Guest Essay by Kip Hansen
This is Part 4 of a four part series. If you are not familiar with The Fight Against Global Greening – Part 1, Part 2 and Part 3 you can either read them in their entirety and then read this, or read the introduction of Part 1 up to the line “Let’s look at #1” and then read this. — kh
Carl Zimmer of the NY Times has said “‘Global Greening’ Sounds Good. In the Long Run, It’s Terrible.”. In collaboration with Dr. J. E. Campbell of the Sierra Nevada Research Institute, he has stated that position, offering us these:
Bad Things About Global Greening: (quoted from Zimmer’s article)
1. “More Photosynthesis Doesn’t Mean More Food“
2. “Extra Carbon Dioxide Can Make Plants Less Nutritious”
3. “More Plants Won’t Prevent Climate Change”
4. “Global Greening Won’t Last Forever”
In Part 1, we looked at the question of the relationship between increased photosynthesis and food production (Zimmer’s #1). In Part 2, we discussed the claim that “extra carbon dioxide can make plants less nutritious”. And in Part 3 we discussed the fact that Global Greening, by itself, would not stop climate change.
In this final and shorter segment, I discuss the implications of the obviously true fact that Global Greening won’t last forever.
Let’s Look at #4: “Global Greening Won’t Last Forever”
Here’s what Zimmer and Campbell say:
Global Greening Won’t Last Forever
There’s still a lot that Dr. Campbell and his colleagues don’t understand about global greening. Most importantly, they don’t know how long it will last.
As temperatures rise and rainfall patterns change, plants may stop soaking up extra carbon dioxide.
“Plants are quietly scrubbing the air of one China’s worth of carbon. What frightens me is knowing this can’t go on forever,” said Dr. Campbell. “If respiration catches up with photosynthesis, this huge carbon reservoir could spill back into our air.”
“There’s a wild card out there.”
— Carl Zimmer, “NY Times article “Global Greening….it’s Terrible“
I’ll try to do a better job of stating Zimmer’s (and Campbell’s) position than they do.
Zimmer admits that the subject of Global Greening is young and still full of unknowns…the usual list includes known unknowns, unknown unknowns, etc. It is refreshing to see an admission of anything less than Omnipotence and Settled Science.
“Most importantly, they don’t know how long it will last,” Zimmer says.
Well, neither do I (nor do you or anyone else). There is pertinent science on the topic though — greenhouse men have been growing flowers and other horticultural crops under enhanced CO2 for many years and there doesn’t seem to be an upper limit of CO2 concentrations that the atmosphere will be reaching, at least in this or the next century.
So, although various plants have their individual CO2 saturation points (the point at which increasing CO2 does not increase photosynthesis – colored orange), the general figure given for maximum benefit by many experts is 1000 ppm. [The graph above is only illustrative.] The important bit is that plants generally keep increasing photosynthesis with additional CO2 — up to about 1000 ppm.
The 21st Century average annual increase in atmospheric CO2 is around 2.5 ppm per year, so that gives us, if everyone keeps emitting CO2 at the same rate, and no one even tries to meet Paris emission reduction targets, 240 more years of possible Global Greening effect from CO2 enhancement. Of course, some plants will top out at 800 ppm, some at 900 ppm, some plants will find they don’t get enough water and some won’t find sufficient nutrients.
Now Zimmer and Campbell are afraid that at some point the horror-story RCP 8.5 scenario will actually come to pass, the planet’s average surface temperature will rise so high and droughts become so extensive (well, wherever it is not flooding) that plants will not only stop absorbing China’s portion of emissions, but will die and all that carbon will be released back into the atmosphere — all at once — as CO2 through the breakdown of the plant debris. This is what Campbell means when he says “If respiration catches up with photosynthesis, this huge carbon reservoir could spill back into our air.”
It is certainly true that if all the plants died — or even if just a great percentage of the plants died — decomposition, through natural processes, would begin to breakdown the plant material on the ground and in the ground into simpler compounds and CO2 would be emitted — the principle of biological respiration in the carbon cycle. Here is The Carbon Cycle.
Zimmer’s catastrophic fears will not be realized because of the grey boxes in the Carbon Cycle diagram — these are Carbon Stores. They are unlike Campbell’s “reservoir of carbon” analogy — they are not a big dammed lake full of carbon dioxide that is posed to “spill” back into our air. We see “Respiration” right above the black-and-white cow in the diagram. More correctly, the flow of CO2 to the atmosphere from Decay and part of the exchange with the oceans can also be considered Respiration in the biological carbon cycle. The Carbon Stores have been created as carbon dioxide has been transformed through photosynthesis and the actions of plant and animal life into vegetation (leaves, stems, tree trunks, woody brush), it has become soil and the organic matter in the soil, some is locked up in the surface waters of the oceans and much has sunk to the deep ocean not to be seen for centuries or millennia, sediments on the ocean floor are carbonaceous and will eventually become sedimentary rock through the process of rock formation, some has become and will become deposits of oil and coal and gas and some is locked up in the bodies of all the planet’s animal life, including 8 billion human beings.
Dr. Campbell must be very confused if he truly thinks that the “end of Global Greening” would result in any sort of threatening sudden spill of carbon back into the atmosphere.
As I discussed in Part — it is the bio-sequestration of carbon and once sequestered, the carbon will not return to the atmosphere as carbon dioxide for varying lengths of time — on a time scale ranging from days to millennia.
But Zimmer and Campbell fear another aspect of Global Greening: What if man keeps emitting 40-50-60 billion tons of CO2 every year and things are being kept in check somewhat by the fact that Nature will have been soaking up 10-12-15 billion tons of that CO2 annually, and then suddenly Nature is CO2-saturated and photosynthesis levels off while CO2 emissions keep rising and rising? Well, I guess that is within the realm of possibility — but like many alarmists visions of the future, it relies on the assumption that things will only stay the same or get worse — and neglects the more likely possibility that Mankind will mitigate the ill effects and reinforce and take advantage of the good effects of our changing world and climate.
I don’t think that it is overly optimistic to think that in the next 150 years we will see energy breakthroughs that obviate our worries of Global Warming by eliminating the need to produce electricity energy by burning hydrocarbons — oil, gas, coal, wood.
In the last 150 years, we have gone from the burning of peat, wood and charcoal; through the massive coal age; and the petroleum age. The nuclear age got off to a good start, only to be stalled by the fears of the anti-nuke activists. One hopes that with the newest designs for nuclear power plants and the hopes of fusion, the nuclear age will really get going again.
What we needn’t worry about are the groundless fears expressed by Dr. Campbell and parroted by Zimmer in the NY Times — the fact that Global Greening will not last forever is a simple biological fact and has no foreseeable downsides for mankind.
Global Greening is not terrible — GLOBAL GREENING is WONDERFUL.
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Author’s Comment Policy:
To those who have managed to read all four of the essays in the series, congratulations, you exceed my expectations….I barely managed enough patience to write them. In retrospect, I could have combined Parts 3 and 4. I did think it was important to put the senseless fear mongering of Zimmer and Campbell to rest — countering them with basic science.
What I worry about is that the average NY Times reader is so deficient in basic science education that they will have read Zimmer’s “Global Greening…Its Terrible” and not seen through the illogic and pseudo-science. Hope that some of them may read here springs eternal.
As always, appreciate you having put in the time to read here.
Address your comments to “Kip…” if you are speaking to me personally, and I’ll try to field your question or concern.
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Quick Links:
The Fight Against Global Greening – Part 1
The Fight Against Global Greening – Part 2
The Fight Against Global Greening – Part 3
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