The real global warming swindle

[Starfury]

I don't know how many people are aware of The Great Global Warming Swindle, the recent documentary aired on Channel 4 in the UK that purported to debunk Global Warming. It tried to chalk up GW to sun spots, etc.

Anyway, the right wingers are in a tizzy over it as you'd expect, but here's a good article that should help deflate them.

A Channel 4 documentary that claimed global warming is a swindle was itself flawed with major errors which seriously undermine the programme's credibility, according to an investigation by The Independent.

The Great Global Warming Swindle, was based on graphs that were distorted, mislabelled or just plain wrong. The graphs were nevertheless used to attack the credibility and honesty of climate scientists.

A graph central to the programme's thesis, purporting to show variations in global temperatures over the past century, claimed to show that global warming was not linked with industrial emissions of carbon dioxide. Yet the graph was not what it seemed.

Other graphs used out-of-date information or data that was shown some years ago to be wrong. Yet the programme makers claimed the graphs demonstrated that orthodox climate science was a conspiratorial "lie" foisted on the public.

(...)

Read the rest (it's very good!) at http://news.independent.co.uk/environment/climate_change/article2355956.ece

Enjoy!
:headbang:

[Prophet 451]

1. No surprise

I didn't even watch teh show but the Beeb's Have Your Say page (which tends to attract RW nutters for some reason) has been flooded with comments along the lines of "this proves global warming was a hoax".

[arenean]

2. Warning!

I'm afraid this prog has been much more significant than many others in the UK, and I understand this documentary is likely to go on a ‘world tour’ so it is VITALLY important that a
strong response is needed to how much airplay it gets elsewhere. A casual listen to a BBC phone in last night showed the skeptics back out of their holes again because of this programme.


I work at the Met Office in the UK, and to say we are 'slightly miffed' by the contents of this programme would be a bit of an understatement! This filmmaker has a history of climate change scepticism, and he originally wanted to call it "Apocalypse? My A**e". Which goes to show the high scientific level he was aiming for. Unfortunately, the lies contained in the programme have completely muddied the waters, and set back education on this issue quite a number of years. Not happy.

To add more to The Independent article, here's the issues I had with the "science" of this programme.... (unfortunately, I can't add my graphs here)...

Graph Problems!
"Graph of historical temperatures back 1000 years showing clear "medieval warm period (MWP)" and "little ice age" with current temperatures lower than MWP."

*Figure from IPCC first assessment report 1990 Figure 7.1. i.e. over 16 years old.

*The figure was symbolic did not use quantified data.

*More recent reconstructions using proxy data don't show anything like the same amount of warmth in the MWP.

*MWP and the Little Ice Age were regional phenomena, not global variations like today.

"CO2 lags behind temperature in ice cores (of 100,000yrs length) by ~800 years "

*ice cores show CO2 leading and lagging temperatures at different times.

*The main driver of variations over the timescales of 100,000s yrs is thought to be due to orbital changes of the Earth around the Sun. The change in CO2 is thought to be a positive feedback to the initial driver.

"Global temperatures warmed more between 1880 and 1940 than 1975 to present "

No. They used a data series with a strange filtering (~30 year window?) that seemed to show little warming since 1980. But latest temperature data show warming has been greater and growing faster than in early 20th century.


"Solar activity follows temperatures perfectly during 20th century "

* This measure of solar activity is "solar cycle length" and does not look the same as other measures of solar activity, i.e. sunspots, solar irradiance, magnetic field strength or cosmic rays (which all differ to some lesser or greater extent with each other).

*The figure conveniently ends before 1980.

*Assumes no other factors have any influence on climate

*When more recent data is included and the filtering for end-points corrected for, the correspondence isn't so "perfect".

"Solar activity follows temperature perfectly over 400 years "

*Again better covered in Laut 2003, below figure and caption lifted from paper.

*Basically there are serious questions about how the data is used.

* Assumes no other factors have any influence on climate .See also Damon 2004

"Temperature in Arctic follows solar not ghg variations"

*Comparing only CO2 changes with just solar is misleading, are any other factors thought important?

*As far as I am aware no climate scientist thinks that climate is driven solely by ghgs or CO2. Other factors make important contributions, obviously more important in the past when ghgs was not being produced by humans. One should look at the major factors together, GHGs, sulphate aerosols, land use, carbonaceous aerosols, ozone changes and of course the natural influences of solar and volcanic changes.

*During the 20th century, evidence points to solar possibly being important in the early part of the century, but since the 1960s solar irradiance (or other solar activity measures) has not been increasing in activity.

"Temperature and cosmic rays correlate over 600 million years "

*There are a number of problems with this. See Rahmstorf 2004 for more details

*50 data points (meteorites) used to construct 600 million years of cosmic ray history

*The proxy data for temperatures were filtered to emphasize periods around 150million years

*Periodicity of cosmic rays deduced from the 50 data points and then tuned (“which best fits the ice age epochs” Shaviv 2003) within large uncertainties to fit the periodicity and phase of the temperature reconstruction. Some shifts ~60 million years.

*No mention in Shaviv 2003 work of influence of continental drift, mountain building and other bio-geological factors on long term climate variations.



A large number of the scientific statements were either misinterpretated, misleading or plain wrong science.
e.g. here are a few of the howlers:

* Volcanoes produce more CO2 than human - (They don't. Human activity produced 150x more CO2 than volcanoes!)

* CO2 emissions from humans are not causing CO2 in atmosphere increase -(Isotopic C and oxygen measurements say otherwise)

* Temperatures increased more in the first half of the century than the second half - (They didn't)

* Solar variations match temperatures perfectly - (No evidence of that when correct data used)

* Cosmic rays cause cloud variations - (Not proven, and even if it was temperatures have increased when cosmic rays have not changed)

* Medieval warm period was warmer than now - (Not according to proxy measurements ... well at least "likely")

* there are a lot more....

[Starfury]

3. Thanks for the head's up!

Here's an excellent repository of graphs and links that can help folks get out the message:

http://www.globalwarmingart.com/

[Dead_Parrot]

4. Thanks, arenean...

...you should fire that off to realclimate.org as well - They're probably aware of most of that, but they might have missed a few bits. :hi: