analysis of the carbon cycle, which exclusively uses data for the CO2 concentrations and fluxes as published in AR5, shows that also a completely different interpretation of these data is possible, this in complete conformity with all observations and natural causalities.
I expect there will be a concerted effort by the faithful to try and debunk this (and it has already started).
But I am inclined to give credence to this work – and not merely because it is in general agreement with my own conclusions about the Carbon cycle. Back in 2013 I posted
Even though the combustion of fossil fuels only contributes less than 4% of total carbon dioxide production (about 26Gt/year of 800+GT/year), it is usually assumed that the sinks available balance the natural sources and that the carbon dioxide concentration – without the effects of man – would be largely in equilibrium. (Why carbon dioxide concentration should not vary naturally escapes me!). It seems rather illogical to me to claim that sinks can somehow distinguish the source of carbon dioxide in the atmosphere and preferentially choose to absorb natural emissions and reject anthropogenic emissions! Also, there is no sink where the absorption rate would not increase with concentration.
Carbon dioxide is accumulating in the atmosphere by about 15 GT CO2/ year. The accuracy of the amounts of carbon dioxide emitted by transpiration and by the oceans is no better than about 2 – 3% and that error band (+/- 20GT/year) is itself almost as large as the total amount of emissions from fossil fuels.
This paper in Nature would not have have had any chance of being published a few years ago. But times are changing.
CNRS:“The possibility of major climate change in the Atlantic region has long been recognized and has even been the subject of a Hollywood movie: The Day After Tomorrow. To evaluate the risk of such climate change, researchers from the Environnements et Paléoenvironnements Océaniques et Continentaux laboratory (CNRS/University of Bordeaux) and the University of Southampton developed a new algorithm to analyze the 40 climate models considered by the latest report from the Intergovernmental Panel on Climate Change (IPCC). Their findings raise the probability of rapid North Atlantic cooling during this century to nearly 50%. Nature Communications publishes their work on February 15, 2017”.
My own view is that man-made global warming is insignificant and virtually impossible to measure. The apparent climate turbulence we may currently be experiencing is probably the exhibition of instabilities as climate shifts from an interglacial paradigm to the, more normal, glacial conditions. The transition will probably be “rapid” in geologic terms which probably means a thousand years or so. Major volcanic eruptions (VEI>6) are overdue. This interglacial has lasted some 13,000 years and is also, relatively, long. I think it feasible that 2 or 3 major volcanic eruptions in relatively quick succession could provide the conditions to trigger a full transition. Once glacial conditions are established they will last for about 100,000 years. And we will then be very thankful for all the fossil or nuclear energy we can have available to us.
Giovanni Sgubin, Didier Swingedouw, Sybren Drijfhout, Yannick Mary, Amine Bennabi. Abrupt cooling over the North Atlantic in modern climate models. Nature Communications, 2017; 8 DOI: 10.1038/ncomms14375
Abstract: Observations over the 20th century evidence no long-term warming in the subpolar North Atlantic (SPG). This region even experienced a rapid cooling around 1970, raising a debate over its potential reoccurrence. Here we assess the risk of future abrupt SPG cooling in 40 climate models from the fifth Coupled Model Intercomparison Project (CMIP5). Contrary to the long-term SPG warming trend evidenced by most of the models, 17.5% of the models (7/40) project a rapid SPG cooling, consistent with a collapse of the local deep-ocean convection. Uncertainty in projections is associated with the models’ varying capability in simulating the present-day SPG stratification, whose realistic reproduction appears a necessary condition for the onset of a convection collapse. This event occurs in 45.5% of the 11 models best able to simulate the observed SPG stratification. Thus, due to systematic model biases, the CMIP5 ensemble as a whole underestimates the chance of future abrupt SPG cooling, entailing crucial implications for observation and adaptation policy.
Even The Guardian (a high priest of the man-made global warming religious fantasy) is compelled to report!!
CNRS Press Release:
Current climate models all foresee a slowing of the meridional overturning circulation (MOC)2—the phenomenon behind the familiar Gulf Stream, which carries warmth from Florida to European shores—that could lead to a dramatic, unprecedented disruption of the climate system. In 2013, drawing on 40 climate change projections, the IPCC judged that this slowdown would occur gradually over a long period of time. The panel’s findings suggested that fast cooling of the North Atlantic during this century was unlikely.
Oceanographers from the EU EMBRACE project team reexamined the 40 projections by focusing on a critical spot in the northwest North Atlantic: the Labrador Sea. The Labrador Sea is host to a convection system ultimately feeding into the ocean-wide MOC. The temperatures of its surface waters plummet in the winter, increasing their density and causing them to sink. This displaces deep waters, which bring their heat with them as they rise to the surface, preventing the formation of ice caps. To investigate this phenomenon in greater detail, the researchers developed an algorithm able to detect quick sea surface temperature variations. Their number crunching revealed that 7 of the 40 climate models they were studying predicted total shutdown of convection, leading to abrupt cooling of the Labrador Sea: by 2–3 °C over less than 10 years. This in turn would drastically lower North Atlantic coastal temperatures.
But is such rapid cooling a real possibility? (After all, only a handful of the models supported this projection.) To answer this question, the researchers honed in on the critical parameter triggering winter convection: ocean stratification. Indeed, 11 of the 40 models incorporated vertical variation in the density of oceanic water masses. And of these 11 models, which we may furthermore consider to be the most reliable, 5 (i.e., 45% of the models) predicted a rapid drop in North Atlantic temperatures.
That the onset of glacial (cold) and interglacial (warm) periods on earth are a consequence of the Milankovitch cycles is almost certain. Researchers have now developed a model which seems to be able to explain why and when glacial periods end to give interglacial conditions. Exactly what cause glacial conditions to be triggered remains to be discovered.
P. C. Tzedakis, M. Crucifix, T. Mitsui, E. W. Wolff.A simple rule to determine which insolation cycles lead to interglacials. Nature, 2017; 542 (7642): 427 DOI:10.1038/nature21364
Abstract: The pacing of glacial–interglacial cycles during the Quaternary period (the past 2.6 million years) is attributed to astronomically driven changes in high-latitude insolation. However, it has not been clear how astronomical forcing translates into the observed sequence of interglacials. Here we show that before one million years ago interglacials occurred when the energy related to summer insolation exceeded a simple threshold, about every 41,000 years. Over the past one million years, fewer of these insolation peaks resulted in deglaciation (that is, more insolation peaks were ‘skipped’), implying that the energy threshold for deglaciation had risen, which led to longer glacials. However, as a glacial lengthens, the energy needed for deglaciation decreases. A statistical model that combines these observations correctly predicts every complete deglaciation of the past million years and shows that the sequence of interglacials that has occurred is one of a small set of possibilities. The model accounts for the dominance of obliquity-paced glacial–interglacial cycles early in the Quaternary and for the change in their frequency about one million years ago. We propose that the appearance of larger ice sheets over the past million years was a consequence of an increase in the deglaciation threshold and in the number of skipped insolation peaks.
…. In a new study published today in Nature, researchers from UCL (University College London), University of Cambridge and University of Louvain have combined existing ideas to solve the problem of which solar energy peaks in the last 2.6 million years led to the melting of the ice sheets and the start of a warm period.
During this interval, Earth’s climate has alternated between cold (glacial) and warm (interglacial) periods. In the cold times, ice sheets advanced over large parts of North America and northern Europe. In the warm periods like today, the ice sheets retreated completely.
It has long been realised that these cycles were paced by astronomical changes in the Earth’s orbit around the Sun and in the tilt of its axis, which change the amount of solar energy available to melt ice at high northern latitudes in summer.
However, of the 110 incoming solar energy peaks (about every 21,000 years) only 50 led to complete melting of the ice sheets. Finding a way to translate the astronomical changes into the sequence of interglacials has previously proved elusive.
Professor Chronis Tzedakis (UCL Geography) said: “The basic idea is that there is a threshold for the amount of energy reaching high northern latitudes in summer. Above that threshold, the ice retreats completely and we enter an interglacial.”
From 2.6 to 1 million years ago, the threshold was reached roughly every 41,000 years, and this predicts almost perfectly when interglacials started and the ice sheets disappeared. Professor Eric Wolff (University of Cambridge) said: “Simply put, every second solar energy peak occurs when the Earth’s axis is more inclined, boosting the total energy at high latitudes above the threshold.”
Somewhere around a million years ago, the threshold rose, so that the ice sheets kept growing for longer than 41,000 years. However, as a glacial period lengthens, ice sheets become larger, but also more unstable.
The researchers combined these observations into a simple model, using only solar energy and waiting time since the previous interglacial, that was able to predict all the interglacial onsets of the last million years, occurring roughly every 100,000 years.
Dr Takahito Mitsui (University of Louvain) said: “The next step is to understand why the energy threshold rose around a million years ago — one idea is that this was due to a decline in the concentration of CO2, and this needs to be tested.”
The results explain why we have been in a warm period for the last 11,000 years: despite the weak increase in solar energy, ice sheets retreated completely during our current interglacial because of the very long waiting time since the previous interglacial and the accumulated instability of ice sheets. …..
Milankovitch Cycles (Wikipedia)
What would cause the current interglacial to end remains to be discovered. It’s only my speculation of course but I suspect that a trigger event is probably needed. Possibly 2 or 3 major (VEI >6) volcanic eruptions over a short period, with large amounts of dust, which in turn led to a a few “years without summers”, could provide such a trigger for an unstoppable process. However the onset of full glacial conditions would still take a few thousand years. The availability of high energy densities would probably make it (relatively) easy for humans to continue to thrive and prosper (as they have done through other glacial periods with much lower energy availability).
The “global temperature” is calculated by dividing the world into a grid, determining the temperature applying to each grid element and then “calculating” (not a simple average) a “global temperature” to apply to the world. The problem is that there are actual measurements (raw data) for just about 20% of the grid elements. These 20% are then used to “fill in” temperatures for all the other grid elements. There are algorithms devised first for “correcting” the raw data, then there are those governing the manner in which the corrected data are to be combined to fill in empty grid elements, and further algorithms to be used when combining all the elements of the grid to give a single “global temperature”. The accuracy of the raw data is only about 0.1ºC while the “global temperature” is presented to 0.001ºC, and differences of the order of 0.001ºC are used to make conclusions for “policy” decisions. Climategate 1 revealed how data has been cherry picked and fudged for the first time. The deception continues.
Dr John Bates (formerly of NOAA) is now blowing the whistle on how the NOAA has manipulated climate data:
John Bates received his Ph.D. in Meteorology from the University of Wisconsin-Madison in 1986. Post Ph.D., he spent his entire career at NOAA, until his retirement in 2016. He spent the last 14 years of his career at NOAA’s National Climatic Data Center (now NCEI) as a Principal Scientist, where he served as a Supervisory Meteorologist until 2012.
…….. NOAA Administrator’s Award 2004 for “outstanding administration and leadership in developing a new division to meet the challenges to NOAA in the area of climate applications related to remotely sensed data”. He was awarded a U.S. Department of Commerce Gold Medal in 2014 for visionary work in the acquisition, production, and preservation of climate data records (CDRs). He has held elected positions at the American Geophysical Union (AGU), including Member of the AGU Council and Member of the AGU Board. He has played a leadership role in data management for the AGU.
A look behind the curtain at NOAA’s climate data center.
I read with great irony recently that scientists are “frantically copying U.S. Climate data, fearing it might vanish under Trump” (e.g., Washington Post 13 December 2016). As a climate scientist formerly responsible for NOAA’s climate archive, the most critical issue in archival of climate data is actually scientists who are unwilling to formally archive and document their data. I spent the last decade cajoling climate scientists to archive their data and fully document the datasets. I established a climate data records program that was awarded a U.S. Department of Commerce Gold Medal in 2014 for visionary work in the acquisition, production, and preservation of climate data records (CDRs), which accurately describe the Earth’s changing environment.
The most serious example of a climate scientist not archiving or documenting a critical climate dataset was the study of Tom Karl et al. 2015 (hereafter referred to as the Karl study or K15), purporting to show no ‘hiatus’ in global warming in the 2000s (Federal scientists say there never was any global warming “pause”). The study drew criticism from other climate scientists, who disagreed with K15’s conclusion about the ‘hiatus.’ (Making sense of the early-2000s warming slowdown). The paper also drew the attention of the Chairman of the House Science Committee, Representative Lamar Smith, who questioned the timing of the report, which was issued just prior to the Obama Administration’s Clean Power Plan submission to the Paris Climate Conference in 2015.
In the following sections, I provide the details of how Mr. Karl failed to disclose critical information to NOAA, Science Magazine, and Chairman Smith regarding the datasets used in K15. I have extensive documentation that provides independent verification of the story below. I also provide my suggestions for how we might keep such a flagrant manipulation of scientific integrity guidelines and scientific publication standards from happening in the future. Finally, I provide some links to examples of what well documented CDRs look like that readers might contrast and compare with what Mr. Karl has provided.
Of course the mainstream, politically correct media have no time for this. However David Rose of the Mail on Sunday is one of the few reporters who still has the nerve to question the fanatic, religious orthodoxy on this subject.
PUBLISHED: 22:57 GMT, 4 February 2017 | UPDATED: 01:05 GMT, 5 February 2017
The Mail on Sunday today reveals astonishing evidence that the organisation that is the world’s leading source of climate data rushed to publish a landmark paper that exaggerated global warming and was timed to influence the historic Paris Agreement on climate change.
A high-level whistleblower has told this newspaper that America’s National Oceanic and Atmospheric Administration (NOAA) breached its own rules on scientific integrity when it published the sensational but flawed report, aimed at making the maximum possible impact on world leaders including Barack Obama and David Cameron at the UN climate conference in Paris in 2015.
The report claimed that the ‘pause’ or ‘slowdown’ in global warming in the period since 1998 – revealed by UN scientists in 2013 – never existed, and that world temperatures had been rising faster than scientists expected. Launched by NOAA with a public relations fanfare, it was splashed across the world’s media, and cited repeatedly by politicians and policy makers.
But the whistleblower, Dr John Bates, a top NOAA scientist with an impeccable reputation, has shown The Mail on Sunday irrefutable evidence that the paper was based on misleading, ‘unverified’ data.
It was never subjected to NOAA’s rigorous internal evaluation process – which Dr Bates devised.
His vehement objections to the publication of the faulty data were overridden by his NOAA superiors in what he describes as a ‘blatant attempt to intensify the impact’ of what became known as the Pausebuster paper. …….
NOAA data manipulation (from David Rose – Mail on Sunday)
There will be more whistle-blowers now stepping out from behind the woodwork.
The three Milankovitch orbital cycles, due to eccentricity (100,000 years), axial tilt (41,000 years), and precession (23,000 years) have long been thought to be connected to the onsets of glacial or interglacial conditions. New research now suggests that growth of sea ice in the Southern Hemisphere at particular times of the Milankovitch cycles could be the trigger for a new glacial age. The work suggests that different orbital cycles have been predominant at different times.
“For the past million years or so, the 100,000-year glacial cycle has been the most prominent. But before a million years ago, paleoclimate data suggest that pace of the glacial cycle was closer to about 40,000 years. That suggests that the third Milankovitch Cycle, which repeats every 41,000 years, was dominant then.”
Jung-Eun Lee, Aaron Shen, Baylor Fox-Kemper, Yi Ming. Hemispheric sea ice distribution sets the glacial tempo. Geophysical Research Letters, 2017; DOI: 10.1002/2016GL071307
The proxy record of global temperature shows that the dominant periodicity of the glacial cycle shifts from 40-kyr (obliquity) to 100-kyr (eccentricity), about a million years ago. Using climate model simulations, here we show that the pace of the glacial cycle depends on the pattern of hemispheric sea ice growth. In a cold climate the sea ice grows asymmetrically between two hemispheres under changes to Earth’s orbital precession, because sea ice growth potential outside of the Arctic Circle is limited. This difference in hemispheric sea ice growth leads to an asymmetry in absorbed solar energy for the two hemispheres, particularly when eccentricity is high, even if the annual average insolation is similar. In a warmer climate, the hemispheric asymmetry of the sea ice decreases as mean Arctic and Antarctic sea ice decreases, diminishing the precession and eccentricity signals and explaining the dominant obliquity signal (40-kyr) before the mid-Pleistocene transition.
Climate simulations show how changes in Earth’s orbit alter the distribution of sea ice on the planet, helping to set the pace for the glacial cycle.
Earth is currently in what climatologists call an interglacial period, a warm pulse between long, cold ice ages when glaciers dominate our planet’s higher latitudes. For the past million years, these glacial-interglacial cycles have repeated roughly on a 100,000-year cycle. Now a team of Brown University researchers has a new explanation for that timing and why the cycle was different before a million years ago.
Using a set of computer simulations, the researchers show that two periodic variations in Earth’s orbit combine on a 100,000-year cycle to cause an expansion of sea ice in the Southern Hemisphere. Compared to open ocean waters, that ice reflects more of the sun’s rays back into space, substantially reducing the amount of solar energy the planet absorbs. As a result, global temperature cools.
“The 100,000-year pace of glacial-interglacial periods has been difficult to explain,” said Jung-Eun Lee, an assistant professor in Brown’s Department of Earth, Environmental and Planetary Studies and the study’s lead author. “What we were able to show is the importance of sea ice in the Southern Hemisphere along with orbital forcings in setting the pace for the glacial-interglacial cycle.”
In the 1930s, Serbian scientist Milutin Milankovitch identified three different recurring changes in Earth’s orbital pattern. Each of these Milankovitch Cycles can influence the amount of sunlight the planet receives, which in turn can influence climate. The changes cycle through every 100,000, 41,000 and 21,000 years.
The problem is that the 100,000-year cycle alone is the weakest of the three in the degree to which it affects solar radiation. So why that cycle would be the one that sets the pace of glacial cycle is a mystery. But this new study shows the mechanism through which the 100,000-year cycle and the 21,000-year cycle work together to drive Earth’s glacial cycle.
The 21,000-year cycle deals with precession — the change in orientation of Earth’s tilted rotational axis, which creates Earth’s changing seasons. When the Northern Hemisphere is tilted toward the sun, it gets more sunlight and experiences summer. At the same time, the Southern Hemisphere is tilted away, so it gets less sunlight and experiences winter. But the direction that the axis points slowly changes — or precesses — with respect to Earth’s orbit. As a result, the position in the orbit where the seasons change migrates slightly from year to year. Earth’s orbit is elliptical, which means the distance between the planet and the sun changes depending on where we are in the orbital ellipse. So precession basically means that the seasons can occur when the planet is closest or farthest from the sun, or somewhere in between, which alters the seasons’ intensity.
In other words, precession causes a period during the 21,000-year cycle when Northern Hemisphere summer happens around the time when the Earth is closest to the sun, which would make those summers slightly warmer. Six months later, when the Southern Hemisphere has its summer, the Earth would be at its furthest point from the sun, making the Southern Hemisphere summers a little cooler. Every 10,500 years, the scenario is the opposite.
In terms of average global temperature, one might not expect precession to matter much. Whichever hemisphere is closer to the sun in its summer, the other hemisphere will be farther away during its summer, so the effects would just wash themselves out. However, this study shows that there can indeed be an effect on global temperature if there’s a difference in the way the two hemispheres absorb solar energy — which there is.
That difference has to do with each hemisphere’s capacity to grow sea ice. Because of the arrangement of the continents, there’s much more room for sea ice to grow in the Southern Hemisphere. The oceans of the Northern Hemisphere are interrupted by continents, which limits the extent to which ice can grow. So when the precessional cycle causes a series of cooler summers in the Southern Hemisphere, sea ice can expand dramatically because there’s less summer melting.
Lee’s climate models rely on the simple idea that sea ice reflects a significant amount of solar radiation back into space that would normally be absorbed into the ocean. That reflection of radiation can lower global temperature.
“What we show is that even if the total incoming energy is the same throughout the whole precession cycle, the amount of energy the Earth actually absorbs does change with precession,” Lee said. “The large Southern Hemispheric sea ice that forms when summers are cooler reduces the energy absorbed.”
But that leaves the question of why the precession cycle, which repeats every 21,000 years, would cause a 100,000-year glacial cycle. The answer is that the 100,000-year orbital cycle modulates the effects of the precession cycle.
The 100,000-year cycle deals with the eccentricity of Earth’s orbit — meaning the extent to which it deviates from a circle. Over a period of 100,000 years, the orbital shape goes from almost circular to more elongated and back again. It’s only when eccentricity is high — meaning the orbit is more elliptical — that there’s a significant difference between the Earth’s furthest point from the sun and its closest. As a result, there’s only a large difference in the intensity of seasons due to precession when eccentricity is large.
“When eccentricity is small, precession doesn’t matter,” Lee said. “Precession only matters when eccentricity is large. That’s why we see a stronger 100,000-year pace than a 21,000-year pace.”
Lee’s models show that, aided by high eccentricity, cool Southern Hemisphere summers can decrease by as much as 17 percent the amount of summer solar radiation absorbed by the planet over the latitude where the difference in sea ice distribution is largest — enough to cause significant global cooling and potentially creating the right conditions for an ice age.
Aside from radiation reflection, there may be additional cooling feedbacks started by an increase in southern sea ice, Lee and her colleagues say. Much of the carbon dioxide — a key greenhouse gas — exhaled into the atmosphere from the oceans comes from the southern polar region. If that region is largely covered in ice, it may hold that carbon dioxide in like a cap on a soda bottle. In addition, energy normally flows from the ocean to warm the atmosphere in winter as well, but sea ice insulates and reduces this exchange. So having less carbon and less energy transferred between the atmosphere and the ocean add to the cooling effect.
The findings may also help explain a puzzling shift in the Earth’s glacial cycle. For the past million years or so, the 100,000-year glacial cycle has been the most prominent. But before a million years ago, paleoclimate data suggest that pace of the glacial cycle was closer to about 40,000 years. That suggests that the third Milankovitch Cycle, which repeats every 41,000 years, was dominant then.
While the precession cycle deals with which direction the Earth’s axis is pointing, the 41,000-year cycle deals with how much the axis is tilted. The tilt — or obliquity — changes from a minimum of about 22 degrees to a maximum of around 25 degrees. (It’s at 23 degrees at the moment.) When obliquity is higher, each of the poles gets more sunlight, which tends to warm the planet.
So why would the obliquity cycle be the most important one before a million years ago, but become less important more recently?
According to Lee’s models, it has to do with the fact that the planet has been generally cooler over the past million years than it was prior to that. The models show that, when the Earth was generally warmer than today, precession-related sea ice expansion in the Southern Hemisphere is less likely to occur. That allows the obliquity cycle to dominate the global temperature signature. After a million years ago, when Earth became a bit cooler on average, the obliquity signal starts to take a back seat to the precession/eccentricity signal.
Lee and her colleagues believe their models present a strong new explanation for the history of Earth’s glacial cycle — explaining both the more recent pace and the puzzling transition a million years ago.
Whatever one may think of Trump, his transition team’s questions for the Department of Energy are penetrating. They are causing some little worry among the adherents of the man-made global warming religion.
Man-made climate change (actually the lack of such), vast grants to companies which go bankrupt in the night, jaunts to resorts for climate meetings, prolonging nuclear power …. are all apparently within the sights of the transition team.
The questions and Willis Eschenbach’s comments are reproduced below
Questions for DOE
This memo, as you might expect, is replete with acronyms. “DOE” is the Department of Energy. Here are the memo questions and my comments.
1. Can you provide a list of all boards, councils, commissions, working groups, and FACAs [Federal Advisory Committees] currently active at the Department? For each, can you please provide members, meeting schedules, and authority (statutory or otherwise) under which they were created?
If I were at DOE, this first question would indeed set MY hair on fire. The easiest way to get rid of something is to show that it was not properly established … boom, it’s gone. As a businessman myself, this question shows me that the incoming people know their business, and that the first order of business is to jettison the useless lumber.
You cannot have “global” warming which applies differently to different parts of the globe. If man-made CO2 is having any significant effect on “global” temperature it must be an effect that is visible in both the Arctic and the Antarctic. Even if all the Arctic ice melts but the Antarctic ice does not then “global” warming is clearly not “global”.
A new study by Reading University shows that Antarctic ice is largely unchanged over 100 years and increasing over the last 3 decades. The man-made “global” warming theory is just not possible with these results.
21 Nov 2016
Estimating the extent of Antarctic summer sea ice during the Heroic Age of Antarctic Exploration
Tom Edinburgh1,a and Jonathan J. Day11Department of Meteorology, University of Reading, Reading, UK acurrently at: Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, UK
Received: 13 Apr 2016 – Published in The Cryosphere Discuss.: 29 Apr 2016 Revised: 11 Sep 2016 – Accepted: 18 Sep 2016 – Published: 21 Nov 2016
Abstract.In stark contrast to the sharp decline in Arctic sea ice, there has been a steady increase in ice extent around Antarctica during the last three decades, especially in the Weddell and Ross seas. In general, climate models do not to capture this trend and a lack of information about sea ice coverage in the pre-satellite period limits our ability to quantify the sensitivity of sea ice to climate change and robustly validate climate models. However, evidence of the presence and nature of sea ice was often recorded during early Antarctic exploration, though these sources have not previously been explored or exploited until now. We have analysed observations of the summer sea ice edge from the ship logbooks of explorers such as Robert Falcon Scott, Ernest Shackleton and their contemporaries during the Heroic Age of Antarctic Exploration(1897–1917), and in this study we compare these to satellite observations from the period 1989–2014, offering insight into the ice conditions of this period, from direct observations, for the first time. This comparison shows that the summer sea ice edge was between 1.0 and 1.7° further north in the Weddell Sea during this period but that ice conditions were surprisingly comparable to the present day in other sectors.
Citation: Edinburgh, T. and Day, J. J.: Estimating the extent of Antarctic summer sea ice during the Heroic Age of Antarctic Exploration, The Cryosphere, 10, 2721-2730, doi:10.5194/tc-10-2721-2016, 2016.
Ice observations recorded in the ships’ logbooks of explorers such as the British Captain Robert Scott and Ernest Shackleton and the German Erich von Drygalski have been used to compare where the Antarctic ice edge was during the Heroic Age of Antarctic Exploration (1897-1917) and where satellites show it is today.
The study, published in the European Geosciences Union journal The Cryosphere, suggests Antarctic sea ice is much less sensitive to the effects of climate change than that of the Arctic, which in stark contrast has experienced a dramatic decline during the 20th century. ……
……. Jonathan Day, who led the study, said: “The missions of Scott and Shackleton are remembered in history as heroic failures, yet the data collected by these and other explorers could profoundly change the way we view the ebb and flow of Antarctic sea ice.
“We know that sea ice in the Antarctic has increased slightly over the past 30 years, since satellite observations began. Scientists have been grappling to understand this trend in the context of global warming, but these new findings suggest it may not be anything new.
“If ice levels were as low a century ago as estimated in this research, then a similar increase may have occurred between then and the middle of the century, when previous studies suggest ice levels were far higher.”
The new study published in The Cryosphere is the first to shed light on sea ice extent in the period prior to the 1930s, and suggests the levels in the early 1900s were in fact similar to today, at between 5.3 and 7.4 million square kilometres. Although one region, the Weddell Sea, did have a significantly larger ice cover.
Published estimates suggest Antarctic sea ice extent was significantly higher during the 1950s, before a steep decline returned it to around 6 million square kilometres in recent decades.
The research suggests that the climate of Antarctica may have fluctuated significantly throughout the 20th century, swinging between decades of high ice cover and decades of low ice cover, rather than enduring a steady downward trend.
To pretend that politicised science does not exist is to be naive. To state as a religious conviction that man-made CO2 is causing global warming is little different to the religiously expressed beliefs by politically correct media that Brexit would not happen or that Trump could not win. Climate “scientists” and their gullible followers need to remember that all beliefs can only exist in the space of ignorance.
I dislike algorithms for “calculating” an artificial “global temperature” by “adjusting” and “weighting” raw data to suit pre-conceived notions of what final result should be. It gets worse when the “adjustments” about past temperatures are variable and are themselves “adjusted” every year. The reports about every year being hotter than the last are actually just a statement that “adjustments” every year are greater than the last.