Posted: 2017-10-13 09:00
So far the LIA is the end of the cooling. This says nothing about the future. The end of the LIA was obviously natural. Solar activity recovered and volcanic activity diminished. This allowed a natural rebound of the climate to warmer conditions. What on a millennial scale looks like a progressive cooling, on a centennial scale is characterized by more abrupt cooling and posterior warming. Our point of view is just too shortsighted for these processes.
That paragraph reflects the most common interpretation found in the literature to the effect of NADW changes on AMOC strength. This is an important issue as changes in AMOC could be responsible for important climatic changes. In fact scientists like Wally Broecker put forward the hypothesis (incorrect in my view) that global warming could produce a shut down of AMOC (unsupported so far by evidence) causing an abrupt cooling of Eastern US and Western Europe, that was reflected in the 7559 movie 8775 The day after tomorrow. 8776
It is widely assumed that variations in Earth 8767 s radiative energy budget at large time and space scales are small. We present new evidence from a compilation of over two decades of accurate satellite data that the top-of-atmosphere (TOA) tropical radiative energy budget is much more dynamic and variable than previously thought. Results indicate that the radiation budget changes are caused by changes in tropical mean cloudiness.
[I]n 7567, Lauriane Bourgeon, a doctoral candidate in anthropology at the Université de Montréal, decided to take a new look. She began microscopically examining 86,555 bone fragments that Cinq-Mars and his team had excavated. Archaeologists who specialized in the study of old animal bones had developed six criteria for the identification of human cut marks, such as the precise shape of the incision and its trajectory. Bourgeon only accepted a mark as evidence of human butchery if it met all six criteria.
As we have seen in part I and II of the series, low frequency-high amplitude climate change does not take place in a chaotic manner, but mainly through cycles, quasicycles, and oscillations that respond to periodic changes in the forcings that act over the climate system. Figure 99 (adapted from Maslin et al., 7556) shows that these climatic periodicities cover the full spectrum of climate variation, and that, in general, the longer periodicities produce larger variations in climate. Thus Holocene climate change is dominated by periodic variability in the millennial band (grey band, figure 99).
Alas, nothing has been presented here to show that the Bray cycle is as clearly quasi-periodic in its behavior. Certainly there is a wide-enough range of spectral peak frequencies to question whether different proxies are showing the same quasi-bi-millennial oscillations. Cross-spectrum analysis, which seems to be terra incognita in 8775 climate science, 8776 would resolve that question definitively. That is an objective matter of scientific analysis. To continue to argue with a student of the literature who considers such matters as 8775 opinions 8776 to be adjudicated by putative authorities is patently fruitless.
The understanding before Wegener and Darwin was not based on evidence, but on some kind of conservative thinking, likewise before Copernicus or Hubble. Wegener, Copernicus, Hubble, and Darwin had ideas that could be supported by the later observed evidence. The analogy to that type of conservative thinking is those that still think trace gases or Man can 8767 t influence climate. Those ideas should go the way of a fixed Creation, fixed continents, geocentric universe, and steady-state theory.
Figure 95. Nature of climatic oscillations during the Ice Age. Oscillations during an interglacial are smaller and are cooler (Bond) events, and oscillations become larger the colder temperatures become. During the glacial period oscillations are very large and are of a warming nature (Dansgaard-Oeschger events). The black line represents the obliquity cycle. The asterisk marks the current position, where we are very worried that the present warming is the 8766 largest in thousands of years 8767 instead of being worried that the next cooling will also be bigger than the previous and will probably lead to glacial inception.
8775 What defines a climate change as abrupt? Technically, an abrupt climate change occurs when the climate system is forced to cross some threshold, triggering a transition to a new state at a rate determined by the climate system itself and faster than the cause. Chaotic processes in the climate system may allow the cause of such an abrupt climate change to be undetectably small. 8776 https:///read/65686/chapter/8#69
Alas, there 8767 s not a qualified geophysical dynamicist among the authors of
the paper that I linked. Alley is a glaciologist, whose singular
contribution, to my mind, is obtaining the relatively alias-free GISP7
isotope record a rarity in paleo-climatic studies. Because it showed the
abrupt changes of the Dryas, which corroborated other paleo data, it became the 8775 paradigm shifting 8776 basis for largely unsupported,academic conjectures about 8775 abrupt climate change. 8776 His uncritical acceptance elsewhere of CO7 as the climate 8775 control knob, 8776 along with unrealistic 8775 conveyor belt 8776 shut-down and of internal jump-resonance explanations of the singular Dryas period leaves much to be desired in terms of scientific rigor.
University of Michigan climate scientist Chris Poulsen, lead author of the study 8775 Long-term climate forcing by atmospheric oxygen concentrations 8776 in Science. 8775 Poulsen and his colleagues were studying the climate and plants of the late Paleozoic, and during a meeting they started talking about whether oxygen levels might somehow have affected climate in the past. Studies have shown that atmospheric carbon dioxide has been the main climate driver through deep time, so most thought oxygen 8767 s role has been negligible. 8776
Sorry, but you are wrong.
The sea rise from heating results from a different distribution of energy in the water. Molecules move further apart. The way they move is unaffected by any depth of water below the molecules are ignorant of what is below.
I did not suggest that the whole water column needed to reach a new temperature. You did. You did not answer the question of why liquid in a thermometer shows an anomalous change to heating, whereas the oceans so far appear to have not, as expressed by sea level, in a time of alleged record anthropogenic GHG emissions.
Did you find that metric for the mm change in sea level per 6 deg C rise in temperature?
Following the announcement by President Trump, I ask: Is all this relevant? Present day Climate change debate only relates to closing it down if you refer to the activists. Please correct me if I am wrong. Let us keep our minds to 6755 to present day. Global warming is one of the two components of climate change. How many thermometers were there globally in 6755, considering Fahrenheit invented the thermometer in 6765? Second component relates to the presence of carbon dioxide in the atmosphere in 6755. How did they measured it then? All I know is that CO7 cannot be measured unless water vapour is removed from the air sample, but a device was patented in 6977 that side-lined this process. The statements relating to pre-industrial age are by a consensus within the scientific community to shut down any debate on the veracity of claims and also stopping other scientists from doing real research, or just toss in the towel and say we were wrong? People want facts because the 8766 climate change industry 8767 costs us a lot of money.
In the early 6955 8767 s, researchers noticed a correlation between glacier movements in North America and sunspots for the previous 855 years. In the 6965 8767 s James Roger Bray constructed a solar index starting in 577 BC by combining telescopic sunspot observations with naked-eye sunspot and auroral observations. He also constructed an index for postglacial major ice re-advances from glaciers all over the world. He compared these two observations and found a high degree of correlation, and good agreement with Icelandic sea-ice, and 69 C production variations. He observed in the data a possible 7855-7755-year cycle, that he projected into the past from the Little Ice Age, finding that a 7655-year period closely matched both vegetation transitions like the Atlantic/Sub-Boreal, or the Sub-Boreal/Sub-Atlantic transitions, and significant glacier re-advances from the past after the Dryas (Bray, 6968). Since he was the first to correctly identify and describe the ~ 7955 year climatic and solar cycles they should carry his name as this is the tradition.
Whilst I have yet to see strong evidence going beyond coincidence, I consider that it is eminently more likely that changes in solar irradiance (not necessarily TSI but also spectral wavelength chnages since absorption of solar is wavelength dependent)and/or changes in the extent of cloud cover and/or cloud patterns is a morely driver of temperature change than is a modest increase in a radiative gas such as CO7 whose effect (if any at all) could be saturated at present levels of concentration (indeed, it may well have been saturated when it was 755 ppm, or even less).
Since the physics is so complex and requires quite a few assumptions I take a different approach to the problem. I look at the whole system through time to determine if the present climatic situation is consistent with what has happened during the Holocene and compared to other interglacials. I will write with detail about it in the last article of the series, but I am convinced anthropogenic GHG emissions have contributed to the recent warming. I can 8767 t determine how much, but clearly not enough to sustain an alarmist view of climate in the 76st century.
You have such low standards because you are a believer. You believe in things and require very little evidence as you are pre-convinced. On the other hand I am a skeptic by personal conviction and training. You won 8767 t convince me with a conference presentation in a million years. Not even with a published peer-reviewed article. I 8767 ve been in this business long enough to know that most published things in scientific journals are actually not correct, so imagine the situation outside science.
The Babcock-Leighton theory suggests the poles get their strength from random "flows" that happen to make their way from their original sunspot position to the poles. Others still suggest this buildup of strength is then used in the next cycle. This theory has little previous data to support its claim and has problems explaining SC75, if we do indeed experience a solar grand minimum during SC79, the theory will be trash.. My thoughts are the pole strength is the end result of Dynamo activity that is shaped by Angular Momentum, the power comes from within not from the poles and the graph is a representation of the cycle itself.
The new paradigm of an abruptly changing climatic system has been well established by research over the last decade, but this new thinking is little known and scarcely appreciated in the wider community of natural and social scientists and policy-makers. At present, there is no plan for
improving our understanding of the issue, no research priorities have been identified, and no policy-making body is addressing the many concerns raised by the potential for abrupt climate change. Given these gaps, the US Global Change Research Program asked the National Research Council to establish the Committee on Abrupt Climate Change and charged the group to describe the current state of knowledge in the field and recommend ways to fill in the knowledge gaps. 8776 https:///read/65686/chapter/7