Climate Change/Global Warming & the Leaf Area Index -- The Greening of Planet Earth
CO2 isn't a pollutant, in fact, plants love it. As one man said, "It's the Greening of Planet Earth."
Writing as background for their work, Mao et al. (2013) note that "recently, a new global LAI [leaf area index] product was derived from the NDVI [normalized difference vegetation index] version 3g of the Advanced Very High Resolution Radiometer (AVHRR) for Global Inventory Modeling and Mapping Studies (GIMMS) (GIMMS-LAI3g), providing an unprecedented estimate of monthly to annual distribution of vegetation dynamics over the whole globe (Zhu et al., 2013)." For their own study, the six scientists assessed the historical trends of the global remote-sensing-derived LAI and the prognostic LAI simulated at half-degree spatial resolution by CLM4 (Community Land Model version 4) between 1982 and 2009, with their main objective being "to gain insight into various mechanisms controlling these vegetation tendencies."
In discussing their findings Mao et al. report that "both the remote-sensing product and CLM4 offline simulations demonstrate significant increasing trends of annual vegetation growth during the last three decades." And they say their factorial experiments indicate that "CO2 fertilization was more important than climate variation in determining the magnitude of the temporal trend in LAI at the global scale, in each hemisphere, and for most of the modeled plant functional types over their study period, in agreement with a previous study using an independently developed model (Piao et al., 2006)."
The CO2 fertilization effect of the carbon dioxide emitted to the atmosphere by mankind's burning of fossil fuels, such as coal, gas and oil, is beginning to assume its vaulted position of being a tremendous boon to the biosphere, as all of humanity and the entirety of the world's animal life depend ultimately upon having a sufficient supply of plant life to sustain themselves.
https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/gbc.20026 (unique global data set of 80 forest FLUXNET sites)
The LAI (Leaf Area Index) & rising CO2 levels. Just as many agricultural staples perform well (increased yields, less irrigation required, double-cropping) under higher CO2 levels, vegetation (LAI) in China has responded positively to higher CO2 levels. CO2 isn't the boogeyman the envirokooks make it out to be.
According to Piao et al. (2015), the reliable detection and attribution of changes in vegetation growth are essential prerequisites for “the development of successful strategies for the sustainable management of ecosystems.” And indeed they are, especially in today’s world in which so many scientists and policy makers are concerned with what to do (or not do) about the potential impacts of CO2-induced climate change. However, detecting vegetative change, let alone determining its cause, can be an extraordinarily difficult task to accomplish. Nevertheless, that is exactly what Piao et al. set out to do in their recent study.
More specifically, the team of sixteen Chinese, Australian and American researchers set out to investigate trends in vegetational change across China over the past three decades (1982-2009), quantifying the contributions from different factors including (1) climate change, (2) rising atmospheric CO2 concentrations, (3) nitrogen deposition and (4) afforestation. To do so, they used three different satellite-derived Leaf Area Index (LAI) datasets (GLOBMAP, GLASS, and GIMMIS) to detect spatial and temporal changes in vegetation during the growing season (GS, defined as April to October), and five process-based ecosystem models (CABLE, CLM4, ORCHIDEE, LPJ and VEGAS) to determine the attribution.
With respect to detection, this work revealed that most regions of China experienced a greening trend indicative of enhanced growth across the time period studied (see Figure 1). Overall, 56 percent of the area studied experienced a significant increase in greening (95% level) when using the GLOBMAP dataset, compared with 54 and 31 percent using the GLASS and GIMMIS datasets. Those regions with the largest greening trends include southwest China and part of the North China Plain…
With respect to attribution, Piao et al. report that “the combined effect of CO2 fertilization and climate change with the effect of nitrogen deposition, leads to the conclusion that these three factors are responsible for almost all of the average increasing trend of LAIGS observed from the satellites” (see Figure 2). They also report that “at the country scale, the average trend of LAIGS attributed to rising CO2 concentration is estimated to be ... about 85% of the average LAIGS trend estimated by satellite datasets,” while noting secondarily that the enhanced nitrogen deposition driven by fossil fuel combustion and agricultural fertilization is likely the source of the remaining portion of China’s enhanced vegetation growth, citing the findings of Reay et al. (2008), Thomas et al. (2009), Fleischer et al. (2013) and Yu et al. (2014)…
In considering the researchers' several findings, it is clear that the fossil fuel combustion that has resulted in the rise in atmospheric CO2 and enhanced nitrogen deposition over the past three decades has provided a great benefit to Chinese vegetation. As illustrated in Figure 2, led primarily by the increase in CO2, that benefit has been more than sufficient to compensate for the negative effects of climate change that also occurred over that time period. Thus, it would seem far more prudent to celebrate CO2 instead of demonizing it, like so many people incorrectly do these days; for atmospheric CO2 is truly the elixir of life!
Another ditty on the LAI (Leaf Area Index) & the greening of planet earth. It's why so many agricultural staples are doing well.
We’re happy to report here that a new scientific paper reports that the world is greening—in the best sense of the word. Published this week in the scientific journal Nature Climate Change is a paper titled “Greening of the Earth and its drivers” by a collection of 32 authors representing a combination of research programs from around the world. The authors compiled a large collection satellite observations of parameters associated with vegetative health collected since 1982, sorted through it, analyzed it, and then reported:
“We show a persistent and widespread increase of growing season integrated LAI (greening) over 25% to 50% of the global vegetated area, whereas less than 4% of the globe shows decreasing LAI (browning).”
Figure 1 [at the link] shows the spatial distribution and magnitude of the greening trends. This is about as good of a large-scale environmental result as one could ever hope for. Figure 1. Observed trends in leaf area index (LAI)—a measure of the quantity, density and health of vegetation during the growing season from 1982-2009. Positive trends indicate “greening,” negative trends indicate “browning.” The world is bathed in shades of green and blue. Source: Zhu et al., 2016.
What is the driver of this overwhelmingly positive outcome? Again from the authors: “Factorial simulations with multiple global ecosystem models suggest that CO2 fertilization effects explain 70% of the observed greening trend, followed by nitrogen deposition (9%), climate change (8%) and land cover change (LCC) (4%).”
“CO2 fertilization” is a result of increasing atmospheric concentrations of carbon dioxide—an important plant fertilizer—primarily caused by carbon dioxide released from the chemical processes associated with the burning of fossil fuels to produce energy. And to think that some folks want to try to dial back this benefit…
It is interesting to note that most of the “integrated assessment models” (IAMs) that have been developed and designed to try to determine the “social cost of carbon”—that is, the monetary impact of the emission of each additional ton of carbon dioxide summed over the next 300 years—do not incorporate the positive effects of carbon dioxide fertilization. The primary exception to this situation is the FUND model developed by Dr. Richard Tol. Unsurprisingly, Tol’s model produces a much lower social cost of carbon than the other IAMs. Given that carbon dioxide fertilization and the positive impacts it has of the planet’s plant life is a firmly established scientific reality (as further evidenced by the new findings reported here) you’d think that any IAM that didn’t include it would be summarily rejected. Instead, such models are embraced by the Obama Administration and used to justify all manner of federal regulations.
And before we leave this new greening paper, we want to point out the comparison made by the authors of the patterns of observed trends with those projected to have occurred from a leading climate/vegetation model (Figure 2). We draw your attention to the western half of the United States. Here, the climate/vegetation model produced large (in area and magnitude) browning trends, driven by a general drying trend over the period of record. The observations on the other hand, show little, if any, trends towards browning, and instead show a general, mild, greening over the region…
The authors explain: “Such pronounced negative trends were not captured by any of the three satellite products. Our analysis indicated that models may be over‐sensitive to trends in precipitation as soil water holding capacities maybe under‐estimated in models, and deep rooting, ecosystem composition changes (e.g. shrubification) are not modeled, which is consistent with previous studies.”
In other words, the models don’t have their, er, stuff, together. And as a consequence, they project negative outcomes that don’t materialize.
We’ve been over here, revisiting the LAI (Leaf Area Index) in this era of unchecked CO2. More CO2 has helped planet earth, we also need more Ritalin for Progressive ecokooks like “Face Bloat” Sam Seder & Alexandria Ocasio-Cortez.
A recent Science paper by J-F. Busteri and 30 named coauthors assisted by 239 volunteers found, looking at global drylands (about 40% of land areas fall into this category), that we had undercounted global forest cover by a whopping “at least 9%.” 239 people were required to examine over 210,000 0.5 hectare (1.2 acre) sample plots in GoogleEarth, and classify the cover as open or forested. Here’s the resultant cool map:
This has been the subject of a flood of recent stories, blog posts, tweets, and whatever concerning Bastin et al. But here at the Center for the Study of Science, we’re value added, so here’s some added value.
Last year, Zaichin Zhu and 31 coauthors published a remarkable analysis of global vegetation change since satellite sensors became operational in the late 1970s. The vast majority of the globe’s vegetated area shows greening, with 25-50% of that area showing a statistically significant change, while only 4% of the vegetated area is significantly browning. Here’s the mind-boggling map:
Trends in Leaf Area Index, 1978-2009. Positive tones are greening, negative are browning, and the dots delineate where the changes are statistically significant. There is approximately 9 times more area significantly greening up than browning down.
Hope you’re sitting down for the money quote: “We show a persistent and widespread increase of growing season integrated LAI (greening) over 25% to 50% of the global vegetated area, whereas less than 4% of the globe shows decreasing LAI (browning). Factorial simulations with multiple global ecosystem models show that CO2 fertilization effects explain 70% of the observed greening trend…”
And the other greening driver that stood out from the statistical noise was—you guessed it—climate change. Now, just for fun, toggle back and forth between the two maps. As you can see, virtually every place where there’s newly detected forest is greening, and a large number of these are doing it in a statistically significant fashion. This may lead to a remarkable hypothesis—that one of the reasons the forested regions were undercounted in previous surveys (among other reasons) is that there wasn’t enough vegetation present to meet Bastin’s criterion for “forest,” which is greater than 10% tree cover, and carbon dioxide and global warming changed that.
Global warming/climate change is going to kill the planet! Death by Leaf Area Index (LAI)!
Satellite observations indicate the Earth has become much greener in recent decades. According to scientists, the overwhelming majority of the “significant increases in tropical forests and the forests of North America, Eurasia, and China” since the early 1990s can be attributed to the combination of CO2 fertilization (56%) and climate change (35%).
What follows are 12 peer-reviewed articles saying generally the same thing—CO2 has greened the earth & that’s good for all of us.
On the social costs of carbon (and a good hypothetical example on what we can do) & how planting trees (this dovetails w/ the Leaf Area Index).
A recent article in The Guardian trumpeted the findings of a new study published in Science that found massive tree planting would be—by far—the cheapest and most effective approach to mitigating climate change. Ironically, the new thinking shows the pitfalls of political approaches to combating so-called “negative externalities.” The good news about tree planting disrupts the familiar narrative about carbon taxes that even professional economists have been feeding the public for years. The whole episode is an example of what Ronald Coase warned about, in his classic 1960 article showing the danger in the traditional approach of using taxes to fix alleged market failures…
Citing a figure that planting a new tree costs roughly 30 cents, Prof. Crowther remarked that we could plant the target of 1 trillion trees by spending about $300 billion. Sure, that’s a big number, but its nowhere close to the economic cost of imposing a worldwide carbon tax, the “solution” that many economists have been promoting for years as a no-brainer. (William Nordhaus’ model in its 2007 calibration estimated that even his modest carbon tax would cause several trillion dollars [in today’s dollars] in economic compliance costs, while the more aggressive proposals would cause more than $20 trillion in economic costs.)
This episode is a specific example of the type of problem Ronald Coase warned about. Specifically, the carbon tax logic assumed that the problem was, “People are emitting too much carbon dioxide and we need to coerce them into scaling back.” But what if instead the problem was, “People aren’t planting enough trees, and we need to coax them into planting more”?
To give some quick numbers: By some estimates, a single healthy tree can sequester up to a ton of carbon dioxide by the time it reaches 40 years old, and we also read that a silver maple tree will absorb 400 pounds of carbon dioxide by the time it reaches 25 years old.
So consider a coal-fired power plant that is going to emit a ton of carbon dioxide in order to produce some additional electricity. If the pro-tax economists had gotten their way, there would be a $42 tax levied on the power plant, since the Obama EPA estimated that that was the “social cost of carbon” for the year 2020.
Yet if there is room on Earth for more trees—given the plans of everybody else—that Obama-era estimate greatly overstates the harm of the emission. Rather than imposing $42 in damages as the EPA calculations suggested, the power plant owner could spend a mere $3 to plant 10 trees, meaning that over the next two decades the trees would have absorbed more than the additional emissions, and would in fact continue reducing CO2 in the atmosphere for decades beyond.
As this simple example illustrates, a carbon tax of $42 would have been a gross overkill. It would have led power plants and other firms to scale back their emissions in very costly ways that stifled economic growth, when—apparently—there was a much cheaper solution available. And notice throughout all of this discussion, I am stipulating the basic externality framework for the sake of argument, and am merely showing the problems that Ronald Coase demonstrated with this one-size-fits-all way of thinking.
So, instead of massive carbon taxes on evil emissions, let’s just plant more trees & this can be done at the county/municipal level. If done on the federal level, who knows how much cronyism will be employed as some government contractors will use leverage to gain a foothold in a pork-filled, Soviet-style Five Year Tree Planting Plan.
Progressives will shirk at this solution (which is an actual “green” solution) because they don’t get to tell you what to do & control your life. Many of these folks are incapable of holding together their marriage or raising their own kids, what business do they have controlling my carbon footprint?
Stan Seder can’t hold a job that doesn’t require him being a social medial celebutard & Alexandria Ocasio-Cortez’s toughest task prior to becoming a Congressman was making a Manhattan & busing a table.
What business do these pukes have telling me what to do?
Speaking of carbon sequestration:
On natural activities that sequester carbon (carbon sinks).
Ballantyne et al. (2012) write that "although approximately one-half of total CO2 emissions is at present taken up by combined land and ocean carbon reservoirs (Schimel et al., 2001)," coupled climate/carbon-cycle models "predict a decline in future carbon uptake by these reservoirs, resulting in a positive carbon-climate feedback (Friedlingstein et al., 2006)."
In an effort to shed more light on the subject, Ballantyne et al. used "global-scale atmospheric CO2 measurements, CO2 emission inventories and their full range of uncertainties to calculate changes in global CO2 sources and sinks during the past fifty years." And what did those calculations reveal?
The five U.S. scientists say their mass balance analysis shows that "net global carbon uptake has increased significantly by about 0.05 billion tonnes of carbon per year and that global carbon uptake doubled, from 2.4 ± 0.8 to 5.0 ± 0.9 billion tonnes per year, between 1960 and 2010." In discussing the implications of these findings in the concluding paragraph of Ballantyne et al.'s Nature article, they state that "although present predictions indicate diminished C uptake by the land and oceans in the coming century, with potentially serious consequences for the global climate, as of 2010 there is no empirical evidence that C uptake has started to diminish on the global scale." In fact, as their results clearly indicate, just the opposite appears to be the case, with global carbon uptake actually doubling over the past half-century.
The Regressive Dumocrat might retort, “Derp, are you saying that this negative feedback loop (higher CO2 coupled with carbon sinks sequestering more CO2) will continue into perpetuity? Are you saying that more CO2 will always be sequestered, even to the point where or atmosphere could be pure CO2, which would kill you?”
Uh, no. Just as lifting weights will make you stronger & stronger, you will still never get to the point where you can lift an aircraft carrier out of the Pacific & carry it to Las Vegas. I don’t know what the limit is & neither do you. Stop being stupid.
I actually had a detractor at one point suggest that “if our atmosphere were pure CO2, we would all die.” No kidding, Mr. Wizard? Radon is beneficial in small amounts, but deadly in large amounts – so is water – what’s your point dummy?
We've been here before. Conventional wisdom predicts as forest become aged; they don't sequester nearly as much carbon.
Noting that "old-growth forests on Changbai Mountain have been well protected from human activities and provide a living laboratory for studying forest carbon sequestration under natural environmental conditions," the ten researchers say that they "used data from permanent plots measured periodically in 1981 and 2010 to quantify carbon densities for Korean pine-broadleaf mixed forest, coniferous forest and Erman's birch forest on Changbai Mountain" in "one of the largest nature reserves in China," which occupies the area between latitudes 41°43' and 42°26'N and longitudes 127°42' and 128°17'E.
Zhou et al. report that "from 1981 to 2010, the mixed, coniferous and birch forests on Changbai Mountain experienced increases in above-ground, below-ground and total carbon densities," such that "the total carbon densities of the three old-growth forests increased by 84, 29 and 55 tons of carbon per hectare, respectively," which increases were even greater than those of the old-growth forests studied by Harmon et al. (2004) and Luyssaert et al. (2008). Contrary to what had long been believed by many, Zhou et al. say their findings are "consistent with the suggestion of Luyssaert et al. (2008) and Zhou et al. (2006) that old-growth forests can continue to accumulate carbon," which fact has now been proven to be the case in several other studies as well.
Natural carbon sinks/carbon sequestered.
[T]wo U.S. researchers report that the results of their analyses indicate that the global land carbon sink is intensifying, and that it is doing so at a rate of 0.057 PgC/year/year, resulting in 1.65 PgC of additional uptake over the period examined (1980-2008), which finding, in their words, "is consistent with related findings in recent years," citing in this regard the studies of Cao et al. (2002), Cao et al. (2005), Le Quere et al. (2009) and Piao et al. (2009). As ever more anthropogenic CO2 is emitted into the atmosphere and the air's CO2 concentration rises ever higher, so too does the photosynthetic prowess of earth's terrestrial vegetation grow ever stronger, as the great global greening of the earth gains ever more momentum and sucks ever more CO2 out of the air and incorporates it into living biomass and soil organic matter, thereby muting the rate of global warming that would otherwise prevail in the absence of this important negative feedback phenomenon.
Global warming and carbon sequestering activities (negative feedbacks). Do northern peatlands serve as effective carbon sinks?
In the words of the authors, "carbon accumulation rates increased from 13.4 to 101.2 g C/m2/year during the last 8000 years," with a long-term average value of 27.3 g C/m2/year. This mean rate significantly exceeds the 18.6 g C/m2/year obtained for boreal, subarctic and arctic peatlands based on measurements made at 33 sites in the Northern Hemisphere (Yu et al., 2009); and they state that this relatively high accumulation rate "was likely caused by high primary production associated with a warmer and wetter temperate climate." Cai and Yu say their study implies that "northern peatlands can continue to serve as carbon sinks under a warmer and wetter climate, providing a negative feedback to climate warming," which is the exact polar-opposite of what has historically been claimed by the world's climate alarmists.
The authors write that "carbon sequestration as a climate change mitigation policy has received significant attention over the past several years," and they note that planting young fast-growing trees to absorb excess atmospheric CO2 "has recently gained potentiality, leading to identification of tree species with high CO2 sequestration capacity."
As their contribution to this endeavor, Rasineni et al. grew well-watered-and-fertilized five-week-old fast-growing Gmelina arborea [Greater sink capacity in G. arborea was associated with efficient carbon accumulation] trees out-of-doors at the University of Hyderabad, India, within open-top chambers maintained at ambient and ambient+100 ppm atmospheric CO2 concentrations throughout the 120 days of that region's spring and summer seasons, while they periodically made numerous measurements of the trees' physical properties and physiological prowess.
At the conclusion of the spring and summer growing seasons, the trees in the modestly-elevated CO2 chambers exhibited net photosynthetic rates that were 38% greater than those of the trees growing in ambient air; and aided by a significant CO2-induced reduction in leaf transpiration rates, the mean instantaneous water-use efficiency of the leaves of the CO2-enriched trees was 87% greater than that of the ambient-treatment trees. And as a result of these CO2-induced plant physiological benefits, the above-ground biomass of the CO2-enriched trees at the end of the growing season was found to be 45% greater than that of the trees growing in ambient air, while their total biomass (above and below ground) was 53% higher.
In discussing their findings, Rasineni et al. note that elevated atmospheric CO2 "persistently enhanced all the growth characteristics in Gmelina, including plant height, number of branches, internodes, internodal distance, aerial biomass and total plant biomass."’
It’s widely known that in earth’s past the climate was much different and CO2 levels have been much lower & higher. In addition, the global warming alarmists often, in misguided fashion assume that higher CO2 levels drive the temperature higher & that if CO2 levels continue to increase we’re doomed. They leave out a lot of factors, such as albedo and natural carbon sinks, even carbon sinks that are older than dirt.
It was once believed that significant carbon sequestration by forests only occurs when they are young and growing vigorously... Tan et al. (2011) suggest that it is not really so, reporting the fact that stands of trees with ages in excess of 200 years have been demonstrated by several research groups to act as carbon sinks in both coniferous and mixed forests, citing the work of Hollinger et al. (1994), Law et al. (2001), Roser et al. (2002), Knohl et al. (2003), Paw et al. (2004), Desai et al. (2005) and Guan et al. (2006). And they go on to buttress this claim by reporting the results of their own study of the subject, in which they employed an eddy covariance technique to examine the carbon balance of a more-than-300-year-old subtropical evergreen broadleaved forest that is located in the center of the largest subtropical land area of the world in the Ailao Mountain Nature Reserve (24̊32'N, 101̊01'E) of Yunnan Province in Southwest China.
There, in addition to their micrometeorologically-based eddy flux carbon budget estimation, the six scientists conducted a tree inventory of one hectare of forest located within the footprint of the eddy flux tower they employed in November of 2003 and again in November of 2007, after which they compared measurements of tree diameter at breast height (DBH) between the two times and employed site specific allometric equations to derive mean yearly biomass production from the measurements obtained at the two times, while they also assessed aboveground litter production via the amount captured each year in 25 litter traps that were randomly distributed within the one-hectare plot.
As a result of their efforts, Tan et al. determined that the mean annual net ecosystem production of the forest was approximately 9 tC/ha/year, which suggests, in their words, that "this forest acts as a large carbon sink." In addition, their inventory data indicated that about 6 tC/ha/year was contributed by biomass and necromass. And they report that approximately 60% of the biomass increment was contributed by the growth of large trees with breast height diameters in excess of 60 cm. Clearly, the old notion of old trees contributing next to nothing to global carbon sequestration is manifestly invalid.
Lane et al. (2013) write that biological soil crusts or BSCs "are made of cyanobacteria and other bacterial species, algae, lichens, mosses and microfungi," and "cover up to 70% (Belnap and Lange, 2003) of the soil surface of many drylands," which themselves "cover approximately 41% of the Earth's terrestrial surface and support more than one-third of the global population," according to Reynolds et al. (2007). And they note Elbert et al., (2012) indicate "the estimated total global carbon net uptake of BSCs has been approximated as 3.9 Pg/year (corresponding to approximately 7% of global net primary production uptake)."
Working with dynamic gas exchange chambers and cyanobacteria-dominated BSCs taken from the Kalahari Sand soils of southern Africa, Lane et al. set out to quantify short-term changes in carbon exchange (respiration and photosynthesis) of these BSCs when the air's CO2 concentration was doubled to approximately 800 ppm under two different wetting treatments of 2 and 5 mm of applied water, characteristic of "light and heavy rainfall events," respectively. In doing so, the seven UK scientists report the BSCs that received 5 mm of wetting increased their rate of carbon sequestration by approximately three-fold, and those subject to 2 mm of wetting increased their rate of carbon sequestration by a full order of magnitude!
In the final paragraph of their paper, Lane et al. state "BSCs have the potential to fix carbon under limited soil moisture availability and nutrient poor soils (typical of drylands)," especially in the case of BSCs dominated by nitrogen fixing cyanobacteria. And, therefore, they conclude "undisturbed BSC-covered drylands could be enhanced carbon sinks, and play an increasingly significant role in global carbon budgets in years to come."
The authors write that "about 17,500 years ago, atmospheric CO2 concentration started to rise from 180 ppm, levelled off at 280 ppm around 15,000 years ago, and broadly remained at 280 ppm until the Industrial Revolution," whereupon it began to rise again, recently reaching the 400 ppm mark, with many people expecting it to rise to 700 ppm by the end of the current century.
Wondering "whether the transition from current to higher CO2 can be thought of as a continuation of the past trajectory of low to current CO2 levels," Temme et al. "performed a meta-analysis of low CO2 growth experiments on 34 studies with 54 species," quantifying "how plant traits vary at reduced CO2 levels."
The four Dutch researchers report that "on average across all species," a 50% reduction in current atmospheric CO2 reduced net photosynthesis by 38%, intrinsic water use efficiency by 48% and total plant dry biomass by 47%.
Temme et al. conclude that in terms of carbon gain and whole-plant growth rate, responses to low CO2 are, in fact, somewhat more extreme than responses to high CO2, the latter of which gradually diminish in magnitude as the air's CO2 concentration rises higher and higher.
Again, if a Regressive goes bonkers & states, “are you sayin’ der CO2 levels could hit 100,000ppm & der plants would still do well?”
No, but it’s obvious from the evidence that CO2 levels increasing to 400ppm has been a boon to plant life – the hair on fire screeching about the end of mankind because of this is right up there w/ the insanity concerning an ice-free Arctic in the summer or a billion people dying in famines from crop failures (ala Paul Ehrlich) – which also didn’t happen.
Predict the Apocalypse, when it doesn’t happen, wait 10 years & do it again. Wash, rinse, repeat.
Old trees sequestering more CO2, despite their age. Higher CO2 levels are a boon to plant life, in this case the Japanese cedar (Chrytomeria japonica D. Don). So are trees >90 years of age in a carbon-neutral state?
Determined to find the answer to this question, Cheng et al. selected "twelve even-aged Japanese cedar stands along a stand age gradient from 37 to 93 years," with the aim of investigating tree density, mean diameter at breast height (DBH), basal area (BA) and canopy height and biomass carbon stocks, after which they went on to determine various relationships among these stand characteristics and tree biomass and stand age. Results indicated "present Japanese cedar plantations in the Xitou area of Taiwan are still developing," and "live tree biomass carbon stocks continue to accumulate beyond the normal rotation period or even beyond a stand age of 90 years."
In light of such data-driven facts, Cheng et al. conclude that "if Japanese cedar stands are not harvested, they can provide a carbon sink by storing carbon in tree biomass," such that "in association with the increases in tree DBH with stand age, maintaining this ageing process can be a forest management mechanism for the reduction of greenhouse gas emissions."
The idea that planting more trees instead of carbon taxes is a win, unless you despise economic growth like Bernie Sanders & Alexandria Ocasio-Cortez – folks who never made a dime in the private sector anyways.
Old trees are good at sequestering CO2, so higher levels of it won't be a problem for an aging forest. The global warmist kooks claim incorrectly that forests > century old, all things considered aren't even net carbon sinks. This is false. Climate models also failed miserably at this, assuming old forests weren't net carbon sinks, when they are.
Many of the examples in that extended article have been covered above.
Writing as background for their work, Wu et al. (2014) state that "changes in climate and atmospheric CO2 and nitrogen (N) over the last several decades have induced significant effects on forest carbon (C) cycling." But they go on to say that "contributions of individual factors are largely unknown because of the lack of long observational data and the undifferentiating between intrinsic factors and external forces in current ecosystem models." Thus, they set out to determine such. More specifically, working with over four decades (1956-2001) of forest inventory data that they obtained at 3432 permanent sample sites in maritime and boreal regions of British Columbia (B.C.), Canada, along with continuous flux measurements acquired at three chronosequence forest sites, Wu et al. describe how "growth enhancements were reconstructed and partitioned into contributions of climate, CO2 and N after removal of age effects," which they accomplished with the help of the process-based InTEC model (Chen et al., 2003) that considers the role of stand development when simulating various forest processes.
In the words of the eight scientists, results indicated "that climate change contributed a particularly large amount (over 70%) of the accumulated growth enhancement, while the remaining was attributed to CO2 and N, respectively." Wu et al. conclude their work by stating "climate warming is contributing a widespread and significant growth enhancement in B.C.'s forests," which they imply was a doubly-significant positive phenomenon, in light of the fact that in addition to the obvious growth enhancement benefit, "forest ecosystems that sequester carbon from the atmosphere play an important role in Earth's carbon budget by offsetting the increase in atmospheric carbon dioxide caused by fossil fuel emissions and land-use change."
We've been here before, old forests do a fine job of sequestering carbon.
According to Schrumpf et al. (2014), "temperate forests are assumed to be organic carbon (OC) sinks, either because of biomass increases upon elevated CO2 in the atmosphere and large nitrogen deposition, or due to their age structure." Yet they say "respective changes in soil OC and total nitrogen (TN) storage have rarely been proven," and "it is still unresolved where the carbon goes," citing Ballantyne et al. (2012) and Levin (2012).
In an attempt to resolve some of these issues, Schrumpf et al. "analyzed OC, TN and bulk densities of 100 soil cores sampled along a regular grid in an old-growth deciduous forest at the Hainich National Park, Germany, in 2004 and again in 2009." The three German researchers found that "concentrations of OC and TN increased significantly from 2004 to 2009, mostly in the upper 0-20 cm of the mineral soil, with average annual accumulation rates of 65 ± 29 g OC/m2/yr and 7.8 ± 2 g N/m2/yr." And they say the soil OC increases "are estimated to be ~10% of aboveground C gains," and that both the "soil OC and TN gains at the Hainich site seem to be due to increasing litter input, likely because the forest is accumulating biomass."
Schrumpf et al. conclude that their work "supports earlier studies indicating that the old-growth forest at the Hainich National Park is still accumulating OC in soil." And they say "it adds to the growing number of studies showing that soils of temperate forests are currently C sinks."
The 38 authors - hailing from 14 different countries: Argentina, Cameroon, China, Colombia, the Democratic Republic of the Congo, France, Germany, Malaysia, New Zealand, the Republic of Panama, Spain, Taiwan, the United Kingdom and the United States of America - write that "a widely held assumption is that after an initial period of increasing growth, the mass growth rate of individual trees declines with increasing tree size." But they then go on to demonstrate that this assumption is wrong.
Stephenson et al. say they "conducted a global analysis in which [they] directly estimated mass growth rates from repeated measurements of 673,046 trees belonging to 403 tropical, subtropical and temperate tree species, spanning every forested continent."
"For all continents," the international team of researchers found that "aboveground tree mass growth rates (and, hence, rates of carbon gain) for most species increased continuously with tree mass (size)," while further noting that "the rate of mass gain increased with tree mass in each model bin for 87% of species, and increased in the bin that included the largest trees for 97% of species." In fact, they say that "even when we restricted our analysis to species achieving the largest sizes (maximum trunk diameter >100 cm; 33% of species), 94% had increasing mass growth rates in the bin that included the largest trees."
In further discussing their findings, Stephenson et al. say that "large, old trees do not act simply as senescent carbon reservoirs but actively fix large amounts of carbon compared to smaller trees," adding that "at the extreme, a single big tree can add the same amount of carbon to the forest within a year as is contained in an entire mid-sized tree." And in this regard, they say their findings "further indicate that the extraordinary growth recently reported in an intensive study [Sillett et al., 2010] of large Eucalyptus regnans and Sequoia sempervirens, which included some of the world's most massive individual trees, is not a phenomenon limited to a few unusual species." In fact, they state that "rapid growth in giant trees is the global norm" and that "it appears to hold regardless of competitive environment."
This article (the first one) covers several topics, but I'm focusing just on observations concerning carbon sinks, in this case the Southern Ocean & CO2 uptake there. As pointed out by another poster, climate models were throwing cold water (pun intended) on Southern Ocean carbon sequestration, but they turned out to be incorrect. Surprise!
First up is a pair of papers, one by Swiss researcher Peter Landschützer and colleagues and the other by a team led by University of Colorado’s David Munro, that examined trends in the rate of carbon dioxide uptake in the Southern Ocean. In each case, the authors report that carbon uptake has been increasing there during the 21st century. This is good news.
Carbon dioxide uptake is basically the opposite of carbon dioxide emissions. As emissions increase and the atmospheric concentration grows, this puts a pressure on some carbon sinks to expand—notably the standing biomass of vegetation (through carbon fertilization) and the carbon content in the oceans (through Henry’s Law). In fact, the proportion of human carbon dioxide emissions that are being taken up by carbon sinks has been pretty constant for the past 150 years—meaning the sinks are expanding to offset a significant portion of our growing emissions.
Even though the behavior found in the new research paper is confirming expectations, it is worth highlighting in that over the past couple of years several papers were published and subsequently rose to prominence suggesting that the rate of carbon dioxide uptake by the Southern Ocean was slowing down and this was an indication that the carbon sink there was saturating. This had some segments of the climate alarmosphere in a tizzy (google “ocean carbon sink saturating” for some examples). The worry spiral went like this: CO2 emissions were leading to climate changes that were leading to less carbon update by the oceans which was leading to more CO2 in the atmosphere which was leading to more climate change which… you get the point. Uncontrolled positive feedback. The new findings pretty much stamp out this overheated concern.
From Landschützer et al.: “Several studies have suggested that the carbon sink in the Southern Ocean—the ocean’s strongest region for the uptake of anthropogenic CO2—has weakened in recent decades. We demonstrated, on the basis of multidecadal analyses of surface ocean CO2 observations, that this weakening trend stopped around 2002, and by 2012 the Southern Ocean had regained its expected strength based on the growth of atmospheric CO2.”
And from Munro et al: “Overall, [our results are] suggesting that the Southern Ocean is playing an ever-increasing role in taking up atmospheric CO2.”
So it seems that the apparent slowdown in the rate of carbon dioxide uptake in the Southern Ocean was most likely just a passing blip in what is natural variability—the level of which was previously underestimated. No cause for alarm.
Another blurb on old-growth forests, old trees sequestering more CO2 than previously thought. We've been here before, most ecokooks believe that as trees & forests age, their ability to sequester CO2 diminishes & they suffer a slow death. Not true.
Working in the Andean Cordilleras region of southern Chile, Urrutia-Jalabert et al. performed a series of analyses on tree ring cores they obtained from long-lived Fitzroya cupressoides stands, which they say “may be the slowest-growing and longest-lived high biomass forest stands in the world.”
Focusing on two of the more pertinent findings of their study, as shown in Figure 1 below, both the basal area increment (a surrogate for aboveground woody biomass accumulation) and intrinsic water use efficiency (a measure of drought resistance) of Fitzroya dramatically increased over the past century. Commenting on these trends, the authors write “the sustained positive trend in tree growth is striking in this old stand, suggesting that the giant trees in this forest have been accumulating biomass at a faster rate since the beginning of the [20th] century.” And coupling that finding with the 32 percent increase in water use efficiency over the same time period, Urrutia-Jalabert et al. conclude the trees “are actually responding to environmental change.” Indeed they are. Magnificently.
With respect to the cause of these favorable developments, the researchers state “we believe that this increasing growth trend…has likely been driven by some combination of CO2 and/or surface radiation increases,” adding that “pronounced changes in CO2 have occurred in parallel with changes in climate, making it difficult to distinguish between both effects.” Thus, it is clear that of the two views predicting the future of old-growth forests, the one most likely to occur (and which is actually occurring in the southern Chilean Andes) is the one in which the benefits of CO2 win out over model projections of climate-induced demise.
Research from the University of New Hampshire finds that the increase in carbon dioxide (CO2) emitted into the atmosphere by human activity and fossil fuels is altering the way forests grow and use water. Scientists found that trees in the United States respond to this rise in CO2 by using it to grow faster or by conserving water, depending on whether water is abundant or scarce. Their results differ from existing literature about how forests are helping to mitigate climate change…
The study, recently published in the Proceedings of the National Academy of Sciences, focused on the water-use efficiency of forests, which is the tradeoff between CO2 uptake during photosynthesis and water loss during transpiration, or the evaporation of water through plant leaves. Trees take in water and CO2to grow and they emit water vapor through pores in their leaves as a result; they can adjust the amount they take up or emit based on changing environmental conditions. Scientists previously suspected the increase in atmospheric CO2 levels would cause trees to lose less water, but this new research provides a more complicated story…
Water-use efficiency has been increasing in trees across the globe, but it was unclear how and why that’s been happening. The research team examined eight sites representing a range of water availability across the country. Researchers extracted 30-year tree cores from the two most dominant tree species on each site and analyzed them for carbon and oxygen isotopes — a technique not previously used for this application, but one that ultimately helped scientists discern what is happening with the trees… The researchers also found that different tree species have different capabilities and make different carbon/water tradeoffs. Because climate variability is increasing, the implication is that maintaining a diversity of tree species will help forests continue providing the climate mitigation benefits we rely on. Researchers hope the results will encourage scientists who model climate change to incorporate plants into their equations.
This may be one of the reasons why climate sensitivity to a hypothetical doubling of CO2 levels (I’ll explore that at a later date) is much lower than what the ecokooks have suggested. If they were right, we should be burning into oblivion (hypothetically speaking) right now, but the planet & its greenery is making adjustments for us.
It’s obvious from the wrong-headed predictions of doom from the ecokook lobby that the science is not settled & they may want to read some real science at some point.