tag:blogger.com,1999:blog-28837843.post589317705152378988..comments2024-03-19T07:10:27.303-07:00Comments on Quark Soup by David Appell: Crop Yields Under Global WarmingDavid Appellhttp://www.blogger.com/profile/03318269033139447591noreply@blogger.comBlogger17125tag:blogger.com,1999:blog-28837843.post-48138239628398704662018-05-17T03:51:52.876-07:002018-05-17T03:51:52.876-07:00Oops, wrong link.
C4 Plants, Examples, and C4 Fami...Oops, wrong link.<br /><a href="http://www.cropsreview.com/c4-plants.html" rel="nofollow">C4 Plants, Examples, and C4 Families </a>OnymousGuyhttps://www.blogger.com/profile/09132474758071908026noreply@blogger.comtag:blogger.com,1999:blog-28837843.post-30393999932800393032018-05-16T23:00:17.753-07:002018-05-16T23:00:17.753-07:00David --
1. I did address, "We also find t...David -- <br /><br />1. I did address, "We also find that the overall effect of warming on yields is negative, even after accounting for the benefits of reduced exposure to freezing temperatures." I addressed it by accepting the results of that paper, that the overall effect of warming on US wheat production would be negative.<br /><br />2. Droughts: you quote one paper. My view of climate change beliefs comes from the IPCC scientists. Please correct me if I am wrong, but AFAIK the IPCC has not stated as an agreed-upon scientific conclusion that global warming has already caused an increase in droughts or that it will definitely cause an increase in future droughts.<br /><br />Cheers <br /><br />David in Calhttps://www.blogger.com/profile/09068188536758619565noreply@blogger.comtag:blogger.com,1999:blog-28837843.post-49434141390498344442018-05-16T13:59:09.658-07:002018-05-16T13:59:09.658-07:00This will exhaust my knowledge of plant biology, b...This will exhaust my knowledge of plant biology, but at the American Chemical Society meeting, there was discussion of the different response to climate change of C3, C4, and CAM plants. See <a href="%E2%80%9Cwww.cropsreview.com/c4-plants.html%E2%80%9D" rel="nofollow">www.cropsreview.com/c4-plants.html</a>OnymousGuyhttps://www.blogger.com/profile/09132474758071908026noreply@blogger.comtag:blogger.com,1999:blog-28837843.post-31222537908365945532018-05-15T19:38:51.466-07:002018-05-15T19:38:51.466-07:00Robert Hass — "Nostalgia locates desire in th...Robert Hass — "Nostalgia locates desire in the past, where it suffers no active conflict and can be yearned toward pleasantly."David Appellhttps://www.blogger.com/profile/03318269033139447591noreply@blogger.comtag:blogger.com,1999:blog-28837843.post-17169325218724253282018-05-15T19:38:05.561-07:002018-05-15T19:38:05.561-07:00David in Cal said...
I loved and admired Scientifi...David in Cal said...<br /><i>I loved and admired Scientific American as a high school student in the late 1950's. You can choose not to believe me, but IMHO it is not the same magazine today.</i><br /><br />Everyone thinks things were better in their childhood. Memory isn't very objective.David Appellhttps://www.blogger.com/profile/03318269033139447591noreply@blogger.comtag:blogger.com,1999:blog-28837843.post-28625418820200029752018-05-15T19:36:20.672-07:002018-05-15T19:36:20.672-07:00George: Good points, thanks.
The yields discussed...George: Good points, thanks.<br /><br />The yields discussed here for corn and soybeans are increasing about 1.0-1.1%/yr. World population is increasing just a little faster (1.2%/yr) than that. US population is increasing about 0.7%/yr. David Appellhttps://www.blogger.com/profile/03318269033139447591noreply@blogger.comtag:blogger.com,1999:blog-28837843.post-4872298981408425582018-05-15T19:28:07.795-07:002018-05-15T19:28:07.795-07:00David, re: droughts:
Guest post: Climate change i...David, re: droughts:<br /><br />Guest post: Climate change is already making droughts worse, Benjamin Cook, CarbonBrief, <br />https://www.carbonbrief.org/guest-post-climate-change-is-already-making-droughts-worse/<br /><br />David Appellhttps://www.blogger.com/profile/03318269033139447591noreply@blogger.comtag:blogger.com,1999:blog-28837843.post-85925438663068018242018-05-15T19:24:45.521-07:002018-05-15T19:24:45.521-07:00David in Cal, you didn't address this:
"...David in Cal, you didn't address this:<br /><br />"We also find that the overall effect of warming on yields is negative, even after accounting for the benefits of reduced exposure to freezing temperatures."<br />-- "Effect of warming temperatures on US wheat yields," Jesse Tack et al, PNAS 4/20/15<br />http://www.pnas.org/content/early/2015/05/06/1415181112David Appellhttps://www.blogger.com/profile/03318269033139447591noreply@blogger.comtag:blogger.com,1999:blog-28837843.post-43369215055641570312018-05-15T19:23:50.707-07:002018-05-15T19:23:50.707-07:00David in Cal said...
David -- Your link doesn'...David in Cal said...<br /><i>David -- Your link doesn't fully refute my points. It looks at US only and wheat only, thus not dealing with two of the possibilities that I mentioned:</i><br /><br />Where is your own data proving your claims?<br /><br /><i>1. As the the US warms, some farms will switch from wheat to crops that do better under warmer weather.</i><br /><br />So people will just no longer need the crops for which the climate becomes too warm to grow? <br /><br /><i>2. Farming in very cold areas like Canada and Russia will surely benefit from a somewhat warmer climate.</i><br /><br />And those in the south who grow the same crops won't go out of business?David Appellhttps://www.blogger.com/profile/03318269033139447591noreply@blogger.comtag:blogger.com,1999:blog-28837843.post-65246860016338057452018-05-14T14:01:02.998-07:002018-05-14T14:01:02.998-07:00Over time, crop yields aren’t solely linked to cli...Over time, crop yields aren’t solely linked to climate conditions. Yields also vary according to international demand for crops. Farmers plant in anticipation of future demand, contracts for grains, ... <br />Yield is an ‘imprecise’ term to the extent that it also includes the production of seeds collected for planting. Rule of thumb: aim for three or more seeds being collected for every seed planted. Crop yields are affected by improved farming methods, improved strains of crop developed for characteristics more suited to growing conditions or with greater output of grain/plant.<br />Patterns of crop yields are changing – static around equatorial regions through to increasing towards polar regions. <br />Patterns of rainfall are changing – while rainfall increases with warming, it is not spread evenly over time or across crop cultivations. When it does rain, it can be torrential, causing flooding, with little or no follow up rain. And weeds with their short seeding cycle also benefit, more than crops, from warming and rain.<br />And on, and on, ... George Montgomeryhttps://www.blogger.com/profile/07042191140401441348noreply@blogger.comtag:blogger.com,1999:blog-28837843.post-83387730019968540922018-05-14T10:35:20.438-07:002018-05-14T10:35:20.438-07:00David -- Your link doesn't fully refute my poi...David -- Your link doesn't fully refute my points. It looks at US only and wheat only, thus not dealing with two of the possibilities that I mentioned:<br /><br />1. As the the US warms, some farms will switch from wheat to crops that do better under warmer weather.<br /><br />2. Farming in very cold areas like Canada and Russia will surely benefit from a somewhat warmer climate.<br /><br />I think I'm a fair amount older than you. I loved and admired Scientific American as a high school student in the late 1950's. You can choose not to believe me, but IMHO it is not the same magazine today.<br /><br />CheersDavid in Calhttps://www.blogger.com/profile/09068188536758619565noreply@blogger.comtag:blogger.com,1999:blog-28837843.post-17447697362660896672018-05-14T10:22:11.397-07:002018-05-14T10:22:11.397-07:00"The article doesn't address the advantag..."The article doesn't address the advantage of a longer growing seasons in cooler areas."<br /><br />"We also find that the overall effect of warming on yields is negative, even after accounting for the benefits of reduced exposure to freezing temperatures."<br />-- "Effect of warming temperatures on US wheat yields," Jesse Tack et al, PNAS 4/20/15<br />http://www.pnas.org/content/early/2015/05/06/1415181112<br />David Appellhttps://www.blogger.com/profile/03318269033139447591noreply@blogger.comtag:blogger.com,1999:blog-28837843.post-37059147870420783282018-05-14T10:19:16.260-07:002018-05-14T10:19:16.260-07:00"It's sad how Scientific American has dec..."It's sad how Scientific American has declined from the fine magazine it used to be."<br /><br />That's bullshit. Just because you don't like what it says, you smear it. Deniers feel the need to do that a lot.<br /><br />Yes, it is known that AGW will bring more drought. Even with more evaporation (there is already known to be more water vapor in the atmosphere from AGW.) <br /><br />Why does it matter, in an article like this, how much more warmer it will get? The fact is, no one knows, because no one knows how much CO2 we will admit, or the precise value of ECS. David Appellhttps://www.blogger.com/profile/03318269033139447591noreply@blogger.comtag:blogger.com,1999:blog-28837843.post-16772885218394664332018-05-14T09:29:12.536-07:002018-05-14T09:29:12.536-07:00David -- It's sad how Scientific American has ...David -- It's sad how Scientific American has declined from the fine magazine it used to be. The article you linked to is tendentious. It doesn't have an unbiased scientific POV.<br /><br />E.g., it asserts that climate change will bring drought, even though that consequence is not agreed-upon. In fact, there's a plausible theory that global warming might bring more ocean evaporation leading to higher rainfall. The article lacks numbers. How large is the effect of warming and the effect of higher CO2? The article doesn't address the advantage of a longer growing seasons in cooler areas. Nor does it adjust for the possibility that farmers will change their crop mixture to accommodate higher temperatures.<br /><br />Cheers<br />David in Calhttps://www.blogger.com/profile/09068188536758619565noreply@blogger.comtag:blogger.com,1999:blog-28837843.post-77204921125975835412018-05-13T14:49:44.837-07:002018-05-13T14:49:44.837-07:00David: But higher CO2 also brings higher temperatu...David: But higher CO2 also brings higher temperatures and changes to precipitation, neither of which are good for plants. Also, the nutritional quality of plants decreases with higher CO2.<br /><br />"Ask the Experts: Does Rising CO2 Benefit Plants?" Annie Sneed, Scientific American 1/23/18<br />https://www.scientificamerican.com/article/ask-the-experts-does-rising-co2-benefit-plants1/<br />David Appellhttps://www.blogger.com/profile/03318269033139447591noreply@blogger.comtag:blogger.com,1999:blog-28837843.post-9546966446024626432018-05-13T13:24:57.646-07:002018-05-13T13:24:57.646-07:00Higher levels of CO2 are beneficial to plants. Th...Higher levels of CO2 are beneficial to plants. That's why greenhouses put in extra CO2. I do not have figures immediately at hand, but I am confident that the positive impact of extra CO2 has so far been much larger than the (possible) negative impact of higher temperatures. <br /><br />CheersDavid in Calhttps://www.blogger.com/profile/09068188536758619565noreply@blogger.comtag:blogger.com,1999:blog-28837843.post-23973413323403292712018-05-12T02:16:40.693-07:002018-05-12T02:16:40.693-07:00I think I agree with you: https://mustelid.blogspo...I think I agree with you: https://mustelid.blogspot.co.uk/2018/05/crop-yields-under-global-warming.htmlWilliam M. Connolleyhttps://www.blogger.com/profile/05836299130680534926noreply@blogger.com