"So who or what are you going to trust? Unproven predictions based
on theoretical models of how the entire earth-ocean-atmosphere system
is believed to operate, as best as our present knowledge of these complex
and interrelated entities and their numerous sub- and sub-sub- systems
allows us to approximate them? Or the projections of a simple but
straightforward empirical relationship based on real-world
observations that has a proven track record of providing an excellent
representation of atmospheric CO2 concentration for fully 350 years?"
-- Craig & Keith Idso, Center for the Study of Carbon
Dioxide and Global Change 

"It is highly probable that the urban-induced surface radiant
temperature increase of 13C per decade calculated for the Zhujiang Delta
of China has introduced an urban warming bias in the near-surface air
temperature records of weather stations located there. Removing
and/or filtering out such biases in temperature series remain a daunting
task for researchers examining global climate change. This
challenging work must be done, however, before any change in air
temperature can be ascribed to CO2-induced global warming.
  --Center for the Study of Carbon Dioxide and Global Change 

    Scientific American, September 2001

SCOTIA, 28 August 2001

    People's Daily, 23 August 2001

    CO2 Science Magazine, 29 August 2001

    CO2 Science Magazine, 29 August 2001

    CO2 Science Magazine, 22 August 2001

    CO2 Science Magazine, 8 August 2001

    CO2 Science Magazine, 2001

    CO2 Science Magazine, 22 August 2001

     CO2 Science Magazine, 29 August 2001

(11) THE COOLING IN 1805-1820
     Timo Niroma <>


>From Scientific American, September 2001

EDINBURGH, SCOTLAND--Once upon a time ice as much as a kilometer thick
engulfed the earth. Glaciers scoured the nearly lifeless continents, and sea
ice encapsulated the oceans--even in the tropics. The planet's only solution
to the deep freeze was to wait for volcanoes to release enough heat-trapping
carbon dioxide to create a runaway greenhouse effect. A brutal episode of
warming ensued, not only melting the ice but also baking the planet.

Three years ago a group of Harvard University researchers proposed this
revolutionary idea--dubbed the snowball earth hypothesis--about the
potential of the planet for severe climate reversals. Since then, scientists
have hotly debated the details of the events, which occurred as many as four
times between 750 million and 580 million years ago, in a time known as the
Neoproterozoic. But just how the earth first plunged into a snowball-style
ice age has been unknown. Now the original purveyors of the snowball earth
hypothesis have proposed a trigger: methane addiction.

At a scientific conference in Edinburgh this past June, geochemist Daniel P.
Schrag described the addiction scenario: Just before the first snowball
episode, the ancient earth kept warm by relying on methane--a greenhouse gas
60 times more powerful than carbon dioxide. The methane had begun leaking
slowly into the atmosphere when massive, icy methane hydrate deposits within
the seafloor became destabilized somehow. As a result, carbon dioxide levels
decreased, and methane became the world's dominant greenhouse gas.

The trouble with the planet's dependence on methane is that the gas
disappears quickly in an oxygen-rich atmosphere. An interruption in the
methane leak left the earth in dire need of greenhouse gases, and the
climate tumbled into a deep freeze before volcanoes could release enough
carbon dioxide to make up for the lost methane. "I'm not sure I totally buy
this idea--it's outrageous," Schrag admitted at the conclusion of his
presentation. "But it's the only idea that explains the carbon isotope crash
just before the glaciations."

Such bizarre drops in carbon isotope values have been recorded in the rocks
beneath the jumbled layers deposited by the glaciers of snowball events at
several locations around the world. But as provocative as the methane
addiction hypothesis may be, it left the conference audience with many

Alan Jay Kaufman, a University of Maryland geochemist who first measured
some of the carbon isotope crashes, pointed out that a dramatic decrease in
biological productivity in the oceans can also cause carbon isotope values
to fall and remain low over periods of a million years or so. But based on
estimates of sedimentation rates of the rocks in question, Schrag and others
think the crash could have occurred over a shorter time frame. Still,
Kaufman is skeptical: "We don't have any way to look into the rock record
and see a methane buildup."

"It's difficult to test anything that old," Schrag says. But you can look
for carbon isotope crashes in places where their duration may be more
certain, he adds. Several workers have already correlated the carbon isotope
values among Neoproterozoic rocks in Namibia, Australia, California, Canada
and the Arctic islands of Svalbard. Dozens of other deposits of similar age
exist but have not yet been analyzed. The potential triggers of a snowball
earth, it seems, may be as controversial as the details of the event itself.



>From, 28 August 2001

"First International Conference On Global Warming And The Next Ice Age"

An unusual conference at Dalhousie University [20 to 24 August, 2001]
brought together a large number of so-called skeptics and supporters of
manmade climate change. About 100 scientists attended. In simplified terms,
it pitted those who view climate data as important against modelers who
believe that models should get the major emphasis. While the conference did
not resolve any of the crucial issues, it did serve to define areas of
agreement and contention.

Here follows an idiosyncratic summary of the conference. From where I stand,
there are three basic areas in climate science that need to be resolved by
further research and critical discussions:

1. Is the climate currently warming?
2. What causes observed climate variations?
3. Can climate models account for observations?

A separate issue discussed at the conference related to the next ice age,
its timing and its mode of initiation.

1. Is the climate currently warming?

John Christy [University of Alabama, Huntsville] reviewed global weather
satellite observations that show no warming trend in the troposphere during
the last 22 years. It should be noted that climate models all predict that
the troposphere should warm more rapidly than the surface.

The major discrepancy with surface data occurs in the tropical zone. Christy
mentioned the puzzling observation that sea-surface temperature and marine
air temperature show different trends, throwing doubt on the reliability of
the SST results. This issue was not resolved and needs to be addressed in
more detail.

Fred Singer [University of Virginia and SEPP] concentrated his discussion on
proxy data. Tree rings, ice cores, corals, etc. show no appreciable warming
since about 1940 and are in good support of the results from satellites. The
data cover a wide geographic range so that one can argue with some
justification that the global climate has not warmed in the last sixty
years. This of course is in direct contradiction to results from climate

Singer also discussed the phenomena of deep-ocean warming, shrinking of
Arctic sea ice and glaciers, and rising sea levels. All of these have been
blamed on human activities. Singer showed that they can be fully explained
in terms of the delayed effects of previous, naturally caused warming. He
predicted that sea level would continue to rise at the same rate as in past
centuries, irrespective of human activities. This evoked much discussion and
some disagreement on Arctic sea ice and glaciers. The question there was
whether their shrinkage is stabilizing or would continue into the future.

2. What causes observed climate variations?

Most discussion of natural changes of climate is in terms of various
[internally controlled] atmosphere-ocean interactions, like El Nino, North
Atlantic Oscillation, the Arctic Oscillation, the Pacific Decadal
Oscillation, etc. But proponents of [external] solar controls on climate
dominated the conference. The question left unanswered was whether solar
changes could cause the atmosphere-ocean oscillations as primary effects.

Paal Brekke, Theodor Landscheidt, and Paul Damon gave extensive discussions
of solar variability and showed connections between solar cycles and climate
fluctuations. I found particularly compelling the detailed correlations
between Carbon-14 [a proxy for cosmic rays and therefore solar activity] and
Oxygen-18, observed in a stalagmite in a cave in Oman over a period of 3,000
years. [See the appended graph.] Unfortunately, there's no agreement yet on
the physical mechanism that could link cosmic rays to climate changes:
indeed, cosmic rays may not even be the primary influence on the atmosphere.

Ref: U. Neff et al. Strong coherence between solar variability and the
monsoon in Oman between 9 and 6 kyr ago. Nature 411, 290-293, 17 May 2001.

3. Can climate models account for observations?

Unfortunately, modelers were not well represented, so we did not get the
exposure to the GISS model or the Hadley model. But Tony Broccoli [GFDL,
NOAA] did an excellent job of presenting the latest results from GFDL,
Princeton. Successive runs introduced additional forcing, starting with pure
greenhouse, then adding the direct effects of sulfate aerosols [in the form
of surface albedo changes], changes in solar irradiance [Lean], and volcanic
eruptions [Andronova, 1999]. This last run showed a surprisingly low warming
trend of only 0.03 degrees per decade.

However, in discussion it was brought out that the models did not include
the indirect aerosol effects [on cloudiness, as discussed by Grassl, which
are larger than the direct effects], changes in stratospheric ozone, and the
more important solar influences from solar wind and magnetic field changes.

Bill Gray [Colo. State University] pointed to a major deficiency of all
current models that cannot handle the (possibly negative) water-vapor (WV)
feedback produced by drying of the upper troposphere (UT). Gray favors a
feedback mechanism that concentrates intensive cumulus activity into a
smaller area with larger regions of subsidence that remove UTWV.

There is also need to standardize the various radiative forcing effects so
as to facilitate intercomparison between models. Finally, it is important to
validate the models with observations not only on a global scale but also
for each hemisphere separately since some of the forcing [e.g., aerosol
effects] is geographically specific.

4. The next ice age

Using orbital theory calculations, Andre Berger [University of Louvain,
Belgium] demonstrated that the current interglacial period [Holocene] could
last another 40,000 years, a result not widely known. Based on a climate
model developed at his institute, he claimed that if carbon dioxide reaches
levels of more than 750 ppm, it might be sufficient to melt all of the
terrestrial ice.

George Kukla [Lamont Geophysical Observatory], by analogy with the most
recent [Eemian] glaciation, which took place 115,000 years ago, predicted
that El Nino events would warm the equatorial zone supplying the moisture
necessary to develop ice buildup at high Northern latitudes, triggering the
next ice age.

Finally, Richard Peltier [Univ. of Toronto] showed that initiation of the
glaciation process is extremely sensitive to greenhouse forcing. He
calculated that the most recent [Eemian] glaciation would have been
suppressed if the CO2 content had gone from 280 to 365 ppm.


With climate showing little if any current warming, it suggests that natural
variability is masking the enhanced (anthropogenic) greenhouse effect.
Natural variability on a decadal-to-century time scale seems to be caused by
the large variability in solar activity, as shown by cosmic ray variability.
Climate models are grossly overestimating the human influence, probably
because the models are not handling negative feedbacks properly.


>From People's Daily, 23 August 2001

China cypress stumps buried in a bog of primitive forest remains found in
Gaoyao, south China's Guangdong Province, may hold clues to climate changes
several thousand of years ago.

Carbon dating tests show that the trees in the 10-square- kilometer muddy
basin in this tropical region are more than 2,000 years old.

Chinese archeologists were excited at the discovery of the ancient forest
this year. They believe it was a shrinking virgin forest, which used to
stretch across a much larger area along the Pearl River some 2,000 to 5,000
years ago.

Li Pingri, a 70-year-old research fellow with the Geological Institute under
the Chinese Academy of Sciences, is now leading a group of experts to
decipher the code of ancient climates, which can be calculated from the
growth rings of the aged tree stumps.

Li's oldest tree sample is about 12,000 years old; the youngest is 2,030.

"Wider growth rings on the tree sections suggest a mild and rainy climate,
which indicates favorable years for the growth of the tree, while thinner
ones imply cold or disastrous weather, such as drought," said Li.

Most of the trees found here are China cypress that lived 2,000- 3,000 years
ago. However, no trace of China cypress younger than that has been found.

"The simultaneous disappearance of the tropical tree species in the virgin
forest should indicate a widely-spread cold current," said the archeologist.

Historical records said that between the years 1488 and 1893, the tropical
region received snow each winter. The climate gradually turned warmer after

The experts theorize that there may be a pattern to the climate changes. If
the assumption can be proved, warm and cold climates should rotate every 300
to 400 years, and people in Guangdong should have another century to go in
the hottest period of a warm climate term.

The experts will use more tree samples to weave out a map of growth rings
and the corresponding year of weather changes to substantiate their

The plant "lab" is so unusual that an ordinary China cypress is measured
over three meters in trunk diameter. A strong aroma created by old camphor
in the basin can be smelled several meters away.

Copyright 2001, People's Daily


>From CO2 Science Magazine, 29 August 2001

Kasper, J.N. and Allard, M. 2001. Late-Holocene climatic changes as detected
by the growth and decay of ice wedges on the southern shore of Hudson
Strait, northern Qubec, Canada.  The Holocene 11: 563-577.

What was done
Ice wedges are a widespread and abundant form of ground ice in permafrost
regions of the world that deform and crack the soil. During colder periods,
ice wedge activity is enhanced, while in warmer periods it is minimized,
thus providing a record of climate change. In this paper, the authors
examined soil deformations from ice wedge activity as an indicator of
permafrost and climate history over the past 4000 years near Salluit,
northern Quebc (approx. 62N, 75.75W).

What was learned
According to the authors, ice wedge activity was generally present up to
about 140 A.D., reflecting cold climatic conditions. Between 140 and 1030
A.D., however, this activity generally decreased, reflective of warmer
conditions. Then, from 1030 to 1500 A.D., conditions cooled; and from 1500
to 1900 A.D., ice wedge activity was at its peak, when the Little Ice Age
ruled, suggesting that this climatic interval exhibited the coldest
conditions of the past 4000 years.  A warm period prevailed thereafter, from
about 1900 to 1946, followed by a return to cold conditions during the last
five decades of the 20th century, during which time over 90% of the ice
wedges studied reactivated and grew upwards by 20-30 cm.

What it means
The resurgence of ice wedge activity in the latter half of the 20th century
is not consistent with climate alarmist predictions of CO2-induced global
warming. In fact, it is indicative of the exact opposite of their
predictions. As noted by the authors, however, this finding is consistent
with the real-world arctic cooling reported for this time period by
Prysbylak (2000), as well as with a reported temperature decline of 1.1C
observed at the local meteorological station in Salluit.
Copyright 2001. Center for the Study of Carbon Dioxide and Global Change 


>From CO2 Science Magazine, 29 August 2001

Goodman, A.Y., Rodbell, D.T., Seltzer, G.O. and Mark, B.G.  2001.
Subdivision of glacial deposits in southeastern Peru based on pedogenic
development and radiometric ages. Quaternary Research 56: 31-50.

What was done
Soil properties were analyzed from several glacial moraines located in the
Cordillera Vilcanota and Quelccaya Ice Cap region (1330' to 1400'S and
7040' to 7125'W) of southeastern Peru to determine late Quaternary climate
oscillations in this region via data pertaining to fluctuations of alpine

What was learned
Following the Holocene Climatic Optimum, approximately 5000 years ago,
several episodes of glaciation were noted throughout the region of study.
However, according to the authors, "the most extensive [glacial] advance
during the late Holocene in southern Peru occurred during the Little Ice Age
and is dated to <394 100 cal yr B.P. in the Cordillera Vilcanota and <300
80 cal yr B.P. in the Quelccaya Ice Cap."

What it means
While climate alarmists continue to downplay, and even deny, a Little Ice
Age influence on global climate, evidence to the contrary continues to
Copyright 2001. Center for the Study of Carbon Dioxide and Global Change 


>From CO2 Science Magazine, 22 August 2001

Weng, Q. 2001. A remote sensing-GIS evaluation of urban expansion and its
impact on surface temperature in the Zhujiang Delta, China. International
Journal of Remote Sensing 22: 1999-2014.

What was done
Covering an area of 17,200 square kilometers, the Zhujiang Delta (located
between 2140'N and 23N, and 112E and 113 20'E) is the third largest
river delta in China. It has experienced rapid urban development since
economic reforms were instituted there in 1978. In an effort to evaluate the
effect of land use/land cover changes on surface temperatures in this
region, the author conducted a series of analyses on remotely-sensed Landsat
Thematic Mapper data in a Geographic Information System (GIS).

What was learned
Considerable changes in land use were noted between 1989 and 1997. The total
area associated with cropland declined by nearly 50 percent during this time
period, while the area of urban or built-up land increased by nearly the
same percentage. Upon normalizing the surface radiant temperature for each
year (1989 and 1997), the author utilized the GIS technique of image
differencing to produce a radiant temperature change image that was
subsequently overlaid in the GIS with images of urban expansion. The results
indicated that "urban development between 1989 and 1997 has given rise to an
average increase of 13.01K in surface radiant temperature."

What it means
It is highly probable that the urban-induced surface radiant temperature
increase of 13C per decade calculated for the Zhujiang Delta of China has
introduced an urban warming bias in the near-surface air temperature records
of weather stations located there. Removing and/or filtering out such biases
in temperature series remain a daunting task for researchers examining
global climate change. This challenging work must be done, however, before
any change in air temperature can be ascribed to CO2-induced global warming.
Copyright 2001. Center for the Study of Carbon Dioxide and Global Change 


>From CO2 Science Magazine, 8 August 2001

When considering the subject of global warming, and especially when
considering ways to change the way the world does business (emits CO2 to the
atmosphere) based on purported changes in global temperature, it is only
prudent to have a good global record of temperature over as long a time
period as possible. Currently, we are not in great shape in this regard; for
the temperature history most commonly employed in these deliberations
pertains to only a portion of the land area of the globe, which is but a
portion (and a minor one at that) of the entire "water-world" we call earth.
Hence, it is absolutely essential that we obtain more long-term sea surface
temperature (SST) data to shed light on the natural variability of ocean
temperatures, a challenge that several studies are attempting to meet.

Linsley et al. (2000) produced a proxy SST record for the period 1726 to
1997, which they obtained from a 3.5-meter coral core retrieved from the
southwest side of Rarotonga, located at 21.5S and 159.5W in the Cook
Islands.  Their analysis revealed that SSTs in the vicinity of Rarotonga
were at least 1.5C warmer than they are today during a quarter-century
period centered approximately on the year 1745.  Such natural warming, were
it to occur over a similar time period today, would likely be deemed proof
of CO2-induced global warming by climate alarmists, when, of course, it
obviously would not be.

Winter et al. (2000) likewise examined proxy SSTs from north of the equator,
which they derived from oxygen isotope data obtained from coral skeletons of
Montastrea faveolata located on the southwestern shore of Puerto Rico. When
compared to current temperatures, SSTs for the periods 1700-1705, 1780-1785
and 1810-1814 were found to be significantly cooler.

Moving back further in time, other studies continue to document the natural
variability of oceanic temperatures when conditions were both colder and
warmer than at present. Gagan et al. (1998), for example, reported that the
temperature of the tropical ocean at the Great Barrier Reef about 5350 years
ago was 1.2C warmer than the mean that prevailed throughout the early
1990s. Barber et al. (1999) found temperature drops of 1.5 to 3C at marine
and terrestrial sites around the northeastern North Atlantic Ocean
approximately 8200 years ago; and Ruhlemann et al. (1999) report a
significant warming in the western tropical Atlantic during two dramatic
cooling events: Heinrich event H1 (16,900 to 15,400 years ago) and the
younger Dryas event (12,900 to 11,600 years ago).

Perhaps the greatest demonstrations of natural oceanic temperature
variability, however, come from the studies of McManus et al. (1999),
Herbert et al. (2001) and Raymo et al. (1998).  In the study of McManus et
al. (1999), the authors examined a half-million-year-old deep-sea sediment
core in the eastern North Atlantic to infer changes in climate over the last
five glacial-interglacial cycles. They found a number of significant
temperature oscillations throughout the record, but they were of much
greater amplitude during glacial episodes than during interglacials, varying
between 4 to 6C during colder glacial times, and between 1 to 2C during
warmer interglacials.

Herbert et al. (2001) analyzed proxy sea surface temperatures over the past
550,000 years from several marine sediment cores obtained along the western
coast of North America from the southern tip of the Baja Peninsula all the
way up to Oregon. Analysis of the SST data revealed that "the previous
interglacial (isotope stage 5e) produced surface waters several degrees
warmer than today," such that "waters as warm as those now at Santa Barbara
occurred along the Oregon margin."  Furthermore, from the SST histories
presented in their paper, it can be seen that SSTs for this region during
the current interglacial have not reached the warm peaks witnessed in all
four of the preceding interglacial periods, falling short by a margin of 1
to 4C.

Lastly, Raymo et al. (1998) examined the characteristics of an ocean
sediment core obtained from a water depth of nearly 2,000 meters at a site
south of Iceland spanning a time interval of one million years.  They found
that millennial-scale climate oscillations similar in character and timing
to the Dansgaard-Oeschger cycles of the most recent glacial epoch were
occurring in this region well over one million years ago, leading them to
conclude that millennial-scale climate oscillations "may be a pervasive and
long-term characteristic of Earth's climate, rather than just a feature of
the strong glacial-interglacial cycles of the past 800,000 years."

In contemplating these findings, it is clear that neither the glacial nor
the independent millennial-scale climate oscillations of the past
million-plus years were driven by variations in atmospheric CO2
concentration. Hence, there would appear to be little reason to attribute
the observed warming of the past century or so to the concurrent increase in
the air's CO2 content or to expect that any further rise in the air's CO2
content would trigger significant warming in the future.  Nevertheless, many
people do just that.

In a detailed analysis of a vast array of oceanic temperatures spanning the
globe and reaching from the surface down to a depth of 3000 meters, Levitus
et al. (2000) found a 0.06C temperature increase between the mid-1950s and
mid-1990s. Because of the fact that the oceans of the globe have a combined
mass some 2500 times greater than that of the atmosphere, this number, as
small as it looks, is truly significant. But is it correct?

Although their data extended back in time several years beyond the point at
which they specified the warming to begin, Levitus et al. computed the
linear trend in temperature between the lowest valley of their oscillating
time series and its highest peak, ensuring that they would obtain the
largest warming possible. In addition, the strong oscillatory behavior of
the oceanic temperature trend they uncovered all but insures that the next
decade will be one of oceanic cooling. Hence, over a moderately longer time
period, stretching into both the past and future, global ocean warming would
be computed to be much less than what Levitus et al. reported; and the
extended length of record would make the rate of warming smaller still.  Yet
in spite of these readily evident facts, NASA's James Hansen is quoted by
Kerr (2000) as saying that the new ocean-warming data "imply that climate
sensitivity is not at the low end of the spectrum" that has typically been
considered plausible.

But the warped hype does not end with the magnitude of the warming; it
continues with its cause.  Climate modeler Jerry Mahlman, for example,
states - according to Kerr - that the study of Levitus et al. "adds
credibility to the belief that most of the warming in the 20th century is
anthropogenic." Yet Levitus et al. clearly state that "we cannot partition
the observed warming to an anthropogenic component or a component associated
with natural variability."

Which brings one back to the subject of climate sensitivity. To calculate
such a parameter one must have values for both a climate forcing and a
climate response. And if one can't even identify the source of the forcing,
much less its magnitude, it is clearly impossible to calculate a

So maybe the discovery of Levitus and colleagues wasn't the Holy Grail of
current climatology after all; but it was a piece of the puzzle, and a good
one at that.  Nevertheless, there are many additional pieces yet to be
discovered; and even when they are all in hand, we will still have to fit
them together. Even so, some exuberance is in order; but we would do well to
be more temperate in our evaluation of each new scientific finding related
to global climate change.  Knowledge must precede wisdom; and we're still
just scratching the surface of the prerequisite for what we really need.

Barber, D.C., Dyke, A., Hillaire-Marcel, C., Jennings, A.E., Andrews, J.T.,
Kerwin, M.W., Bilodeau, G., McNeely, R., Southon, J., Morehead, M.D. and
Gagnon, J.-M.  1999. Forcing of the cold event of 8,200 years ago by
catastrophic drainage of Laurentide lakes. Nature 400: 344-348.

Gagan, M.K., Ayliffe, L.K., Hopley, D., Cali, J.A., Mortimer, G.E.,
Chappell, J., McCulloch, M.T. and Head, M.J. 1998. Temperature and
surface-ocean water balance of the mid-Holocene tropical western Pacific.
Science 279: 1014-1017.

Herbert, T.D., Schuffert, J.D., Andreasen, D., Heusser, L., Lyle, M., Mix,
A., Ravelo, A.C., Stott, L.D. and Herguera, J.C. 2001. Collapse of the
California Current during glacial maxima linked to climate change on land.
Science 293: 71-76.

Kerr, R.A. 2000. Globe's "missing warming" found in the ocean. Science 287:

Levitus, S., Antonov, J.I., Boyer, T.P. and Stephens, C. 2000. Warming of
the world ocean.  Science 287: 2225-2229.

Linsley, B.K., Wellington, G.M. and Schrag, D.P. 2000. Decadal sea surface
temperature variability in the subtropical South Pacific from 1726 to 1997
A.D.  Science 290: 1145-1148.

McManus, J.F., Oppo, D.W. and Cullen, J.L. 1999. A 0.5-million-year record
of millennial-scale climate variability in the North Atlantic. Science 283:

Raymo, M.E., Ganley, K., Carter, S., Oppo, D.W. and McManus, J. 1998.
Millennial-scale climate instability during the early Pleistocene epoch.
Nature 392: 699-702.

Ruhlemann, C., Mulitza, S., Muller, P.J., Wefer, G. and Zahn, R. 1999.
Warming of the tropical Atlantic Ocean and slowdown of thermohaline
circulation during the last deglaciation. Nature 402: 511-514.

Winter, A., Ishioroshi, H., Watanabe, T., Oba, T. and Christy, J. 2000.
Caribbean sea surface temperatures: Two-to-three degrees cooler than present
during the Little Ice Age. Geophysical Research Letters 27: 3365-3368.
Copyright 2001. Center for the Study of Carbon Dioxide and Global Change 


>From CO2 Science Magazine, 2001

Temperature histories are regularly reconstructed from temperature-depth
profiles obtained from "boreholes" drilled in either soil or ice. Majorowicz
et al. (1999) report the results of such a study based on data obtained from
ten sites scattered across southern Saskatchewan, Canada. They find that
from 1820 to the present, temperatures there rose between 2.5 and 3.0C, the
significance of which, according to the authors, is that the borehole record
suggests that "almost half of the warming occurred prior to 1900, before the
dramatic buildup of atmospheric greenhouse gases," which, we might add, did
not begin in earnest until the late 1940s (Idso, 1982).

In another analysis, Correia and Safanda (1999) used seven boreholes from
locations about 150-200 km southeast of Lisbon, Portugal to construct five
centuries worth of surface air temperature for this region. Evaluated
individually, all seven borehole logs depicted little temperature change
over the first three centuries of record. Thereafter, four of them exhibited
warming trends that began about 1800 and peaked around 1940, one showed a
warming that peaked in the mid-1800s, another was constant across the entire
five centuries, and one actually revealed cooling over the last century.

Larger networks of borehole data have also been examined. Harris and Chapman
(2001), for example, analyzed 439 borehole temperature logs in an effort to
determine the temperature history of the mid-latitude sector of the Northern
Hemisphere (30-60N). As could be expected, the data revealed a vast array
of results for the many sites, with some even depicting cooling over the
past two centuries. In the mean, however, the authors report their analysis
indicates 0.7 0.1C of ground warming between preindustrial time and the
interval 1961-1990.

In the study of Pollack et al. (1998), a surface temperature history was
reconstructed for the past five centuries from 358 boreholes spread
throughout eastern North America, central Europe, southern Africa and
Australia. Nearly 80% of these locations experienced a net warming over this
time period; but fully 20% of them experienced a net cooling, so that the
mean warming over the past 500 years was only 1C, which warming was
accomplished well in advance of the lion's share of anthropogenic CO2
emissions to the atmosphere.

The borehole temperature study with perhaps the largest aerial coverage,
however, belongs to Huang et al. (2000), who used 616 boreholes from all
continents except Antarctica to reconstruct a global temperature history
over the past five centuries.  If all of the assumptions that go into
translating depth profiles of temperature into temporal temperature trends
at the surface of the earth are correct, the mean surface air temperature of
the globe has risen by approximately 1C over the past 500 years, with about
half of the warming coming in the last century.

With respect to boreholes in ice, Dahl-Jensen et al. (1998) used data from
two such sites to reconstruct the temperature history of the Greenland Ice
Sheet over the past 50,000 years.  Temperatures there were 23C colder than
at present 25,000 years ago during the Last Glacial Maximum; but they warmed
to 2.5C above current levels during the Holocene Climatic Optimum 4,000 to
7,000 years ago. The Medieval Warm Period was also 1C warmer than it is
now, and the Little Ice Age was 0.5 to 0.7C cooler. After that time, the
temperature of the Greenland Ice Sheet rose to a maximum around 1930,
whereupon it decreased during the last decades of the 20th century.  These
latter findings, of course, are also in contradiction of the predictions of
state-of-the-art general circulation models of the atmosphere, which suggest
that high northern latitudes should have significantly warmed over this
latter period.

Correia, A. and Safanda, J. 1999. Preliminary ground surface temperature
history in mainland Portugal reconstructed from borehole temperature logs.
Tectonophysics 306: 269-275.

Dahl-Jensen, D., Mosegaard, K., Gundestrup, N., Clow, G.D., Johnsen, S.J.,
Hansen, A.W. and Balling, N. 1998. Past temperatures directly from the
Greenland Ice Sheet.  Science 282: 268-271.

Harris, R.N. and Chapman, D.S. 2001. Mid-Latitude (30-60 N) climatic
warming inferred by combining borehole temperatures with surface air
temperatures. Geophysical Research Letters 28: 747-750.

Huang, S., Pollack, H.N. and Shen, P.-Y. 2000. Temperature trends over the
past five centuries reconstructed from borehole temperatures. Nature 403:

Idso, S.B. 1982. Carbon Dioxide: Friend or Foe? An Inquiry into the Climatic
and Agricultural Consequences of the Rapidly Rising CO2 Content of Earth's
Atmosphere. IBR Press, Tempe, AZ.

Majorowicz, J.A., Safanda, J., Harris, R.N. and Skinner, W.R. 1999. Large
ground surface temperature changes of the last three centuries inferred from
borehole temperatures in the Southern Canadian Prairies, Saskatchewan.
Global and Planetary Change 20: 227-241.

Pollack, H.N., Huang, S. and Shen, P.-Y. 1998. Climate change record in
subsurface temperatures: A global perspective. Science 282: 279-281.

Copyright 2001.  Center for the Study of Carbon Dioxide and Global Change


>From CO2 Science Magazine, 22 August 2001

Since 1979, polar-orbiting satellites have indirectly measured lower
tropospheric temperatures.  From time to time, questions have arisen
concerning the accuracy of this global temperature data set. Wentz and
Schabel (1998), for example, argued that the satellite data had not been
properly adjusted for orbital decay. Yet, after accounting for such decay,
trends in the satellite data continue to display no significant global
warming since 1979. [See for yourself; plot the 1979-2000 MSU satellite data
found in our World Temperatures Section.] This essentially flat trend in the
lower troposphere stands in stark contrast to what is observed in various
surface temperature data sets over this same time interval. [Again, see for
yourself; plot the 1979-2000 surface temperature data from the Jones or GHCN
databases found in our World Temperature Section.]
Gaffen et al. (2000) and Santer et al. (2000) have attempted to determine
the reason for the satellite/surface temperature record discrepancy for the
region of the tropics and for the entire globe, respectively. In examining
the tropics, where Gaffen et al. note the difference between the two trends
is most pronounced, no understanding of the difference could be discerned
using sophisticated climate models. Similarly, Santer et al. (2000) utilized
state-of-the-art computer models, but also could not explain the difference
between these two temperature trends.

Comiso, J.C. 2000. Variability and trends in Antarctic surface temperatures
from in situ and satellite infrared measurements. Journal of Climate 13:

Gaffen, D.J., Santer, B.D., Boyle, J.S., Christy, J.R., Graham, N.E. and
Ross, R.J.  2000.  Multidecadal changes in the vertical temperature
structure of the tropical troposphere.  Science 287: 1242-1245.

Santer, B.D., Wigley, T.M.L., Gaffen, D.J., Bengtsson, L., Doutriaux, C.,
Boyle, J.S., Esch, M., Hnilo, J.J., Jones, P.D., Meehl, G.A., Roeckner, E.,
Taylor, K.E. and Wehner, M.F. 2000.  Interpreting differential temperature
trends at the surface and in the lower troposphere.  Science 287: 1227-1232.

Wentz, F.J. and Schabel, M. 1998. Effects of orbital decay on
satellite-derived lower-tropospheric temperature trends. Nature 394:
Copyright 2001.  Center for the Study of Carbon Dioxide and Global Change



>From CO2 Science Magazine, 29 August 2001

The end is near. According to a study in the 2 August 2001 issue of Nature,
human population growth "is likely to come to an end in the foreseeable
future." How foreseeable? Try 2070. This is the conclusion of Wolfgang Lutz
of the International Institute for Applied Systems Analysis in Laxenburg,
Austria, Warren Sanderson of the Departments of Economics and History at the
State University of New York at Stony Brook, and Sergei Scherbov of the
University of Groningen in The Netherlands. On the basis of their latest
calculations, which are described in their article and supplementary
information available on Nature's world-wide web site, they state that "the
median value of our projections reaches a peak around 2070 at 9.0 billion
people and then slowly decreases."

So what does "the end of world population growth," as the academics title
their paper, have to do with "the end of atmospheric CO2 growth," as we
title this editorial? Just about everything, it turns out, as world
population is one of the best predictors of atmospheric CO2 concentration to
ever come down the pike, as demonstrated by Idso (1989). Based on world
population and atmospheric CO2 concentration data assembled in his book, for
example, augmented by data for 1999 (the year world population reached the
six billion mark), we have derived the two predictive relationships
portrayed in Figures 1 and 2.

Fig. 1. ( Atmospheric
CO2 concentration vs. world population based on data presented by Idso
(1989) updated to 1999, the year earth's population reached the six billion

Fig. 2. Atmospheric CO2 concentration vs. world population based on data
presented by Idso (1989) from 1968 onward, including data for 1999. In our
father's original analysis, 1968 was identified as a point of slight
departure from the relationship defined by all earlier data and, hence, this
relationship probably gives slightly more accurate predictions of the future
than does the relationship of Fig. 1.

The linear relationships of each of these figures have been extended to a
world population of nine billion people, which is where Lutz et al.
calculate the population of the planet to peak in the year 2070, according
to the median result of their several projections. At this population, the
relationship of Fig. 1 predicts an atmospheric CO2 concentration of 412 ppm,
while that of Fig. 2 predicts a concentration of 421 ppm. Furthermore,
beyond this point in time the relationships of the two figures predict that
atmospheric CO2 levels will actually begin to drop, as the planet's
population begins to decline.

These conclusions are dramatically at odds with those of the IPCC crowd, who
predict far greater concentrations for far greater times to come, but they
are far more robust. The equation derived in Fig. 1, for example, is based
on data going all the way back to 1650. For the last three and a half
centuries, it has performed marvelously. To think it will suddenly cease to
apply over the next seven decades is ludicrous. There may be slight
variations ahead; but as the results of Fig. 2 demonstrate, they likely will
be so small as to be essentially insignificant.

So who or what are you going to trust? Unproven predictions based on
theoretical models of how the entire earth-ocean-atmosphere system is
believed to operate, as best as our present knowledge of these complex and
interrelated entities and their numerous sub- and sub-sub-systems allows us
to approximate them? Or the projections of a simple but straightforward
empirical relationship based on real-world observations that has a proven
track record of providing an excellent representation of atmospheric CO2
concentration for fully 350 years? We hope we don't have to spell it out for
you any more than this, or emphasize any additional words. It's truly a
no-brainer: real-world data always win. And in this case, it's already

Dr. Craig D. Idso, President 
Dr. Keith E. Idso, Vice President 

Copyright 2001.  Center for the Study of Carbon Dioxide and Global Change


(11) THE COOLING IN 1805-1820

>From Timo Niroma <>

In the CCNet Climate 18 July 2001 in item 4 "Major Global Cooling Followed
19th Century Volcanic Eruptions" by Harvey Leifert it is stated: "Chenoweth
(...) uses a new data set of global marine air temperature data (1807-1827)
... to show the impact of volcanic eruptions around 1809 (location unknown)
and in 1815 (Tambora, Indonesia). Based on a sudden cooling in Malaysian
temperature data, the author dates the circa-1809 eruption to March-June
1808. ... The author argues that the data confirm that Tambora and the 1808
eruption produced the greatest volcanic-induced surface cooling of the Earth
in the past two centuries."

However, tree rings, Greenland ice, stories or anything shows no great
eruption in 1808-09.

Instead just at that time the Sun has its lowest activity after the Maunder
minimum in the latter part of the 1600's. The decade of 1690 shows
practically no spots on the Sun and at the same time the Europe has its
coldest spell at least in 500 years.

Smoothed by one sunspot cycle the Wolf number goes below 20, or to the value
general during the Maunder minimum, in 1807 to reach the lowest value in
1810 which at the same time is the only spotless year since the Maunder
minimum. This explains very well the cooling.

The Wolf number exceeds 20 only in 1815 and a normal level is reached
(defined as the average after the Maunder minimum) only in 1826.

The Tambora case seems to be a combined effect of the low Sun and the
volcano the Sun being as determining a factor to the cooling as Tambora, if
we compare the case to other corresponding cases.

Timo Niroma

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