Reproduced with permission, copyright Dr. Craig D. Idso.

Study: Climate Change Boosted Plant Growth is Bad

Guest essay by Eric Worrall

University of Michigan models suggest that increased rates of plant growth due to warmer temperatures will boost pollen allergies.

Pollen season is getting longer and more intense with climate change – here’s what allergy sufferers can expect in the future

Published: March 16, 2022 3.08am AEDT

Yingxiao Zhang
Ph.D. Student in Atmospheric Science, University of Michigan

Allison L. Steiner
Professor of Atmospheric Science, University of Michigan

Brace yourselves, allergy suffers – new research shows pollen season is going to get a lot longer and more intense with climate change.

Our latest study finds that the U.S. will face up to a 200% increase in total pollen this century if the world continues producing carbon dioxide emissions from vehicles, power plants and other sources at a high rate. Pollen season in general will start up to 40 days earlier in the spring and last up to 19 days longer than today under that scenario.

As atmospheric scientists, we study how the atmosphere and climate affect trees and plants. While most studies focus on pollen overall, we zoomed in on more than a dozen different types of grasses and trees and how their pollen will affect regions across the U.S. in different ways. For example, species like oak and cypress will give the Northeast the biggest increase, but allergens will be on the rise just about everywhere, with consequences for human health and the economy.

How much pollen is produced depends on how the plant grows. Rising global temperatures will boost plant growth in many areas, and that, in turn, will affect pollen production. But temperature is only part of the equation. We found that the bigger driver of the future pollen increase will be rising carbon dioxide emissions.

The higher temperature will extend the growing season, giving plants more time to emit pollen and reproduce. Carbon dioxide, meanwhile, fuels photosynthesis, so plants may grow larger and produce more pollen. We found that carbon dioxide levels may have a much larger impact on pollen increases than temperature in the future.

Read more:

The abstract of the study;


Projected climate-driven changes in pollen emission season length and magnitude over the continental United States

Yingxiao Zhang & Allison L. Steiner 

Nature Communications volume 13, Article number: 1234 (2022) Cite this article


Atmospheric conditions affect the release of anemophilous pollen, and the timing and magnitude will be altered by climate change. As simulated with a pollen emission model and future climate data, warmer end-of-century temperatures (4–6 K) shift the start of spring emissions 10–40 days earlier and summer/fall weeds and grasses 5–15 days later and lengthen the season duration. Phenological shifts depend on the temperature response of individual taxa, with convergence in some regions and divergence in others. Temperature and precipitation alter daily pollen emission maxima by −35 to 40% and increase the annual total pollen emission by 16–40% due to changes in phenology and temperature-driven pollen production. Increasing atmospheric CO2 may increase pollen production, and doubling production in conjunction with climate increases end-of-century emissions up to 200%. Land cover change modifies the distribution of pollen emitters, yet the effects are relatively small (<10%) compared to climate or CO2. These simulations indicate that increasing pollen and longer seasons will increase the likelihood of seasonal allergies.

Read more:

For starters, I’m pretty sure allergies will not be a problem in the future. Medicines today are far better than what was available when I first developed symptoms. I would be very surprised if allergies are still a significant issue a few decades from now, let alone by the end of the century.

But there is a more immediate counter to this claim. As an asthmatic who also suffers pollen allergy, I have personally observed this issue is more complex than the scientists are suggesting.

There is a reason older people move to warm places like Florida or Queensland, even if they are asthmatic or have allergies.

When I moved from cold Britain to the Australian subtropics, my allergies became easier to manage.

Why? Even though the pollen season is longer in my new home, it seems more spread out.

The pollen explosion in cold places like Britain tends to be short duration but extremely intense. It has to be intense, because the growing season is short. Pollination for many plants must occur right at the start of the growing season, or fruits and seeds might not mature fast enough to be ready before the frost arrives.

In warmer places, there is much less pressure on plants to seize every precious day of growing season. Plants flower most of the year, and fruits like citrus comfortably continue growing through winter, usually maturing the following Spring.

Overall my experience is the move to a warmer climate helped me manage my asthma and hay fever. I encounter my other major trigger, cold air, a lot less frequently in Australia than I did in Britain. The reduced exposure to cold air, and the lack of violent changes in pollen exposure, makes it much easier to manage my asthma and hay fever with medications.

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John Tillman
March 15, 2022 6:09 pm

More pollen allergies, bad!

Less starvation, worse!

Richard Page
Reply to  John Tillman
March 16, 2022 6:12 am

Only the green blob could take a positive, like increased greening of the planet, and spin it until it was a negative. They really are a bunch of manipulative, money-grubbing morons.

Curious George(@moudryj)
Reply to  Richard Page
March 16, 2022 8:01 am

Oh no. Dr. Joseph Goebbels was a pioneer. His methods are widely used today.

Bill Everett
Reply to  Richard Page
March 16, 2022 8:29 am

They are overlooking the distinct possibility (or probability) that the increased vegetation growth is the cause of the atmospheric CO2 growth, especially the growth of broadleaf vegetation. Some OCO-2 mapping has indicated this, but it seems to be ignored. Since the generally accepted contribution to the atmospheric CO2 level by human activity is only five percent or less then blaming that for the CO2 increase appears to be without foundation. Vegetation would seem to be a natural pathway for carbon and oxygen to combine and CO2 to enter the atmosphere.

Charles Higley(@higley7)
Reply to  Bill Everett
March 17, 2022 8:52 am

We need to remember that the half-life of CO2 in the atmosphere is about 5 years (from numerous studies by real scientists), which means it turns over quite rapidly. [Not the 200 or 1000 years claimed by the IPCC and NASA, respectively.] The same is true of methane. There is no way that we can have an influence on atmospheric CO2 with such a short half-life and small contribution.

Charles Higley(@higley7)
Reply to  Richard Page
March 17, 2022 8:49 am

Very simply the whole world should be run according to people with pollen allergies, just like they think we should design society to pretend transpeople are normal and should be celebrated.

Reply to  John Tillman
March 16, 2022 9:59 am

They simply can’t make up their minds, can they?

Plants – GOOD! Oh, wait – Plants = allergies = bad!

I’ve run into earthworms that are smarter than those people. 🙂

Reply to  John Tillman
March 16, 2022 4:45 pm

Finally we have a permanent solution for allergies. Just bring on the ice age.

Win Win situation

high treason
March 15, 2022 6:09 pm

Those that make feeble and pithy excuses to dismiss the great benefits of higher CO2 levels are behaving like tyrants. See Aesops Fable the lamb and the wolf. It describes the behaviour.

Reply to  high treason
March 16, 2022 7:40 pm

The problem is they get the funding because the new religion of the left must been tithed.

March 15, 2022 6:13 pm

No doubt it will also create man-eating plants.

Reply to  John Shewchuk
March 15, 2022 7:06 pm

Feed Me, Seymour!

Reply to  John Shewchuk
March 15, 2022 9:53 pm

And triffids. More doom.

Nick Graves
Reply to  RoHa
March 16, 2022 1:20 am

Triffids would solve the oil shortages and ‘global warming’.

Where do I apply for my grant?

Ed Zuiderwijk
Reply to  John Shewchuk
March 16, 2022 2:16 am

Now there’s an idea. How about selecting them on a preference for alarmists?

Alan the Brit
Reply to  John Shewchuk
March 16, 2022 11:33 pm

Isn’t that the definition of a vegetarian? 😉

Ron Long
March 15, 2022 6:14 pm

Thanks, Eric, I like the sequence of the tree growing better in increased CO2. What I’m wondering is, can you put a lizard in the greenhouse with + 1,000 ppm CO2 and get a dinosaur? That would be cool, err, hot.

John Tillman
Reply to  Eric Worrall
March 15, 2022 6:32 pm

See the Carboniferous, when high O2 meant that the atmosphere over whole continents could catch fire. But Earth enjoyed dragonflies with the wingspans of F-16s.

OK, I exaggerate slightly.

Clyde Spencer
Reply to  John Tillman
March 15, 2022 7:25 pm


Pillage Idiot
Reply to  Clyde Spencer
March 15, 2022 7:33 pm

Checks NYT style guide…

Nope, the narrative requires all airplane references now must be made utilizing the MiG-29!

Richard Page
Reply to  Pillage Idiot
March 16, 2022 6:16 am

Well the Mig 29 does have a shorter wingspan than the F-15!

Patrick healy
Reply to  Eric Worrall
March 16, 2022 12:45 am

Eric I am not a scientist, but if you could arrange a grant – of say a couple of hundred thousand – I feel sure I could russle up a “Scientific study” showing how CO2 makes tadpoles into edible trout – or something.
You have my e-mail address.

Reply to  Patrick healy
March 16, 2022 7:42 pm

I prefer the meat is vegetarian because cows eat grass. So more CO2 gives more grass gives more cows….

Russell Cook
Reply to  Ron Long
March 16, 2022 10:41 am

AGW is capable of all things. Or so we are told. No joke!
Climate change driving evolution so fast that animals are changing in weeks

Extreme climate change is driving evolution in animals so fast that it is creating distinct changes that can be measured in a matter of weeks, according to a leading biologist.

From Caribbean lizards growing larger toe pads to grip trees more tightly as hurricanes become more frequent, to shrinking squid, to larger damselfly wings in Britain – the way nature is adapting is confounding Darwin’s beliefs about the speed of evolution, says Thor Hanson.

Reply to  Russell Cook
March 16, 2022 11:37 am

you can measure distinct evolutionary change in just six weeks

What is the lifespan of these lizards, and how long is their reproductive cycle? This seems rather farfetched.

Reply to  Russell Cook
March 17, 2022 8:18 am

Considering the fact that there has been no change in either the frequency or intensity of hurricanes, it would be very surprising to find out that lizards are adapting to changes that aren’t occuring.

Reply to  Russell Cook
March 17, 2022 1:32 pm

“Climate change doesn’t speed up the process of evolution, per se. But it does create conditions where rapid evolution is more more likely,” he says.”

The whole article is a poorly reported piece. The words they were desperately searching for were “natural selection” not evolution but there hopelessly absent.

March 15, 2022 6:15 pm

“University of Michigan models suggest that increased rates of plant growth due to warmer temperatures will boost pollen allergies.”

Models, models, models. When are academics going to show us some hard science?

Reply to  Bob
March 15, 2022 6:46 pm

Sorry, this reminds me of a true story. There’s a “Hands on Museum” in downtown Ann Arbor a couple of blocks from UM’s campus. The museum has been there a long time.

I saw Emo Philips give a comedy show in Ann Arbor and he said he went to that museum and asked to be directed to the breasts exhibit.

Ed Zuiderwijk
Reply to  Scissor
March 16, 2022 2:18 am

Oh come, pull the other one.

Reply to  Bob
March 15, 2022 8:04 pm

They could by comparing pollen allergies in Maine with those in Florida. The temperature difference between these States far exceeds 6K. But that would take no more than an excel spreadsheet. No model, no money.

Reply to  Bob
March 16, 2022 5:42 am

Is there a model that investigates the reliability of models?

Reply to  Alba
March 16, 2022 10:02 am

My models show that all models are wrong…

Bob Tisdale(@bobtisdale)
March 15, 2022 6:19 pm

The post begins, “University of Michigan models suggest that increased rates of plant growth due to warmer temperatures will boost pollen allergies.”

[sarc on] Time to invest in antihistamines. [sarc off]

Then from the paper abstract we have “As simulated with a pollen emission model and future climate data…

Future climate data? What is “future climate data”? The output of climate models IS NOT data.

It also sounds as though they’re stacking models; i.e. using the output of climate models as inputs to their “pollen emission model”. Ha ha ha ha ha!!!!

The climate research community becomes more distant from reality with every passing year. Oy vey!


Tom Halla
Reply to  Bob Tisdale
March 15, 2022 6:36 pm

Now if only they will take the restrictions off pseudoephedrine allergy tabs.

Reply to  Bob Tisdale
March 15, 2022 6:46 pm

“models” is the 4th word in. No need to read further. It is a great time saver when these garbage articles are presented with “models” right up front.
Everybody, let’s use the new acronym.
YAPOG – Yet another Piece Of Garbage

Future climate data? What is “future climate data”?
To go along with my data correction algorithm, “pasturization”, I am working on a trio of data creation algorithms which produce past data, current data, and future data.
These algorithms have the following advantages:
1) The data set you want is the one which will be produced. No need to put up with actual measurements which may not provide the data you want.
2) Faster, the data programs run very quickly. These is no need to take months or even years collecting data.
3) Cheaper, no need for special instrumentation or extensive field work.
4) Easier, just sit at your desk with a computer. No need to even go outside with all the inconvenience that involves.

Note: These algorithms should only be used in Climate Science. Their use in any field of real science is considered to be career ending misconduct.

I hope this clarification helps.

Reply to  TonyL
March 15, 2022 7:29 pm

Model data could be re-acronymed as
POOMA numbers.

Pulled Out Of My Arse”

Reply to  TonyL
March 16, 2022 12:28 am

I was going to make the same points, but you got there before me.

Thank you for that excellent summary of the utter drivel which passes for Science these days, and shame on Nature Communications for publishing it.

Reply to  Bob Tisdale
March 15, 2022 6:52 pm

This is from Steiner’s The Conversation bio.

“Her research focuses on understanding how emission from the biosphere can affect atmospheric chemistry and air quality, as well as understanding how changes at the land surface can affect regional climate.”

It sounds like a native CCP member wrote it.

Reply to  Scissor
March 16, 2022 3:21 am

More like word salad Bob or Pete Butipedge (spell).

Clyde Spencer
Reply to  Bob Tisdale
March 15, 2022 7:45 pm

Shouldn’t we expect the evolution of plants to better use longer growing seasons to take some time so the plant doesn’t hold back pollen production in a cold year, ‘expecting’ an extended opportunity? That is, they have adapted conservatively to variations in Last Killing Frost (LKF) variations in a manner that doesn’t put them at a reproductive disadvantage if the LKF isn’t consistent. The production of pollen is a Spring event, so the First Killing Frost probably isn’t relevant for pollen, only the ripening of seeds. I’m not sure what kind of evolutionary pressure would result in mid-latitude plants extending their pollen phase much beyond what it currently is because, ultimately, most plants will be constrained by available sunlight to effectively photosynthesize.

This seems to be another of the kind of article that is reaching for something else undesirable to add to the growing list of things that could happen, without any ability to associate a probability.

michael hart
Reply to  Bob Tisdale
March 15, 2022 11:47 pm

They already do it with the economics, Bob.
Imagine, taking the model outputs of the first and second most dismal of all sciences and multiplying them together!

March 15, 2022 6:25 pm

Something about a boy and a wolf.

Gary Pearse
March 15, 2022 6:29 pm

More plants, more pollen. Woo that’s deep! Is that your best shot at the Exxon-Mobil Great Greening Project?

“(greening) due to warmer temperatures”

That’s The Big Lie they use to not credit CO2 for The Great Greening Miracle ^тм, attendant global bumper harvests and expansion of ocean productivity. Well even NOAA couldn’t stomach such a big lie:

U Michigan should be called out on this with a tag ‘shame on you’. The most Greening is occurring in arid regions where there has been no warming at all!

Crispin Pemberton-Pigott
Reply to  Gary Pearse
March 15, 2022 7:03 pm

Like the Sahel. It has pushed the Sahara Desert 500 km north in the past 40 years.

Joao Martins
Reply to  Crispin Pemberton-Pigott
March 16, 2022 4:50 am

Good point!

I remember that, in my university years, along with the “climate cooling” catastroph there was also the Sahel catastroph: Sahara desert growing south and menacing life in the Sahel.

Tom Abbott
Reply to  Gary Pearse
March 16, 2022 3:24 am

““(greening) due to warmer temperatures”

That’s The Big Lie they use to not credit CO2 for The Great Greening Miracle ^тм, attendant global bumper harvests and expansion of ocean productivity.”

I noticed they avoided gving CO2 credit for the additional plant growth around the world.

They are fixated on temperatures. So fixated, they haven’t noticed it has been cooling lately, not warming.

March 15, 2022 6:32 pm

Once again, “studies have shown” that CO2 is e-e-e-vil.

Quelle surprise.

So, we must get to Net Zero as fast as possible. But if we do that, then we’re all gonna DIE!

*Sprained an eyeball there rolling my eyes*

Tom Halla
March 15, 2022 6:33 pm

I have several pollen allergies, but trees and other plants growing better? Good.

Last edited 2 months ago by Tom Halla
Reply to  Tom Halla
March 15, 2022 6:57 pm

I identify as being allergic to propaganda.

March 15, 2022 6:45 pm

There are usually both positive and negative effects to changing situations. Therefore, the questions that needs to be addressed are, ‘Do the total negative effects outweigh the total positive effects, or vice-versa, and can the negative effects be reduced or cancelled using the latest developments in technology?’

For example, we should all be aware that increased CO2 levels increase the growth of most plants and food crops, which are of the C3 type. However, the AGW alarmists tend to concentrate only on the negative effects, and claim that such crops grown in elevated levels of atmospheric CO2, will be less nutritious, ignoring the fact that the nutritional value of food depends on farming practices, soil quality, and the processing of food crops, all of which can be addressed if the nutritional value is a concern.

Reply to  Vincent
March 15, 2022 7:08 pm

Good comment. Dessler illustrates your points in just the first couple of minutes of his opening statement in the following “debate.” He is so severely biased and ignorant that it’s painful to listen to him.

Reply to  Scissor
March 15, 2022 8:26 pm

Agreed concerning Dessler, yet Epstein is worth listening to. He makes
the moral case quite well. And some of the questions suggest that there were a few skeptics in the audience.
Run it at 1.5x speed.

Clyde Spencer
Reply to  Vincent
March 15, 2022 7:51 pm

‘Do the total negative effects outweigh the total positive effects, or vice-versa, and can the negative effects be reduced or cancelled using the latest developments in technology?’

Yes, if the pollen phase should be stretched over a longer time, might it be that allergy sufferers are not affected as severely, or not at all if under a certain threshold?

The unstated, and unexamined assumptions are always a problem.

Reply to  Vincent
March 16, 2022 2:37 am

Commercial growers inject extra CO2 into their greenhouses. Are their fruit and vegetable less nutritious that those grown outdoor? Answer: No.

Reply to  Graemethecat
March 16, 2022 4:59 am

As I mentioned in my previous post, the nutritional value of any crop is dependent on the nature of the farm practices and the soil quality. Therefore, it must be obvious that the nutritional content of any specific crop will vary significantly according to the location where it is grown, the amount and type of fertilizers applied to the soil, and/or the type of farming practice used, such as ‘so-called’ Organic Farming, or Permaculture, or Conventional Till Farming, which strives to produce the maximum yield at the lowest cost.

Some time ago, when I learned that Brazil nuts were a good source of Selenium, I did an internet search to find out how many Brazil nuts are required to provide the recommended daily amount of Selenium. I came across a number of scientific studies which had examined the Selenium content of Brazil nuts grown in many different areas around the globe. What amazed me was that the Selenium content of the average sized nut, say 5 grams, varied by a factor of 10, depending on where the tree was grown.

In other words, if the Brazil nut you are eating was grown in good conditions with plenty of Selenium in the soil, then just one Brazil nut should provide you with the recommended daily dose of Selenium. However, if the tree was grown in an area where there is very little Selenium in the soil, the lack of Selenium will not prevent the tree from growing, but the nuts will contain so little Selenium that you might need 10 nuts to provide your daily allowance of Selenium.

Likewise, the nutritional quality of crops grown in Greenhouses with an increased level of CO2, will vary depending on the amount of fertilizers and the range of minerals applied to the soil in the Greenhouses.

Reply to  Vincent
March 16, 2022 7:07 am

In other words, CO2 is not the controlling factor.

Reply to  Vincent
March 16, 2022 7:05 am

Before we measure whether the positive effects outweigh the negative effects we should come to a consensus on whether particular effects are positive, negative, or don’t matter in the slightest?

Last edited 2 months ago by MarkW
Reply to  MarkW
March 16, 2022 7:49 pm

This is a huge problem because people’s personal preferences vary considerably. Experiments have shown that whilst doubling the amount of CO2 in the atmosphere produces about a 35% increase in C3 crop production, when grown in the same types of soil with the same amount of minerals and the same amount of water, sunshine and temperature, there is a slight decrease in the mineral, vitamin and protein content of the crops grown in elevated CO2 levels.

However, this decrease in mineral and vitamin content is not nearly as much as a 35% decrease, so the total amount of minerals, vitamins and proteins, in the full crop, is still greater when the crop is grown in elevated CO2 levels, and that slight deficiency in minerals can be removed by adding more minerals to the soil, although the issue is very complex because of the role the soil microbiome, such as bacteria, insects and worms.

Is there a consensus on the value of nutrition? If so, why is white rice the preferred choice for most people in the world who eat rice? It’s a well-established scientific fact that stripping the brown husks off rice seeds, to produce white rice, removes significant amounts of vitamins and minerals. As a result, a few countries around the world, including the USA, have made it mandatory to fortify white ice with certain vitamins and minerals before it is sold.

Vitamin and mineral supplements in general can address the problem of nutrient deficiency in the foods we eat, but the problem is, the vitamin and mineral content of any particular crop can vary significantly, so we don’t necessarily know which vitamins and minerals we are deficient in.

Reply to  Vincent
March 17, 2022 6:51 am

“If so, why is white rice the preferred choice for most people in the world who eat rice?”

My guess is simply because it stores better. Good for shipping and for keeping on the shelf. No nutritional value at all in food that you can’t use.

Reply to  Vincent
March 17, 2022 3:16 am

Total lunacy but it still rears its ugly head every now and then. Sure pinched grains are more nutrient-dense than full grains, but the total nutrition available is greater.

But whatever you do, don’t raise the obvious analogy or the morons will start campaigning to ban irrigation because irrigated produce is less nutrient dense than produce raised under water-stress conditions.

Allan MacRae
March 15, 2022 6:49 pm

New Study: The CO2-Drives-Global-Warming ‘Concept’ Is ‘Obsolete And Incorrect’ (
“The IPCC concept that increasing carbon dioxide in the atmosphere causes global warming is three decades out-of-date.”  
− Lightfoot and Ratzer (2022), Journal of Basic & Applied Sciences

Reply to  Allan MacRae
March 15, 2022 7:17 pm

A nice thing about that paper is provides testable projections. If it’s correct we may know it in 3 years or certainly by 2030.

Will alarmists become apologists?

Allan MacRae
Reply to  Scissor
March 15, 2022 8:38 pm

New Study: The CO2-Drives-Global-Warming ‘Concept’ Is ‘Obsolete And Incorrect’ (
This paper is ok – it is essentially a review of the IPCC reports, and of recent work by the Russians and Soon et al, etc. It reflects limited predictive skill because most of the papers that predicted cooling were written after the big El Nino spike of 2016 – thus an observation, not a prediction. More interesting is the predictive skill of MacRae and Paterson (2002) and Landscheidt (2003), who both predicted cooling based on solar activity more than a decade before it started.
I suggest that we don’t have to wait until 2030 to answer the question – cooling is here now – as evidenced by the hundreds of significant very-cold events worldwide, documented by Cap Allon at
Some say global cooling started in Feb2016 but that was the peak of a huge El Nino, so I prefer Feb2020. In either case my 2013 prediction of global cooling starting within ten years is still correct.
Even the moderate cooling observed to date can be dangerous, because global cooling is accompanied by deviations of the polar vortex that destroy humans and crops – such as the extreme cold in south-central USA in Feb 2021 and the current extreme cold in India and China that I expect will cost many lives.
Our cooling predictions from 2002 and 2013 are described in these papers:
CLIMATE CHANGE, COVID-19, AND THE GREAT RESET – A Climate, Energy and Covid Primer for Politicians and Media March 21, 2021, Update 1e May 8, 2021

Joe Gordon
March 15, 2022 6:55 pm

One factor this “study” ignored. If more people have allergic reactions, they will use more Kleenex, thus requiring more harvesting of trees and largely eliminating the original problem.

You really need to include the blow-back factor whenever analyzing climate’s effects on allergies. My own climate model indicates this with near certainty. There’s even a tipping point, beyond which sniffling is no longer tolerated by family members and friends, and that’s nothing to sneeze at.

Reply to  Joe Gordon
March 15, 2022 7:25 pm

I have several pine trees and when they pollinate I occasionally collect some pollen to snack on. After getting past its dry powdery texture, it actually has a pleasant taste sort of like pine nuts, perhaps not surprisingly. It’s reported to be nutritional.

Do inspect the pollen for mites and other small bugs, though they probably taste about the same.

Crispin Pemberton-Pigott
March 15, 2022 6:59 pm

Eric I agree about the warmer being better scenario. I lived in tropical and subtropical countries, and in Ontario, Canada. Which is worst?

Seeing as we are all believers in science, I expect allergies to be a thing of the past by 2100.

The study is based on a 6K rise in 80 years? Dream on! That is 0.75 degrees per decade. Gimme a break.

Apart from having a longer season to have pollen diluting the source, there aren’t all that many bothersome plants that flower multiple times per year. I am going to have to get my head around the argument that longer warm periods means the total mass produced per annum will increase lock-step with temperature. Let’s see some data. It doesn’t work like that in Africa.

i am continuously surprised that people try to make warming into a Bad Thing. There is nothing better about being colder.

For the bean counters: If it was 6K warmer, imaging the reduction is CO2 emissions from space heating!

March 15, 2022 7:57 pm

So I suppose that pollen levels in the lower 48 will not change because for the past 17 rears our temperature has not changed. Refer to the Climate Reference Network.

Tom Abbott
Reply to  DHR
March 16, 2022 3:42 am

The pollen levels should be decreasing in the United States then, because the U.S. has been in a temperature downtrend since the 1930’s, according to Hansen

comment image

The years 1998, and 2016, are tied for the warmest year in the satellite era, (1979 to present). It was warmer in the United States in the 1930’s than either of those two years.

Last edited 2 months ago by Tom Abbott
March 15, 2022 8:14 pm

The authors take pains to note that they are atmospheric scientists. Yet they are modeling plants as if they know something. They should leave plant biology to soil and crop and plant scientists. And leave allergies to allergists and biomedical researchers. These boys are out of their league, but of course they are from the wrong school in Michigan. Should have been Michigan State.

More high school science projects masquerading as dissertation topics. Gotta get those degrees somehow.

dodgy geezer
March 15, 2022 8:14 pm

lots of pollen from better growing plants due to CO2 = bad.

lots of pollen from lots more trees planted due to green initiatives to soak up CO2 = good……

March 15, 2022 8:59 pm

CO2 is amazing. The man gets bigger with rising CO2 levels as well.

Peta of Newark
Reply to  Joel
March 15, 2022 10:47 pm

Amazing innit – the power of magical thinking ans preconceived ideas.
Exactly as the article/story here

Then it gets really rather sad/poignant/stupid or angrifiying.
The guy in the picture (Idso I think his name is) has spent the whole rest of his life and built a career pursuing the claim he makes there and expanding on it.

There is precedent, John Tyndall = the father of all modern climate science.
He did an experiment, got a result and then went on to make One Epic Awful Assumption and an Olympian Leap of Conclusion Jumping
(Ancel Keys did something very similar while Andrew Dessler follows that lead. Dessler wouldn’t know an original thought if one bit his arse)

The guy in the photo doesn’t really actually *know* what experiment he’s done.

Yes he’s got an amazing result but that result was not caused by what he thinks it was caused by.

What is the sad part = the Junk Science, the Kindergarten Experiment, the Primary-School Oversimplification, the Confirmation Bias is that soooooo many other folks cannot see what’s wrong.

Because they’re looking up at the sky – not down at the ground.
Literally, that’s the reason.

Just why the zooming camera shots, a primitive attempt at Photoshopping, were needed rather suggests that the guy himself wasn’t quite sure of his own result.
But was too dim to work it out

Dim‘ being the understatement – we really are now in a scientific Dark Age

Last edited 2 months ago by Peta of Newark
Reply to  Peta of Newark
March 17, 2022 12:28 pm

The guy in the photo doesn’t really actually *know* what experiment he’s done.
Yes he’s got an amazing result but that result was not caused by what he thinks it was caused by.

Peta, can you tell me more??…..

David Baird
March 15, 2022 9:42 pm

I can’t wait for the next fantasy attribution to be global warming causes ED. I guess they can always add some yellow and make the little blue pill green

Reply to  David Baird
March 16, 2022 10:42 am

Apparently there’s a study saying air pollution does:

March 15, 2022 9:52 pm

Pollen! We’re doomed!

March 15, 2022 10:43 pm
Walter Pate
March 15, 2022 11:41 pm

How did pollen suffers survive all the other times in the past the the earth was warmer? somebody do something!!!!

Thomas Gasloli
March 15, 2022 11:58 pm

So according to the U of M scientists we need to stop burning fossil fuels & kill all the plants? 🤔

March 16, 2022 1:30 am

These people and their indomitable pessimism lament a ruined lump of coal while everyone else enjoys the beauty of a diamond. They must be a joy at dinner parties.

March 16, 2022 1:56 am

Yet more unadulterated tosh

Ed Zuiderwijk
March 16, 2022 2:14 am

I knew there was some drawback on plants growing, but never could lay my hand on it. Now I know.

Tom Abbott
March 16, 2022 3:12 am

From the article: “How much pollen is produced depends on how the plant grows. Rising global temperatures will boost plant growth in many areas, and that, in turn, will affect pollen production.”

I think I see a flaw in your narrative. You are apparently assuming, without any evidence, that global temperatures will rise higher. What if they don’t rise higher? I guess that would blow your claims out of the water, if cooling were to happen, wouldn’t it?

Another atmospheric scientist who is assuming too much and basing claims on assumptions, not facts. This is the current state of Alarmist Climate science.

The temperatures have cooled 0.7C from the 2016 highpoint. Stick that in your pipe and smoke it.

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Last edited 2 months ago by Tom Abbott
David Dibbell
March 16, 2022 4:32 am

“University of Michigan models suggest that increased rates of plant growth due to warmer temperatures will boost pollen allergies.” This brings up one of my favorite responses to the climate claims. Why are the northern states like Michigan, where these suggestive models are from, not marketing themselves as obvious havens for all those pollen-challenged climate refugees from Florida?

Michael Nagy
March 16, 2022 4:35 am

Eric, you should see what happens in the spring in Central BC, after several days of no wind. When it does come, yellow clouds of pollen can be seen for miles away. I never suffered, but you are completely right in this article.

Reply to  Michael Nagy
March 16, 2022 5:23 am

Usually the clouds of yellow pollen are pine. Pine pollen is actually too large to cause allergic reactions unless you are particularly sensitive to pine, but if that is the case you will usually see skin rashes as well.. The usual pollens to cause allergy are the smaller ones you don’t see.

Tom in Florida
March 16, 2022 4:50 am

“The pollen explosion in cold places like Britain tends to be short duration but extremely intense. It has to be intense, because the growing season is short.”

This is similar to the difference in summer fun from living in New England and Florida. I grew up in Connecticut where summer fun would start at the end of June and end in early September allowing only a limited time to enjoy summer fun. So you went balls to the wall every weekend to maximize your summer fun before it was over. If you lost even one weekend due to bad weather is was disappointing. Living in Florida for over 30 years now, not so much worry about missing out on good weather days, with so much good weather year around the attitude changes from short intense activity to oh well, no big deal we can always do that another day.

March 16, 2022 5:12 am

Funny, I don’t see any botanists on the authors list. Who checked the model assumptions for comportance with the real world that plants occupy?

I see this often in climate science – invent novel statistical methods with no mathematicians let alone statisticians on the author list; Create plant proxies with no biologist on the author list; Talk about ocean pH without an oceanographer or chemist on the author list; pretend computer games produce real data without a single field check or even professional computer gamer on the author list. (OK, I may have gone to far on the last…)

March 16, 2022 6:35 am

I stopped reading after “University of Michigan models”.

Eric Vieira
March 16, 2022 6:58 am

One could spin it even further: more warming means also more water vapor in the atmosphere and more precipitation, so the increased amount of pollen is washed down by more rainfall, bla bla bla …

March 16, 2022 7:02 am

Whoopie Fuquing Do. CO2 is what greens the earth, so get over yourselves while whining about pollen with the breathlessness of Chicken Little.

March 16, 2022 7:15 am

The absurdity of this premise is real, and the comments are quite amusing and entertaining. However, it has to be noted that someone is getting a PhD from this ‘work’ and a professor is adding another notch to her belt. This will merely add to the cacophony of “scientists” proclaiming the horrors of Climate Change.

That part isn’t amusing.

March 16, 2022 7:25 am

Seems to me this would be easy enough to test in the real world – they could do controlled tests using greenhouses, right?

But I guess models are better than reality?

Bruce Cobb
March 16, 2022 7:56 am

Beware, Climate Change will cause giant, orb-weaving spiders to invade the East Coast and beyond! They build their webs in trees, well off the ground, where bicyclists, joggers, etc. can run into them and be face to face with these creatures. Oops, they already have.
We’re doomed.

March 16, 2022 8:09 am

I guess the climate change crowd never heard of anti-histimines.

Mickey Reno
March 16, 2022 8:23 am

In the future, children won’t know what “going outside to play” means.

March 16, 2022 8:49 am

Academia has prostituted itself into total irrelevance. Never before has the phrase “a recent study” been so utterly sterile of any authority or significance.

Another recent study shows that this will be a good month for Capricorns. Look out for a dark handsome stranger.

Last edited 2 months ago by Phil Salmon
March 16, 2022 8:56 am

they have created the phony narrative that CO2 will set the planet on fire, make oceans rise hundreds of feet, etc. None of that is happening so they search frantically about for ANY support for reducing the paltry human contribution to CO2 and/or warming as the wheels come off the Satanic Gases wagon.

Baghdad Bob global warming.jpg
March 16, 2022 8:57 am

University of Michigan models suggest that increased rates of plant growth due to warmer temperatures

That’s a lie already.

Abundant research has made it clear that the dominant reason for the current greening of the earth (30% increase in plant growth) is increased CO2, and that warming is a comparatively much smaller contributor.

Reply to  Phil Salmon
March 16, 2022 2:13 pm

They both play a role. Tree lines are advancing upwards world wide and northward in the Arctic. I don’t believe there is much of a tree line in the Antarctic.

John I Reistroffer
March 16, 2022 10:10 am


March 16, 2022 10:48 am

That’s like saying I hate having all that gold because it weighs so much, and the stupid goes on.

March 16, 2022 10:53 am

it would literally have to double the pollen to compensate for the environmental destruction and pentuple the pollen to make up for deforestation.

March 16, 2022 12:21 pm

TV and them Cell phones were the start of all this propaganda , they had this planned for a long time and now they are in the open for all of us to see. I wish i had a solution, it will take a better brain than mine to stop this. Climate change lockdowns are coming, mark my words

March 16, 2022 7:38 pm

CO2 is plant food and whereas more plants produce more pollen they also produce more food, emit more oxygen and adsorb more CO2 so overall a win….

Walter Sobchak
March 16, 2022 10:47 pm

Dang, I will have to buy another bottle of Zyrtec every year.

Rhoda R.
March 17, 2022 2:21 am

Gee, if there were NO plants there would be no allergies. Of course, we’d all stave to death but what’s a few bodies when we can avoid allergies.

March 17, 2022 1:15 pm

As a forest geneticist, retired, who spent many springs collecting, drying, and using tree pollen in controlled crosses, I find this “study” a bunch of nonsense. The onset of pollen development and shedding in most North American tree species is driven by photoperiod. Last time I checked, anthropogenic CO2 isn’t yet affecting day length…

Once pollen development begins, temperature and humidity are the key drivers of pollen shedding. Warmer and drier means faster shedding, which means a shorter period of pollen flight. And of course, pollen development and shedding has a strong genetic component, with some clones consistently early, others more mid-season, and others late. Again, warmer and drier will compress the pollination season, wetter and cooler will extend it.

Josh Scandlen
March 22, 2022 7:07 am

So the left is now worried about allergies, eh? Interesting as my question for the last 10 years is do the MASSIVE amount of vaccines put into kids lead to the increased allergies? Between my wife and me there are 12 siblings. Few have any allergies. Yet my 4 kids ALL have major allergies, deathly even in regards to peanuts and other nuts.

The CDC-recommended(demanded?) dosage of vaccines for infants is now above 20. Allergies, asthma, autism, etc. all increasing rapidly. Correlation does not equal causation, I get it. But yet, there is NO study documenting the safety of all these vaccines. None.

(Anyone who suggests an IOM study from 2012, I HIGHLY encourage you to actually read it.)

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