News Release 31-Jan-2020
Boston University
Chi Chen, a Boston University graduate researcher, and Ranga Myneni, a BU College of Arts & Sciences professor of earth and environment, released a new paper that reveals how humans are helping to increase the Earth’s plant and tree cover, which absorbs carbon from the atmosphere and cools our planet. The boom of vegetation, fueled by greenhouse gas emissions, could be skewing our perception of how fast we’re warming the planet.
Taking a closer look at 250 scientific studies, land-monitoring satellite data, climate and environmental models, and field observations, a team of Boston University researchers and international collaborators have illuminated several causes and consequences of a global increase in vegetation growth, an effect called greening.
In a new study, published in Nature Reviews Earth & Environment, the researchers report that climate-altering carbon emissions and intensive land use have inadvertently greened half of the Earth’s vegetated lands. And while that sounds like it may be a good thing, this phenomenal rate of greening, together with global warming, sea-level rise, and sea-ice decline, represents highly credible evidence that human industry and activity is dramatically impacting the Earth’s climate, say the study’s first authors, Shilong Piao and Xuhui Wang of Peking University.
Green leaves convert sunlight to sugars while replacing carbon dioxide in the air with water vapor, which cools the Earth’s surface. The reasons for greening vary around the world, but often involve intensive use of land for farming, large-scale planting of trees, a warmer and wetter climate in northern regions, natural reforestation of abandoned lands, and recovery from past disturbances.
And the chief cause of global greening we’re experiencing? It seems to be that rising carbon dioxide emissions are providing more and more fertilizer for plants, the researchers say. As a result, the boom of global greening since the early 1980s may have slowed the rate of global warming, the researchers say, possibly by as much as 0.2 to 0.25 degrees Celsius.
“It is ironic that the very same carbon emissions responsible for harmful changes to climate are also fertilizing plant growth, which in turn is somewhat moderating global warming,” says study coauthor Dr. Jarle Bjerke of the Norwegian Institute for Nature Research.
Boston University researchers previously discovered that, based on near-daily NASA and NOAA satellite imaging observations since the early 1980s, vast expanses of the Earth’s vegetated lands from the Arctic to the temperate latitudes have gotten markedly more green.
“Notably, the NASA [satellite data] observed pronounced greening during the 21st century in the world’s most populous and still-developing countries, China and India,” says Ranga Myneni, the new study’s senior author.
Even regions far, far removed from human reach have not escaped the global warming and greening trends. “Svalbard in the high-arctic, for example, has seen a 30 percent increase in greenness [in addition to] an increase in [summer temperatures] from 2.9 to 4.7 degrees Celcius between 1986 and 2015,” says study coauthor Rama Nemani of NASA’s Ames Research Center.
Over the last 40 years, carbon emissions from fossil fuel use and tropical deforestation have added 160 parts per million (ppm), a unit of measure for air pollutants, of CO2 to Earth’s atmosphere. About 40 ppm of that has diffused passively into the oceans and another 50 ppm has been actively taken up by plants, the researchers say. But 70 ppm remains in the atmosphere, and together with other greenhouse gases, is responsible the land warming patterns that have been observed since the 1980s.
“Plants are actively defending against the dangers of carbon pollution by not only sequestering carbon on land but also by wetting the atmosphere through transpiration of ground water and evaporation of precipitation intercepted by their bodies,” says study coauthor Philippe Ciais, of the Laboratory of Climate and Environmental Sciences, Gif-sur-Yvette, France. “Stopping deforestation and sustainable, ecologically sensible afforestation could be one of the simplest and cost-effective, though not sufficient, defenses against climate change,” he adds.
It is not easy to accurately estimate the cooling benefit from global greening because of the complex interconnected nature of the climate system, the researchers say. “This unintended benefit of global greening, and its potential transitory nature, suggests how much more daunting, and urgent, is the stated goal of keeping global warming to below 1.5 to 2 degrees Celsius, especially given the trajectory of carbon emissions and history of inaction during the past decades,” says study coauthor Hans Tømmervik of the Norwegian Institute for Nature Research, Norway.
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From EurekAlert!
“….suggests how much more daunting, and urgent, is the stated goal of keeping global warming to below 1.5 to 2 degrees Celsius…” Evidence of their motives is pretty strong in that statement. Not scientific, merely a confirmation bias statement.
I’ve had to read several comments here before being able to fully grasp just how crude and pernicious is the sophistry employed by some who purport to be scientists.
It is shocking to witness such shameless attempts to manipulate impressionable minds with complete desecrations of the truth.
But, after the Greta phenomenon, nothing surprises me much anymore, in this field.
There is no solution here for a problem that does not exist, as far as we actually know.
You’re telling us plants grow better in warm climates rather than cold ones. Yeah, we see that every year, it’s the seasonal cycle.
Have they factored in the extra fossil fuel required to mow the lawn more frequently?
“Green leaves convert sunlight to sugars while replacing carbon dioxide in the air with water vapor, which cools the Earth’s surface”
The ignorance of the author of this sentence is quite staggering. It’s “not even wrong” as we now say. OK, the news article writer is probably an arts graduate, but any even semi-educated person surely knows better. I learned about photosynthesis in primary school, for heaven’s sake. Perhaps they don’t do that any more.
The more I look at it, the more I think that it’s not even not even wrong.
Transpiration raises water to the leaves to be combined with CO2 to make the sugars. Some water vapour enters the atmosphere by this process else the water wouldn’t rise, the more plants so the more water is transpired
Was going to post that same sentence. Beat me to it.
I think whoever wrote that must have been trying to avoid giving credit to mankind’s CO2 for the greening effect. It just ends up being so very wrong.
This entirely Good News had had to be carefully tempered as it isa bit against-the-grain of climate catastrophe.
The fight to make global greening bad is one of the give-aways of the climate alarm movement — there can be nothing bad about global greening — yet, according to the likes of the CJR’s Covering Climate Now, it cannot be allowed to stand as a good news story.
I had a whole series on The Fight Against Global Greening (scroll down to get to the series links).
Actually, the biggest potential problem for humans is not necessarily temperature, rather soil erosion.
Greening also acts against soil erosion, by increasing the number of root systems which bind soil together and increase its resistance to flood-associated topsoil loss.
It is high time it was done. A US Professor at Columbia documented in the late 1940s how European ‘settlers’ in the US completely destroyed vast tracts of once fertile countryside by slash n burn replacement of trees with corn and cows. They denuded slopes of soil, created vast eroded gully systems and wiped out whole areas in under 20 years, moving on to their next vandalism project further west.
I am sure the same story could be told all over the globe, I just have not found the relevant literature to back up what I actually read in print about vandalism in the USA (Go read ‘Trees as Crops’ by J. Russell Smith…..)
Thing is, what you can destroy in 20 years may take 10,000 years to be regenerated by nature.
I just wish mankind could realise how easy it is to destroy and how difficult it is to rebuild.
If it could, maybe it would value what it already had, rather than blithely assuming that ‘it will all just grow back again easy enough’…..
RISING CO2 LEVELS GREENING THE EARTH (COPY OF MY POST OF 29/11/19 AT 2.01 PM, TO ‘NO TRICKS ZONE’ “GREENING OF THE PLANET”.
The Gaia Hypothesis postulates that the world is a self-regulating system that maintains the climate conditions necessary for life via the Carbon Cycle. The increased greening with rising CO2, if correct, could be strong evidence in support of Lovelock’s 1979 speculations about the “role of biota in maintaining a climatic homeostasis”.
Greening is a darkening of the surface from the usual tan (bare dirt) or white (snow).
To spacecraft sensors this would register as a change in the albedo (heat trapping ability) of the planet as a whole.
Time and time again we have seen it demonstrated that there is no direct correspondence between co2 and temperature, only a vague hand wavey type of it got a little bit warm back in the 90’s.
I’ll bet you anything you care to wager there is a direct one to one ratio between increased plant cover and global average temperature. Not talking about GISS. Not talking about Hadcrut. Those two outfits are as crooked as a hound dog’s leg.
There is a one to one correlation between the greening of the planet and the temperature of the planet.
These guys in the article are lost. They have the data right in front of them, too stupid to ask the right question. Too much ego in the room.
And the chief cause of global greening we’re experiencing? It seems to be that rising carbon dioxide emissions are providing more and more fertilizer for plants, the researchers say. As a result, the boom of global greening since the early 1980s may have slowed the rate of global warming, the researchers say, possibly by as much as 0.2 to 0.25 degrees Celsius.
A whole lot of people are being paid a whole lot of money for being a whole lot wrong.
The greening growth in ML CO2 comes from the ocean.
“…harmful changes…” Nope.
Let me help interpret:
“This unintended benefit of global greening…”
Uh-oh, people are starting to figure out that co2 is actually a good thing.
…and its potential transitory nature…”
Just at the very moment we were getting ready to turn it off!!
“…suggests how much more daunting, and urgent…”
So we’d better hurry and get the co2 turned off right away!!
These following rules summarize 40 years experience in climate studies.
The study above epitomizes these rules.
1. NOTHING positive occurs in the climate system. The negative anthropogenic influence is overwhelming .
2. The disaster narrative insists that all climate events be defined as deleterious, without exception.
3. Climate catastrophe requires that positive AND negative trends lead ultimately to future catastrophe
4. Data inconsistent with the desired catastrophic narrative are reanalyzed. Consistent data is accepted.
5. Reanalysis always results in the reanalyzed data giving a result closer to the desired narrative.
6. Positive climate events too large to reanalyze or ignore are, by definition, “ironic” and “unintended”.
7. All negative weather events are “extreme due to anthropogenic climate change.”
8. Positive weather events, by definition, cannot occur.
These rules are rarely broken.
Nicely summarised. And so darn obvious, when you put it like that.
What pains me the most is the readiness with which the largely scientifically illiterate public swallows such garbage.
I’m not a scientist, but I can discriminate between a good argument, based on established facts and clear reasoning, and one which is nothing more than a series of ideologically driven assertions, where data are either deployed as a smokescreen, or left out of account altogether, in service of the approved narrative.
Researcher O.K. Atkin has published several plant CO2 papers with different teams over the years. He made calculations that plant release (efflux) of CO2 into the environment from various parts of the different kinds of plants is 3, or more, times than all the CO2 emitted in the world caused by human “burning” fossil fuels.
Plants use some of the atmospheric assimilated CO2 made into “sugar” by photosynthesis internally to drive their life processes. Processing this sugar through what is called an internal “respiration” cycle generates CO2. This occurs not only in roots, but also in stems/branches.
Although some of this internally generated CO2 is used by roots to finesse root zone pH putting CO2 out into the soil a lot of root generated CO2 goes up the plant stem vasculature (xylem). Moving upward it adds to stem/branch internally generated CO2 that also gets into the xylem channel; transpiration (water going upward inside plant) carries this dissolved CO2 gas along with other solutes.
A portion of transpiration carried internally derived CO2 reaches the leaves (& petioles). The leaves’ expulsion (“efflux”) of this metabolic (“respiration”) derived CO2 is greater at night than during the day.
This is because, in plants, light (day) it’s self inhibits the cycling of “sugar” through the metabolic pathway (Krebs cycle) creating CO2 as an end product. However, elevated temperature & also drought (alone or in combination) are known to even further reduce the metabolic cycling that generates internal CO2.
Thus there is more internal CO2 generated during the dark (with different rates of the process occurring in time phases of ensuing darkness); but in the dark the plant vasculature (xylem) is undergoing less fluid transpiration upwards. When conditions during the day are good (high enough light, minimal stressors & a lot of carbon got fixed by the plants photosynthetically active tissue of leaves/green stems/green petioles) then one estimate is that although a lot of metabolic cycling occurred overnight up to 1/2 of that internally derived CO2 goes out of the leaf/stem/branch at one time or another.
Some of the internally generated CO2 is used in green tissue, mostly leaves, for photosynthesis; this amount varies among plants & also in the context of plant stress parameters. For example: thin leaves have relatively greater internal CO2 going out & waxy leaves have relatively less internal CO2 going out.
I read one estimate is that on average factoring in all terrestrial kinds of plants & environmental niches that 1.5% of the internally generated CO2 is put back out (efflux) from plants. And that elevated CO2 outside a plant leads to a quantitatively lesser percentage of efflux of it’s internally generated CO2; presumably since it is using more of that CO2 in reactions inside the plant.
I remember this Christy/Norris paper regarding irrigation of California’s central valley,
https://journals.ametsoc.org/doi/pdf/10.1175/JCLI3627.1
The effect plants on temperature is not uniform throughout the day, With more plants, expect daytime temperature trends to be lower- plant transpiration puts more latent heat in the air due to plant transpiration,
Expect nighttime temperatures to be warmer, As temperatures cool at night , they’ll hit the dewpoint, which will act as a buffer- keeping temperatures stable over a period of time,
a negative feedback mechanism – who’d have thunk it?
I have written numerous coments since 2013 here at WUWT on the ” Great Global Greening ^тм” and ” Garden of Eden Earth^тм”. I noted that the effect is exponential (fringing growth inwards into arid areas particularly) and that the chemical reaction of photosynthesis is endothermic (cooling), which the authors of this article don’t seem to know, or more likely didnt want to have mention of the cooling effect of the greening chemistry. Their “water vapor cooling” is additive after the fact of photosynthesis cooling.
I made some back of envelope calculations on the significant the effect. It led me to the idea of “Garden of Eden Earth” by mid century. I don’t believe I attracted one comment from either warmist or sceptic. I guess I don’t get a line in the bibliography of the present “breakthrough” research.
Hi Gary Pearse, – I’d like to ask you why you think photosynthesis chemical reactions are “cooling”.
After the light energy splits water & electrons from that get shuttled along there is another kind of light reaction occurring. There are electrons getting to the enzyme
NADP+ to carry, while protons getting pumped to participate in the generation of ATP energy; both of which (NADP & ATP) are upstream of photosynthesis derived “sugar”.
The leaf has tactical molecules to deal with
More specific of a “heating” feature of photosynthesis is that plant mitochondria perform uncoupling; this is what we humans do when shiver to generate heat )instead of using mitochondria just to make ATP energy). The dynamic in plants does not involve shivering & is somewhat technical so anyone interested can read the introductory free full text available on-line of : “Mitochondrial uncoupling protein is required for efficient photosynthesis”.
gringojay: I thank you for the education on the details of photosynthesis. But lets look at the bulk result. On a previously barren spot a tree grows. One can take the tree and later burn it giving off the heat that was present formerly as sunshine. Think coal seams which are remains of destructively distilled plants. Indeed, the amount of carbon in the plant could be thought of as equivalent to anthracite as a minimum measure of this sequestered energy. Cheers, Gary
Is it just me or are these “Climatologists” stunningly ignorant of the most basic scientific concepts?
Limits to growth, being the first obvious one.
More CO2=more plants,all other limits remaining constant.
Who knew photosynthesis needs Carbon Dioxide?
Then their endless outgassing about “furious forest fires” leaves me thinking the fire triangle is beyond their yen.
Have any of them made a bonfire?
Is current climatology a catch all for the mediocre and beta grade university graduates?
frightened people who never leave the air conditioned caves of Academia?
In the spirit of this woe and doom laden paper…Death to the trees.
How dare they prosper when man used fossil fuels instead of wood for energy and provides/returns centuries sequestered carbon dioxide back to the food cycle.
Obviously trees are the enemy.
Of the Cult of Calamitous Climate that is.
Interfering with the projected doom, crushing the computed gospel…Trees they mock us all.
Man made catastrophic global warming via increased CO2 by 2 ppm per year is such a tenuous theory it can’t allow for a negative feedback. All the feedback cycles have to be positive and reinforce each other. All the predicted effects have to take place or it all unravels.
An important point ignored in the article is the tangible benefit of better plant growth. Current estimates are that roughly $500 billion of the roughly $8 trillion of world wide annual commercial agriculture production is due to the CO2 added to the atmosphere since ~1820.
Commercial greenhouses routinely add CO2 to improve quantity and quality of their products.
This web site: http://co2science.org/ has an extensive database of peer-reviewed papers giving results of experiments on adding CO2 for specific plants: http://www.co2science.org/data/plant_growth/plantgrowth.php
Most of the experiments are done in the open air, not greenhouses. This is the FACE (Free Air Caron Enrichment) type of study.
CO2 has no significant effect on climate.
Simple calculations using data from Hitran show increased water vapor is about 10 times more effective than increased CO2 at ground level warming. Added cooling by increased CO2 well above the tropopause counters and perhaps exceeds the tiny added warming from more CO2 at ground level.
Measured water vapor trend has been increasing faster than possible from feedback. https://watervaporandwarming.blogspot.com
Plants are good for something? Who knew?
Carbon dioxide will make plants fat and give them diabetes.
A carbon tax will save them from themselves.
Yes, I am being sarcastic.
Hi Center-left horticulturist, – I do believe you are on to something here. Plant leaves are actually better leaf “sugar” insensitive, which is the inverse of how normally humans respond to blood sugar (diabetics are termed “insensitive” to blood sugar). In simplified terms: there are features about the level of leaf sugar that basically mean excessive sugar there reduces photosynthesis.
A color photograph demonstrating this is Fig.2 in (2008) review “Sugar sensing and signaling”; free full text available on-line. The greened sprout in middle picture labelled “gin” is “insensitive” to sugar; which can be visually compared to the picture labelled “glo” representative of “hyper-sensitivity” to sugar.
Obviously plants are adapted to deal with photosynthetic elaborated “sugar”; their commonest tactic is to redirect it from the leaves (“source” of sugar) to other parts of the plant (where that sugar can “sink” in). We see this tactic under elevated CO2 (eCO2) where relatively more carbon is fixed in the leaf favoring more “sugar” elaboration, & the eCO2 plants get thicker bases/more root.
So your jest is actually true in the sense that eCO2 plants are getting “fat” because their leaves are “insensitive” to sugar. Thus they are better able to keep photosynthesizing & filling up the lower plant architecture (body) “sinks” more. WUWT readers may enjoy the free full text available on-line of (2001) “Sink regulation of photosynthesis”; laymen might find it an easier read than the other report cited immediately above regarding the photos.
I think useful information for this topic could be in the following paper:
Hermann Harde. What Humans Contribute to Atmospheric CO2: Comparison of
Carbon Cycle Models with Observations. Earth Sciences. Vol. 8, No. 3, 2019,
pp. 139-159. doi: 10.11648/j.earth.20190803.13
Are the data from the new CO2 measuring satellite providing a better picture of the possible origins of the increased atmospheric CO2? I haven’t seen much mapping published recently.