I was at the Nine Lessons And Carols event last Tuesday when Johnny Ball famously got slow-clapped off stage after an impromptu climate-change rant. One of the claims he made is something I've heard some (highly educated) colleagues independently repeating - specifically that the anthropogenic global-warming hypothesis must be false because:
"The amount of CO2 produced by man is tiny compared to the volume which is both produced and consumed by life on earth."
In Johnny's lecture he claimed that the amount of CO2 emitted by only spider species is far more than the total amount produced by all of human industry. So if you believe the above, then it stands to reason that CO2 is unlikely to be the cause of global warming since any change that man can cause will create an effect which is negligible.
Is there a source for data that will either debunk or validate the above argument? My guess is that Mr. Ball has cherry-picked his data. If you were to take the emissions over 100 years the spiders would definitely win out, however if you were to look at the last 5 years only I wouldn't be so quick to blame the invertebrates.
Any comments?
I suspect that this thread will kick off another debate that will go round in circles. I have said before I don't feel qualified to comment as I don't have sufficient expertise to tease apart the science from the politics on this subject.
Anyway according to the telegraph on line, (a well known balanced source of unbiased information, incidentally) Mr ball claimed that "spiders’ flatulence was more damaging to the environment than fossil fuels" - so that will be methane then, not CO2
I was at the Nine Lessons & Carols event on Tuesday, and I think he was making a slightly different argument. Spider flatulence was not mentioned.
His reference to spiders was that their respiration produces substantially more CO2 than all of human industry.
I've still not found a source for this - however I've recently been informed that Mr. Ball has an article in the Daily Express which may shed some light on what he actually thinks, rather than what I think he thinks based on a mis-remembered performance late on a work-night.
So does anybody know if there is any firm data which compares the amount of CO2 produced by respiration vs the amount emitted by Human industry?
I wonder if this issue is a red-herring, since biological processes are responsible for a lot of carbon capture, wheras combustion can only release carbon.
Note: I too admit lack of qualification on this subject, hopefully somebody who really understands the science can come along and answer these questions.
If this is true, does it mean there are more spiders about than there used to be? If so, what's the betting people have something to do with it!Originally Posted by salimfadhley
WARNING: WILD SPECULATION AHEAD
I suspect that the "spiders" thing is an example of cherry-picking data:
In any ecosystem, the total amount of respiration done by predators species will be dependent ultimately on the total amount of energy captured by photosynthesis. An environment (like a jungle) which captures more carbon can support a greater population of predators (e.g. spiders) which release some of the carbon captured by trees back into the atmosphere.
Since the process is not 100% efficient, conservation of energy requires that more carbon will be captured than released. Hence even though respiration releases CO2, a healthy ecosystem will reach an equilibrium wrt atmospheric CO2.
Furthermore, I suspect that what limits CO2 capture is not the amount of CO2 in the atmosphere
I think the issue with man-made CO2 is that there's no limit to how much of it we can produce, and I don't recall anybody claiming that the earth's ecosystem has the ability to capture all of the surplus CO2 in the atmosphere.
:-)
Would anybody care to correct my reasoning - like I said before I'm attacking this with only A-Level physics and a faith that most scientists are probably not part of a global climate-change conspiracy.
Sal
Last edited by salimfadhley; 21st December 2009 at 12:35 PM.
Suppose the total amount of CO2 produced by all sources (respiration, volcanoes, sea, spiders, etc) is 100 units (arbitrary) pa. Then suppose the total uptake of CO2 through carbon sinks (trees, sea, etc) is also 100 units pa and the amount in the atmosphere is stable at 1 unit.
Now if spiders produce a massive 1 unit pa, it doesn't matter because it is all absorbed by existing sinks. But if humans produce just 0.01 units pa, even though it is far less than spiders, it will accumulate in the atmosphere at 0.01 units pa because the sinks are saturated. In one century atmospheric CO2 doubles!
I'm fairly sure that there must be some limit to the amount of CO2 we can produce. A high enough concentration in the atmosphere would suffocate us all! More seriously, the amount of free oxygen available would surely set an upper limit?
Yes, I think you are making the same point as me (but more succinctly).
Since the natural sources & sinks of carbon are in equilibrium then if we release carbon which was captured millenia ago then the equilibrium has to change.
I think this is why the CO2 deniers (ball included) have to emphasize the fact that CO2 is captured during photosynthesis, since their belief system depends on the notion that plant's ability to capture CO2 is only limited by the amount of CO2 in the atmosphere.
I suspect that other factors (e.g. sunlight, space, access to nutrients + other species-specific requirments) are actually what limits photosynthesis.
There is a limit:
We can only burn it as fast as we can find it, and practically speaking since carbon fuels are a valuable commodity we can only burn it as fast as we can find a use for it (e.g. when we need to drive to the shops or turn the heating on).
But the point is, unlike our wood-burning ancestors - the carbon in our fuel was captured a long time ago, so unless we use it all up (unlikely in the near future), there's no theoretical limit on how much we can burn.
In the bad old days if you chopped down the entire forest then by definition you couldn't burn any more. Our ability to emit carbon was once limited by the land's ability to capture carbon. This is no longer the case.
A completely fatuous argument.
Here's the facts, our CO2 output is tiny compared to other sources and sinks. However what's important is not the net size but the variability. Spider respiration hasn't changed over the last few centuries where our contribution has increased by many orders of magnitude, not only by burning fossil fuels but by destroying sinks like the rainforest. Therefore this is where we are inclined to look for a cause in the unprecidented spike in CO2 levels. We could argue that point back and forth but theres a decider that puts the argument to bed. The carbon in fossil fuels has a different ratio of isotopes to that respired by spiders. An isotopic analysis of tree rings is where the answer lies. Those denialists who respect our grasp of the debate will be focussing their anti science rhetoric on the isotopes and trying to shoehorn in doubt over the interpretation of these isotopic ratios in tree rings.
Last edited by Matt; 21st December 2009 at 12:58 PM.
Can you expand on this? What does an isotopic analysis of tree-rings tell us about the historical climate?
We all learn at school that the thickness of rings indicates the amount a tree was able to grow in a year, however that does not easily correlate onto temperature alone. I've never heard of people analyzing the isotopes in tree-rings before.
Here's one side of the argument
http://www.realclimate.org/index.php...ities-updated/
Deniers will poo-poo the source, and I believe that such poo-pooing is the entirity of the other side of the argument.
A quick google broadly confirms what Matt is saying.
Articles like this: "The analysis of carbon and oxygen isotopes embedded in tree rings may shed new light on past climate events in the Mackenzie Delta region of northern Canada." http://www.sciencedaily.com/releases...1203141935.htm
are thrown up.
Matt's link explains it and links like mine above confirm that it is a real scientific method.
This is the best site to visit IMO because it addresses the arguments against a human cause for climate change: http://www.newscientist.com/article/dn11462
At last. This is the sort of comprehensible evidence, which I recognize as evidence, that I've been looking for. Thanks Matt, Bob, and TW for those links, and especially thanks Sal for starting this thread.
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