Saturday, 9 February 2013
"Cyril On Global Warming" Part 1 of 3
Anthropogenic Global Warming
The facts and figures
Total % of CO2 in the atmosphere = 0.0395%.
Or 395 parts per million by volume (ppmv).
Best estimates of man’s contribution to ACO2 through burning of fossil fuels is between 25-30% of the post-industrial increase in ACO2. Note; There is no reliable empirical way to determine the actual figure, this is a best guess and we will go with that for now.
Atmospheric CO2 varies from summer to winter and to a lesser degree from day to night, this is due to plants using CO2 in summertime/daytime. ACO2 levels are higher in the winter and at night.
The official measure for ACO2 is taken from the National Oceanic & Atmosphere Administration (NOAA) sited on Mauna Loa, Hawaii.
Link to NOAA, Mauna Loa; http://www.esrl.noaa.gov/gmd/ccgg/trends/
Water vapour is over a magnitude (x10) a better absorber/emitter of Infrared radiation (IR) than CO2, and there is much more water vapour than CO2 in the atmosphere.
Water vapour is not evenly distributed around the globe, it ranges from 0-1% at the poles and deserts to 4% in the tropics, as a general rule there is more w/v over the oceans and less over the continental land masses.
The 4 main heat transfer mechanisms in the atmosphere are thermal radiation, thermal convection, thermal conduction and phase transition (as when water vapour condenses into water droplets in the formation of clouds), of these, convection is by far the largest heat transport mechanism.
General circulation models (GCM) the models used by climate scientists to make projections concentrate on thermal radiation and do not describe well the thermal convection or thermal conduction processes in the atmosphere.
The top 10 feet of the world’s oceans contain more heat than the entire atmosphere.
Green House Gases (GHG) Theory, or the greenhouse effect, is not the same as Anthropogenic Global Warming Theory.
AGW Theory, Its predictions/projections compared to observations
CO2 is the main controller of temperature.
The increase in the Earth’s temperature in the late part of the 20th Century is unprecedented and caused by man’s emissions of CO2.
It is widely accepted by both ‘consensus’ and sceptical scientists that, all things being equal, a doubling of pre-industrial ACO2 levels should result in a temperature increase of 1°-1.2°C.
Near surface warming by CO2 will increase the amount of water vapour in the atmosphere thus enhancing warming by amplification, this is called a positive feedback.
All of the CO2 warming based GCM’s predict a hot spot will form in the upper troposphere at equatorial latitudes.
Global warming will result in more frequent extreme weather events.
Global warming will increase the rate of sea level rise this century.
CO2 induced positive feedback's will overwhelm natural variability reaching a tipping point that will result in catastrophic runaway global warming.
Let’s take a look at the AGW theory predictions one at a time;
1) CO2 is the main controller of Earth’s temperature.
Here is a graph of Earth’s temperature and CO2 levels over geological time;
Notice that for the vast majority of time temperature and atmospheric CO2 levels were a lot higher than today.
450 million years ago there was a glaciation called the Andean-Saharan Glaciation, This happened when CO2 levels were constantly over 3000 ppm, more than 7 times present levels. 300 million years ago there was another glaciation (Karoo) with CO2 levels just a bit higher than today, where is the correlation?
Glaciations come and go because of the Milankovitch cycles which describe the effects on global temperatures caused by Earth’s orbital eccentricity, procession and obliquity.
Oxygen isotope analysis of ice core data shows increase of ACO2 lags temperature rise by centuries, see following links;
There is no evidence that CO2 has ever controlled temperature.
As an aside, we see that from the Cambrian explosion (560 myo) onward the history of evolution of life on Earth prefers warmth and an enriched CO2 atmosphere.
2) Unprecedented warming of the late 20th century.
1850-1880 and 1910-1940 saw a similar increase in temperature rise as the period 1975-2000 despite far lower levels of anthropogenic CO2 emissions.
The warming’s of 1850-1880, 1910-1940 and 1975-2000 all have a trend of +0.16°C per decade, neither of the earlier rises can be attributed to man’s activities.
Correlation does not necessarily indicate causation, however causation must show correlation. Below is a graph with temperatures and ACO2 from 1850-2010.
As you can see from the graph below there is good correlation for temperature and CO2 from 1975-2000, correlation before 1975 is quite poor
The next chart shows very poor correlation for the period 2000-2008.
The next graph (Hadcrut4) shows no global warming since 1998, none of the GCM,s predicted this lack of warming, CO2 levels have continued to increase, once again the GCM’s have shown little predictive skill.
The instrument record clearly shows alternating warming/cooling cycles of approximately 30 years, historic observations and proxy data show larger 500 year (approx.) and 1500 year warming/cooling cycles.
The next graph plots warming periods over the last 5,000 years; none of the historic warming periods can have been caused by anthropogenic emissions.
Using proxy sources scientists have estimated temperature rise of 8°C within 40-50 year period in a Dansgaard-Oerscher event at the end of the geological period known as the Younger Dryas.
Since the end of the little ice age temperature has risen by 0.4°C - 0.8°C (depending on the source used)
There is nothing unprecedented about present day warming.
3) All things being equal a doubling of ACO2 will result in 1°-1.2°C temperature rise.
This is all very well in a controlled laboratory or using mathematical calculations, but climate is none of these things, it’s a partially chaotic non-linear dynamic system, where nothing is ever equal. We will see later how natural fluctuations easily overwhelm CO2 forcing.
4) Co2 effects on water vapour.
Why the weaker GHG Co2 affects the more powerful GHG water vapour and not the other way around is not explained by consensus climate scientists.
Below is the NASA (NVAP) water vapour trend chart;
The following link is an in-depth look at water vapour trends or lack of;
here is global relative humidity since 1948;
5) Troposphere hot spot.
Hundreds of thousands of measurements from radiosondes and satellites have failed to detect the GCM (models) predicted hot spot, this falsifies the models.
6) More frequent and extreme weather events.
There is no evidence for this.
Not surprisingly warming of the atmosphere does not increase either frequency or strength of cyclones, cyclones develop in water temperatures of 26°C or more.
Peer reviewed paper on floods – no upward trend.
2007. Reported Riano et al., on wild fires;
“A single remote sensing data source can provide globally coherent multi temporal spatial information, not only from the visible part of the spectrum but also reflected solar infrared, which can be used to obtain consistent environmental monitoring at the global scale.” … “The main purpose of this study was to identify global patterns of burned area using the 20 years of NOAA-AVHRR data which will provide a more consistent spatial and temporal basis for interpretation than statistics compiled from different sources or short periods (e.g. annual studies).”…
“The global trend statistics in the total number of pixels burned in any month or annually were not significantly different from 0 (at alpha = 0.10 significance level). Therefore, no significant upward or downward global trend was found in the burned area data.”
Nature magazine reports little change in droughts globally over the last 60 years;
Here’s a drought graph for the USA
The widely held perception that extreme weather events have increased in the last few decades is accounted for by the advance in global communications of the past 40, consequently we are hearing about and seeing more raw and shocking footage of natural disasters and extreme weather events than at any time previously.
Of course the old media adage ‘bad news sells’ is as true today as it ever was.
Extreme weather has always happened and always will, as proponents of AGW theory like to shout when it gets cold and snowy, weather is not climate.
7) Sea level rise.
For several thousand years sea levels have risen at a rate of 2.5-3.5 millimetres per year (mmpy).
Over the last century sea level rise looks like this;
The satellite age;
Note the step change in 2003
If sea levels continue to rise at their historic rates (and there is no reason to think otherwise), we can expect a maximum 300mm or 1 foot of sea level rise by the end of this century.
8) Catastrophic runaway global warming.
The doubling of pre-industrial CO2 to 560 ppmv is expected in 2050.
If 10-15 times today's ACO2 content cannot cause runaway global warming. It defies logic to believe that 500-1000 ppmv ACO2 will, it also flies in the face of geological precedent.
In part 2 of this 3 part series we will be looking at;
Solar influences, Ocean oscillations, Clouds,
Climate sensitivity and “Consensus”
Cyril Le Squirrel