Many fascinating eco-climatological issues are raised in these discussions, but for now I just want to chime in on the forest infestation topic.
First, the mountain pine beetle (Dendroctonus ponderosae) problem in Colorado is nearly certainly not the result of warmer winters, as commonly asserted, but rather longer summers allowing multivoltine reproduction, or in other words several breeding cycles per growing season. This has allowed the reproductive rate and net population growth rate to go through the ceiling. Here's a good paper on this: http://www.jstor.org/stable/pdf/10.1086/665007.pdf. from The American Naturalist. Moreover, the evidence for a multidecadal trend toward longer growing season in the regions where the infestation is worst is strong. Secondly, while that pest species is native to N. America, in many instances the extent of damage a pest species will do is closely tied to whether it is an exotic pest or not. Native trees are in general more resilient to native pests for obvious reasons. Without examining such factors as the nature of the climate change in a region, and the biogeography of the pest species, I think it is difficult to draw conclusions regarding the extent to which forest management explains variability in outbreak intensity. John Harte Professor of Ecosystem Sciences ERG/ESPM 310 Barrows Hall University of California Berkeley, CA 94720 USA [email protected] On Jul 7, 2015, at 6:55 AM, Anastassia Makarieva <[email protected]> wrote: > Dear Ron > > Thank you for your further comments. I admire your dedication to save the > Earth -- my own research is driven by the same aspiration. Indeed we appear > to disagree on quite a few things. The aim of my responses to your comments > below is not to (immediately) persuade you but rather to show that a > different (and coherent) view on the available evidence exists that would > justify a different way out of the global climate crisis -- at the same time > ruling out some popular ways as implausible or even dangerous. I think that > knowing that such a view does exist could be useful even if you later choose > to totally neglect it. > > Best wishes, > Anastassia > > > [RWL: With apologies for this final question (based on reading no urgency on > your part about getting back ASAP below 350 ppm of CO2): > Can you explain how your above negative position on bio-based carbon > removal relates (or not) to the often-stated concern that high-latitude > countries believe they could benefit from a warmer climate?] > I do not think that any country in the world will benefit if the global > climate change continues. Moreover, I regret very much that in my country > (Russia) the discussion of global (and regional) environmental problems in > the society is practically non-existent. (And where it sporadically occurs, > it is totally uninformed.) I am doing what I can to improve the situation. > > [RWL3: I have to say I also can “ not quite believe” that natural forests > can handle all the “anthropogenic atmospheric carbon” (i.e mostly fossil > fuels). I look forward to reading more on this.] > > I used this example [with an unexpected carbon sink from natural forests > found] to illustrate that applying the limiting principles to natural > ecosystems [which is what absolutely all current model projections are based > upon] is not a feasable approach. If this sink (of over 1 GtC/yr) had not > been found, people would have said: this is what we had expected! The fact > that it was found, however, did not change the mainstream use of the limiting > principle, mostly because, I think, the latter is what I call "conceptually > simple". > > [RWL11: Biochar proponents rarely use the loaded word “plantations”. Much > more apt to talk about adding a second income stream beyond “food”. I am > disappointed that we are apparently not going to agree on anything related to > biochar. I think you are not appreciating how badly we need to get back to > 350 ppm CO2 and giving too little credit to science. Converting pasture > land back to a forest managed for combined energy and biochar outputs seems > to me to be a much better option than letting that same land return somehow > to an ill-defined “natural” state.] > > In recent years with our novel propositions I got used to reprimands like me > "giving too little credit to [mainstream] science". Having published several > detailed critiques of studies that serve as bricks to what people perceive as > the mainstream, I'd say that my attitude is, rather, that of a critical > insider who does not forget about the major weaknesses in several fields when > drawing far-reaching global conclusions. > > In my view, we badly need to re-gain climate stability. As I said before, > returning back to 350 ppm (by whatever means) does not automatically > guarantee us the desired outcome. Moreover, some efforts aimed at 350 ppm can > produce an opposite outcome. As we all know, global temperature is governed > not only by CO2, but also by clouds which influence both the albedo and the > greenhouse effect. We know that clouds are hugely important, but we do not > know how they impact the climate. [Nothing of the kind -- the more [or less] > clouds, the better.] So if, in a global biochar initiative, we create large > areas that will make a global impact on the cloud cover, this impact can be > destabilising (i.e. leading to more warming). My grounds to think that it > will most likely be destabilising stems from the appreciation that in the > climate system there are serious positive [i.e. destabilising] physical > feedbacks associated with water vapor and that there is no ready explanation > to the thermal stability of climate unless we take natural ecosystems into > account as [very complex] climate regulators. If one accepts that climate > regulation is a complex, non-random regional process formed in each region > during millions years of evolution of natural ecosystems, there are no > grounds to expect that some random collections of species optimized for high > NPP and allowed to operate on large areas will perform that regulation. > > [RWL7: I can’t agree that the fossil 9 Gt C/yr is less important than our > (horrible) “destruction of those natural systems” nor that “.. we would not > have seen any global warming." I also can’t agree that biochar fits this > last phrase “artificial biological system” warning nor that the 9 Gt C/yr of > fossil input is beyond the capability of the existing “natural ecosystem” to > handle the job. I also know of no model that suggests your “would not have > seen” position to be plausible, and so hope you can cite any such model. In > any case we have harmed that natural system, so I still believe biochar has > the potential to “quickly” (i.e. > 5 GtC/yr) get us back to 350 ppm, if > (globally) we take on that task.] > > There are no models that would show that with intact ocean and forests we > would not have seen any global warming even at current CO2 levels -- because > we have lost most of natural forests and disturbed the ocean well before we > could have studied and quantified in detail their global climate regulatory > potential. However, the luft of global temperature sensitivity to carbon > emissions in modern models is very large and via manipulation with the > aerosols' response to growing CO2 concentration the models can be tuned to > simulate almost any response, including [possible] absence of any warming due > to the compensation by other mechanisms that control surface temperature. > > [RWL9: I agree that many forest systems have been handled badly. There are > also some commercial forests that have been progressively more productive. > So, I feel you are giving too little credit to what can be done by skilled > foresters. All land cannot possibly be left to go wild - especially in the > short time we have to do something about getting back to 350 (or less) ppm > CO2. The only rationale I have seen for the huge beetle kill in my own > state of Colorado is a lack of sufficient cold-enough winter days (caused by > CO2). Southern Canada is already experiencing beetle kill; presumable > Russia will follow soon.] > > That bark beetles attack North American forests because of global warming is, > in my view, another "conceptually simple" icon conveniently spread in public. > In my comment I said that managed forests at a certain point become fragile > to any disturbance. You imply that Colorado forests would not have died from > beetles if the temperature were lower. My point was different: I state that > even at current temperatures the forests may not have died (ie beetles could > not have destroyed them) if they had not been weakened by decades of > exploitation, artificial management and suppressed natural recovery > processes. This can be illustrated by comparing managed vs (relatively) > unmanaged forests at the same latitude. E.g. in Alaska in 1990s there was a > huge spike of bark beetle infections (Berman et al. 1998, Figure 2 on p. 32), > while at the same latitude in Eastern Fennoscandia (Russia), where forest > management regime is drastically different, none were registered (Gromtsev > 2002): > "The survey of forests in the regions however revealed no entomological > invasions (Yakovlev et al. 2000). In spite of the significant age of the > surveyed forests, lack of management, frequent fires and a relatively high > abundance of potentially damaging species, stem pests mainly attack already > dead and dying trees, the die-back of which was induced by other reasons." > > I bet you will be unable, using published literature, to disprove my > statement. It is an alternative explanation of a conspicuous pattern. It has > important implications. It means that if you add interference to natural > forests (with very good intentions), they will lose stability and can, at a > certain point, themselves become a (powerful) destabilizer. > > It is also clear that to blame global warming (rather than industrial forest > management) for forest die-back via beetle invasions is in the interest of > the forest industry. > > [RWL10: Perhaps, but there is considerable growing evidence that biochar > improves soil functioning and health - although I agree we cannot yet predict > when, where and how much. No reasonable farmer or forester is going to apply > biochar on a late scale without testing; testing for a given char, soil, and > plant species competition is cheap and easy. The experience with terra preta > soils of a large (4-5x?) increase in biochar-blessed land values near Manaus > Brazil says a lot about climate regulation; there is zero conflict between > biochar’s climate and soil improvement properties.] > > You appear to imply an equality sign between high primary productivity and > efficient climate regulation. It is not the same. High productivity per se > does not guarantee any stabilising climate impact. If we talk about carbon, a > carbon sink is ensured when there is a positive difference between ecosystem > production and decomposition of organic matter: i.e. more carbon is > synthesized than decomposed. So if you just grow productivity, decomposition > can grow as well (or more), with an arbitrary net outcome. The high ecosystem > productivity on terra preta soils says us nothing about whether these > ecosystems can act as a larger or lower carbon sink: we need to know how > decomposition behaves. > > Furthermore, a healthy state of natural ecosystem is not the one with maximum > productivity -- it is the state with optimal productivity allowing maximum > environmental homeostasis. By analogy, a healthy state of human body is not > the state of fever (when our metabolic rate is the highest) -- it is a state > when the metabolic rate (and temperature) is normal. Fever (or increased > productivity) is a reaction of the human body (ecosystem) on a disturbance > aimed to compensate it soonest possible. In this perspective, the > human-derived biochar in the Amazon was perceived by the ecosystem as a > disturbance which it continues to handle by gradually amending the biochar > properties. Note that 500+ years is not a very large period if counted in > tree life spans. > > 4b. One reason to favor biochar is the presumed/claimed increase in NPP > (Terra preta soils giving double or more NPP today (500+ years after > placement) in the Amazon). Should biochar-amended soils then have roughly > double annual evaporation per unit area as well? > > Generally yes, evaporation is proportional to NPP. However, for the biotic > pump we do not just need high evaporation. There is no simple rule of thumb: > the more evaporation, the better. > > Consider how the biotic pump works: the forest has a certain store of > moisture in soil. It takes some of this water and transfers to the atmosphere > by evapotranspiration. Then this moisture condenses, pressure falls, and > winds are driven towards the condensation area. For the system to continue > working, the winds must bring moisture enough to compensate for the > continuous runoff. If the needed moisture does not arrive, the forest will > get drier. > > We thus can see that the biotic pump is a clever investement of moisture: the > forest must spend it wisely to gain more in return than it has spent. No > hopes that a random collection of species optimised for high NPP (i.e. just > for high spending rates) will achieve that goal. E.g. eukalypts and poplars > evaporate a lot, but, not being able to arrange a sufficient moisture inflow, > they just waste the existing ground water until it is totally depleted. > > 4c. More biochar should also give better rainfall retention (less runoff). > Should this lead to more (and more even) annual evaporation (and therefore > more beneficial inland rainfall)? > > Better rainfall retention means more moisture in soil [it is a store]. It > does not impact steady-state runoff [it is a flux, not a store], which is > equal to the net import of moisture via the atmosphere. > > 4e. Generally speaking, biochar feedstock is not hugely critical, aside from > wanting large annual NPP. Probably species could be added or favored that > have maximum particulate release. Can you give any cite to trees that appear > best or worse in this regard? We hear of preferences for micnthus and (very > tall perennial) grasses. Might any also be good particulate emitters? > > See 4b above. We do not need good particle emitters. We need optimal particle > emitters, which emit the right particles at right time in right amounts. > Given their abnormal complexity, we cannot predict these properties a priori. > All we do know is that natural forests ARE such optimal emitters. Chances > that a random collection of species will do the same are, in my view, > non-existent. > > 4h. The SRM side of this list would presumably want to better understand > any changes in albedo that you have been able to work on - especially cloud > brightening, but possibly there are some higher altitude solar radiation > aspects as well. There is tremendous uncertainty on even the sign of the > impact of clouds in climate modeling. Can your work so far address any of > the uncertainties related to the many different kinds and heights of clouds - > on both long and short wavelength radiation? > > Clouds are primarily a product of low-level air circulation: they form when > moist air ascends and cools. In our work we propose that the driving > mechanism behind air circulation and convection is not temperature > differences (which is how it is parameterized in models). It is a very big > claim. If we are correct, this has enormous implications for the problem of > climate stability and the cloud feedback on surface temperature. We have not > yet performed any such analyses -- we are concerned formulating the new > theory in quantitative terms in the first place. But one relevant result that > we obtained is that there is a critical point around 50C where any kinetic > energy generation on Earth would stop (and, hence, most clouds should > disappear). > > 4i. You have stated that ocean evaporation is much smaller than that over > land. However, some on this list are interested in fostering ocean biomass > (more than the biochar community). The Sargasso sea for instance may have > species that emit similarly to trees. Mangroves are fast growing and need > reforestation many places. Should these shoreline biomass species be favored > at all? > > More correctly, I said that over the forest under proper circumstances > (instantaneous) evaporation can be much greater than over the ocean -- > because of high leaf area index (larger evaporative surface per unit ground > surface area). On average, long-term evaporation is limited by solar > radiation, so the ratio between oceanic and forest evaporation is not > directly proportional to leaf area index. > > Shoreline forests are very important as the connect the continental part of > the biotic pump with the moisture source (the ocean). It is a high priority > to preserve/restore coastal forests. > > 4j. I have visited a few island and coastal sites that have a regular cloud > (and I think regular predictable rainfall). Might there have been any that > can relate to either the removal of forests - or reforestation? I am trying > to think through luture low cost experiments - as island > countries/communities are those most supportive of CDR; I understand that > your theory is normally working over 100’s of kilometers. > > Yes, it would be good to have some experiment for restoration of biotic pump > and an island, where natural forest can still be recovered, might be a good > place to start. > > Thank you again for your interest. > Best wishes, > Anastassia > > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.
