"Bond events" might take 750 years to materialize.
A 1500 year cycle could well be how long the entire ocean system takes to cycle.
The 70 year PDO cycle which appears capable of .7degC warming over 33 years may be just 1/4th of all the cycles that add up to a 1500 year cycle and might be just a shortterm harmonic, with each PDO cycle the system may be recharging more thoroughly for a deeper subsequent PDO cycle. To get to the maximum perhaps there needs to be an extended summer period with no ice in the arctic.
Perhaps Tstat will jump in with some references to the underlying natural cooling he has suggested. Milankovitch cycles would not seem to be sufficient to explain the bond events as they might be 4 deg C or more and the Milankovich cycles seem to need about 50,000 years plus to half cycle.
There are a lot of references for events that happen a LOT faster than 750 years
GEOPHYSICAL MONOGRAPH SERIES, VOL. 126, PP. 9-52, 2001
Synthesis of the nature and causes of rapid climate transitions during the quaternary
M. Maslin, D. Seidov, and J. Lowe
The last few million years have been punctuated by many abrupt climate transitions many of them occurring on time-scales of centuries or even decades. In order to better understand our current climate system we need to understand how these past climate transitions occurred. In this study we examine and review the paleoclimate proxies and modeling results for each of the key climate transitions in the Quaternary period. These are identified as: 1) Onset of Northern Hemisphere Glaciation (ONHG), 2) glacial-interglacial cycles, 3) Mid-Pleistocene Revolution (MPR), 4) Heinrich events and glacial Dansgaard-Oeschger (D-O) cycles, 5) last glacial-interglacial transition (LGIT) and the Younger Dryas, 6) interglacial climate transition such as the Intra-Eemian cold event and Holocene D-O cycles. For each climate transition the current theories of causation are critically examined and our own synthesis based on current knowledge is put forward. Most of these transitions appear to be threshold changes where by external forcing combined with internal feedbacks leads to a change in the state of global climate. We argue that bifurcation within the climate system means that it is easier for the global climate to go through these thresholds than it is to return to its previous state. Although this does not necessarily make climate change irreversible, it may provide a mechanism, which facilitates the locking of the climate system into a new equilibrium state. We suggest that the evidence indicates that long-term climate change occurs in sudden jumps rather than incremental changes; which does not bode well for the futurewww.agu.org/books/gm/v126/GM126p0009/GM126p0009.shtmlIf the climate system is a chaotic system with several attractors then it may move to a different attractor relatively swiftly. There will then be inertia as the various elements of the system cool (or heat up) and circulation patterns alter. Looking at the Heinrich, D-O and Bond events these are relatively rapid drops and returns.
Problem is we spend our time talking of averages and not really understanding how averaging hides information. If both poles warm by 20C during their 'winter' the global average will show warming but it may not be apparent anywhere else apart from weather changing. The temperatures in the equatorial regions are relatively constant.
The important aspect is the grow lines for crops. Just a 400 mile move equatorward would result in mass starvation.
By the way, this is an excellent point Nautonnier.
I offer my thoughts on this -
The problem with sudden changes in climate conditions often comes a lack of preparation by populations and their governments.
We will see this occur with the addition of the fallacy of 'man-made global warming' that has consumed minds, resources and most of all - valuable time - for nearly two decades.
From what I can see, what will happen is the same thing (in reverse) that occurred among climate scientists between the 1970s into the late 1980s and early 1990s.
The majority of climate sciences in the late 1960s and 1970s were wholly focused on global cooling. Since 1944, the world's climate was more or less variable, wet and cold. So global cooling and calls for an 'ice age' were all the rage in the 1970s as I remember.
But they got it totally wrong.
Global warming is what took place - governed by the activity of the Sun. But the majority of climate science did not take it seriously until the early 1990s when temperature readings and climate conditions clearly showed that we were in a global warming regime since 1980-81.
It took climate science until the early-to-mid 1990s to come to its senses about this and the federal money out of the Clinton-Gore administration turned most of the baby boomer climate scientists into careerists. These were the same people who questioned if the world was warming back in the 1980s.
Since the mid-1990s right to our present, the fallacy of 'man-made global warming' has poisoned climate science with ideology fueled by waste of money and resources to push something that the laws of physics say is impossible to ever happen on Earth.
Now, this different crop of climate scientists have been pushing 'global warming forever' (just like the climate scientists of the 1970s who pushed global cooling forever.)
My bet is that the climate regime change to global cooling, which will be felt certainly by the early 2020s will take most of climate science by surprise.
The cult of 'man-made global warming' that has emanated since the 1990s from ideological economic and political forces has greatly lowered the knowledge bar on the truths of the Earth's climate.
I continue to maintain as a climate and weather forecaster that there is no such thing as a 'thermal equilibrium' on any time scale of the Earth's climate. The Sun is the reason for global warming.
And it is the laws of physics that govern our planet's climate. Energy transfer is determined by the First & Second Laws of Thermodynamics.
The First Law demands an energy balance while the Second Law requires a thermal gradient for heat transfer. These are the facts - the laws of physics - that prove that the Earth can NEVER become a man-made greenhouse from carbon gas emissions.
Moreover, when global cooling does officially set in - and it surely shall - it will be too late to make the most of long-range preparations that could have made all the difference in getting ready for
global cooling which is much worse than global warming could ever be.
Here we are, nearly the year 2013, and few nations are prepared for global cooling because the IPCC along with many of their associated climate scientists and their AGW minions who cannot forecast seasonal weather (much less years of climate in advance) have spent hundreds of millions of dollars on useless careerist climate scientists and their expensive supercomputers, going to global warming conferences in exotic places as they publish reams of climate journal junk to convince themselves and the world's public that the world will 'warm forever.'
That is a recipe for disaster with global cooling truly on the way.
We are going to see it too in a little under 10 years and certainly by the time of the next major ENSO (2021-2023.)
So while M. Maslin, D. Seidov and J. Lowe say that "
... bifurcation within the climate system means that it is easier for the global climate to go through these thresholds than it is to return to its previous state..." I say that this is not so, that the Earth's climate is never in an equalized state, but oscillates as a true variable climate system on a water planet should perform.
They continue by stating,
"Although this does not necessarily make climate change irreversible, it may provide a mechanism, which facilitates the locking of the climate system into a new equilibrium state. We suggest that the evidence indicates that long-term climate change occurs in sudden jumps rather than incremental changes; which does not bode well for the future."Again, it is my astrometeorological premise that what the 'evidence' will show is that it is the 'minds' and 'assumptions' of climate scientists and the roles they played in convincing leaders and the public of the lie that the Earth's climate is in an 'equilibrium state' and that humanity is causing planetary 'climate change,' i.e., global warming.
Quoting Roy Clark -
"The global warming ‘debate’ has become detached from its foundations in physical science and degenerated into an argument over belief in empirical pseudoscience. The energy transfer processes that determine the Earth’s surface temperature are dynamic - not static.
The local surface temperature is always changing on both a daily
and a seasonal time frame. The Earth’s climate has to be described in terms of at least six (6) separate energy transfer processes coupled dynamically to four (4) thermal reservoirs.
There can be no climate equilibrium on any time scale. It is impossible for the large scale equilibrium-based climate models to predict climate change.
They have been fraudulently hard wired to produce global warming. Once this is understood, the whole pseudoscientific façade of forcings and feedbacks and climate sensitivity factors
collapses. A doubling of the atmospheric CO2 concentration can have no effect on the Earth’s climate.
The removal of the artificial climate equilibrium concept also introduces a climate averaging paradox. Climate is the long term trend in the weather patterns, usually determined over a minimum of 30 years.
Since there is no equilibrium, climate must be calculated as it is measured, as a long term average of short term variations. There is no simplifying calculation of an equilibrium climate state that can be substituted for the real long term climate average."The evidence shows that the false belief in 'man-made global warming' will come as a shock by the arrival of the new climate regime I've been forecasting - global cooling - which will not come by 'sudden jumps' but by a
transitional one where incremental climate changes were ignored by ideological forces bent on rewriting the laws of physics that govern our planet's climate.
I have been warning for years, that the lies and distractions of anthropogenic global warming has consumed great resources and attention away from the global cooling regime to come.
The whole 'man-made global warming' mania has been and is based on a lie - on a ponzi scheme of massive proportions - that has its foundations built entirely on sand.
This will be finally proven out by the climate itself. When, by the early 2020s and long before global cooling will reach its peak in the mid-2030s where the ideological clamor over the lie of anthropogenic global warming will be widely accepted as being the giant albatross around the neck of the world which prevented preparation for the blasting cold storms, floods, droughts and very cold temperatures that is the climate regime of global cooling.
Also see ->
pjmedia.com/blog/global-cooling-a-far-more-dangerous-fate/And it
is coming. That has been and will continue to be my climate forecast for the world. Forewarned is forearmed. You all had best get ready.
