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Politics : Politics for Pros- moderated -- Ignore unavailable to you. Want to Upgrade?

To: The Dodgy Ticker who wrote (642047)	9/16/2017 2:18:04 AM
From: frankw1900	1 Recommendation Recommended By The Dodgy Ticker Read Replies (1) \| Respond to of 793868

Interesting article you referenced ( politico.com ). I'm reminded of a discussion I had with a person elsewhere a couple of years ago. He was complaining about both the oceanic over fishing and destruction of salmon habitat in the Fraser River system that had led to decreasing size of salmon spawning runs. I was intrigued because at that very time the Fraser was having the largest sockeye spawning run, as far as anyone could tell, in history! For a couple of weeks it was the cheapest animal protein the chinese super market was selling. I looked into it for a couple of reasons. First, it's certainly the case that the Fraser watershed is in better shape than it was 60 - 70 years ago. It doesn't release water as fast. Second a lot of work has been done to make sure migrating salmon can make the trip upriver reasonably unimpeded and salmon fishing on US and Canadian controlled waters is highly regulated. Third it was certainly the case the sockeye runs had been low. There was speculation the loss might have been caused by warmer water temperatures - AGW, right? Fish biologists gave an explanation. The fish that returned in the previous low migration years were malnourished and their survival rate was low. The bumper year fish were not malnourished . The explanation was that the N Pacific ocean had been fertilized by volcanic activity in Kamchatka leading to a burst of growth in the microbiota and thus the food chain. My point is it pays not to jump to conclusions. But I'll speculate on not much data (as in practically none), and jump to a conclusion which is definitely questionable. I last took a biology course over fifty years ago. Plants store starch in their leaves as an energy sink, (as analogously animals do with fat), and use it for their metabolic processes. So with increased CO2 and increasing metabolic rate the amount of starch in a leaf proportionate to other substances increases. (Can a grazing animal's microbiome cope? Probably, although it will have to eat a larger weight of leaves to keep its symbionts happy). With the increased metabolic activity the proportions and amount of K, P and N and trace minerals the plant requires will change. So the type of fertilization and other supplementation farmers do will need to change. Given the huge science driven change in agriculture world wide creating much greater yields nearly everywhere, it seems to me it's extremely likely scientists and plant breeders can breed/modify basic crops to be more nutritious despite the change in plant behavior due to increased CO2. It's a good thing US, Canada and Europe still have great aggie schools.

To: The Dodgy Ticker who wrote (642047)	9/16/2017 11:48:23 AM
From: DMaA	1 Recommendation Recommended By Bruce L Read Replies (2) \| Respond to of 793868

As I understand this abstract, plants globally are adapting to the increase of CO2. Which you'd expect in a world with an atmosphere constantly in flux. Atmospheric evidence for a global secular increase in carbon isotopic discrimination of land photosynthesis Significance Climate change and rising CO2 are altering the behavior of land plants in ways that influence how much biomass they produce relative to how much water they need for growth. This study shows that it is possible to detect changes occurring in plants using long-term measurements of the isotopic composition of atmospheric CO2. These measurements imply that plants have globally increased their water use efficiency at the leaf level in proportion to the rise in atmospheric CO2 over the past few decades. While the full implications remain to be explored, the results help to quantify the extent to which the biosphere has become less constrained by water stress globally. Abstract A decrease in the 13C/12C ratio of atmospheric CO2 has been documented by direct observations since 1978 and from ice core measurements since the industrial revolution. This decrease, known as the 13C-Suess effect, is driven primarily by the input of fossil fuel-derived CO2 but is also sensitive to land and ocean carbon cycling and uptake. Using updated records, we show that no plausible combination of sources and sinks of CO2 from fossil fuel, land, and oceans can explain the observed 13C-Suess effect unless an increase has occurred in the 13C/12C isotopic discrimination of land photosynthesis. A trend toward greater discrimination under higher CO2 levels is broadly consistent with tree ring studies over the past century, with field and chamber experiments, and with geological records of C3 plants at times of altered atmospheric CO2, but increasing discrimination has not previously been included in studies of long-term atmospheric 13C/12C measurements. We further show that the inferred discrimination increase of 0.014 ± 0.007‰ ppm-1 is largely explained by photorespiratory and mesophyll effects. This result implies that, at the global scale, land plants have regulated their stomatal conductance so as to allow the CO2 partial pressure within stomatal cavities and their intrinsic water use efficiency to increase in nearly constant proportion to the rise in atmospheric CO2 concentration. m.pnas.org