Empirical falsification as formulated by Karl Popper is one of the bedrocks of modern science. This is the idea that in order to tell if a scientific theory has any truth to it, one needs to come up with a falsifiable test of the theory, whereby it could be disproved through a single observation. Otherwise the theory cannot scientifically valid or useful in determining if it is likely to be true.
I have recently challenged someone to come with such an empirical falsification for anthropogenic global warming. Here is the list he came up with:
quote:
1) sustained global cooling 2) greater warming at the equator than at the poles 3) greater warming during the day than at night 4) greater rainfall in continental interiors 5) milder weather along coastlines 6) treelines moving toward the equator 7) increasing arctic ice.
I already see a problem with these points as they test global warming (GW), but not anthropogenic global warming (AGW). However, that's the problem, many that adhere to AGW, believe one nearly needs to show that GW is taking place and/or that is unprecedented.
However, I am curious whether anyone here can come up with a better list of empirical falsification of AGW or whether or not you believe that his list is adequate.
While the clear demonstration of GW is useful in getting the message across to the general public, climate scientists do not think that just showing GW is taking place is adequate. The big test is to show it is taking place but also to rule out or to quantify all the causes.
Further, since it is not a question of whether CO2 causes warming, but how much, and how big is its impact, there is a bit of a judgement call to be made as to what counts as "disproof". For example, a warming of under 1C this century would mean that our fears were misplaced even if it were attributed to CO2.
In the end the judgement call made by politicians and people is what is really important. For example, a genuinely sceptical blogger did a statistical study of the temperature record and established that natural variability meant that it was statistically possible for a 0C rise in the next 10 years to be consistent with a 2.6C rise in the next 100 years. But AGW will be a very hard sell if temperatures are the same as now in 10 years time.
Getting back to the question, we know exactly how to solve this problem according to Popper's requirements. Create 100 copies of the solar system that are identical apart from earthly levels of CO2. More realistically, rather than falsifying of the greenhouse gas theory, one needs to show that the greenhouse warming is a lot less. eg
1. by identifying other causes of warming, 2. by identifying new or bigger negative feedbacks,
Some planets appear to be warming. Some cooling. None have long-term data. Many have different climate forcings (on Mars increasing dust levels cause warming).
1. Proof that A causes B is not proof that B cannot cause A. 2. Yes if it cooling is observed over a long period. 3. Proof that A happened without B is not proof that A cannot also be caused by B.
I have recently challenged someone to come with such an empirical falsification for anthropogenic global warming.
Would not Popper stand back and first ask "What is AGW". It would be defined by a set of observable and sometime measureable real qualities. These qualities would have to be self consistent ie they all stand or they all fall. eg is your definition a set of predictions from models that could be challenged? So are you really asking the question "what would empirically falsify the models?".
If you were to list the qualities that distinguished AGW how would you demonstrate they are consistent qualities of something real.
You could have an arbitrary list and test it. Those qualities that pass the test could then be defined as AGW.... but what value would such an exercise be?
As you see I'm struggling with your question or at least the assumed causality implicit in it.
It seems the person you challenged to come up with a list didn't understand the word 'anthropogenic'.
The "falsifiable test" is obviously was human intervention involved. Then you can go on to ask to what degree was this influenced by human intervention (that's when it gets more complicated).
The differences between GW and AGW can be easy to recognise, or so obscure that you wouldn't believe it unless the observations were convincing. This is the nature of the debate! GW, or for that matter global cooling (GC), isn't fully understood, so it's difficult to allocate the anthropogenic effect proportionately.
What we need is a central body that has clout with research that can improve our understanding of climate per se. This shouldn't be the WMO or the IPCC, but a 'world climate research faculty' with its focus on understanding.
I work for a world-class climate research facility. Is that good enough?
I know you do Steve and this is nothing personal, but a 'facility' is there to be used by those that wish to employ it. There is a 'break' in the science aspect with the IPCC in that the IPCC asks world governments to make research available in the sectors that need greater understanding, but it's up to governments to decide whether they should take this up, or not. Does this not leave research - and thus progress - in the hands of politicians (yet again)?
Moreover, the IPCC have one hand tied behind their back because they've chosen the path of anthropogenic forcings. It is necessary to understand the 'forcing' per se before the anthropogenic component can be convincingly revealed.
Now a faculty that can draw from its own finance would be able to make its own research in the direction for which it was 'set up' for. Hopefully this would be towards a better understanding of 'climate' and the 'how and why' of how it can change. This could only be of benefit to the IPCC.
The reason I excluded the WMO is simply because they are already 'set up' for 'other practices'.
Moreover, the IPCC have one hand tied behind their back because they've chosen the path of anthropogenic forcings. It is necessary to understand the 'forcing' per se before the anthropogenic component can be convincingly revealed.
If you have that impression it is only because you've seen the headline results. There are plenty of people observing the sun, characterising other emissions, monitoring ozone, monitoring water vapour and precipitation etc. etc. as I said, one way of disproving CO2 is to find another forcing that can account for some or all of the observed warming.
Monitoring isn't what I had in mind and good though it is, I'm sure we would all like to see this improved.
It isn't that CO2 needs to be disproved, it's more that other substances that lead to a climate change forcing need to be proven against CO2. We are just informed that black carbon on ice may have an ice melt forcing of up to 60% of that imposed by CO2 in the Arctic. What of tropospheric ozone (and I don't mean the health hazard)?
It may only be that I'm impatient, but I for one would like to see more results from research in other areas instead of being 'force fed' with CO2 so frequently.
It may only be that I'm impatient, but I for one would like to see more results from research in other areas instead of being 'force fed' with CO2 so frequently.
Does the IPCC report say anything about black carbon?
Where's the 60% figure from. Bearing in mind that 60% of anything at the poles is not a lot.
Does the IPCC report say anything about black carbon?
I don't think so. I'm quoting from realprimate's link to a hearing by the committee on Oversight and Government Reform in the USA. The environment hearing that examined black carbon and global warming. Bottom of page 1 in the 'So it appears that Arctic ice isn't vanishing after all'. The one I recommended for the video?
On the web page they quote that up to 30% of the warming in the Arctic is due to black carbon, but in the video its forcing is presented at < 60% of CO2 there. It's a long video though. I downloaded it and watched it in 'Real Player' at my leisure.
They don't allow me to edit my posts, so let me attempt to clean it up again.
I wrote,
quote:
2) A rise in man-made CO2 levels during a period of cooling.
Steve M wrote,
quote:
2. Yes if it cooling is observed over a long period.
How about the period of three decades of cooling from the 1940's to the 1970's during which there were sustained increases in man-made CO2.
Is this not a long enough period to falsify AGW? And if not, then why not? How would you determine what is the correct length of time to wait for proof?
2. Yes if it cooling is observed over a long period.
I'd better qualify that and say that you also have to take into account aerosols, volcanoes and solar changes. PS there was cooling from 1940-1950 and then a slow rate of warming (steady temperatures to 1970 in the Northern hemisphere. More obvious warming in the southern hemisphere).
Re global temperature, it's just a silly theoretical idea that is not really applicable to the earth where no matter which way you measure the temperature the trends are similar because the structure of the earth's temperature remains more or less the same (ie. it's always cold at the poles and hot at the tropics etc.)
If the link disappears, google "tim lambert mckitrick essex"
timlambert.org/2004/05/mckitrick3/
I think the final comment from McKitrick demonstrates a certain amount of chutzpah.
Originally posted by suricat: On the web page they quote that up to 30% of the warming in the Arctic is due to black carbon, but in the video its forcing is presented at < 60% of CO2 there. It's a long video though. I downloaded it and watched it in 'Real Player' at my leisure.
2. Yes if it cooling is observed over a long period.
I'd better qualify that and say that you also have to take into account aerosols, volcanoes and solar changes.
This is what I find so frustrating about arguing with AGW proponents. Find a counter-example, and there is immediately a search for a different explanation. Yet when non-believers do the same, they are accused of being devious.
Originally posted by M Batchelor: How about the period of three decades of cooling from the 1940's to the 1970's during which there were sustained increases in man-made CO2.
Is this not a long enough period to falsify AGW? And if not, then why not? How would you determine what is the correct length of time to wait for proof?
Hi MB,
I keep hearing about this 40's to 70's cooling so did some surfing. (Don't you all love my cut'n'pastin?)
In fact the much-vaunted “global cooling 1940 to 1970″ is not real ... trend for that time period is -0.25 +/- 0.3 deg.C/Century, again not statistically significant.
The cooling is from about 1944 to 1951, the rest of that time shows no sign of any significant change.
The only isolated decades which have statistically significant trends are (all in deg.C/Century):
I’ll keep saying it: there is not cooling from ~1940 to ~1975.
Trend analysis of GISTEMP data from 1940 to 1975 indicates a temperature change rate of -0.15 +/- 0.25 deg.C/century. Note the error range is larger than the value, so the indicated trend is not statistically signficant.
The only real “global cooling” is from 1944 to 1951. Seven years. That’s all, folks. For the remaining period in question, from 1951 to 1975, the indicated trend is +0.07 +/- 0.5 deg.C/century. This indicates warming, not cooling, although again the trend is not statistically significant.
Let’s all face the truth: global cooling from the 40s to the 70s is a myth.
UNQUOTE
The second one's from:-
http://www.grida.no/climate/ipcc_tar/wg1/053.htm QUOTE The period 1946 to 1975 had no significant change of temperature, though there was a small non-significant, but regionally more marked, cooling over
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