Relax everyone - new NASA study says double CO2 no big deal

Relax? No big deal? I don't see that in the NASA news item.

"Bounoua stressed that while the model's results showed a negative feedback, it is not a strong enough response to alter the global warming trend that is expected."

""This feedback slows but does not alleviate the projected warming," Bounoua said."

"Scientists agree that in a world where carbon dioxide has doubled – a standard basis for many global warming modeling simulations – temperature would increase from 2 to 4.5 degrees C (3.5 to 8.0 F). (The model used in this study found warming – without incorporating the plant feedback – on the low end of this range.)"

 

Oh no, another "does global warming exist" debate.

 

1) What the research showed is that modeling the interaction with plants in that specific way reduced predicted warming by 0.3 degrees C.

2) They started from a baseline model that was on the low end of the range of climate sensitivities (1.94 C for a doubling of C02). That's how they got their 1.64 degrees C per doubling.

3) So the right way to think of this is:
3a) If they are right about what will happen to land-based plants (and of course, you realize there is significant disagreement in the scholarly literature on this point),
3b) Then you can take whatever your prior expectation of warming was, for a doubling of C02, and knock it down by 0.3 degrees C.

4) I certainly found it hard to get my mind around the proposed mechanism, but I haven't studied this area well. They assumed more green leaf area on land and more efficient photosynthesis, leading to higher rates of transpiration. And that faster water cycle -- greater evapotranspiration -- kept the surface cooler. Hmmm. But transpiration just moves heat from one place to another. Where did the heat go? Beats me. As long as its not on the surface, that's good enough for me.

This is at least as interesting as other models of likely impact on plants. The fact that they could plausibly find an impact that large is interesting in its own right, whether or not there's a strong empirical basis for it. You can back-solve from the stated land and global impacts to infer 0.17 degrees cooling over the oceans. That certainly won't (e.g.) save the summer polar ice cap, and, to the extent that the non-green areas of the world act like the oceans (no plants, so no evapotranspiration cooling), it arguably would not be enough to prevent the eventual melt of the Greenland ice cap, if that were going to occur in your model absent this effect. So the effect is large, yet I do not feel relaxed by it.

5) From what I could get my hands on, I couldn't tell whether or not they had a stronger empirical basis for their approach than others. I.e., I couldn't say whether this is merely different but plausible, or actually better, than prior research in this area.

5A) My uninformed bias is that, given that humans already use a large fraction of the globe's potentially arable land, and that most of the rest isn't good for much, and that the world's population is currently doubling every 35 years or so (or, at least, doubled in the past 35 years), the assumption of significantly more green leaf area in the world's future seems questionable. But I would defer to informed opinion about that.


6) The UK Register is not the place to find an unbiased writeup of anything to do with climate change.

Yes, here's the NASA press release (Edit: As referenced already by Fuzzy1). The actual article is behind a low ($9) paywall.
http://www.nasa.gov/topics/earth/features/cooling-plant-growth.html

 

My guess is if they chose a model in the middle or dare I say the high end of range they would be accused of "fear mongering" regardless of how likely the model is to be right.

 

If they chose the middle or high end it would be a case of the following;

[ame=http://en.wikipedia.org/wiki/The_Boy_Who_Cried_Wolf]The Boy Who Cried Wolf - Wikipedia, the free encyclopedia[/ame]

 

In this case the wolf is real!

 

I didn't see it mentioned from my skimming of the article, but does it take into account the loss of "green" while we continue to cut down the trees, etc for building purposes? The more buildings that continue to be built, there's that much less sq footage for "green" to accomodate the CO2 as well. My understanding is that we are cutting down more trees and faster than we are replanting and they can grow back. Is that still the case?

I'm not discounting the study or it's conclusions, but I don't have enough knowledge to know as much at this point. I'm always open for facts and learning more, so please share what facts you have for the rest of us to help further our understandings.

 

OP has been trolling around here for years arguing that CO2 is not a global warming mechanism. I find it amusing that now he is reduced to relying on research that does not dispute the fundamental process at all. "right all along?" No, more like the kind of gross illogic that denialists are made of.

As far as the specific article goes without the inane denialist noise, I am sure that additional processes, both positive and negative, will be found as the globe heats up. Did the model used account for effects on forests harmed by AGW ? That by itself I suspect will way overshadow any increase in ground cover. There is no doubt that land use (or misuse, as the case requires) is a big component of overall global temperature increase. Hoping that GW will span a natural land response that lets humans happily continue burning fossil fuels is simple idiocy.

 

My guess would be that they chose the model because the code could be easily modified -- either because they wrote the code, or because it was set up in such a way that this effect could easily be integrated with the existing code. That's what I would do. The point of the paper was the delta generated by their new approach to modeling the reaction of land-based plants. Any reasonable starting point would do for that. But I'm not wiling to pay the $9 to read the article on the off chance that they explain why they chose that starting point.

 

Stages of AGW denial:
1. "There is no global warming."
2. "There is global warming, but it's not a problem."
3. "Global warming is a problem, but it's all natural and not our fault."
4. "Global warming is our fault, but the only thing we can do now is adapt to it."
5. The denier either dies of old age or starts voting Democrat.

 

Global warming exists! So does global cooling! It's just a question of when. Both events have occurred in the past and no doubt they will occur again in the future. The question about the global warming currently happening should be; Should this be happening now and if not, are we causing it to happen prematurely? If that question can be answered, then we'll need to take action. If statistically we find the earth is going through it's normal warming period, there's not much we can do about it.

 

Real or otherwise ... what with coal/oil peak production on the near horizon (especially using a geological time scale), what we can't seem to decide on will ultimately become moot and self correcting. Once we use up our non-renewable resources (which will reduce CO2 belching) we will be forced to do things differently. But heck, why worry about that untill it's too late, right?

 

lol, geologically we'll be at peak oil in the next instant. Yeah, either way the carbon will eventually come down. The question is how much we want/are going to pay for it. The more we release the greater the chance that we're going to be paying a lot.

 

The longer we wait to address any number of problems, the higher the costs! CO2 Emission/Peak oil/Peak coal/Nuke waste handling just to name a few!

 

are these the same scientists who claim that life can be supported by arsenic instead of phosphorous?

 

was that debunked? I seem to recall hearing about that on NPR the other day.

 

I say lets see how 12/21/2012 goes, I'll get back to you all on the CO2 thing on the 22nd.....hopefully

 

Is that the day North Korea drops a nuke on Iran and blames the USA?