The Grapes of Climate Wrath

Recently, this billboard was spotted in the DC Metro Subway by Heartland Senior Fellow Edward Hudgins. 

Photo by Ed Hudgins

The implication is that more carbon dioxide—produced from driving your car instead of taking the Metro—will have the effect of making grapes smaller and therefore affect wine production levels and perhaps quality. This 2014 paper, “The impact of climate change on the global wine industry: Challenges & solutions,” suggests a wide range of negative effects on the wine industry due to “climate change” resulting from increased CO2, but it also offers solutions.

The source of this concern is an abundance of research articles published in recent years that suggest crop yields will be reduced as ambient atmospheric CO2 concentrations increase. Yet in spite of these warnings, we have clear evidence that crop yields of all types throughout the planet have dramatically increased in the past 50 years, while CO2 levels have increased. Some of these  trends are due to better farming and irrigation practices, some due to selective breeding to make better varieties that have higher yields and increased resistance to diseases, and, yes, some of it is due to increasing CO2 in our atmosphere that allows for more efficient photosynthesis and better internal plant water management.

After all, isn’t the latter reason why many greenhouse operations inject highly elevated levels of CO2 into their greenhouse operations? Here is an excerpt from a Canadian report on Carbon Dioxide in Greenhouses:

Carbon dioxide (CO2)is an essential component of photosynthesis (also called carbon assimilation). Photosynthesis is a chemical process that uses light energy to convert COand water into sugars in green plants. These sugars are then used for growth within the plant, through respiration. The difference between the rate of photosynthesis and the rate of respiration is the basis for dry-matter accumulation (growth) in the plant. In greenhouse production the aim of all growers is to increase dry-matter content and economically optimize crop yield. CO2 increases productivity through improved plant growth and vigour. Some ways in which productivity is increased by COinclude earlier flowering, higher fruit yields, reduced bud abortion in roses, improved stem strength and flower size. Growers should regard COas a nutrient.

That said, I looked specifically at how grape size would be affected and found a University of California Davis paper that specifically addressed this issue. In “Berry Size and Yield Paradigms on Grapes and Wines Quality,” the researchers concluded:

Myths are creative explanations similar to scientific hypotheses, and when not subjected to scientific tests they can become perfect hypotheses that explain perfectly what they are supposed to explain. Here we evaluated with data two longstanding and widely held paradigms of viticulture for which there had previously been little quantified observations: large berries and high yields are inferior. The data are clear in that the results of independent means of changing berry size and yield produced qualitatively different results. This renders the generalizations asserted in both of the paradigms untenable. The high yield, low quality paradigm may be applicable to environments in which sugar accumulation is limiting factor because reducing crop generally increases the rate of increase in sugar concentration in the remaining clusters. We draw these conclusions about the dependence of composition on yield and berry size: the viticultural practices used to control yield in a vineyard are more important than the yield values per se in determining the quality of the resulting grapes and wines; and the environmental conditions determine berry size are more important the size per se in determining the quality of the grapes and resulting wines.

In other words, the practices of the viticulturalist have more of an impact on the quality of berries than anything else, and larger grapes sizes aren’t necessarily better for wine production, despite what the myths promoted by the DC Metro might suggest.

So, whom would I trust on wine? The DC metro or the vitculturalists and researchers themselves?

I’ll go with the vitculturalists every day of the week and twice on Sundays. Salud!

73 thoughts on “The Grapes of Climate Wrath

    • Larger is better for selling – the right sugar content is better for eating

      Regards –

      Former sweet cherry grower

      • This talking about wine not table grapes.

        The existing paradigm is that large bloated grapes ( excess watering or fertilising to maximise per acre yield ) are inferior in quality for wine production. One key factor is sugar concentration which determines final wine alcohol level. Over irrigation is basically a means of watering down your wine.

        The cited text says this is “not necessarily” the case since other factors are important. I don’t see it saying it is incorrect.

        Smaller grapes are generally a good thing , so the climate worriers can stop worrying about the quality of the wine going down as the world burns around us.

        • Have you ever wondered why your meat shrinks so much when cooked (It does normally, yes. But do you see how much water comes out?). Water is added to increase weight to, literally, pump up volume (Price).

        • “The cited text says this is “not necessarily” the case since other factors are important. I don’t see it saying it is incorrect. ”

          Yeah, not incorrect, it is just BS.

  1. The best European and North American wines are produced in the hottest weather. The Viking warm saw wild grapes growing in Nova Scotia. Fermentation produces CO2, and if the subway wasn’t a filthy, polluting, multi-billion dollar cost sink, it would still be a miserable ride — even without a functionally illiterate poster.

    • We have wild grapes growing well, now, here in southern New Brunswick. The best area I have found is on Goat Island in Grand Lake.


    • You have to try and hold your breath for the entire journey to be truely green. Greta tried it on a recent train trip but she found she had to sit down at times on the floor to recover.

      • Crowded and confined spaces increase CO2 concentrations in the range 800ppm/v +. In the picture I saw, she was all alone, apart from the photographer. So much for over-crowded public transport she was complaining about.

        Try Tokyo, Japan, or Honk Kong, or the Victoria line in London.

  2. Surely it is better to have small berries for those high tannin wines that you cellar? I’m guessing that is where the myth started. Old production methods required high tannins for wines to keep for long periods.

    • Why would one “Keep” wine? seems . . . . counterintuitive, counterproductive, and a crime against fellowship.

      • Just like the fellow who has more cars than he can drive or the woman that has more shoes than she can ever wear, we tend to buy more of the things we love than makes sense to someone who does not share our appreciation. I don’t find a cellar with a couple thousand bottles of wine, counter intuitive nor an obstacle to fellowship. Quite the opposite, it all makes total sense to me. No one other than my family has ever seen the wine, it is just a pile of boxes. A good friend at the age of 95 asked me for advice as he ordered twenty cases from me. “But, Tom….how well will it age?

  3. …paper, …suggests a wide range of negative effects on the wine industry due to “climate change” resulting from increased CO2, …

    Well of course it does.
    Bless their little hearts.

  4. Sorry to be off topic a bit, but grapes of wrath fits.

    Surprise! Greta Thunberg BIOPIC reveals cameras were rolling from day one of her ‘viral’ rise

    Teenage environmental activist Greta Thunberg is the subject of a forthcoming documentary film – made by a crew that has followed her since the early days of her school strike. Still believe her rise to fame was an accident?

  5. It’s a joke, friends. “Wine” not take Metro? Get it? I live in DC, there are a half-dozen variants on this theme, all with a lame pun as a kicker. The point is to get you to ride the train.

  6. The logical conclusion is that the grape growers should ferment fewer grapes to reduce their CO2 emissions so there will be more grapes.

  7. ‘Could’

    So by exactly the same logic CO2 ‘could’ (and probably will to be honest) make grapes bigger.

    So… again by the same logic, why emit with pride?

    CO2 Positive and PROUD

    • But more CO2 will probably increase the sugar levels as well. After all, that is the product of photosynthesis.

  8. I feel some personal research coming on! I’m going to jump into this with both feet! My wife won’t stop me this time. Isn’t science wonderful?

  9. As long as hops are OK, I’m not going to get hopping mad.

    (Are they so desperate that they’re trying to scare the winos now!!)

  10. I don’t think any among us doubt it GT’s ‘meteoric’ rise is a highly orchestrated campaign, we just wonder just how much she is in control of her own destiny, or manipulated by those around her. Probably a bit of both.

    I always pitied the children of doorstepping zealous religious groups who dragged their offspring around with them to try to guilt us into their spiel. They never got anything more than a polite ‘no thanks’. I doubt that chastising the parents or guardians for their behaviour would have swayed the children much, better they see the ‘client’ as polite and pleasant, not the sinners their parents try to portray.

  11. ” many greenhouse operations inject highly elevated levels of CO2 into their greenhouse operations”

    plants get all the press….try growing algae or plankton cultures without it….can’t be done

  12. For red grapes the flavor is in the skins. High quality requires small even berry size. Overcropping on the other hand is simply a matter of adding water.

  13. “This 2014 paper, “The impact of climate change on the global wine industry: Challenges & solutions,” suggests a wide range of negative effects on the wine industry due to “climate change” resulting from increased CO2, but it also offers solutions”

    The explanation of the oddity that all climate impacts are bad, that all bad things are climate impacts, and that in the science of climate impacts there is no good impact and no attribution failure in the face of large uncertainties is that climate science is not unbiased objective scientific inquiry but agenda driven to provide the rationale needed for a pre-determined climate action agenda. The climate action agenda is not made to fit the science but rather it is the science that has to fit the climate action agenda

  14. Well if this is a warning about the vintage trampled out where the grapes of climate wrath are stored, then I am going to go and loose some fateful ‘carbon’ with my terrible swift Ford…

    I’ll get my coat

  15. Hmmm… CO2 is turned into sugar in grapes, whether they go into wine production or not. More CO2 means a higher sugar content and subsequently, a better fermentation process. If they don’t have enough sugar to go into the fermentation vat and then the barrels, they are sold as table grapes, as well as turned into raisins. And frankly, the smaller the grape when it ripens, the more concentrated the sugars are.

    So what was the complaint, again? Are these people really so dumb that they desperately HAVE to let us know just how little they know about plants, for starters, and the whole grape/wine business overall?

    This is ridiculous. What a bunch of quacks they are!!! They never miss a chance to let us know how very – well, uninformed – they are, do they? (‘I’m being nice. Not sure they’re worth the effort.)

    Now if only I could find one last bottle of Lost Cellars White….

    • If they don’t have enough sugar to go into the fermentation vat . . . sold as table grapes

      Not likely. Most table grapes sold in the USA (elsewhere, I haven’t a clue) are seedless.
      Classic wine types**, such as Sangiovese or Cabernet Sauvignon , have small seeds (pips). Watermelon seeds are better for a spitting contest.

      Low sugar musts can be mixed with those with higher sugar or sugar can be added. Local laws apply.


      • Red grapes and black grapes are not seedless, and if they don’t have a high enough sugar content, they frequently end up in the table grapes bin.

        Oddly, I know people who make their own wine and they add sugar to the fermentation process, getting a rough, and sometimes very heady, but very friendly wine. Goes well with apple-smoked cheddar cheese….

  16. While they may think Climate Change shrinks grapes, Climate Change actually shrinks the human prefrontal cortex.

  17. What devalues Australian grapes is insufficient water (environ-mental flows see fresh water flushed down arid inland Australia’s biggest river system to keep a once largely-saline coastal lake system sufficiently fresh to please the green mind, if such a thing is possible).

    That and smoke chemicals from bushfires (thanks to green policies that allow non-green vegetation to build up to catastrophic levels).

    Our recently increased carbon dioxide levels are overwhelmingly good for plants.

    Now that is proven science.

  18. We have wild grapes growing well, now, here in southern New Brunswick. The best area I have found is on Goat Island in Grand Lake.


  19. The Earth has stupidly (as far as life is concerned) been sequestering most of its atmospheric CO2 into the lithosphere for the last hundred fifty million years.

    At the end of the last glaciation atmospheric CO2 levels dipped into the 175-185 ppm range. Terrestrial plants die en masse below 150 ppm.

    Global warming occurs at the end of glaciation, at remarkable rates sometimes.

    Interglacial maximums typically occur during the first temperature escalation out of the “ice box”. These Optimums are from 5 to 7 C warmer than now. That amount of warming (only 10,000 years ago) would trigger far more positive H2O “greenhouse” feedback than CO2 @ 800 ppm (doubling) would generate. There was no runaway warming then (warming ALWAYS peaks coming out of glaciations… no Venusian boiling oceans)…and there would be no runaway warming now from the far less forcing available from even a doubling of CO2.

  20. Grapes:
    Love hot weather.
    Love long warm seasons. i.e. the later the season, the higher the sugar levels.

    Grapes detest rain near the harvests! Unfortunately grapevines channel all a lot of the rain they soak up right into the berry, swelling berry sizes and diluting both the flavors and sugars.
    Think of it as adding a lot of water to the grape juice before fermentation. It results in a watered down product with less flavor.

    DC Metro has a history of not being the smartest of advertisers on their commuter trains.

    • “DC Metro has a history of not being the smartest of advertisers on their commuter trains.”

      But people are constantly bombarded with the global warming, CO2-is-bad meme, and it winds up being normalized. We need something to counter that. A media presence, if possible.

      I know Heartland tries the occasional billboard, but have they ever done a 20 second spot on Fox News, for example? Why not advertise WUWT, too? Put out something like “The Polar Bears are doing just fine. Find out on the world’s most viewed site on global warming and climate change:“.

      It wouldn’t take much to get to a larger audience, make some waves. I’d contribute to a fund to get something, anything, out there to help counter the WWF, Greta, NPR, BBC, and the DC Metro.

  21. Just as long as Metro doesn’t go into wine making. Imagine the results.

  22. As long as my cheese is okay, I think I will be fine. Cheese doesn’t need a good wine to be delicious.

    Oh wait, cheese requires something from a cow’s stomach. And the only way to get rennet from the cow’s stomach is to slaughter it. And since anything that makes like enjoyable causes global warming, I guess I can’t have cheese either. No wine, no cheese, what ever will I do?

  23. It’s big lie repetition, as simple as that. And the only remedy is big truth repetition.
    “[I]n the big lie there is always a certain force of credibility; because the broad masses of a nation are always more easily corrupted in the deeper strata of their emotional nature than consciously or voluntarily; and thus in the primitive simplicity of their minds they more readily fall victims to the big lie than the small lie, since they themselves often tell small lies in little matters but would be ashamed to resort to large-scale falsehoods.

    “[T]he most brilliant propagandist technique will yield no success unless one fundamental principle is borne in mind constantly and with unfiagging attention. It must confine itself to a few points and repeat them over and over. Here, as so often in this world, persistence is the first and most important requirement for success.” – Adolph Hitler

  24. A few years ago. we used to visit a greenhouse for our weekly supply of tomatoes and cukes. We often parked nose in to a very large tank of ice coated Co2- appaently sending its life giving gas into luscious red beefsteak tomatoes and cucumbers.
    Obviously Mother Nature wasn’t supplying enough Co2 to enable plants to reach their God -given potential. Those who want to restrict Co2, are denying the ability to feed mankind. That seems to fit the meaning of “criminal negligence”.

  25. Those ignoramuses know nothing of the amour of the grape.
    Smaller berries produce a wine with ‘deep purple colour.
    Aromas of rich dark currants, nectarine skins, gushing blackberry, but lots of fragrant tobacco, rich soil, white flowers, smashed minerals and metal.
    Medium-bodied and saucy but racy acidity stabilises the wine nicely with the robust tannins.
    Deep red currants and ripe cherries, laden with mocha, loamy soil, charred herbs, pencil shavings, roasted hazelnut.
    Dense like characters that make it perfect for cellaring’.

  26. I’m for introduction of CO2 tax for farmers.
    Those free riders, farmers and wine producers, are using CO2 I have paid and therefore own, without paying m any dividend.
    Where is my fair share of income?
    Have you seen how rich they became? How big where all the SUVs they drove in recent protests?
    I deserve bigger wheels too.

  27. When I lived in New Zealand and in a very nice wine growing region north of Wellington called the Wairarapa. Featherston to be exact, the whole region was growing grapes, and some olives. It is a very good wine region, specifically for whites due to soil chemistry however, it is on the “wrong” side of the Rimutakas and that is not good, not good so much as grape growers have to hire helicopters to fly over vineyards so as to stir up still and “frosty” air to prevent frost damage to crops. Well, that was the gig when I lived there. Maybe it is better there now since Ardern has banned CO2.

  28. Once again, the problem is that we do not drink wine made from grapes grown in the Parallel Universe of Broken Climate Models.
    In the real world, I suggest you consult:
    The Wine Spectator
    The Wine Advocate
    James Suckling
    Incidentally, The University of California, Davis (Department of Oenology?) is able to craft custom vines that are specifically suited to growing wine grapes in the various microclimates in California.
    If you think “Climate Change” is having an adverse effect on wine production, check the ratings of Chateau Mouton Rothschild for the past 20 years.

  29. As a daily DC Metro rider, that’s not the only warmunist ad running. There’s also the one exhorting you to ride Metro so you can make hurricanes less powerful. Also, beer making is being threatened. Then there’s the obligatory save the North Pole meme.

  30. The Romans reportedly grew grapes for wine on the island of Great Britain. Wine grapes more recently have been grown in Minnesota. Cold, more than CO2 seems to be a larger problem. Growers in Minnesota may have been under the impression the climate there was going to warm in recent years. Not enough, it appears. Note sections on “Bad Weather” and “Extreme Crop Losses.”

  31. The idea that a a degree or two will devastate viticulture is arrant nonsense.

    Look at the example of Spain, using French and Australian planting styles and drip irrigation to replace the Arid resistant traditional method of vine spacing, they’ve managed to take yields from 20hl/ha to over 100 hl/ha

    They’ve also managed to achieve this with more northern varietals such as Cabernets and Syrah’s against the background of a warming climate.

    So should there be a warming in Burgundy or Bordeaux be assured there is a wealth of practical experience and proven methods that will allow them to cope.


  32. Pretty much anyone who knows anything about the plant metabolism also knows that increased CO2 gives us much-improved plant growth. Talk to greenhouse growers – they add CO2 to the air in their greenhouses. In all logic, more CO2 must lead to bigger grapes, not smaller ones.

  33. When I first came to the Napa Valley there were only a few nights that I could sit outside without wearing a sweater. That is still the case. Warm days and cool nights are a key climatic factors in producing fine wine, but soil and vineyard site still determine ultimate wine quality, The change in climate here has been small. The change in viticulture has been dramatic. From rootstocks that promote ripening, grape canopy management, irrigation management, elimination of vine virus, re-and planting of more appropriate clones of grape varieties. In the winery all manner of techniques have change over the decades. Many tools remain in the box if conditions change.

    Dramatic differences in wine quality from vintage to vintage have lessened while the quality of the best wines has only improved. A large part of this is advancement in technique and a smaller part of this has been a more dependable and advantageous climate. Nights are still chilly, days are still warm, and we are better able to harvest our grapes before the damaging rains that arrive in the fall. Yes, some winemakers have used this advancement to produce high alcohol, dark, intense and dense wines, that some of us do not prefer and consider overblown, but this is only enabled by the number of options now available in the winemaker’s playbook.
    As a winemaker in the Napa Valley for five decades I have only seen a general improvement in wine quality from 1969 to the present. I expect this to continue indefinitely.

  34. There’s an aspect of this CO2 debate that I have not seen discussed, and I find intriguing.
    Firstly, there appears to be a consensus that water vapour is more of a greenhouse gas than CO2.
    Secondly, water evaporates from large bodies of water, precipitates, and a large portion of it is
    returned to the atmosphere. Some trees process larges volumes of water, hence the clearing of
    “invasive species” in South Africa.
    Thirdly studies have shown that under increased atmospheric CO2 conditions trees have less
    stomata and use less water (i.e. reduced evapotranspiration).
    This would appear to indicate that CO2 is a limiting nutrient for those trees, but that is not the
    million dollar question.
    That question would be: If CO2 is reducing water vapour in the atmosphere, and water vapour
    is a more potent greenhouse gas than CO2, is the increased CO2 not cooling, rather than heating, the atmosphere? Comments welcome…

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