Global Warming on Free Republic
Posted on 03/05/2011 10:30:10 AM PST by AFPhys
Plants eat plant food.... and eat more of it when more is available. Who’da thunk it?
Plants eat plant food.... and eat more of it when more is available. Who’da thunk it?
Global Warming on Free Republic
Great post dude!
If the earth wasn’t a self correcting system, we probably wouldn’t have made it this long...
You know what this means....a worldwide campaign against GLOBAL DRYING!
What do you believe accounts for the humidity changes since 1950? How do you assess the affect of the changes on temperature?
From the paper linked at post#36: “We propose that the ongoing optimization of gsmax is eventually limited by species-specific limits to phenotypic plasticity... [and]... that adaptation will continue beyond double CO2. ... and will continue to do so throughout this century.” The researchers apparently disagree with your estimation that plants’ limits of adaptation will be rapidly reached. (I’m not a botanist, so I have to rely solely on their expertise.)
Just what I was thinking. If plants are giving up less water vapor, bodies of water (oceans, lakes -- even rivers)will give up more so that the atmosphere reaches the relative humidity that it wants to be at for a given atmospheric temperature.
I don’t really understand the altered title. The article doesn’t seem to provide the conclusion suggested by the altered title. And changes in one source don’t necessarily add up to the total for the hydrological cycle. Far from saying this evidence saves the day against global warming, the article suggests some ecosystems (like the Florida Everglades) may collapse as a result.
It appears you did not study the graph of humidity changes during the past 60 years that I included.
To what would you ascribe the humidity changes since 1950?
There certainly has been a drastic change, particularly evident at the higher altitudes, but also discernible at the surface Certainly, with higher temperatures, simple physical chemistry would call for higher humidity, but that definitely has not been the situation. For some reason, the oceans, lakes, etc., are not supplying the requisite humidity “it wants to be at for a given atmospheric temperature.”
Would you consider it at all possible that the “missing humidity” is due to the mechanism described in this research? Bear in mind that the warmists are ascribing man’s puny 2% share of CO2 production as the sole cause of CO2 rising from 280->380ppm since 1880 or thereabouts.
I don't know. What did it look like for the previous 60 years? Or the 60 years before that?
Is it cyclical?
There have been no temperature changes outside the margin for error. I seriously doubt that there is any way to accurately measure a planet-wide average humidity.
Look at the two pics you posted. On the one with the greater number of stomata do you see any room for significant additions? Once the area of the leaf surface has become tightly packed with stomata that is pretty much the upper limit.
Agreed about the pictures. However, the researchers presumably did not rely only upon those pictures, but on other data delineated in the papers. In particular, they noted that they expected this type of adaptation to continue throughout the 21st century, as CO2(presumably) rose rather rapidly. I kind of glazed over when it got to GSmax, etc...
I gather you are more experienced in this specific area than I am. I would appreciate it if you gave me a better explanation of the reason they believed that GSmax and such things would dictate continued negative feedback on moisture release, as well as why they believed that the adaptation would continue throughout the century, as well as why you differ with their opinion.
The humidity data are derived from balloon flights, and appear to be generally accepted.
The 300mb data changes are clearly substantial since 1950. Cyclic or not, there is a clear monotonic decrease since that time. Correlation (not causation): there has been a monotonic increase of CO2 along with this decrease of humidity.
Increasing water vapor definitely increases temperatures according to “greenhouse theory”, which I believe is well accepted. Therefore, the decrease in humidity has clearly lowered the “trapping” of heat at that 300mb level in the last 60 years, and less clearly but certainly suggestively, at lower altitudes. If we allow that this otherwise unexplained decrease in humidity is due to changes in vegetative release of moisture with increased CO2, this represents a large negative feedback with increasing CO2 that is not remotely accounted for, or even mentioned, by the IPCC.
Whether it is cyclical or not is not germane to this particular discussion.
I don't know what your level of experience/knowledge of the topic is but I am not well-versed in it. I'm just relying on common sense to see that plants can only adapt so far in either direction re stomata number and size. Also re humidity levels and plants affect on it compared to the vast expanses of water. I can't believe that plants would ever compare as a source to the oceans.
One thing I find compelling re atmospheric CO2 levels is the estimate of what they were when land plants developed. I don't recall the figure but it was much higher than it is now. It may be a shaky assumption but it seems likely to me that land plants took off when conditions were near optimal not marginal.
OK - well, I am depending on these particular researchers for their estimates of the limits of adaptability for the plants they studied. I’m a physicist with strong chemistry background, not a biologist, so I have to defer to them in this.
What really intrigues me about this research is that it provides a mechanism for the change in humidity that has been observed. I agree with you at first thought, oceans, etc., would be more important sources of humidity, but the temperature change over the last half century would then argue for higher humidity, not lower. That is contrary to balloon observations, which I consider to be eminently reliable, and that data argues that some other process must be in play.
Seems to me that if a scientific society would argue that a few percent additional annual release of CO2 by man would increase atmospheric CO2 by 50%, it is valid to argue that a change of humidity release by vegetation of a few percent could have a similar countervailing effect.
Which is what about a half degree Centigrade? IOWs within the margin for error?
Seems to me that if a scientific society would argue that a few percent additional annual release of CO2 by man would increase atmospheric CO2 by 50%, ...
But that is entirely false. Atmospheric CO2 hasn't increased 50% or even a small fraction of that if I recall the figures on that correctly.
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