[andyt]

No, they wouldn't use trees. They'd use some sort of grass crop would be my guess, or anything else the cycles quickly. Caleb stated it inelegantly. It's not the first generation of plants that will have this problem, but some time down the road. At some point, the rate of decay will be slower than the increased rate of growth of the plants, and no more nutrients available to support more rapid growth = CO2 uptake.

So a little atmospheric CO2 increase will lead to higher crop yields, but keep increasing atmospheric CO2 and the system will no longer act as a carbon sink. Also, rainfall and soil nutrients (ie those not derived from plant matter) will be limiting factors. Atmospheric Nitrogen can only be fixed so quickly to make it available for plants: http://www.extension.umn.edu/agricultur ... -in-soils/

http://onlinelibrary.wiley.com/doi/10.1 ... x/abstract

$1:

On the whole, terrestrial higher-plant responses to increasing atmospheric CO2 concentration probably act as negative feedbacks on atmospheric CO2 concentration increases, but they cannot by themselves stop the fossil-fuel-oxidation-driven increase in atmospheric CO2 concentration. And, in the very long-term, atmospheric CO2 concentration is controlled by atmosphere-ocean C equilibrium rather than by terrestrial plant and ecosystem responses to atmospheric CO2 concentration.

CO2 is only one factor affecting plant growth. It should be obvious that if you increase a particular factor, another one comes into play in limiting growth. And as the above article says, CO2 interferes with plant respiration (imagine yourself in an atmosphere too high in CO2), and that can limit growth as well.


Also, to match the rate of our CO@ output, we'd need huge swaths of tropical forest to keep atmospheric CO2 at our current level.


But all that aside, it occurred to me that atmospheric CO@ has risen dramatically since we've been measuring it.

0:

Capture.PNG [ 84.48 KiB | Viewed 108 times ]

So obviously the various carbon sinks (the ocean is the big one) are not taking up all the carbon we are spewing. Meanwhile, we continue to cut down the rain forest, reducing that particular sink. Turns out the Boreal Forest isn't a good sink in the first place. Pinning your hopes on the tropical rainforest as allowing us to spew at will is idiotic.

For the deniers it's much better to hang your head on the fact that climate warming doesn't seem to perfectly match CO2 increases and our understanding of the warming it would lead to. As discussion of that I"ll leave to Zippy.

[andyt]

$1:

1. CO2 enhanced plants will need extra water both to maintain their larger growth as well as to compensate for greater moisture evaporation as the heat increases. Where will it come from? In many places rainwater is not sufficient for current agriculture and the aquifers they rely on are running dry throughout the Earth (1, 2).

On the other hand, as predicted by climate research, we are experiencing more intense storms with increased rainfall rates throughout much of the world. One would think that this should be good for agriculture. Unfortunately when rain falls in short, intense bursts it does not have time to soak into the ground. Instead, it quickly floods into creeks, then rivers, and finally out into the ocean, often carrying away large amounts of soil and fertilizer.

2. Unlike Nature, our way of agriculture does not self-fertilize by recycling all dead plants, animals and their waste. Instead we have to constantly add artificial fertilizers produced by energy-intensive processes mostly fed by hydrocarbons, particularly from natural gas which will eventually be depleted. Increasing the need for such fertilizer competes for supplies of natural gas and oil, creating competition between other needs and the manufacture of fertilizer. This ultimately drives up the price of food.

3. Too high a concentration of CO2 causes a reduction of photosynthesis in certain of plants. There is also evidence from the past of major damage to a wide variety of plants species from a sudden rise in CO2 (See illustrations below). Higher concentrations of CO2 also reduce the nutritional quality of some staples, such as wheat.

4. As is confirmed by long-term experiments, plants with exhorbitant supplies of CO2 run up against limited availability of other nutrients. These long term projects show that while some plants exhibit a brief and promising burst of growth upon initial exposure to C02, effects such as the "nitrogen plateau" soon truncate this benefit

5. Plants raised with enhanced CO2 supplies and strictly isolated from insects behave differently than if the same approach is tried in an otherwise natural setting. For example, when the growth of soybeans is boosted out in the open this creates changes in plant chemistry that makes these specimens more vulnerable to insects, as the illustration below shows.


6. Likely the worst problem is that increasing CO2 will increase temperatures throughout the Earth. This will make deserts and other types of dry land grow. While deserts increase in size, other eco-zones, whether tropical, forest or grassland will try to migrate towards the poles. Unfortunately it does not follow that soil conditions will necessarily favor their growth even at optimum temperatures.

In conclusion, it would be reckless to keep adding CO2 to the atmosphere. Assuming there are any positive impacts on agriculture in the short term, they will be overwhelmed by the negative impacts of climate change.

Added CO2 will likely shrink the range available to plants while increasing the size of deserts. It will also increase the requirements for water and soil fertility as well as plant damage from insects.

[Xort]

DrCaleb DrCaleb:

If all he can do is attempt to ridicule me, which I realize is all he has left, at the very least proper grammar would show some small effort on his part.

So care to share the nature of these tests you claim to have witnessed?

Also when you said that trees would die and release all their CO2 what sort of time scale were you thinking of?

Andjust for the record we are talking about carbon dioxide not cobalt right? Cause you said Co2 not CO2 before.

So great job with your grammar, maybe you can work on your scientific accuracy.

[N_Fiddledog]

andyt andyt:

And as the above article says, CO2 interferes with plant respiration (imagine yourself in an atmosphere too high in CO2), and that can limit growth as well.

No it doesn't. It says...

$1:

Plant respiration may be inhibited by elevated CO2 concentration

In fact the whole abstract is "may be", "could be", and "can". So basically you're offering hypotheses up as proof of another hypothesis.

BTW what exactly are you trying to say? What are the actual parameters of your hypothesis? You appear to be insinuating that plant growth as a result of added CO2 will destroy the rain forest. Where is the actual proof of that?

Explain the existence of centuries old Douglas Firs in our rainforests. I've seen some pretty big, old looking trees in tropical rain forests as well.

There appears to be evidence of large old trees in the forests of the Dinosaur age as well. Also some pretty big living creatures. CO2 levels were about 4 or five times what they are now in those bad ol' days, weren't they? How is that possible if too much CO2 kills biomass? Come to think of it, what do you mean by too much?

More than this?

$1:

And now for some good news about lettuce. Six scientists from China and Australia tell us in their introduction that “It is considered that the optimal concentration of carbon dioxide (CO2) for plant growth is 800–1000” ppm. We agree wholeheartedly and wonder why so many people refuse to acknowledge the incredible biological benefit plants receive from elevated CO2. Jin et al. introduced a method of increasing CO2 concentrations in greenhouses by composting plant residues and animal manures (you might wait to try this in your own home). They tested their idea and found they could double atmospheric CO2 in the greenhouses with the composting materials. They grew plants in these greenhouses, and the edible shoot weight of leaf lettuce increased by 257% while for stem lettuce, the yield increased by 87%. If you are interested, celery yield increased by 270% and Chinese cabbage increased yield by 227% — all thanks to elevated CO2.

http://www.worldclimatereport.com/index ... /#more-418

When are you expecting levels of more than 1000 ppm? 2100? 22? If it's fossil fuel created increase you're worried about, are those levels of CO2 increase even possible by human involvement?

Until you can answer real world questions like that with more than another hypothesis, I'm going to say, "Carbon dioxide emissions help tropical rainforests grow fast - so what?"

[N_Fiddledog]

It's kind of lucky CO2 helps rainforest grow fast too. A lot of rainforest was lost as a result of the Kyoto accord. It was most evident in Indonesia where vast swaths of rainforest was mowed down to make room for palm oil plantations. Palm oil, you see, could be cashed in for carbon credits. Damn near drove the Orangutans to extinction.

I think something similar was happening in Brazil as well.

[N_Fiddledog]

Also Andy if you're going to quote something from that garbage site, SkepticalScience.com, at least have the guts to post a link.

I won't address it until you do.

[Xort]

N_Fiddledog N_Fiddledog:

It's kind of lucky CO2 helps rainforest grow fast too. A lot of rainforest was lost as a result of the Kyoto accord. It was most evident in Indonesia where vast swaths of rainforest was mowed down to make room for palm oil plantations. Palm oil, you see, could be cashed in for carbon credits. Damn near drove the Orangutans to extinction.

I think something similar was happening in Brazil as well.

A possible CO2 credit farm would be to chop down trees and then put them in buildings acting as very long term carbon stores and then regrow trees.

Do you think logging companies will be making more from the carbon credits than their lumber anytime soon?

[andyt]

N_Fiddledog N_Fiddledog:

andyt andyt:

And as the above article says, CO2 interferes with plant respiration (imagine yourself in an atmosphere too high in CO2), and that can limit growth as well.

No it doesn't. It says...

$1:

Plant respiration may be inhibited by elevated CO2 concentration

In fact the whole abstract is "may be", "could be", and "can". So basically you're offering hypotheses up as proof of another hypothesis.

BTW what exactly are you trying to say? What are the actual parameters of your hypothesis? You appear to be insinuating that plant growth as a result of added CO2 will destroy the rain forest. Where is the actual proof of that?

Explain the existence of centuries old Douglas Firs in our rainforests. I've seen some pretty big, old looking trees in tropical rain forests as well.

There appears to be evidence of large old trees in the forests of the Dinosaur age as well. Also some pretty big living creatures. CO2 levels were about 4 or five times what they are now in those bad ol' days, weren't they? How is that possible if too much CO2 kills biomass? Come to think of it, what do you mean by too much?

More than this?

$1:

And now for some good news about lettuce. Six scientists from China and Australia tell us in their introduction that “It is considered that the optimal concentration of carbon dioxide (CO2) for plant growth is 800–1000” ppm. We agree wholeheartedly and wonder why so many people refuse to acknowledge the incredible biological benefit plants receive from elevated CO2. Jin et al. introduced a method of increasing CO2 concentrations in greenhouses by composting plant residues and animal manures (you might wait to try this in your own home). They tested their idea and found they could double atmospheric CO2 in the greenhouses with the composting materials. They grew plants in these greenhouses, and the edible shoot weight of leaf lettuce increased by 257% while for stem lettuce, the yield increased by 87%. If you are interested, celery yield increased by 270% and Chinese cabbage increased yield by 227% — all thanks to elevated CO2.

http://www.worldclimatereport.com/index ... /#more-418

When are you expecting levels of more than 1000 ppm? 2100? 22? If it's fossil fuel created increase you're worried about, are those levels of CO2 increase even possible by human involvement?

Until you can answer real world questions like that with more than another hypothesis, I'm going to say, "Carbon dioxide emissions help tropical rainforests grow fast - so what?"

See the various critiques about greenhouse experiments. Also discussions on limiting factors that come into play in real world situations. Also expected greater desertification under global warming - ie water becomes the limiting factor. Also that C4 plants do not show greater growth with more CO2. And on and on.

But what does all that matter? We know that atmospheric CO2 concentrations have risen sharply since the beginning of the industrial age, and that the rate global CO2 emissions continues to rise. The natural laboratory called planet earth tells us that these emissions are not being absorbed by sinks, otherwise atmospheric CO2 would not be increasing. So, we can harp all we want about greater CO2 concentrations increasing plant growth. The increased plant growth, such as it may be, is not acting as a carbon sink and preventing rise in atmospheric carbon. IN fact at some point the sinks will be full and start overflowing, ie atmospheric CO2 will rise even faster as the sinks stop absorbing any further increases in Carbon output.

This discussion shouldn't really interest you at all, since it doesn't prove there's no AGW. All it shows is that atmospheric carbon would be even higher if these sinks weren't operating. As I said, just keep focusing on the fact that temps have not risen in lockstep with CO2 concentrations, and hope that this continues to be the case, that unknown factors are acting to cool the amosphere and that these factors don't flip and temp rises faster than increases in CO2 would predict.

[N_Fiddledog]

No you don't seem to understand.

You're under the impression the last little chunk of geologic history was normal. It wasn't. We were actually in a period of Carbon dioxide deprivation in comparison to the larger history of the earth. We were down to 200 ppm of carbon dioxide. All life on earth dies if you go below 180.

I'm not sure we're even at normal levels yet, and it's been much, much higher. Biologic diversity has thrived at much higher levels.

And why are you so sure the current increase is not largely natural?

You have your hypotheses about what might happen if greenhouse levels CO2 were used in the non-hothouse world. Good for you. Just don't preach it as fact. If you do I'll say "Prove it", and you can't. Yes I read what you posted. It's nothing. Just another John Cook fairytale.

What we do know is people who grow plants for a living increase the levels of carbon dioxide to their hothouses. Why do you think they do that?

"Carbon dioxide emissions help tropical rainforests grow fast". Show me why that's incorrect. If you can't, what's the problem?

[N_Fiddledog]

But I'll tell you what, Andy. If you're going to bring John Cook and his BS labeled site of "Skeptical Science" into this you lose any right to complaint if I lay a little Anthony Watts on you.

This is from a thing Watts did for his award winning science blog. It's part of a post originally titled, "The big list of failed Climate Predictions"

Things warmist scientists and preachers predicted that did not come true.

# 99.

2005, Andrew Simms, policy director of the New Economics Foundation: “Scholars are predicting that 50 million people worldwide will be displaced by 2010 because of rising sea levels, desertification, dried up aquifers, weather-induced flooding and other serious environmental changes.”

****

http://wattsupwiththat.com/2014/04/02/t ... edictions/

See, that's the problem with things like "desertification" predictions. There's too much evidence they turn out to be incorrect.

[andyt]

N_Fiddledog N_Fiddledog:

No you don't seem to understand.

You're under the impression the last little chunk of geologic history was normal. It wasn't. We were actually in a period of Carbon dioxide deprivation in comparison to the larger history of the earth. We were down to 200 ppm of carbon dioxide. All life on earth dies if you go below 180.

We're not even at normal levels yet, and it's been much, much higher. Biologic diversity has thrived at much higher levels.

What is "normal?" What were climatic conditions like during this "normal" period. How were humans doing at the time?

N_Fiddledog N_Fiddledog:

You have your hypotheses about what might happen if greenhouse levels CO2 were used in the non-hothouse world. Good for you. Just don't preach it as fact. If you do I'll say "Prove it", and you can't. Yes I read what you posted. It's nothing. Just another John Cook fairytale.

What we do know is people who grow plants for a living increase the levels of carbon dioxide to their hothouses. Why do you think they do that?

Irrelevant.

$1:

But an unprecedented three-year experiment conducted at Stanford University is raising questions about that long-held assumption. Writing in the journal Science, researchers concluded that elevated atmospheric CO2 actually reduces plant growth when combined with other likely consequences of climate change -- namely, higher temperatures, increased precipitation or increased nitrogen deposits in the soil.

The results of the study may prompt researchers and policymakers to rethink one of the standard arguments against taking action to prevent global warming: that natural ecosystems will minimize the problem of fossil fuel emissions by transferring large amounts of carbon in the atmosphere to plants and soils.

"Perhaps we won't get as much help with the carbon problem as we thought we could, and we will need to put more emphasis on both managing vegetation and reducing emissions," said Harold A. Mooney, the Paul S. Achilles Professor of Environmental Biology at Stanford and co-author of the Dec. 6 Science study.

He noted that the Stanford study is the first ecosystem-scale experiment to apply four climate change factors across several generations of plants.

http://news.stanford.edu/pr/02/jasperplots124.html

N_Fiddledog N_Fiddledog:

"Carbon dioxide emissions help tropical rainforests grow fast". Prove they don't.

You mean faster, don't you. And you mean increased atmospheric CO2, not emissions, don't you? And my point has been, there will be a limit to that increase in growth rate, after which increased CO2 won't cause anymore increase in growth rate.

$1:

IN short-term experiments under productive laboratory conditions, native herbaceous plants differ widely in their potential to achieve higher yields at elevated concentrations of atmospheric carbon dioxide1–8. The most responsive species appear to be large fast-growing perennials of recently disturbed fertile soils7,8. These types of plants are currently increasing in abundance9 but it is not known whether this is an effect of rising carbon dioxide or is due to other factors. Doubts concerning the potential of natural vegetation for sustained response to rising carbon dioxide have arisen from experiments on infertile soils, where the stimulus to growth was curtailed by mineral nutrient limitations2,3,10. Here we present evidence that mineral nutrient constraints on the fertilizer effect of elevated carbon dioxide can also occur on fertile soil and in the earliest stages of secondary succession. Our data indicate that there may be a feedback mechanism in which elevated carbon dioxide causes an increase in substrate release into the rhizosphere by non-mycorrhizal plants, leading to mineral nutrient sequestration by the expanded microflora and a consequent nutritional limitation on plant growth.

http://www.nature.com/nature/journal/v3 ... 616a0.html


And, the planet has already proven that our carbon sinks aren't able to maintain atmospheric co2 at a static level. Whether the source is man made or natural, whether a particular ecosystem is a carbon sink or source, it's all irrelevant, since CO2 is increasing. Now according to you, this is wonderful and just a return to normal.

[andyt]

$1:

The last time there was this much carbon dioxide (CO2) in the Earth's atmosphere, modern humans didn't exist. Megatoothed sharks prowled the oceans, the world's seas were up to 100 feet higher than they are today, and the global average surface temperature was up to 11°F warmer than it is now.

As we near the record for the highest CO2 concentration in human history — 400 parts per million — climate scientists worry about where we were then, and where we're rapidly headed now.

There is no single, agreed-upon answer to those questions as studies show a wide date range from between 800,000 to 15 million years ago. The most direct evidence comes from tiny bubbles of ancient air trapped in the vast ice sheets of Antarctica. By drilling for ice cores and analyzing the air bubbles, scientists have found that, at no point during at least the past 800,000 years have atmospheric CO2 levels been as high as they are now.

Other research, though, shows that you have to go back much farther in time, well beyond 800,000 years ago, to find an instance where CO2 was sustained at 400 ppm or greater.

For a 2009 study, published in the journal Science, scientists analyzed shells in deep sea sediments to estimate past CO2 levels, and found that CO2 levels have not been as high as they are now for at least the past 10 to 15 million years, during the Miocene epoch.

“This was a time when global temperatures were substantially warmer than today, and there was very little ice around anywhere on the planet. And so sea level was considerably higher — around 100 feet higher — than it is today,” said Pennsylvania State University climate scientist Michael Mann, in an email conversation. “It is for this reason that some climate scientists, like James Hansen, have argued that even current-day CO2 levels are too high. There is the possibility that we’ve already breached the threshold of truly dangerous human influence on our climate and planet."

http://www.climatecentral.org/news/the- ... xist-15938


I also skimmed past a site that seemed to say that high CO2 levels are associated with causing ice ages. If so, that would be no picnic either - Europe was almost depopulated during the last one, and America of course didn't have any people.

[N_Fiddledog]

N_Fiddledog N_Fiddledog:

"Carbon dioxide emissions help tropical rainforests grow fast". Prove they don't.

andyt andyt:

You mean faster, don't you. And you mean increased atmospheric CO2, not emissions, don't you? And my point has been, there will be a limit to that increase in growth rate, after which increased CO2 won't cause anymore increase in growth rate.

No I mean exactly what I said. Notice the quotation marks. Now look up. What's the title of this thread. OK, now here comes the tough part. Think...

[N_Fiddledog]

Now I'm going to show you what's meant by "Geologic Time". There are critiques of this one, but it will help you with the time scale.



I don't think anybody's disputing the basic relationship of the Jurassic period to now. Check out those readings. You know a little bit about that period from the movies, right? OK, now let's try our new exercise again. Ready? Think...

[andyt]

N_Fiddledog N_Fiddledog:

N_Fiddledog N_Fiddledog:

"Carbon dioxide emissions help tropical rainforests grow fast". Prove they don't.

andyt andyt:

You mean faster, don't you. And you mean increased atmospheric CO2, not emissions, don't you? And my point has been, there will be a limit to that increase in growth rate, after which increased CO2 won't cause anymore increase in growth rate.

No I mean exactly what I said. Notice the quotation marks. Now look up. What's the title of this thread. OK, now here comes the tough part. Think...

Here is the title from your source: "Carbon dioxide emissions help tropical rainforests grow faster" it makes sense, yours doesn't, although they should have started the sentence with "Increased"

They also say: "'This is good news, because uptake in boreal forests is already slowing, while tropical forests may continue to take up carbon for many years.'
In total, they estimate that forests and other vegetation absorb around 2.7 billion tonnes of carbon dioxide, about 30 per cent of that emitted by humans.
As emissions add more carbon dioxide to the atmosphere, forests worldwide are using it to grow faster."

Seems they have no doubt the increased CO2 in the atmosphere is from humans.

Also, despite increasing atmospheric CO2, your own source demonstrates that Ecosystems will reach their limit of increasing growth rates/higher carbon absorption. (Boreal forest rates slowing down). How much longer will the tropical rainforest be able to act as a carbon sink before it reaches saturation? Then that extra carbon will all go into the atmosphere.


Also this: "However, he added that changes in water supply to forests due to changing climate and deforestation could alter the amount of carbon dioxide tropical forests are absorbing." As I was saying, other factors besides CO2 limit growth. Water is only one of them.


I don't think you answered my question about what the planet was like last time we were at 400 ppm CO2, and how humans were doing at the time.