AN URGENT SIGNAL FOR THE COMING ICE AGE
Peter Harris
http://icecap.us/images/uploads/ANURGENTSIGNALFORTHECOMINGICEAGE.pdf
INTRODUCTION
When paleoclimatologists met in 1972 to discuss how and when the present
warm climate would end , termination of this warm climate we call the
Holocene seemed imminent and it was expected that rapid cooling would
lead to the coming ice age. These ideas were based on the 1M year
analogue for climate transitions first proposed by Milankovitch over 60
years ago, which has been demonstrated to show the correlation of
glacial and interglacial climate with solar insolation as it is
modulated by our changing distance from the sun. These data sets may be
used to serve as a signal for the coming ice age. Orbital geometry was
approaching similar conditions to those of the previous transitions to
ice.
But soon it was observed that global temperature was increasing and at
about this time Global Climate Modeling GCM received more attention and
the Milankovitch analogue was forgotten. There has been no further
discussion about the coming ice age.
THE AGW DIVERSION
Perhaps underwriting the idea that our consumption of carbon and
production of CO2 was contributing to climate warming was the work of
Loutre and Berger and the paper by Loutre in 2000 claimed that the
Holocene would extend for at least another 30 000 (KY) years because of
the effect of CO2 concentration as a greenhouse gas.
It was acknowledged in this paper that the orbital geometry 400KY which
featured muted amplitude, was the "best and closest analogue to our near
future climate", but inexplicably the Global Climate Model LLN2-D NH was
"tuned" to replicate the past 200KY climate transitions when insolation
amplitude was at it's highest level over the 400KY cycle and quite
unlike present conditions. Using different values for CO2 it was found
that "best agreement with SPECMAP is obtained near
210ppmv CO2 ".
Then using a modeled Holocene they projected climate using a range of
CO2 forcing, and they re****ted that there was no transition to ice for
at least 30KY into the future.
The algorithm for this process is not disclosed but the authors rightly
list the limitations of the model in which CO2 is considered as an
external forcing ie the carbon cycle is not simulated by the model.
Clouds and the hydrological cycle are simplified and so is the heat
trans****t to middle and deep ocean. In addition, regional changes such
as the North Atlantic and over Europe are not simulated "and might
depart from the global trend"
It is unfortunate that these limitations appear to have been ignored and
the AGW hypothesis was born and has occupied science and the media ever
since. The Milankovich analogue has been forgotten.
But the reality is that CO2 is not driving temperature up , in fact the
data below suggests that global T may be cooling since 1998 and CO2
continues to climb.
Remote Sensing Systems Advanced Microwave Sounding Units Satellite
Temperature data, Anthony Watts analysis here.
There is further detailed material here in a paper by Dr Willie Soon
which shows that there is no evidence to sup****t global warming by CO2.
The concentration of CO2 varies according to the temperature of the
ocean and CO2 follows T. If the present decline in T continues we can
expect to see a decline in the rate of CO2 as more is dissolved in a
cooler sea. This paper by Professor Lance Endersbee explains the
processing of CO2 by the ocean.
The climate trends during the Holocene, and also the regular sudden
climate transitions between the ice ages and the interglacial climate
over the past 1M years are better explained by reference to the great
external driver, the Sun.
There is abundant archeological evidence to show that global Temperature
is closely correlated with solar activity. Here is a chart which shows
how solar activity has correlated with climate during the Holocene. The
data is based on analysis of Carbon 14 which varies in concentration
according to the level of solar activity.
Solar activity over the past 70 years has been greatest for 8000 years
and is the most likely cause of the recent temperature trend through
1998 that has been wrongly attributed to CO2 warming.
THE SIGNAL FOR THE NEXT ICE AGE
The evidence for the solar insolation signal for the ice ages is
contained in the Milankovitch analogue which has been overlooked for
over 30 years.
The data below was compiled by the mathematicians Quinn, Levine et al in
1991 and Insolation values due to Precession, Obliquity and Eccentricity
as well as total insolation or Solar Forcing are charted on the same
time scale as Stages of Glaciation representing climate. This climate
data was provided by Lisieckie and Raymo and is based on sediment
proxies. The climate data shows close agreement with Ice core data based
on a different proxy.
Produced in 1991 this chart confirms the correlation of climate
transitions with insolation which is modulated by Earth position in
orbit and was first proposed by Milutin Milankovitch over 60 years ago.
The work was published by the mathematicians Quinn et al as " A 3
Million year Integration of Earths Orbit"; The Astronomical journal 101
pp 2287-2305, June 1991.
MILANKOVICH ANALOGUE DATA QUINN ET AL 1991 Copyright
In studying the analogue there is no use of a GCM which is subject to
limitations and interpretation. Use of the analogue is based on simple
observation of clear empirical data and the archeological record of
temperature. The data and the correlation are sound.
The interglacial stages are shaded grey by the authors, and the glacial
stages are clear.
The signal for each transition to ice can be found by careful inspection
of the data and projections.
By reference to this chart we can make the following observations:
..
The glacial stages are only slightly affected by up to 3 cycles of Solar
Forcing as glaciation continues up to the next sudden transition which
occurs near peak Eccentricity. The process for these sudden recoveries
is not fully understood.
..
Every interglacial (shaded grey) survives for a single half cycle
maximum in Solar Forcing or total insolation, (yellow) and expires when
insolation is in rapid decline and we are near that position now. The
interglacials at 200 and 600KY are split because Precession (red) and
Obliquity (green) combine in opposite phase to defeat Eccentricity and
the interglacial tem****arily returns to ice.
..
Conversely total insolation at 400KY is forced into a second half cycle
and the interglacial is extended to 28,000 years. Because muted
Eccentricity at 400KY is considered a precedent for present conditions,
the 28KY interglacial has been widely misre****ted as evidence for an
extended Holocene. From the data we can see we have no such additional
insolation half cycle. Insolation now is in rapid decline from a single
peak.
..
Each of the "Ice Ages" over the past 1M years corresponds with the
minimum half cycle of Eccentricity (blue) which is the predominant
orbital factor. We are close to the Eccentricity half cycle minimum now.
..
Counter intuitively every transition occurs from peak global T ;We may
have a decline in T since a peak in 1998 .
..
It follows that every transition occurs when polar ice melt has peaked.
We have ice rebuilding in some regions now.
..
Last transition to ice occurred about 120KY ago when T was 5 degC hotter
than now and polar ice melt was greater than now. The average cycle is
100KY and the coming transition is overdue.
..
By inspection we can see that all of the transitions have occurred when
Solar Forcing (ie total Insolation) was very close to the present level.
..
In addititon to the above which relates to the Milankovitch cycles we
have a coincident decline in solar activity.
..
Solar activity is dormant now and cycle 24 is delayed.
A MECHANISM FOR THE SUDDEN CHANGE TO ICE
The variations in Insolation seen in the data are not sufficient alone
to explain the sudden climate transitions from interglacial to ice and
reverse. The data provides a template for timing the changes based on
the extended correlation but there must be an internal mechanism to
explain the rapid process.
At the tipping point for each transition, global T has peaked. This
follows from the fact that Earth has been receiving peak insolation
throughout the interglacial for about 10,000 years. Polar ice melt has
peaked and the polar seas are freshened which may affect circulation of
the MOC and interrupt heat exchange with the equator leading to sudden
NH cooling.
In addition it has been proposed by William Kininmonth, meteorologist
and former head of Australia's National Climate centre, that atmospheric
heat and humidity trans****t to the NH would offer a larger contribution
to variations in heat budget if it could be shown to respond to the
100KY cycle.
I think that this factor which is driven by equatorial SST will indeed
have a 100KY signature because the 100KY transitions correspond to T
max. and SST will also peak near T max in accordance with the 100KY
cycle.
This proposal offers the further advantage that it would provide a
faster response which helps to explain the rapid climate change observed
in the transitions. It is significant to note that at this tipping
point, energy trans****t to the NH is at a peak and there is abundant
humidity trans****ted to the NH at a critical time when insolation is in
rapid decline.
These are the conditions which favour maximum precipitation in the NH
winter. These are the conditions NOW.
I think that the rapid decline to ice conditions will occur by the
following process:
As T declines under rapidly declining insolation the precipitation will
increasingly be snow and as albedo increases more heat will be
reflected. Initially cloud cover will insulate the snow from summer
insolation. Insolation continues to decline.
As T further declines water vapour in the NH will be reduced and at T
zero deg C it will practically disappear leading to a sudden elimination
of water vapour GHG.
Then positive feedback due to this process will lead to a rapidly
widening region of sub zero T and glaciation will begin to expand. There
will be a decrease in cloud cover allowing more heat to escape in
winter. In this way the sudden transition to ice has commenced.
The geological record shows that the transitions are sudden, long term
and extreme. All of the Milankovitch parameters for a transition are
satisfied by the present orbital position. We have already seen extreme
NH winter conditions and T appears to be declining in the short term.
The decline will continue under rapidly declining insolation and the
coincident effect of reduced solar activity which has also been
correlated with temperature in the past.
It is possible that we may have already entered the sudden stage of the
transition.I would challenge: is there a good reason why the analogue
will not apply now?
It is overdue time for engineers and scientists to reconsider the
Milankovitch analogue and to plan for the contingency of an imminent
transition to ice. I think that the AGW hypothesis has proven to be a
costly diversion of resources .
Peter Harris
Retired Engineer
April 2008
--
Warmest Regards
Bonzo
"America in Longest Warm Spell Since 1776; Temperature Line Records a
25-year Rise" New York Times, March 27, 1933
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