Claim: Winter Cover Crops May Exacerbate Global Warming

Guest essay by Eric Worrall

Warmer winters are now a bad thing…

Winter crops may cause unintended warming, study says

A new study shows that fields with crop cover showed significantly warmer winter temperatures than fields with no cover or just short stubble.

Author: Cory Reppenhagen
Published: 11:02 AM MST January 5, 2019
Updated: 6:54 PM MST January 5, 2019

Farmers grow crops or leave dying vegetation in their fields over the winter. A new study from the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, shows they may be causing unintended climate warming.

“When they stick out above the snow, they can warm winter temperatures,” Danica Lombardozzi, a plant ecophysiologist with NCAR, said.

Lombardozzi headed this new study that showed warming caused by crop cover absorbing high amounts of sunlight. She used computer modeling to find that fields with crop cover showed significantly warmer winter temperatures than fields with no cover or just short stubble.

“On average, that increased air temperature by 5.5 degrees Fahrenheit or 3 degrees Celsius. A significant temperature rise,” Lombardozzi said.

Read more: https://www.9news.com/article/weather/winter-crops-may-cause-unintended-warming-study-says/73-638fe14a-1997-4ad6-9eac-244d6bfc30c7

The abstract of the study;

Cover Crops May Cause Winter Warming in Snow‐Covered Regions

D. L. Lombardozzi G. B. Bonan W. Wieder A. S. Grandy C. Morris D. L. Lawrence
First published: 12 September 2018

Cover crops, grown between cash crops when soil is fallow, are a management strategy that may help mitigate climate change. The biogeochemical effects of cover crops are well documented, as they provide numerous localized benefits to farmers. We test potential biogeophysical climate impacts of idealized cover crop scenarios by assuming that cover crops are planted offseason in all crop regions throughout North America. Our results suggest that planting cover crops increases wintertime temperature up to 3 °C in central North America by decreasing albedo in regions with variable snowpack. Cover crops with higher leaf area indices increase temperature more by decreasing broadband albedo, while decreasing cover crop height helped to mitigate the temperature increase as the shorter height was more frequently buried by snow. Thus, climate mitigation potential must consider the biogeophysical impacts of planting cover crops, and varietal selection can minimize winter warming.

Plain Language Summary

Planting cover crops is an agricultural management technique in which crops are grown in between cash crop seasons when the soil would otherwise be fallow. Cover crops provide many local benefits to farmers and can increase carbon storage in soils. In this study, we test how planting cover crops in all agricultural regions in North America can change wintertime temperatures. Model simulations suggest that cover crops can warm winter temperatures up to 3 °C in regions with variable winter snowpack, such as central North America. Planting cover crop varieties that are less leafy or get buried under the variable snowpack can help to minimize winter warming. Our study suggests that the climate mitigation potential of cover crops may be offset in these regions if cover crop varieties are not carefully selected.

Read more: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL079000

My question – why didn’t someone try to get some field measurements? I mean you can understand in some cases it would be difficult to set up a field study, but in this case taking field measurements would have been trivial; ask farmers for their temperature data. A polite request to farmers interested in the study not to plant some of their monitored fields with winter cover crops would have completely avoided the need to rely on models.

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79 thoughts on “Claim: Winter Cover Crops May Exacerbate Global Warming

  1. I would think that in the US most folks living above the Mason-Dixon line (further south is probably more realistic) would welcome warmer winters.

  2. This tells us that the government is throwing too much money into trying to manufacture a story where one does not exist. What is the difference if winter crops change the average temperature in Saskatchewan fields from -25ºC to -23ºC? How exactly is the planet worse off?

    On the plus side, ridiculous stories like this one is pushing the public towards giving rationalism a chance.

  3. “…why didn’t someone try to get some field measurements? … taking field measurements would have been trivial; ask farmers for their temperature data … would have completely avoided the need to rely on models…”

    Typing in “r u n” [Enter] is a lot easier, and the grant check cashes just the same

      • I do real world “testing” on my farm in southern Kansas every year.

        The study is correct (at least on the sign) that the areas with ground cover are warmer in the winter.

        However, the opposite effect occurs in the spring. The bare earth absorbs more sunlight and has less insulation. The effect is noticeable as the days lengthen prior to the equinox. I have had several years where the cover areas stayed frozen solid for weeks after the exposed dirt was thawed.

        We even use this process for wildlife enhancement. We disked a large swath around a section of the native grass meadow two falls ago. Last March, we saw 14 deer and 30 turkeys feeding in the disked area – with no other wildlife visible elsewhere. The insects hatch earlier in the bare dirt (for the turkeys). Likewise, the earliest forbs emerge first in the warmed soil (for the deer).

        • Your comment is much more convincing than the government-funded “model simulations.” Before the whitecoats set about “carefully selecting” cover crops I certainly hope they consult someone with practical experience, like you.

        • Sum-bitch! Someone actually using weather observations to improve upon nature.

          Quick! Send in the EPA to shut him down.

      • Hey! My Airfix Spitfire I got when I was 8 was pretty correct!

        I mean I had to make my own Brrrrralllll AckAckAckAck noises, but apart from that, COMPLETELY a real Spitfire.

        (My 109E I made a bit of a dog’s of. Totally messed up the paint. Inconvenient truth. Let’s not talk about that one.)

  4. “decreasing albedo in regions with variable snowpack”

    I’ve been told the Earth’s albedo is a constant: 0.3 – and that’s the value used in equations concerning the Earth’s temperature.

    Now we’re recognizing that the Earth’s albedo is dynamic? Can we re-evaluate those equations?

    • “Now we’re recognizing that the Earth’s albedo is dynamic? Can we re-evaluate those equations?”

      Only if the resulting headline reads “… Worse than Previously Thought.”

    • Yes Thomas:
      This figure of 0.3 Albedo and that of 0.62 for Emissivity are both back engineered figures and have slipped into being constants for computers. Both, however are variable and should not be used for predictive purposes. Otherwise you are locked into circular logic.
      The same applies to the purported 1.6 watts/sq.m greenhouse effect, which is also a logical error if one extracts one’s brain from out of the computer.

  5. Baby it’s cold outside. Let’s plant cover crops all over our yard to help keep us warmer this winter.

  6. “…why didn’t someone try to get some field measurements? … taking field measurements would have been trivial; ask farmers for their temperature data … would have completely avoided the need to rely on models…”

    Maybe Lombardozzi et al are afraid that a field test would not give the political correct answer.

    • Maybe Lombardozzi et al are afraid that a field test would not give the political correct answer.

      Certainly their pencils have erasers.

        • That reminds me of the old joke about the Mathematicians’ expense consists of pencils and erasers. And the Philosophy department is even cheaper- they don’t need erasers.

  7. The comparison should not have been cover-crop-planted fields with no-cover fields but cover-crop-planted fields with fields that were not farmed. Before human agriculture there were native plants that look more like cover crops than stubble.

    • In much of the world, thanks to modern farming techniques being able to raise more crops per acre, the total number of acres being farmed has been dropping over the last 40 decades or so.
      According to this study, allowing plants to grow on these fields that used to be farmed creates warming.
      I wonder how much of the recent warming is due to this, rather than CO2?

        • That big movements in temperature preceed increases in CO2 in the ice cores is not evidence that CO2 has no impact on temperature. It is only evidence that on these scales, we can’t see the influence.

    • This is pure sensationalized crap. While actual data gathering would have been useful, what exactly could be determined? That lower albedos increase energy absorption…we know this already.
      This is strictly an albedo issue. Fresh white snow cover has an albedo of .95 (it reflects 95% of incoming solar radiation). ANYTHING that decreases this albedo such as dust, exposed ground cover, detritus, etc. will increase that patch of ground’s temperature due to the higher energy absorption.
      They might as well have said “plant growth extending above the snow cover reduces the albedo” and the paper might not have been published due to the “duh!” factor.

  8. Gee, I always thought warmth from the earth escaping during the winter was a good thing and would think capturing it during winter would be beneficial even though the amount would be extremely miniscule. So grateful we have people being payed to show how wrong I was. (sarc)

  9. This again?

    There have been articles on this site related to this phenomenon over the years. It’s not new knowledge, to scientists or naturalists.

    So why was this even a question? Moreover, the bigger question is, “so what?” Does this local phenomenon really have a global effect? Does it even have a net effect?

    If the albedo (reflectivity) is low (vs snow cover), and that’s for the short winter days, then the emmissivity is likely much higher (vs snow cover), so the warmer daytime temps radiate into space in the long evenings, especially w/ the dry winter air.

    Net effect? Nil.

    Except that the crops stored some of that deadly CO2! Which is a big deal, right?

    • The primary reason for winter cover and “no till” practices is to retain soil moisture. Secondary reason is erosion control from winter winds and from early spring rains that occur prior to the emergence of the spring crop.

      Storing more CO2, retaining more soil moisture, controlling erosion – those farmers sure are stupid! /s off

    • “Moreover, the bigger question is, “so what?””

      BINGO! That goes for the entire Global Cooling, Ozone Hole, Global Warming/Climate Change media feeding frenzy over the last 50 years.

  10. Wow, there is just no pleasing these clowns. Sound agricultural practices encourage the use of winter manures to protect the soil from winter erosion and plow under in the spring for increased fertility. This entire study is a waste of money and time, total hogwash.

  11. Better living through computing. NCAR (as we know) is one of the epicenters of climate alarm-ism. Hard to miss the implication that this study leans toward land use changes as a possible cause of temperature changes.

    Believe many here have been pointing that out for a long time

  12. Excerpted from commentary:

    She (Danica Lombardozzi) used computer modeling to find that fields with crop cover showed significantly warmer winter temperatures than fields with no cover or just short stubble.

    “WOWEEEEEE”, ….. I betcha ifffen Ms Lombardozzi had employed female modeling for her “cover verses no cover” study that her results would have been directly opposite. 🙂

  13. Eureka !
    I always thought that end of the ice age allowed farming to spread to middle and higher latitudes.
    Oh, no it was not. It was farming that warmed-up the globe and brought the end to that pesky ice age.
    Nobel prize due to Lombardozzi et al, no doubt about it. /sarc

    • Wow, so it was just poor farming practice that doomed the Greenland settlements. It makes more sense all the time /sarc

  14. In other words, cover crops return the land to something a bit closer to what was normal prior to man clearing the land to plant crops.

  15. Experiment:
    Measure the temperature of the soil within a foot of a well plowed road road, one that plows the snow off as necessary to keep it snow free in any northern state or provence. Then measure the soil temperature ten or twenty yards/meters away from the road where the snow has accumulated to a depth of a foot or so.
    Has been my experience that it is easier to dig a hole in the ground when there is a foot or so of snow on the ground where you dig than digging in a spot where the ground has had no snow cover for several weeks (assuming same local air temperature).

    • Farmers in the U.S. Midcontinent region also run that experiment with slightly different variables.

      Winter wheat with snow cover (for insulation) has no problem surviving a bitter 3-day incursion of polar air.

      However, winter wheat that is fully exposed to the cold air will frequently exhibit frost burn (and subsequent reduced yields) in Kansas.

      I think the wheat farmers farther north can suffer full mortality of portions of their planted winter wheat when it lack a snow blanket.

  16. “On average, that increased air temperature by 5.5 degrees Fahrenheit or 3 degrees Celsius. A significant temperature rise,” Lombardozzi said.
    ≠===========
    Yikes!! Not only do we need a carbon tax. Now we need a farm tax. Otherwise Canada will become too hot to support life as we know it.

    Forget winter vacations to Mexico and the Caribbean. Come up to Tuktoyaktuk in January to enjoy the tropical delights of the Arctic ocean and Northern Lights.

    With the new highway 10 in place it is a quick drive from the sweltering heat of America in winter. Just turn right at Frostbite Falls and head north. Can’t miss it.

  17. I blame the Chinese. By making all of our products for funny-money, Americans have nothing useful to do. This woman actually has a job, a car, food and a place to live.

  18. Exactly right. Research funds are the primary goal as subsidy farming is the reason for unnecessary energy sources. I agree with our new radical Congressperson Ocasio-Cortez that the USA needs a Green New Deal to defund the Green Old Deal. Well… that may not be a perfectly accurate presentation of her views but why quibble over small details.

  19. The model used in this study shows this area of study might have some possible merit. However, it rests on the scientifically unsound assumption that warming is bad. Further, I hardly hear any adults complain about winter being too warm. Most of us would be quite happy to warmer winters.

    And the up to 3 degrees C of warming? Sounds way, way, way to high. But at least they are working on something other than CO2 as a possible cause of warming.

  20. And what is genuinely depressing & sad about this entire thing is that albedo changes on the ground would explain the whole Global warming Change thing. And some.

    Question to them:

    There are 60 million+ New People arriving on Planet earth every year.
    What are they eating? Where are they living? How can they simply vanish? Is it really possible that over the last 50 years all those new houses, cities and farms have made precisely zero affect on Earth’s albedo?

    How can scientifically educated people have such closed minds and blinkered eyes.
    Then they put this junk behind a paywall.

    What A Mess we are in……

    • They have closed minds and blinkered eyes precisely because they are educated in a system which values Plato over Aristotle. Whereas Plato thought the best way to understand the world was to sit in a chair (or recline on a couch) and think about it, Aristotle insisted it was necessary to go out and measure it.

  21. Yet where is the concern about runnoff and water quality? Having winter crops helps stabilize the soil and uptake nutrients that would otherwise find itself polluting our nation’s waters. Water quality and conservation are much more important than some “study”.

  22. Why would someone do a computer-game-only study on something so stupendously easy to perform field trial verifications of?!!! I really don’t understand why this was accepted for publication – where’s the verification. Do reviewers not even reading these reports anymore?

  23. WOW! Amazing discovery! Higher albedos reduce energy absorption and lower albedos increases absorption.
    Perhaps their next step will submit a plan to blanket the winter hemisphere with fresh snow cover daily so as to reduce global warming! I see snow making machines to be the next big investment!
    (sarc)

  24. Basically, it comes down to this….the environmental, leftist view is that anything humans do is bad for the environment and must be eliminated. The best thing to do, therefore, is drastically reduce the population. I would propose that the environmentalists put their rhetoric into action and eliminate themselves first.

    • Do you know, it’s never themselves that they see as being in need of eliminating, it’s everyone else.

  25. Know what else reduces albedo, and “exacerbates global warming”? Trees, especially evergreens. Sorry kiddos, no more christmas trees – they contribute to “global warming”, and so are evil. And plastic ones are made from evil oil, so none of them either. And don’t get me started on how evil Santa is.

  26. Uh ohs, clearing roads, parking lots and driveways of snow also “exacerbates global warming” – twice: first because of all the nasty “carbon pollution” produced by snow clearing operations and second, from the reduced albedo. Maybe we should go back to rolling the snow instead, and putting metal tracks on our cars.

  27. Probably trivial but interesting. If a field growing crops is warmer than snow covered soil it may be due to absorbed energy (albedo change) but it may also be at least in part due to the actions of the crop itself. Some plants – especially those growing in snowy regions actively control their temperature by releasing energy. I know homeothermic plants sounds ridiculous, and of course its not at the level achieved by mammals but it is real. It was initially discovered by finding plants in snow covered fields with a ring around the plant which was clear of snow. That prompted further investigation which showed the phenomenon.

  28. Following on from my previous comment that the plants themselves may be raising the temperature by releasing heat, (rather than just a change in albedo) look up thermogenic plants. Apparently the Voodoo lily (amorphophallus) can raise its temperature by up to 15C above the ambient! Skunk cabbages do pretty well too.
    All plants of course practice thermal regulation by controlling water evaporation from their leaves (compare well watered hydrangeas versus those with very limited water availability on a hot day). Its a significant reason why trees can lower the temperature of their environment on a hot day. Thermogenesis however refers to the opposite where the plant maintains itself at a temperature higher than ambient.

  29. Straight to the Computer Models(tm).

    My current belief is that the sole purpose higher education in our current generations is to stop unemployable people from cluttering the job market.

    Studies like this to little to convince me otherwise.

  30. “Cover crops, grown between cash crops when soil is fallow”

    “A new study shows that fields with crop cover showed significantly warmer winter temperatures than fields with no cover or just short stubble.”

    What this kook is claiming to model is that land with normal plants growing cause warming during the winter. Don’t any of these alleged researchers think? Or at least visit field sites to observe the null condition?

    Farming has zero to do with the claim, except that farmers do strip vegetation during harvest, while leaving plant residues to improve the soil.

    Defund this quack!

  31. And the net result on the World Climate of all winter cover crops everywhere is around 1/10th of 1/100th of 1/1000th … in effect 0 (zero).
    An interesting effect, to be sure, locally, but not alarming.

  32. paywalled to protect?? themselves from ridicule, while keeping funding
    this mob is so stupid they aren’t worth feeding, and i hope theyre not breeding more like em

  33. This article is based on conflation and cherry picking. Plus appealing to emotion and ignorance rather than science.

    First, the idea that one’s personal comfort via a warm winter is bad for the climate is the ridiculous appeal of this post. But is that even the premise of the post? What else can one conclude? It isn’t specified! Therefore the article is based on extremely poor communication, poor or absent analysis of the science behind the investigation covered, and is a total advertisement and propaganda D-word people ( charitably called Skeptics here because they can’t face facts) who NEVER get up off their couches and do any science.

    Assumptions like “warmer winter good, colder winter bad” totally personal, and if you spent 10 seconds thinking about it, totally localized. For people living close to the tropics or near deserts, warmer winters can actually be more deadly. In some places, Winters are the only times crops can be grown. Or outdoor activities can be safely done.

    Also warmer winters also mean, by extension, because overall temperatures are going up, that summers are also warmer. warmer Summers can destroy crops in areas where higher temperatures are deadly or prevent growth or cause drought. So there’s a whole lot of narrow-mindedness, lack of science and outright stupidity with the entire premise of this article. Its premise is absent except by vague inference, there is no scientific analysis involved, there’s not even logical analysis about potential consequences of warmer winters!

    The conflation amounts to equating climate change with local weather.

    The cherry picking is picking one tiny study out of the vast data and evidence for global warming, and assuming one could refute ALL global warming evidence based on a localized trend, which looks only like one contributor of many to global warming.

    That is NOT scientific. The author clearly shows no respect for science, and couldn’t be a legitimate respected scientist because she’s unwilling to do the work, and is ignorantly appealing to your emotions, not analytical abilities–those who are skeptical mainly because they are unable to actually DO climate science and grasp the far bigger picture and evidence involved.

    Either she’s not smart enough to understand the science of global warming, or she knows you’re not smart enough to understand it. Therefore the intent is either based on ignorance or pure evil– to make you even more ignorant so that you oppose mainstream science which is informing us how to save Humanity from a trend we ourselves have created. The intent is to prejudice you against something you clearly, by dint of your comments, cannot understand and she evidently fails to understand or wants to dupe you about.

    The dangers of climate change have nothing to do with one’s personal comfort–“warm Winters are now a bad thing” –until you actually live on a seashore where the ocean height rises 3 to 10 ft.

    Until you live in Japan and the entire base of your main food source, fishing, is completely wiped out. Because of a catastrophic great dying of species – mass extinction event – due to warming so speedily that species cannot possibly cope with the rapid changes.

    Yeah, wiping out your main food source is kind of a bad thing. Yeah, destroying homes and all the businesses your City built on the beach is kind of a bad thing. Yeah, when an ocean covers an island that’s your home, that’s kind of a bad thing.
    Yeah, when a 7 degree rise in AVERAGE temperatures leads to occasional 20 degrees higher swings that kill crops you depend on to live, and older people and babies die of heatstroke, that’s kind of a bad thing.
    Not kind of, it actually IS A BAD THING.

    The main issues with climate change have NOTHING to do with apparently simplistic views like:
    “Hey! Look how nice and warm it’s going to get! Climate change is good! WHEEEE! Extra summer, kids!”

    “Those dumb-dum scientists, they don’t even care how much more ice cream we can eat and swimming we can do now! Ya nattering nabobs of negativism!”

    The issues include how rapidly the changes are happening, how few species will be able to cope, how the rising acidification of the ocean may well destroy most species within 50 years because of a mass extinction event, how weather overall changes including getting worse and less predictable, and other ill effects that the writer or original poster completely fails to grasp or mention.

    Those who do the Science of global warming understand it’s complex. They work with other scientists to grasp the big picture. Almost everyone posting and commenting here fails by picking out that one tree in the forest, shouting,

    “Ooh, THAT tree doesn’t match the others! Proved you wrong!” and totally fails to see the big picture.

    Of course, it’s obvious that most here are unable to realize that you don’t see the big picture (self reflection failure), because most of you aren’t smart enough to notice there IS a big picture, that you’re not smart enough to understand all the parts you keep looking at separately and how they interact with the big picture, and that you keep repeating this ignorant, unintelligent pattern WITHOUT LEARNING anything.

    As Patrick, the mentally challenged starfish in SpongeBob says,
    “Stupid people are always blissfully unaware of just how stupid they really are. [drool…..]”

    So keep posting: hold up your plastic streamers in the wind and breathe people, breathe.

    That’s what most of your comments here are worth– on the most popular, NOT the most scientific website on global warming.

    You truly want to criticize climate science in a valid SCIENTIFIC way, get the climate science degree, do the work, put in the years of study required.

    Stop being lazy armchair critics, prove how smart you are. Then you might not look like such an idiot.

    [??? .mod]

    • A cover crop actively growing over winter will be using energy to capture carbon dioxide to build leaves and roots, and some of that carbon flow in the roots will be stored in the soil long term via the glomalin pathway. Granted, in the middle of winter, not much of this will be happening, but each side of that period, it will. As much of the atmospheric CO2 rise has come from soil cultivation, and as cover cropping tends in the opposite direction, it would seem to be a good thing. There is also the benefit in protecting soil against erosion.

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