Increased leaf abundance is a double-edged sword
From the AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE
A new global assessment reveals that increases in leaf abundance are causing boreal areas to warm and arid regions to cool. The results suggest that recent changes in global vegetation have had impacts on local climates that should be considered in the design of local mitigation and adaptation plans. A substantial portion of the planet is greening in response to increasing atmospheric carbon dioxide, nitrogen deposition, global warming and land use change. The increase in leafy green coverage, or leaf area index (LAI), will hold important implications for climate change feedback loops, yet quantifying these impacts on a global scale can be challenging. Here, Giovanni Forzieri and colleagues analyzed satellite data of global LAI coverage between 1982 and 2011.
Their results varied depending on the local biome, where increased LAI in boreal regions caused a reduction in surface albedo (reflection of sunlight), and thus resulted in a warming effect; in contrast, increased LAI in arid regions caused an increase in transpiration, and thus drove a cooling effect. What’s more, the authors found that these relationships between LAI and surface biophysics were amplified up to five times under extreme warm-dry and cold-wet years. They estimate that, across about 60% of the global vegetated area, greening has buffered warming by about 14%; for the remaining areas, which mostly include boreal zones, LAI trends have amplified the raise in air temperatures, leading to an additional warming of about 10%.
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The study:
And this is a problem?
And this is a problem?
What part of photosynthesis did I miss? Isn’t part of “albedo” directs the absorbed energy into leaf chemical processes, inherently endothermic?
Exactly my first reaction.
It appears that they are assuming the energy retained by the changing albedo is converted into thermal energy. The principal function of foliage is convert incoming radiation into chemical energy.
Odd that this did not get picked up by the usually insightful and rigorous process of peer review !
The study link seems to be missing.
I don’t see the “doubled-edged” aspect of this. So CO2 and climate change are making cold (boreal) climates a bit milder (good news!) and making hot, arid deserts a bit cooler (good news!). What’s not to like?
Yeah, I don’t see a problem. How again are more even temperatures a bad thing?
It’s only with respect to development of climate models. They argue that the leaf abundance (complete with a new three letter acronym) is a negative in warm and arid regions due to evapotranspiration and is a positive reinforcing mechanism in forested regions closer to the poles. Such areas include the massive forest land in the Pacific Northwest.
The net effect is slightly negative.
I haven’t read the study, but I think that forests are always cooler than neighboring areas next to a forest off the regions. Arid areas cool off quickly at night, but the net effect of increased greening should be a negative reinforcement in tropical and boreal areas.
Here is the study (paywalled) http://science.sciencemag.org/content/early/2017/05/24/science.aal1727
I don’t think they are arguing that greening is a negative. It has to do with mitigation strategies. This means when Al Gore sells you a tree to offset your carbon emissions, that tree will be more valuable in arid regions rather than boreal regions.
lorcanbonda,
LAI is hardly new. It has been in the literature almost as long as multispectral imaging satellites have been in orbit.
Anything happening in earth’s ecosystem or climate is automatically bad, in order to justify
100300 billion a year going to faceless and never-accounted UN agencies every year.Right. Since so many people are clamoring for equality in everything else.
More even is extreme you know…
lorcanbonda @ur momisugly 3:59
These are not new concepts, but as you say, the development of climate models have not included such information. Now that this has been identified, perhaps some will, some won’t. How much will it cost to find out. Who cares?
Reminds me of Donald Rumsfeld’s statement about unknown unknowns.
The abstract notes:
I guess that includes the planning can be less aggressive or skipped altogether. They had to make it sound scary to get read, circulated, and provide funding for a followup study.
Some people really like scary stories. I do too, but I know it is fiction.
“complete with a new three letter acronym”
Doncha just love TLA’s.
“How again are more even temperatures a bad thing?”
It would mean less violent weather, fewer hurricanes and tornadoes, which is certainly a problem for warmistas.
Insurance Provider’s would have a boom. Less weather damages in some area’s. Flood insurance would Exponentially increase because of people living below the High Water Markers of Coastal Regions and inland low area’s would be under water. The government’s would lose land and taxes from them in some regional area’s and others would increase usable land. Governments want stability and Climate Change is anti-stability. Consider the North American Waterways of the past when all glaciers melt .. as an example. This is why the Government wants the Earth to stand still in a cold interglacial period. All the rest is just hype to get people onboard, thinking they can change the environment…by taxing everybody.
So let me get this right:
1: We cut down trees and reduce forest areas and leaf cover and it is a bad thing. This I agree with.
2: The planet grows better because of Co2 and better leaf coverage and this is also bad?????
Where is the common ground in all of this? The green backs that are being spent to fund this silliness. If trees could grow money all of our problems would be solved:)
CO2, not Co2 (which is cobalt!).
The other edge is that this is yet another factor that can not be accounted for in “the models.” Life was so much easier when all these ways in which “nature” reacts that can’t be predicted much less digitized, came into the world consciousness. This sort of reaction throws a billion dollars worth of modelling out the window.
I reckon an oncrease in leaf abundance in th Nulabor Plain, Australia, would be beneficial, if somewhat surprising.
I bring this silliness up to highlight the nonsense of global meaning of local phenomena.
There has a staggering increase in vegetation on the Nullarbor over the last few years.
What? Are there two trees there now?
So “There has a staggering increase in vegetation on the Nullarbor over the last few years.” I guess the one tree has two leaves now.
Global Leafing. Scary.
That should be the next term used by United Nations: “Global leafing” – I like that – hilarious. 🙂
“The results suggest that recent changes in global vegetation have had impacts on local climates that should be considered in the design of local mitigation and adaptation plans.”
No – the results suggest that the world is greening and that the only ones who are concerned about that are the Watermelons – the Greens.
And real people don’t design local mitigation and adaptation plans.
Well, they do, but THEY call it buying a leaf rake and some huge trash bags.
Does anyone know of a community that has a “local mitigation and adaptation plan”?
I’d love to see one just to see what it says.
I didn’t even know we needed a mitigation plan until now. I’ll have to look around for something to mitigate.
It used to be called “basic infrastructure”. But since most governments are negligent in keeping up with “basic infrastructure”, pretending that “climate change” is responsible for the bad outcomes of infrastructure negligence is a useful tactic.
The Mayor of my city is proposing that we abandon low-lying parts of the city in order to adapt to accelerating sea-level rise. Local tide gauges show no acceleration in the last 150 years…
It’s a shame some dog did not eat this 4th graders homework.
hahaha
I thought that was the job of the Russians – they do everything else that’s evil!
Hmm perhaps they should ask for funding from Homeland Security?
So the Greenie weenies do want, or don’t want, the world to become greener? Will they ever be happy, unless and until they control every aspect of everyone’s life in the whole world?
I do hate raking leaves in the fall so put me down in the “con” column. Wait I don’t mean I’m going along with the con…
Who needs to rake leaves? Crank up that 2-cycle exhaust spewing leaf blower and blow them in to the neighbor’s yard. /sarc of course.
I do miss the old days when we raked huge piles of oak and maple leaves, jumped in to them, and OMG, the horrors!, parents would burn the piles in the street!. Still miss the aroma of burning leaves in the Autumn.’
One autumn I was walking home late at night through a wealthy suburb of Brighton and heard a rustling noise from every garden. Becoming intrigued, I looked over someone’s hedge. To my a amazement, I saw a group of foxes having a wild time playing in the buildup of dried leaves. It was the same in every single garden!
So much goes on that we rarely see, even in suburbia.
Of course it is bad…more poison ivy, thriving invasive species, etc. Never any good possibilities.
I saw that alarmist paper discussed (here?) several years ago….claimed global warming would encourage more growth of poison oak and ivy, which is of course bad. It was one of the few alarmist claims I believed, but I realized the poison oak and ivy could grow better not because of a slightly warmer climate, but just directly from the increased carbon dioxide, as would be true for most other vegetation, too.
I remember that article and have been looking for it. Does anyone rmember where it was publised?
This one?
http://www.pnas.org/content/103/24/9086.abstract
Biomass and toxicity responses of poison ivy (Toxicodendron radicans) to elevated atmospheric CO2
Mohan, et al. (2006)
One word…KUDZU!
Although I saw an interesting link that kudzu is edible and supposedly as nutritional as kale.
Jake
Horse stall bedding is as “nutritious” as kale.
I wonder what the effect is for crop lands? I know the yields are up but what effect if any is there on temps?
Also in arid regions doesn’t transpiration also humidify the air increasing the likelihood of clouds which reduce nighttime cooling?
It’s complex. There are lots of things to consider. One thing is that some of the solar energy is used in photosynthesis and doesn’t contribute to heating the environment. link I wonder if they considered that?
I think when they calculate the carbon dioxide balance, the energy used is considered as part of the equation.
The biggest issues in comparing mature greenlands to constantly growing crop lands is the evapotranspiration which is something Roger Pielke has made a career studying.
This study is not claiming that greening is “good” or “bad”. It is talking about the reinforcing effects of using forest as a way to mitigate the effects of climate change. The gist of the study is that planting trees in some areas of the world will have a more positive effect than other areas.
I agree CommieBob: Would not it be equal to the number of calories of energy in the plant? 4kcal/per gram of sugar/starch/protein – and 9 for fat?
Just like they had to get rid of the Medieval Warm Period, they have to get rid of the perceived benefits of global greening…
Warming is good. Why does anyone want to “ameliorate” climate change, if that change be warming?
Exactly. We are in an INTER-GLACIAL! Any warming is good.
Regrettably, all good things come to an end.
The more we know, it seems the less we truly know.
“Ignorance expands in proportion to knowledge.”
—Vulliamy’s Law (anticipated by Goethe.)
“The smartest man in the whole round world really don’t know that much.”
Mose Allison
“It’s not as good as we thought!” –AAAS
Leaves 🍃 of doom
https://youtu.be/z5fOsgrAJiU
I was really disappointed when I found out that the Venus Fly Trap didn’t actually come from Venus.
easy mistake to make. It is the flies are from Venus. The plant traps the “Venus Fly”. Exported from Venus to Earth years ago to bug us.
Well put ferdberple . Not many people know that distinction.
Pros? Yup. Cons? Nope. Boreal forest warms a bit. Yeah, from minus 40 winter, with a bit more vegetation summers for the natives to harvest. Drylands like Sahel cooler in summer with more fodder for nomads and their herds. Nothing not to like anywhere. Ridiculous paper.
Leaves are evil
Leaves are evil
Haven’t seen the study and it may answer this question, but from what I see in the post the data they used was satellite measures for LAI. It is not clear to me how they then determined the change in albedo (measured, modelled, estimated) and the impact of that on local temperature trends. If that was all modelling then lots of reasons to be sceptical. Assuming reduced albedo led to warming may make sense but when it is due to increased vegetation some component of that increased absorbed solar radiation is now being converted photochemically into plant starches and sugars, not heat. In addition increased vegetation cover has additional effects many of which may affect local temperature in different directions such as increased evapotranspiration and movement of heat from surface to higher in the troposphere, increased retention of water in soils, buffering of diurnal temperature variation etc. The big message for me is more CO2 in atmosphere leads to more plant mass and overall more biomass, i.e. CO2 is a good thing for carbon-based life on Earth.
“Assuming reduced albedo led to warming may make sense but when it is due to increased vegetation some component of that increased absorbed solar radiation is now being converted photochemically into plant starches and sugars, not heat.”
But then aren’t the chemical potential energy of the starches and sugars oxidized when they are eaten producing mostly heat?
Yes the plant starches and sugars are ultimately converted back to heat when consumed or when decomposed, likewise when burned. But the discussion is about increasing green biomass, which translates to accumulation of radiated solar energy as biochemical potential energy thus diminishing the amount available to heat the radiated surface as long as plant mass is accumulating.
Awesome. More Flora absorbed solar radiation by shading the ground causing heat above it while cooling below it. Who’d of thunk such a thing…maybe a cave man sitting under a tree eating fruit. He did need science to tell him that.
As Willis showed recently, albedo isn’t the whole story. there is also the counter-intuitive issue of surface area exposed to the air, which is likely not accounted for in the models.
the problem with all models is that they all assume that the person that built the model fully understands the underlying physical processes. but if that was true there would be no need for iterative simulation style models such as are used in climate forecasting. One could simply just calculate the “n th” state directly.
Think of it this way. Climate models calculate the n+1 state based on the n state, for example:
Xn+1 = 1 + 11 / xn – 3
But the problems is that there is always some amount of error in each iteration, such that over time the error builds up with each iteration and eventually the result is mostly error and very little answer. However, if one fully understands the iteration, then it can be reduced to an equation without iteration:
x² – 4x – 8 = 0
now one can directly calculate the future state of the model without iteration, and as such the error term does not build up. Climate science is missing the mathematics to directly calculate the future state of the climate directly from first principles, independent of the current state, and thus cannot eliminate the error in model forecasting. Error is fundamental to the iterative design of climate models.
That raises an interesting mathematical point. Since climate IS substantially stable there must be some BIG NEGATIVE feedback beyond T^4 going down.
It ought to be possible to calculate to 95% confidence bounds beyond which climate will not go. Like ± 2 °C.
That won’t tell you where climate WILL go, but it offers strong probabilities to where it WON’T go.
Which is what politicians need to know if they have any real interest in real climate at all.
Which I doubt to a 95% confidence level.
Garbage in = Garbage out.
Without doing the maths and doing direct observation then areas with vegetation are cooler than those without. Perhaps there is a modifying affect with vegetation and wetlands which may elevate averages, so that night time temps in a desert near the equator can drop to freezing as there is nothing to store the day time heat, while a forest anywhere will have higher nighttime temps. Just calculating what temperatures will be using Albedo is very insufficient as it takes no account of the physical properties and Averages don’t tell you what is going on. And I really doubt that plants and animals are able to respond to averages.
From the article: “A new global assessment reveals that increases in leaf abundance are causing boreal areas to warm and arid regions to cool. The results suggest that recent changes in global vegetation have had impacts on local climates that should be considered in the design of local mitigation and adaptation plans.”
What are they going to do, organize against CAGW on a neighborhood level now?
They already are – look to what your schools are teaching your children.
So just another blatant cash grab?
“CO2 causes greening. How can we paint that as bad?”
“I know, let’s say it causes warming because of lower albedo!”
“Excellent! Can we tax trees, maybe? Those conference parties are getting quite expensive, and we need some more funds… “
We are creating more and more urban landscape. Is it considered arid or boreal?
Oh, wow, and I have always wondered why it takes so long for the Springtime temperatures in the northern latitudes to “warm back up” from their freezing conditions of the past winter.
Silly me, I never realized that I had to wait until after the Springtime “greening” of the biomass occurred before I could start enjoying the increased “warming” of the springtime temperatures.
Yours Truly. …… Eritas Fubar
A cup and a half of coffee and I still can’ figure out what “buffered warming by about 14%” means. I guess that must be good (when I was a kid Bufferin advertised on TV).
In summary: mankind is greening Earth. Cool climates are warming and warm climates are cooling. On average outside air temperature change is incredibly stable, staying within 0.5 °C over a century.
In my opinion marginal phobias should be treated in hospitals, not in parliaments. Stating with fear of leaves, weather and biospheric carbon.
Maybe this is just an excuse to cut down more tree for Drax, or to make way for wind turbines . !
I see nitrogen deposition, is included in the drivers for leaf abundance. Presumably one of the sources for this is diesel ICE. I have long wondered what the difference is between various Nox compounds produced by Diesel engines and those produced naturally by lightening and micro-organisms.