Two comments: Most freshwater ecosystems are P, not N, limited, which might account for absence of an N-response in aquatic systems.
Yes, partial stomatal closure under higher CO2 can result in higher water use efficiency but there is no evidence to support the idea that this will fully compensate for altered water availability. John Harte Distinguished Professor of the Graduate School Ecosystem Sciences ERG/ESPM University of California Berkeley, CA 94720 [email protected] > On Jun 18, 2022, at 2:45 AM, Ye Tao <[email protected]> wrote: > > Hi all, > > Thanks to Renaud for the link, and Stephen and John for initiating this > discussion. I personally find the framing of CO2 as a toxin unhelpful and > will likely contribute to further confusing the public to delay action on > decarbonization. One would have a hard time convincing ecologists, > agricultural scientists, and chemists from condoning the ultra-simplified > message that is simply contrary to experimental observations. > > I remember literature from a few years ago establishing that the perturbation > to the N:C ratio was less pronounced for aquatic plants such as macroalgea, > with many species maintaining nitrogen levels upon increasing growth rate due > to CO2 fertilization. There has also been a lot of work on identifying and > improving rice cultivars that are able to maintain or improve N:C ratio in > addition to reaping the benefits of CO2 fertilization. I don't have my > complete list of literature on this computer but here is a recent paper > <https://ecologicalprocesses.springeropen.com/articles/10.1186/s13717-020-00238-5>. > Global water use efficiency of plants have most certainly benefited from > CO2 fertilization <https://www.pnas.org/doi/10.1073/pnas.1816686116>, > offsetting a part of the increasing evaporative loss due to warming.Thermal > stress is by far the most serious threat, and that elevated CO2 is actually > helping to curb some of the impact > <https://www.researchgate.net/profile/Jin-Hyeob-Kwak/publication/226982321_Dry_matter_and_nitrogen_accumulation_and_partitioning_in_rice_Oryza_sativa_L_exposed_to_experimental_warming_with_elevated_CO2/links/00b7d53b9c94ea0341000000/Dry-matter-and-nitrogen-accumulation-and-partitioning-in-rice-Oryza-sativa-L-exposed-to-experimental-warming-with-elevated-CO2.pdf>. > > > John mentions herbivory changes. Another mechanism by which herbivory > increases is increased basal energy requirement by herbivors as a result of > temperature increase. This effect also extend to predators, thus > establishing heat as the unique universal climate stressor. > > Ye > > On 6/17/2022 12:48 PM, SALTER Stephen wrote: >> Hi John >> That is good to know. I had heard that greenhouse owners thought it useful >> to increase CO2. I expect that they would also be adding other stuff. But >> the question I wanted people to think about was having CO2 levels below >> preindustrial. >> Stephen >> >> From: John Harte <[email protected]> <mailto:[email protected]> >> Sent: Friday, June 17, 2022 5:42 PM >> To: SALTER Stephen <[email protected]> <mailto:[email protected]> >> Cc: Renaud de RICHTER <[email protected]> >> <mailto:[email protected]>; healthy-planet-action-coalition >> <[email protected]> >> <mailto:[email protected]>; Healthy Climate >> Alliance <[email protected]> >> <mailto:[email protected]>; Healthy Climate >> Initiative<[email protected]> >> <mailto:[email protected]>; >> [email protected] <mailto:[email protected]> >> Subject: Re: [geo] RE: Carbon Dioxide Is a Pollutant. Please Help Establish >> That Fact. >> >> This email was sent to you by someone outside the University. >> You should only click on links or attachments if you are certain that the >> email is genuine and the content is safe. >> Actually people have “consulted the vegetables” about this. Carefully >> controlled CO2 manipulation experiments generally reveal that when plants >> are subjected to higher CO2 levels, with everything else, including water, >> N, and P, remaining at ambient levels, then either the C:N ratio of plant >> tissue increases and as a result herbivory increases so that herbivores can >> get their needed nitrogen, or not much at all happens because of water >> limitation. In both cases there is little or no net increase in production. >> >> There are of course circumstances in which increasing CO2 can augment >> production but they are unlikely to be found in the real world, especially >> in a world in which water supply has been altered by the climate effects of >> increasing CO2. >> >> >> John Harte >> Distinguished Professor of the >> Graduate School >> Ecosystem Sciences >> ERG/ESPM >> University of California >> Berkeley, CA 94720 >> [email protected] <mailto:[email protected]> >> >> >> >> >> >> >> >> >> >> >> >> On Jun 17, 2022, at 9:31 AM, SALTER Stephen <[email protected] >> <mailto:[email protected]>> wrote: >> >> Hi All >> Has anybody consulted the vegetables about carbon dioxide being a pollutant? >> Some of my best food . . . >> Stephen >> >> From: [email protected] >> <mailto:[email protected]> >> <[email protected] >> <mailto:[email protected]>> On Behalf Of >> Renaud de RICHTER >> Sent: Friday, June 17, 2022 4:25 PM >> To: healthy-planet-action-coalition >> <[email protected] >> <mailto:[email protected]>>; Healthy Climate >> Alliance <[email protected] >> <mailto:[email protected]>>; Healthy Climate >> Initiative <[email protected] >> <mailto:[email protected]>> >> Subject: Carbon Dioxide Is a Pollutant. Please Help Establish That Fact. >> >> This email was sent to you by someone outside the University. >> You should only click on links or attachments if you are certain that the >> email is genuine and the content is safe. >> Greenhouse gases must be legally phased out, US scientists argue >> https://www.theguardian.com/environment/2022/jun/16/greenhouse-gases-must-be-legally-phased-out-us-scientists-argue >> >> <https://www.theguardian.com/environment/2022/jun/16/greenhouse-gases-must-be-legally-phased-out-us-scientists-argue> >> >> You can sign the petition >> https://cprclimate.org/about/actions-campaigns/petition-to-epa/ >> <https://cprclimate.org/about/actions-campaigns/petition-to-epa/> >> >> ---------- Forwarded message --------- >> De : James Hansen <[email protected] <mailto:[email protected]>> >> Date: ven. 17 juin 2022 à 16:53 >> Subject: Carbon Dioxide Is a Pollutant. Please Help Establish That Fact. >> >> >> >> View this email in your browser >> <https://mailchi.mp/caa/carbon-dioxide-is-a-pollutant-please-help-establish-that-fact?e=bee29348b6> >> >> A PDF of this Communication is available on my webpage >> <https://columbia.us1.list-manage.com/track/click?u=0ebaeb14fdbf5dc65289113c1&id=4b161c144d&e=bee29348b6>, >> along with prior Communications and other resources. >> >> <~WRD1838.jpg> >> <https://columbia.us1.list-manage.com/track/click?u=0ebaeb14fdbf5dc65289113c1&id=61aef7a59e&e=bee29348b6> >> >> Tweet to your followers >> <https://columbia.us1.list-manage.com/track/click?u=0ebaeb14fdbf5dc65289113c1&id=63506ffd2f&e=bee29348b6> >> >> <~WRD1838.jpg> >> <https://columbia.us1.list-manage.com/track/click?u=0ebaeb14fdbf5dc65289113c1&id=9ac18d788d&e=bee29348b6> >> >> Share on your Facebook >> <https://columbia.us1.list-manage.com/track/click?u=0ebaeb14fdbf5dc65289113c1&id=5f2311ae81&e=bee29348b6> >> >> <~WRD1838.jpg> >> <http://us1.forward-to-friend.com/forward?u=0ebaeb14fdbf5dc65289113c1&id=c3d4e889f2&e=bee29348b6> >> >> Forward to your friends >> <http://us1.forward-to-friend.com/forward?u=0ebaeb14fdbf5dc65289113c1&id=c3d4e889f2&e=bee29348b6> >> <~WRD1838.jpg> >> >> Fig. 1. Global surface temperature relative to 1880-1920 mean. >> >> >> Carbon Dioxide Is a Pollutant. Please Help Establish That Fact. >> >> May 2022 Temperature Update >> >> 17 June 2022 >> James Hansen, Makiko Sato and Reto Ruedy >> >> CO2 fits perfectly EPA’s definition of a chemical substance that presents >> “an unreasonable risk of injury to health or the environment.” Congress, >> with strong bipartisan agreement, established the Toxic Substances Control >> Act (TSCA; acronym pronounced tosca) in 1976 and – with bipartisan support >> again – strengthened the law in 2016. This law has been used successfully to >> phase out or reduce many substances, including asbestos, lead in paint, >> PCBs, and CFCs[1]. EPA has broad latitude in how to achieve reductions and >> can work with other agencies for that purpose. >> >> Citizens may petition EPA on the need to address a pollutant under TSCA. EPA >> must respond to a petition within 90 days. Yesterday several of us[a] >> delivered to EPA a petition[2] for phase out of greenhouse gas (GHG) >> pollution to restore a stable and healthy climate. The prospects for EPA to >> accept their obligation will be much improved if we can present them with an >> impressive list of endorsers of the petition. Please examine the petition >> and consider adding your name as an endorser of the petition >> <https://columbia.us1.list-manage.com/track/click?u=0ebaeb14fdbf5dc65289113c1&id=2fb4f391a2&e=bee29348b6>. >> United States citizens are especially relevant as endorsers, but there is >> also value in support of world citizens for what is a global problem. >> >> Fig. 1, our global temperature update, is a reminder that the world is >> headed inexorably toward hotter conditions, as the cooling effect of the >> current strong La Nina barely got global temperature down to the increasing >> trendline of global temperature. The 12-month running-mean temperature is >> already heading toward the next global record that will occur in conjunction >> with the next El Nino.[3] >> >> >> [a] Dan Galpern (Hansen’s long-time attorney, who worked for months on this >> petition), Donn Vivianni (retired EPA scientist who alerted us to the TSCA >> potential for greenhouse gases), Lisa Van Susteren (physician, writer and >> world’s leading authority on the psychiatric effects on young people of >> daily news about growing climate impacts while adults do little to alter the >> course), and atmospheric chemist John Birks, and Hansen. (Co-petitioner >> climate accountability analyst Richard Heede could not be present for the >> delivery to EPA). >> >> <~WRD1838.jpg> >> >> Fig. 2. Cumulative 1751-2020 fossil fuel carbon emissions (tons C/person; >> 2020 populations). Horizontal lines are multiples of the global mean. The >> order of individual nations from left to right is based on cumulative >> national emissions. >> >> Fig. 2 is a reminder that the United States is most responsible for the >> fossil fuel CO2emissions that are the dominant cause of human-made climate >> change. We can also be leaders in the solution if we begin to make the >> polluters pay via a steadily rising carbon fee with the funds distributed to >> the public (a conservative, bipartisan approach). Of course, the timing has >> to be right. The best time was years ago. If the rising price had started a >> decade and a half ago, when Obama and Biden were elected and had the >> opportunity afforded by a global financial emergency, U.S. emissions and >> fossil fuel use would be down at least 40% and we would have plenty of >> excess energy capacity to help Europe with its near-term fossil fuel energy >> demands. >> >> Evoking TSCA will not demand an instant carbon price – the timing needs to >> be sensible. However, it will be a huge step, putting us on a course with >> the potential to address the climate problem globally. The huge U.S. economy >> allows the opportunity to affect the global approach via border duties on >> products from countries that do not have a carbon fee. >> >> Other policies also need to be sensible. Whose idea was it to immediately >> halt import of Russian fuels? The predictable effect was to raise the price >> of fossil fuels, causing huge pain in the West – and in the rest of the >> world, which thus must choose to look the other way as Ukraine suffers. >> >> What courage. When Putin says that he will get angry if we send the weapons >> that Ukrainians need to defend their nation, our leaders quake and instead >> take actions that sacrifice Ukrainian lives, raise our own energy costs, and >> increase Putin’s profits needed to wage war. >> >> It’s expecting a lot to ask young people to understand what their political >> leaders are doing, but as we mentioned in last month’s temperature update >> <https://columbia.us1.list-manage.com/track/click?u=0ebaeb14fdbf5dc65289113c1&id=eb7444bd9d&e=bee29348b6>, >> that seems to be necessary, and young people have tremendous potential >> political power. More on that later. >> >> <~WRD1838.jpg> >> >> Hansen, Van Susteren, Vivianni and Galpern about to deliver petition (Birks >> was photographer). >> >> >> [1] CFCs hardly seemed toxic. In early advertisements, the chemical industry >> showed a person breathing in “harmless” CFCs, but then we discovered their >> impact on the ozone layer and their greenhouse gas effect. Likewise, CO2 was >> initially thought to be a beneficial gas; and so it is, if you limit the >> dosage. >> [2] Viviani, D.J., J. Birks, R. Heede, L. Van Susteren, J.E. Hansen, Climate >> Science, Awareness and Solutions, and Climate Protection & Restoration >> Initiative, Petition to the Environmental Protection Agency to Phase-out >> Greenhouse Gas (GHG) Emissions and Remove Legacy GHGs, 16 June 2022. Part I >> <https://columbia.us1.list-manage.com/track/click?u=0ebaeb14fdbf5dc65289113c1&id=a3eadf6339&e=bee29348b6> >> and Part II >> <https://columbia.us1.list-manage.com/track/click?u=0ebaeb14fdbf5dc65289113c1&id=1a22f9b679&e=bee29348b6> >> (Select scientific and economic considerations). >> [3] The promised discussion about the record current planetary energy >> imbalance will need to wait a while. >> >> >> Donate to CSAS Columbia >> <https://columbia.us1.list-manage.com/track/click?u=0ebaeb14fdbf5dc65289113c1&id=928d0a0d50&e=bee29348b6> >> >> Donate to CSAS, Inc. >> <https://columbia.us1.list-manage.com/track/click?u=0ebaeb14fdbf5dc65289113c1&id=bcedf79104&e=bee29348b6> >> >> >> FOLLOW US HERE >> >> <~WRD1838.jpg> >> <https://columbia.us1.list-manage.com/track/click?u=0ebaeb14fdbf5dc65289113c1&id=68286aa474&e=bee29348b6> >> >> Subscribe to my future Communications >> <https://columbia.us1.list-manage.com/track/click?u=0ebaeb14fdbf5dc65289113c1&id=889aa1bfce&e=bee29348b6> >> <~WRD1838.jpg> >> <https://columbia.us1.list-manage.com/track/click?u=0ebaeb14fdbf5dc65289113c1&id=349a9d7da7&e=bee29348b6> >> >> CSAS EI Website >> <https://columbia.us1.list-manage.com/track/click?u=0ebaeb14fdbf5dc65289113c1&id=51ede4fa96&e=bee29348b6> >> <~WRD1838.jpg> >> <https://columbia.us1.list-manage.com/track/click?u=0ebaeb14fdbf5dc65289113c1&id=901835be4a&e=bee29348b6> >> >> CSAS, Inc. 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