Climate experts' "rapidly rising levels of anxiety "

[Bernie Gunther]

The point of this calculation is the very favorable rate of exchange between carbon in the atmosphere and carbon in the soil. To stop the carbon in the atmosphere from increasing, we only need to grow the biomass in the soil by a hundredth of an inch per year. Good topsoil contains about ten percent biomass, [Schlesinger, 1977], so a hundredth of an inch of biomass growth means about a tenth of an inch of topsoil. Changes in farming practices such as no-till farming, avoiding the use of the plow, cause biomass to grow at least as fast as this. If we plant crops without plowing the soil, more of the biomass goes into roots which stay in the soil, and less returns to the atmosphere. If we use genetic engineering to put more biomass into roots, we can probably achieve much more rapid growth of topsoil. I conclude from this calculation that the problem of carbon dioxide in the atmosphere is a problem of land management, not a problem of meteorology. No computer model of atmosphere and ocean can hope to predict the way we shall manage our land.

source above.

Yeah, I can kind of see his point here, but in the real world we're losing topsoil at an extremely alarming rate.

So it's a reasonable 'what if?' but not entirely convincing as a reason for giving aid and comfort to the deniers.

 

[DotCommunist]

My post-apocalypse planning skills aren't going to look so stupidly paranoid in years to come. Fuck nature, bring it on. I'm ready for it.

 

[free spirit]

[serious mode]
so this is going to be a Freeman Dyson thread then is it?

ok then.

some points...

1 - The only real method he offers up of achieving his increase in soil deposition is the use of no-til farming methods together with some vague thing about possible GM crops. Both of these methods can logically only possibly affect land that is used for arable farming. Leaving aside how practical his no-til farming, or GM ideas actually are in a time when food production needs to be maximised, the actual proportion of the land area he's talking about that is used for arable farming is around 12% (possibly 15% allowing for deserts). So what he's actually talking about is needing to add around 6/10 - 9/10 of an inch of top soil per year on average across all the arable land in the world.

Given that it's entirely unrealistic to expect even close to half of farmers across the world converting their farming practices in this manner, what we're really talking about is needing to add maybe 2-3 inches per year of top soil for those farms that participate in his scheme... based on a hopelessly optimistic idea of 20-50% of farmers converting their farming practices in the manner suggest.

2-3 inches increase per year is blatently never going to be achievable, therefore Professor dyson is spouting shit.

2 - It looks like he's implying somehow that fossil fuel reservoirs naturally interact on short timescales with the other carbon reservoirs of atmosphere, land plants, soil, and the surface layer of the ocean, when he says that 'They all interact strongly with one another'. This is obviously bollocks as the fossil fuel reservoirs have been almost entirely locked away entirely seperately from the other 4 reservoirs for millions of years until we came along and decided to reintroduce all that locked away carbon into the mix.

3 - He is right that land use is a major factor in the carbon cycle, but overlooks the fact that land use change over the whole of recent history has been in the direction of adding carbon to the atmosphere / reducing the biosphere's ability to absorb carbon from the atmosphere.

I presume Professor Dyson is a better physicist than he is ecologist or environmental scientist... maybe he should stick to his subject area and stop putting out stupid stuff like this that can only turn him into a laughing stock, at the same time as adding to the public perception of scientific confusion over such an important issue.

 

[Bernie Gunther]

Well, he's a bright enough guy although about 309yrs old. He spent WW2 helping the RAF work out how to start firestorms in places like Dresden, made his rep in physics as a collaborator of Feynmann, helping to pull together quantum electrodynamics from the diverse approaches of Feynmann, Schwinger and Tomonaga.

He's most famous for Project Orion though ... *boom!*, *boom!*, *boom!*, *boom!*, *boom!* ....

 

[free spirit]

Well, he's a bright enough guy although about 309yrs old. He spent WW2 helping the RAF work out how to start firestorms in places like Dresden, made his rep in physics as a collaborator of Feynmann, helping to pull together quantum electrodynamics from the diverse approaches of Feynmann, Schwinger and Tomonaga.

He's most famous for Project Orion though ... *boom!*, *boom!*, *boom!*, *boom!*, *boom!* ....

I'm sure he is bright and all that, which is why I find it strange that he'd risk his reputation by coming out with such ill thought out bollocks.

 

[free spirit]

another example of a physicist not understanding ecology...

[FONT=Verdana, Arial, Helvetica, sans-serif]At the same time, roughly six thousand years ago, there were deciduous forests in Northern Europe where the trees are now conifers, proving that the climate in the far north was milder than it is today.[/FONT]

That doesn't prove the climate was milder at all. Presuming what he says is true about the deciduous forests, this could plausibly be explained by differences in the rates at which conifers and deciduous woodland are able to recollonise large areas of land that have been vacated by retreated ice sheets.

Conifer seeds are transported over relatively short distances mainly by the process of getting caught up in animals fur, as well as by floating down rivers and streams, though the majority of rivers and streams would be flowing away from the retreating Ice sheets.

Depending what type of deciduous trees he's on about, their seeds can be spread rapidly over long distances by birds eating the berries, migrating north and shitting the seeds out, meaning they can move tens of miles per generation. Also pioneer species such as mountain ash, are well adapted to growing successfully on pretty much bare rock, which is all that would have been left across much of the land once the ice retreated... where as conifers need more soil to grow successfully. Mountain ash and the like also mature quickly from being seeded to producing seeds, so would move northwards to recolonise the land much quicker over all than conifers.

Essentially pioneer species such as mountain ash would have reached and fully colonised the northern mountains he's on about far quicker than the conifers. Even once the conifers had reached the areas, they'd then have had to pretty much wait for several generations of mountain ash and other plants to grow, decay and produce the soil the conifers need to thrive, and it would only be at that point that the conifers would gradually be able to start to dominate the landscape in the way they do now as they start to outgrow the deciduous trees whenever a gap develops in the tree canopy.

It's perfectly possible IMO that it'd take several thousand years for the whole process to reach the point where conifers could once again dominate the areas he's on about, and for deciduous forests to dominate these areas before that.

ie. that ain't proof Professor Dyson.

 

[Jonti]

Holocene climatic optimum

The Holocene Climate Optimum was a warm period during roughly the interval 9,000 to 5,000 years B.P.. This event has also been known by many other names, including: Hypsithermal, Altithermal, Climatic Optimum, Holocene Optimum, Holocene Thermal Maximum, and Holocene Megathermal.

This warm period was followed by a gradual decline until about 2,000 years ago.

source

 

[david dissadent]

source

T

he holocene climate optimum coincides with the period the strongest climate forcing mechanism of the past three million years was at a near peak, that is the 60 deg N June July average insolation. That peak also had thousands of years to take into account the other feedback mechanisms like the forcing back of the snowline, glaciers and ice cap to lower the albido of the earth and increase the energy absordbed. What is more the oceans would have had time to absorb the additional energy and reach an equilibrium which would have not then (as now) had the oceans acting as a heat sink taking thermal energy out of the air. Moreover the melting of tundra would have taken place over millenia allowing relatively small increases in methane as it decomposes to CO2 so quickly. Our current temprature is not a stable one but one that will continue to increase for many decades to come due to feedbacks having to stabalise.

Our current temperature is not the destination...... it is the departure lounge.

 

[Jonti]

Yeah, great chart, and kudos to Nathan R. Williams for putting on his site.
http://www.people.cornell.edu/pages/nrw22/
Credit where credit's due!

 

[david dissadent]

Yeah, great chart, and kudos to Nathan R. Williams for putting on his site.
http://www.people.cornell.edu/pages/nrw22/Credit where credit's due!

I just plucked any one of the same graphs from here (I have the same thing in my photobcket...
http://images.google.co.uk/images?hl=en&q=milankovitch cycle&um=1&ie=UTF-8&sa=N&tab=wi


But it was created by Robert A. Rohde from publicly available data and is ultimately sourced at Global Warming Art project.

http://www.globalwarmingart.com/

If however you have any data that contradicts the graph in anyway I am sat here waiting.

 

[Jonti]

source above.

Yeah, I can kind of see his point here, but in the real world we're losing topsoil at an extremely alarming rate.

So it's a reasonable 'what if?' but not entirely convincing as a reason for giving aid and comfort to the deniers.

Why let them set the agenda? Deliberate liars will continue to lie anyway.

Other than that, it looks as if you are in agreement with what Professor Dyson says in his Edge piece ...

At present we do not know whether the topsoil of the United States is increasing or decreasing. Over the rest of the world, because of large-scale deforestation and erosion, the topsoil reservoir is probably decreasing. We do not know whether intelligent land-management could increase the growth of the topsoil reservoir by four billion tons of carbon per year, the amount needed to stop the increase of carbon dioxide in the atmosphere. All that we can say for sure is that this is a theoretical possibility and ought to be seriously explored.

 

[Jonti]

I just plucked any one of the same graphs from here (I have the same thing in my photobcket...
http://images.google.co.uk/images?hl=en&q=milankovitch cycle&um=1&ie=UTF-8&sa=N&tab=wi


But it was created by Robert A. Rohde from publicly available data and is ultimately sourced at Global Warming Art project.

http://www.globalwarmingart.com/

If however you have any data that contradicts the graph in anyway I am sat here waiting.

Why should you imagine that?

Although the scale makes it very hard to see, the graph is consistent with what I quoted above

The Holocene Climate Optimum was a warm period during roughly the interval 9,000 to 5,000 years B.P.. This event has also been known by many other names, including: Hypsithermal, Altithermal, Climatic Optimum, Holocene Optimum, Holocene Thermal Maximum, and Holocene Megathermal.

This warm period was followed by a gradual decline until about 2,000 years ago.

 

[david dissadent]

Why should you imagine that?

Although the scale makes it very hard to see, the graph is consistent with what I quoted above

This graph makes the scale clearer alghough I cant test to its veracity the numbers are consistant with what my understanding....

But if you want to challange anything be my guest and post the calculations....

Oh and the final point, since you accept that the holocene climate optimum included all of the positive feedbacks having had a chance to fully exert themselves and the insolation in June July being at a near peak, why did you post about them without explaining clearly the difference in circumstance between the holocene climate optimum and the current climactic situation, especialy with respect to the dominant 65 deg North June July insolation signal?

 

[Jonti]

Here at #36, free spirit seems to take issue with professor Dyson's factually accurate comment that the climate in the far north roughly six thousand years ago was milder then than it is today.

So I pointed him to a Wikipedia article, that's all.

 

[free spirit]

source

I wasn't arguing about whether or not the holocene period was warmer than now or not, more on a technicality of him using the presence of desiduous woodland in an area now covered in conifers as proof.

Proof would indicate that there were no other possible explanations, whereas what he's doing is more jumping to a conclusion that fits his hypothesis.

He could be right, but then it's impossible to tell because he's given no references to any research that would back up his idea by investigating and discounting other possible causes of this phenomenum.

I just don't like the way he just glibly tells the audience in effect that temperature is the only reason why an area of land that is now coniferous forest could have been deciduous in the past, when it's not.

maybe I'm nit picking, but it just demonstrated to me that he is definately a physicist, thinking like a physicist, trying to use ecology to prove something that it doesn't prove.

 

[Bernie Gunther]

Why let them set the agenda? Deliberate liars will continue to lie anyway.

Other than that, it looks as if you are in agreement with what Professor Dyson says in his Edge piece ...

Dyson is Emeritus Prof or something at Cornell. It would be easy for him to check with Cornell's ecology Prof David Pimentel about soil erosion. Which is happening to a very disturbing extent.

10m hectares per year according to Pimentel's book. If he was arguing that this was a more pressing problem than climate change he might have a point. But as far as I can see he isn't arguing that.

 

[Jonti]

Maybe.

Don't get me wrong, yours was a gem of an essay, and I thoroughly enjoyed it. All the same, what the Professor said about the climate in north europe at that time was completely correct.

 

[Jonti]

He rather clearly says that over the world as a whole the topsoil is probably decreasing.

What matters here is that this is an important metric. And as Dyson says ...

At present we have no way to measure or even to guess the size of this effect. The aggregate biomass of the topsoil of the planet is not a measurable quantity. But the fact that the topsoil is unmeasurable does not mean that it is unimportant.

 

[free spirit]

the reason that I thought that technicality was relevant is that the main thrust of his arguement seems to be about that whole 1/10th of an inch per year figure for soil growth to offset the carbon being emitted into the atmosphere (or 1/100th of an inch for the actual biomass component of the soil)...

[FONT=Verdana, Arial, Helvetica, sans-serif]I do not want to confuse you with a lot of numbers, so I will ask you to remember just one number. The number that I ask you to remember is one hundredth of an inch per year.[/FONT]

The reason for picking him up on his use of the presence of deciduous trees in a currently coniferous forest as proof of it having been a warmer climate, was simply that it strengthened my belief that his understanding of the ecology side of things is probably not that great, and that people therefore shouldn't be taking his ideas about using soil management to offset the anthropogenic carbon emissions too seriously... as I'd previously shown from some pretty basic look at his figures.

eta - apologies for the crap grammer / writing style of this post... my head is hung in shame

 

[david dissadent]

Here at #36, free spirit seems to take issue with professor Dyson's factually accurate comment that the climate in the far north roughly six thousand years ago was milder then than it is today.

So I pointed him to a Wikipedia article, that's all.

I am not FS, but his argument seems to indicat that the the angiosperm desciduous colonising faster than the gymnosperm conifers is in itself insufficient evidence of greater temperature. As Freeman Dyson as quoted in this thread has provided no other proxy data I can see his point. Proxy data normaly requires multiple corroborating sources to confirm it and it can be very local in results. I'm afraid that more than the person a poster is responding too is reading the thread therefore it is often necessary to flesh out what you are trying to say (precisely) and too scope out the limits of the points a post is trying to make.

Edited to add, ok seems the argument has moved on since I wrote this...

 

[Bernie Gunther]

He rather clearly says that over the world as a whole the topsoil is probably decreasing.

What matters here is that this is an important metric. And as Dyson says ...

Dyson appears to suggest that we have no strong evidence one way or another about the destruction of topsoil, he says that it's 'probably decreasing' globally, but we have convincing and supportable estimates of the net loss, for example Pimentel's ~10m ha per year.

If he wants to claim that we don't know for sure whether topsoil is increasing or descreasing, despite overwhelming evidence that it's being lost in massive amounts each year, then I think it's fair enough to ask him to explain why.

Especially given that his argument for ignoring the model evidence for climate change appears to rest on extremely improbable assumptions about the restoration of topsoil and hence increased sequestration from vegetation.

I think what he's arguing is a very interesting case of 'what if?' but it's complete bullshit if it's claimed to apply it to the real world in which arable land is being destroyed by out-of-control capitalism at a horrific rate.

 

[Jonti]

10m ha per year is a measure of land area. You can measure that with aerial and satellite imaging.

He's talking about biomass in the topsoil -- how do you measure that?

 

[Bernie Gunther]

You can link them, with satellite imagery you're actually deducing the topsoil extent from the biomass, but the rate of change involved in soil erosion is so horrific that I think that it just makes nonsense of his claims.

 

[free spirit]

He rather clearly says that over the world as a whole the topsoil is probably decreasing.

What matters here is that this is an important metric. And as Dyson says ...

eta this post's also addressing Bernie...

the current decrease in topsoil is largely due to soil erosion - ie soil being either washed away, or blown away.

Some of it will be getting digested by microbes and such like leading to carbon being emitted back into the atmosphere, but that's not the main process leading to the loss of soil.

I'm not really clear what impact soil erosion has on atmospheric co2 levels, as the carbon will still largely be locked up in the soil, it'll just be at the bottom of the sea. I guess the processes of decomposition will be different when it's under the sea to when it's on land, but I'd be inclined to think the carbon would be more locked away when it's under water than when it's on land if anything.

What matters is whether carbon dioxide levels in the atmosphere are increasing or not, which they blatantly are.

Freeman Dyson's contention that we can simply make land use changes to offset CO2 emmissions from burning fossil fuels in any meaningful way has no connection with the reality of the situation unfortunately. Changing landuse practices so that land use change stops being a net contributor to increased atmospheric co2 levels would be a good starting point, and it's possible that land could be managed better to maximise it's CO2 uptake and retension, but there's just no way it's as small a problem as he's trying to make out.

 

[Jonti]

Changing landuse practices so that land use change stops being a net contributor to increased atmospheric co2 levels would be a good starting point...

Damn right it would!

It is shocking that it is a net contributor of CO2 to the atmosphere!

 

[david dissadent]

At present we do not know whether the topsoil of the United States is increasing or decreasing.

link from Jonti

Can you provide a single source to indicate that US topsoil is increasing? Everyting I have read including talking to numerous US farmers is that topsoil is decreasing. Not only that but the soil left is much less dense in bioactivity and needs artificial sources of energy to keep it productive.

 

[free spirit]

10m ha per year is a measure of land area. You can measure that with aerial and satellite imaging.

He's talking about biomass in the topsoil -- how do you measure that?

what he's actually talking about really is the sequestration of carbon from the atmosphere into the soil via the biosphere.

that can be estimated reasonably well by measuring the annual carbon flux of different vegetation types at different lattitudes (and potentially height, air temperature, insolation etc), then matching that data up with global remote sensing data to give you the area of each vegetation type at different latitudes, heights, temperatures etc to give you a reasonable estimate of the annual global carbon flux from the land based biosphere.

I'm pretty sure this has been done, though there's probably scope for increasing the accuracy through ever more detailed data fields.

 

[Jonti]

You can link them, with satellite imagery you're actually deducing the topsoil extent from the biomass, but the rate of change involved in soil erosion is so horrific that I think that it just makes nonsense of his claims.

One simply cannot measure the biomass is the topsoil. Not directly. One could do sums, but they'd need to be backed by a mass of world-wide empirical measurements.

He's hinting that's the kind -- just one kind -- of the information you need if you want to start actively to manage the interactions between your five short-term reservoirs of CO2.

 

[Bernie Gunther]

Yes, but we know for sure (he implies otherwise) that this particular resevoir is being depleted at a horrific rate.

 

[Jonti]

He strongly implies we should be in a position accurately to measure and if necessary manage this short-term reservoir of CO2; and by implication each of the five (they are the atmosphere, the land plants, the topsoil in which land plants grow, the surface layer of the ocean in which ocean plants grow, and our proved reserves of fossil fuels).

Do you think this is such a bad idea?