Gee, I said that here years ago, pointing out obvious unknown factors.
John Larkin pointed out that absent strong negative feedbacks, Earth would've fried or frozen a long time ago.
In fact the early attempts at modeling did exactly that, freezing or frying the planet, and the feedbacks that would correct that (such as accurate clouds, dynamic albedo and vegetation) are still missing or mishmash.
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>> >> The geological record shows that the earth has been quite a bit warmer
Right. Personally, with no particular justification, I suspect cloudiness increases with temp., decreasing solar absorption. Simple, straightorward (and possibly wrong).
Yep. The whole thing's a giant, non-linear oscillator with a zillion interactive feedbacks.
Modelling, they've tweaked the terms to where the global temp stays within the limits _they expect_, but that doesn't mean they--either the tweaked factors or the predictions--are right!
There was claimed to be observational evidence for an increased importance of variations in solar radiation on climate, but the paper that made the cl aim was shown to include several unfortunate errors. Solar variation is a minor influence at best, and doesn't explain the warming over the last cent ury.
Actually, there isn't. Lindzen hypothesised such a process, but when tested against observation, his hypothesis was falsified.
Sure. They were all less unknown than you claimed, so what yo were proclaim ing was your ignorance, rather than your scepticism.
John Larkin also points out that CO2 is good for plants, when plants react to higher CO2 levels by having fewer stomata in their leaves, so they can g et the same amount of CO2 - CO2 is hardly ever a growth restricting factor
- while losing less water - because plants rarely have access to all the wa ter they could use.
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In James Arthur's "expert" opinion. He also thinks that the Climategate lea ked e-mails revealed actual abuses.
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They didn't. "Ice ages" are rare, and seem to need the right distribution o f land masses near the poles to support the albedo-increasing ice sheets ne eded to support an ice age.
The most recent high CO2 period - the Paleocene-Eocene Thermal Maximum, som e 55.8 million years ago
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certainly didn't end in an ice age. It seems to have started off as a high methane period, judging by the spike in the isotope ratios, but methane bec omes CO2 within a century or so.
That exactly what has happened at every ice-age to inter-glacial transition for the last million years or so - we've got ice-core samples detailing ex actly what went on - and is probably what has been going on for the past 2.
6 million years when the current "ice age" kicked in.
There's enough positive feedback for the tiny Milankovitch effect to drive the switch between ice ages and interglacials. We've lost most of the albed o-driven positive feedback - the Arctic Ocean ice cover (which we are losin g) and the Greenland ice sheet (which may slide off into the Atlantic in a century or two) aren't as big as the Laurentian and Northern European ice s heets, but the CO2 and water-vapour positve feedback are in fine shape.
We've recently got to know more about this, and more than we knew in 2007 - there have been a couple of papers published in the last year or so. Here' s a puff about a paper published in April last year
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It seems that Greenland ice sheet sliding off into the North Atlantic and s topping the Gulf Stream for 1300+/-70 years (the Younger Dryas) was a criti cal phase in the transition from the last ice age to the current interglaci al.
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The heat that usually flowed north with the Gulf Stream flowed south in to the southern ocean, and warmed it up enough to release enough CO2 to move u s firmly into an inter-glacial.
Everything is possible, but John Larkin's hypotheses tend to be easily fals ified.
This is nonsense. Positive feedback needs to be quite big to force a latch- up.
The albedo-based positive feedback stops when the ice-sheets have all melte d, and slows down a lot when the ice-sheets closest to the equator have mel ted.
The H2O vapour positive feedback - on it's own - has never been big enough to drive us into latch-up. Venus may not have been so lucky.
Very likely wrong - clouds appear in rising and cooling air, and vanish whe n the air is falling and warming. By conservation of matter, cloud cover is close to 50% whatever the temperature.
And it's the only way in which we can explain why the tiny Milankovitch eff ect can synchronise ice age to interglacial transitions.
"Zillion"?
It strongly suggests that they have got it roughly right.
ation. British science journalists don't know much about science, and are p articularly prone to print articles given to them by the denialist propagan da machine.
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I did address the merits of the article, and you've snipped those comments, without marking the snip. This is a fairly clear indication that you favou r knee-jerk ragging over rational discussion.
Pointing out that an article is probably biassed propaganda - when it is - is scarcely either knee-jerk ragging or propagandist behaviour.
Your tendency to parade obvious propaganda as if it were serious comment pu ts you firmly in the propagandist domain. I hope you get paid for it - thou gh anybody who did pay you wouldn't exactly be getting value for money. Unm arked snips aren't the royal route to becoming a trusted source.
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It's a selective presentation of a NASA finding. Even you should be aware o f the difference. And even you should have been aware that the fact that ve getation absorbs CO2 was included in the climate models.
The NASA update was about the amount of vegetation doing the absorbtion. I t delivered better data, which is presumably now incorporated into the late st versions of the models, which do get bigger and better as more data beco mes available.
When you first started peddling this line, we had very little data from the Argo buoys. We now know quite a bit more about what the oceans are doing, but you don't seem to have noticed, and seem to be happy to quote a 2007 de bate as if it represented current knowledge.
Watch out. If we do manage to get Greenland warm enough for it's ice sheet to slide off into the North Atlantic, we could stage a re-run of the Younge r Dryas, and turn off the Gulf Stream.
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This happened at the end of the last ice age. If it happens again, Detroit will get much colder still. Global warming won't slow down, but there will be local climate change around the North Atlantic, while the southern ocean will get warmer (from all the warmth that normally flows north with the gu lf stream) and absorb less of the CO2 we are currently pumping into the atm osphere.
A re-run of the Younger Dryas might decrease the US capacity for pumping CO
2 into the atmosphere - enough snow and you won't be able to get the gasoli ne to the cars that normally burn it - but probably not enough to help.
That was the conventional wisdom. NASA's recent measurements suggest that with more CO2 to play with they are acting as a carbon sink. Since tropical rain forests are being cut back in Amazonia and Indonesia, this came as something of a surprise.
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James Arthur picked up a reference to this in the UK Daily Mail - and wants to tell us that this is more evidence that anthropogenic global warming is a scam. He finds a lot of "evidence" of this.
There seem to be deeper coral reefs in unexpected places
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They don't grow particularly fast, and trawling has wrecked a lot of them.
Will this continue, producing peat or some other form of trapped carbon? or just plateau at a higher level of live biomass. It doesn't seem particularly suprising that elevated CO2 levels will slow decay and enhance photosynthesis, the oceans are absorbing C02 too, but in that case it's just dissolved in the water.
. Our results, however, show significant tropical uptake and, combining . tropical and extratropical fluxes, suggest that up to 60% of the . present-day terrestrial sink is caused by increasing atmospheric CO2.
So the rate of sinking is caused by the increase, not by the present levels, by my reading they aren't predicting that tropical forests will become sustained carbon sinks at some higher constant CO2 concentration.
As far as I know, tropical rain forests don't produce peat. Fungi and insec ts eat any dead plant tissue - notably termites and ants that cultivate cel lulose-digesting fungi.
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Elevated CO2 levels probably work by allowing leaves to get by with fewer s tomata, limiting water loss, so the same plant can grow bigger with access the same amount of water. More CO2 on it's own won't enhance photosynthesis or slow decay, or at least not so much that you'd notice. 400ppm CO2 is 54 % more than we had from the end of the last ice age to the start of the ind ustrial revolution, but it doesn't make a lot of difference to the Gibb's free energy of CO2 in the atmosphere or plant tissue.
Obviously not. More CO2 in the atmosphere means a slightly higher mass of c arbon tied up in tropical rain forest. As the atmospheric CO2 level rises, more of it will end up in the tropical rain forest, but this isn't an area that creates peat bogs that eventually turn into coal beds and oil fields - you need a colder climate for that.
t to higher CO2 levels by having fewer stomata in their leaves, so they can get the same amount of CO2 - CO2 is hardly ever a growth restricting facto r - while losing less water - because plants rarely have access to all the water they could use.
Bill certainly explains why the planet was so lush and foliage so abundant in past times, creating today's enormous fossil fuel deposits--CO2 stunted the m! (Maybe that's why eco-minded prehistoric plants buried terra[sic]tons of carbon--to protect their children.)
ying
eaked e-mails revealed actual abuses.
Those are objective, historical facts about the models and their historical results.
Climategate doesn't impress you because you don't care about facts so much as outcome, so long as their misstatements support your point of view.
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h-up.
Mere lack of negative feedback ensures latchup. Absent negative feedback, e .g., temperature-related loss, net heat accumulates indefinitely.
A flashlight bulb in a highly insulated container will eventually hit 1,000 oC.
Or if heat loss permanently exceeds input, the system eventually freezes.
Integrating wrong extrapolated energy balances doesn't--and won't ever-- predict long-term temperatures. Feedbacks have to be included, and they ha ve to be right.
ted, and slows down a lot when the ice-sheets closest to the equator have m elted.
That would certainly explain(*) the saw-tooth temperature record, where temperature slowly creeps up until all the snow melts, minimal albedo, then crashes into the next glaciation.
(*) Not.
[...]
If that's what that suggests to you, you're easily bamboozled. There are an infinite number of functions and curve-fits to match any dataset. A tweaked current match in no way guarantees *any* predictive ability whatsoe ver.
To the extent the current models have been tried empirically, they've utterly failed five, ten, or fifteen years ago to project today's observations. In science-talk, that means they're WRONG.
These sorts of obvious oversights by hysterics make climastrology boring, a nd its hysterics even more so. If you really cared you'd conserve, but you do n't.
Yes, finally you have one of the important elements of global warming figured out. Cold weather kills off a large number of parasitic and invasive species' individuals, and is essential for many plants' survival.
An acquaintance who grew up in Hawaii tells me that potatoes are an exotic vegetable there: the weather never gets cold enough to kill off nematodes in the soil, so that potatoes cannot be grown locally. There's a pine bark beetle in Canada that has a similar effect on softwood forests; if you miss the cold of winter a few years in a row, the beetles fluorish while the forest dies.
Horseshit. That or somebody made a really bad typo.
Plants produce O2 NOT CO2. They CONSUME CO2. Any created by their decay takes decades to produce, and comes nowhere close to matching the O2 they produced in their lifetime.
We would all otherwise be dead by now.
What we need to do is get RID of some of the water here, and also HALT the growth of deserts and 'desert regions'.
We need to reduce the CHLORINE cloud hanging over the south pole.
That takes airships. A lot of them. Sweepers.
The water should be taken to The Moon, and some things should be mined from The Moon in that exchange series as well as well.
We need a super sized railgun that has an advanced pre-acceleration stage that keeps the railgun stage from turning the payload into plasma. Shoot parcels of water up there until we get several gigatons off the planet. We should fight to restore the old oceanic shelf that was here back when Atlantis actually existed. The planet has been taking on water its entire life. We just do not see it. There is a lot of water vapor in space, and an object entering our atmosphere is not a requirement for us to attract water. Solar wind probably actually drives it into the atmosphere (on that side), then gravity keeps it.
We can do things down here too...
We should also build huge polar freshwater storage reservoirs in the desert regions, filled with water that comes from polar ice only, thereby reducing its size (read growth rate at center) as well.
Huge, suspended cities can be built in front of and over the reservoirs. They get artificially humidified air from the water stores. That same air is also cooled, and those cities can enjoy comfortable living in the heart of a desert.
If you look at a trend of estimated CO2 over the past few hundred million years, it's pretty scary: we are running out. Absent some natural intervention, or people digging up and burning fossil fuels, we are running out.
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Plants would mostly die out if that trend continued. You can't keep sequestering carbon forever.
act to higher CO2 levels by having fewer stomata in their leaves, so they c an get the same amount of CO2 - CO2 is hardly ever a growth restricting fac tor - while losing less water - because plants rarely have access to all th e water they could use.
t in
hem!
Huh? Current atmospheric CO2 levels are relatively low. The sun was less br ight in the Carbonifierous - when a lot of our fossil fuel deposits were la id down.
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The most likely reason so much coal got laid down back then was that the te rmites and the ants hadn't then evolved their symbiotic relationship with c ellulose digesting fungi, so you could have peat bogs closer to the equator than you can these days.
Plants seem to be even less interested in the world they are leaving for th eir off-spring that Tea Party Republicans, but then again plants can't thin k, while the Tea Party merely thinks irrationally.
leaked e-mails revealed actual abuses.
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Sure. Early climate models were crude and prone to crash. So were early air craft.
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The Climategate revelations didn't impress the various committees of enquir y either, who all found that the activities revealed were perfectly respect able. Your point of view doesn't leave you willing to notice this.
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Wrong. Consider the geometric series a+ar+ar^2 ....
It's sum over n terms is a.(1- r^n)/(1-r)
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The sum becomes infinite if r is equal to or greater than one.
Positive feedback is fine within that limit - determinate and predictable.
We aren't talking about heat accumulating indefinitely, but rather about th e process of the heat from the sun warming the earth and eventually being r e-radiated to space.
00oC.
Correct, but irrelevant. The effective radiating altitude of the earth's at mosphere is always going to be at -18C (or 255K if you prefer absolute temp erature). Anthropogenic global warming means that the effective radiating a ltitude goes up a bit, making the temperature down at the surface a bit war mer.
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ight/
Again irrelevant to the planetary situation. The sun keeps on shining and t he earth's atmosphere keeps on radiating that heat away.
have
It's a pity you don't understand what that means.
elted, and slows down a lot when the ice-sheets closest to the equator have melted.
It's not intended to. The real explanation is rather more complicated.
Perfectly correct, as far as it goes - which isn't very far. Climate modell ers are constrained by atmospheric physics, so they don't have an infinite number of functions that they can use to fit their model to reality, and th ey have a lot of data about temperature distribution up through the atmosph ere for a more or less complete set of latitudes and longitudes - more for some regions than others. They aren't fudging a fit to a thin data set, and only the pig-ignorant could imagine that they were.
John van Neumann's primitive climate models - back around 1955 - already si mulated the gross features of atmospheric circulation, like Hadley cells
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All mathematical models are over-simplifications and thus necessarily WRONG , which doesn't stop them from being useful. Ten years ago we knew very lit tle about the deep oceans currents - the surface currents like the Gulf Str eam are better known - and we'd just started launching the Argo buoys to fi nd out about them.
We did know enough to know that El Nino/La Nina and the Atlantic Multidecad al Oscillation were important, but we didn't know enough about the ocean cu rrents involved to model them.
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and
don't.
It's boring - to you - because you don't know enough to understand it, and don't want to know enough to understand it or to appreciate that your Scroo ge-like habits are of negligible impact.
You ought to understand enough to appreciate that the action required to re verse, or at least slow down anthropogenic global warming has got to be glo bal in scope. Your political aversion to collective action on this - or any scale - makes it unlikely that you'll ever be able to nerve yourself to ac quire that level of understanding.
In the meantime you are content to look like a sucker for denialist propaga nda. If you thought about the rubbish you spout, you'd be embarrassed, but the political message is attractive enough that you can suppress any intell ectual integrity that you might once have had.
alue of edibles, and not all plants respond equally, meaning invasives of n o significance as a food source start to crowd out the more important speci es.
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Not a lot of it. We seem to be on track to dig up and burn several hundred million years worth of sequestered carbon in the next few hundred years. Ev en that won't raise the CO2 levels in the atmosphere to what they were in t he Carboniferous. Most carbon seems to get sequestered as carbonate rock, a nd recycled by volcanoes when the carbonate rock gets subducted.
There's a proposal to deal with the current CO2 surge by grinding up billio ns of tons of olivine and spreading it on every available sea-shore amongst many other places.
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atechange23.pdf
ence.
NASA's work
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is observational. Climate science is complicated and we need to know a lot more about our planet before we can dot all the "i"s and cross all the "t"s .
Sadly for you denialist stance, we already know quite enough to be perfectl y sure that digging up fossil carbon and burning it as fuel is a really bad idea, and we need to stop doing it as fast as we reasonably can. Dismantli ng modern industrial civilisation and engineering a population crash (which would be the long term consequences of business as usual) aren't required, but diverting the next few decades of economic growth into preserving the planet might be prudent.
eact to higher CO2 levels by having fewer stomata in their leaves, so they can get the same amount of CO2 - CO2 is hardly ever a growth restricting fa ctor - while losing less water - because plants rarely have access to all t he water they could use.
nt in
them!
Sadly for that argument, the sun has been getting brighter over the same in terval.
Back in the Carboniferous, you needed about 3000ppm of CO2 in the atmospher e to avoid an ice age. Now it's down to 260ppm.
In some 5 billion years, the sun will evolve into a red giant, and even a R epublican would recognise that it would then be a good idea to expand the E arth's orbit and put it a little further from the sun. It may become necess ary rather earlier.
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