The Missing Greenhouse
Signature
Dr David Evans
(david.evans@sciencespeak.com)
21 July 2008
Background Briefing
Each possible cause of global warming has a
different pattern of where in the planet the warming occurs first and the most.
The signature of an increased greenhouse effect is a hotspot about 10 km up in
the atmosphere over the tropics.
We have been measuring the atmosphere for
decades using radiosondesÑweather balloons with thermometers that radio back
the temperature as the balloon ascends through the atmosphere. They show no
hotspot whatsoever.
So an increased greenhouse effect is not the
cause of the recent global warming.
So we now know for sure that carbon emissions are not a significant
cause of the global warming.
The theoretical signatures come from the latest
big report from the IPCC, which is the most authoritative document for those
who believe carbon emissions caused global warming. The IPCC Assessment Report
4 (AR4), 2007, Chapter 9. Figure 9.1, in Section 9.2.2.1, page 675, shows six
greenhouse signature diagrams.
http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_Ch09.pdf
.
In each diagram the horizontal axis is the
latitude, from the north pole (90 degrees north) through the equator to the
south pole (90 degrees south). The vertical axis shows the height in the
atmosphere, marked on left hand side shown as 0 Ð 30 km (and on the right hand
side as the corresponding air pressures in hPa). The coloured regions on each
diagram shows where the temperature changes occur for each possible cause
(red +1¡C, yellow +0.5¡C, green −0.5¡C,
blue −1¡C per century).
The signature of increased solar irradiation
(that is, of the sun getting a bit hotter).
Warming would be moderate through most of the
atmosphere.
The signature of a large volcanic eruption that
emits huge clouds of ash and fumes.
There would be moderate warming above 14 km, and
moderate cooling below that.
The signature of an increase in well-mixed
greenhouse gases (such as due to carbon
emissions). Warming would be concentrated in a
distinct Òhot spotÓ about 8 Ð 12 km
up over the tropics, less warming further away,
turning to cooling above 18 km.
The signature of more ozone depletion (both
tropospheric and stratospheric). Moderate
warming below 12 km, moderate cooling above 12
km.
The signature of increased industrial pollution
(specifically, of direct sulphate
aerosols). Moderate cooling below 14 km mainly
in the northern hemisphere, moderate
warming above 14 km over the tropics.
The theoretical signature expected by the IPCC,
found by combining the five
signatures above in the proportions the IPCC
believe those causes contributed to global
warming. The distinct hotpot 8 Ð 12 km up over
the tropics due to increased
greenhouse warming dominates the theoretical
combined signature.
(By the way, the IPCC omitted signature data for
what most skeptics believe is the prime suspect for global warming, namely
clouds/cosmic rays/the sunÕs magnetic field. Clouds are the main factor that
control the earthÕs temperature, and are the least understood and most poorly
represented factor in the climate models. Cloud formation is strongly affected
by the number of high energy cosmic rays falling on the earth, but the sunÕs
magnetic field shields us from some of these rays. Cosmic rays have a chilling
effect on the earthÑthey cause more low clouds. In periods of higher solar
activity the sunÕs magnetic field is stronger and shields us from more of these
rays, so the earth gets hotter. The earthÕs magnetic field is too weak to
significantly influence the number of rays striking the earth. Although the
correlation between high energy cosmic rays and the earthÕs temperature is very
high, it is only a correlation and at this stage we cannot prove that this is
the cause of the recent global warming. The IPCC focuses only on human
emissions of carbon, other greenhouse gases, and industrial pollution as causes
of global warming, and vigorously ignores the possibility of solar-magnetic
causes.)
The other main authoritative source for the case
that carbon emissions caused global warming is the US Climate Change Science
Program (CCSP). Atmospheric temperatures have been measured by radiosondes (at
all heights) since the 1960s, and by satellites using microwave sensors (up to
5 km) since 1979. The CCSP published the results for 1979 Ð 1999 in part E of
Figure 5.7 in section 5.5 on page 116:
http://www.climatescience.gov/Library/sap/sap1-1/finalreport/sap1-1-final-chap5.pdf
The axes and colours are as per the signature
diagrams above, except that the horizontal axis only goes from 75 degrees north
to 75 degrees south, there is no data around 60 degrees south, the vertical
axis only goes up to 24 km, and dark blue above becomes purple here. The data
is called the ÒHadAT2 temperature dataÓ.
The observed signature.
This diagram is confirmed by more radiosonde
data collected after 1999, and also after May 2006 when this diagram was
published.
The theoretical combined signature expected by
the IPCC contains a prominent and distinct hotpot over the tropics at 8 Ð 12 kms.
This hotspot is the signature feature of an increase in greenhouse warming.
The observed signature at 8 Ð 12 km up over the
tropics does not contain a hotspot, not even a little one.
Therefore:
1.
The
IPCC theoretical signature is wrong. So the IPCC models are significantly
wrong.
2.
The
signature of increased greenhouse warming is missing. So the global warming
from 1979 to 1999 was not due predominately to increased greenhouse warming,
and was therefore not due to carbon emissions.
The
observed signature shows cooling above 16 km, which strongly suggests that the
global warming was not due to increased solar irradiation, volcanoes, or
increased industrial pollution (aerosols). The observed signature looks like a
combination of increased ozone depletion, possibly a decrease in industrial
pollution, and an unknown signature or signatures.
When the signature was found to be missing,
alarmists objected that maybe the readings of the radiosonde thermometers might
not be accurate and maybe the hotspot is there but went undetected. The
uncertainties in temperature measurements from a radiosonde are indeed large
enough for a single radiosonde to maybe miss the hotspot. Yet hundreds of
radiosondes have given the same answers, so statistically it is not
possible that they collectively failed to notice
the hotspot. Recently the
alarmists have suggested we ignore the radiosonde thermometers, but instead
take the radiosonde wind measurements, apply a theory about wind shear, and run
the results through their computers to estimate the temperatures. They then say
that the results show that we cannot rule out the presence of a hotspot. If you
believe that you believe anything.