Trillions and Trillions of Trees make that 'giant sucking sound' of CO2 from the atmosphere

WUWT reader P Wilson writes;

There are just over three trillion trees on Earth, according to a new assessment. The figure is eight times as big as the previous best estimate, which counted perhaps 400 billion at most.

It has been produced by Thomas Crowther from Yale University, and colleagues, who combined a mass of ground survey data with satellite pictures.

The team tells the journal Nature that the new total represents upwards of 420 trees for every person on the planet. The more refined number will now form a baseline for a wide range of research applications – everything from studies that consider animal and plant habitats for biodiversity reasons, to new models of the climate, because it is trees of course that play an important role in removing the greenhouse gas carbon dioxide from the atmosphere.


The press release from Yale:



Seeing the forest and the trees, all 3 trillion of them

A new Yale-led study estimates that there are more than 3 trillion trees on Earth, about seven and a half times more than some previous estimates. But the total number of trees has plummeted by roughly 46% since the start of human civilization, the study estimates.

Using a combination of satellite imagery, forest inventories, and supercomputer technologies, the international team of researchers was able to map tree populations worldwide at the square-kilometer level.

Their results, published in the journal Nature, provide the most comprehensive assessment of tree populations ever produced and offer new insights into a class of organism that helps shape most terrestrial biomes.

The new insights can improve the modeling of many large-scale systems, from carbon cycling and climate change models to the distribution of animal and plant species, say the researchers.

“Trees are among the most prominent and critical organisms on Earth, yet we are only recently beginning to comprehend their global extent and distribution,” said Thomas Crowther, a postdoctoral fellow at the Yale School of Forestry & Environmental Studies (F&ES) and lead author of the study.

“They store huge amounts of carbon, are essential for the cycling of nutrients, for water and air quality, and for countless human services,” he added. “Yet you ask people to estimate, within an order of magnitude, how many trees there are and they don’t know where to begin. I don’t know what I would have guessed, but I was certainly surprised to find that we were talking about trillions.”

The study was inspired by a request by Plant for the Planet, a global youth initiative that leads the United Nations Environment Programme’s “Billion Tree Campaign.” Two years ago the group approached Crowther asking for baseline estimates of tree numbers at regional and global scales so they could better evaluate the contribution of their efforts and set targets for future tree-planting initiatives.

At the time, the only global estimate was just over 400 billion trees worldwide, or about 61 trees for every person on Earth. That prediction was generated using satellite imagery and estimates of forest area, but did not incorporate any information from the ground.

The new study used a combination of approaches to reveal that there are 3.04 trillion trees — roughly 422 trees per person.

Crowther and his colleagues collected tree density information from more than 400,000 forest plots around the world. This included information from several national forest inventories and peer-reviewed studies, each of which included tree counts that had been verified at the ground level. Using satellite imagery, they were then able to assess how the number of trees in each of those plots is related to local characteristics such as climate, topography, vegetation, soil condition, and human impacts.

“The diverse array of data available today allowed us to build predictive models to estimate the number of trees at each location around the globe,” said Yale postdoctoral student Henry Glick, second author of the study.

The resulting map has the potential to inform scientists about the structure of forest ecosystems in different regions, and it can be used to improve predictions about carbon storage and biodiversity around the world.

“Most global environmental data is thematically coarse,” said Matthew Hansen, a global forestry expert from the University of Maryland who was not involved in the study. “The study of Crowther et al. moves us towards a needed direct quantification of tree distributions, information ready to be used by a host of downstream science investigations.”

The highest densities of trees were found in the boreal forests in the sub-arctic regions of Russia, Scandinavia, and North America. But the largest forest areas, by far, are in the tropics, which are home to about 43% of the world’s trees. (Only 24% are in the dense boreal regions, while another 22% exist in temperate zones.)

The results illustrate how tree density changes within forest types. Researchers found that climate can help predict tree density in most biomes. In wetter areas, for instance, more trees are able to grow. However, the positive effects of moisture were reversed in some regions because humans typically prefer the moist, productive areas for agriculture.

In fact, human activity is the largest driver of tree numbers worldwide, said Crowther. While the negative impact of human activity on natural ecosystems is clearly visible in small areas, the study provides a new measure of the scale of anthropogenic effects, highlighting how historical land use decisions have shaped natural ecosystems on a global scale. In short, tree densities usually plummet as the human population increases. Deforestation, land-use change, and forest management are responsible for a gross loss of over 15 billion trees each year.

“We’ve nearly halved the number of trees on the planet, and we’ve seen the impacts on climate and human health as a result,” Crowther said. “This study highlights how much more effort is needed if we are to restore healthy forests worldwide.”

Researchers from 15 countries collaborated on the study. There were 14 researchers from across the Yale community who contributed to the study.

The article at Nature:

255 thoughts on “Trillions and Trillions of Trees make that 'giant sucking sound' of CO2 from the atmosphere

  1. Funny that they previously underestimated the total number of trees by nearly a full order of magnitude, but they’re still just sure that we’ve eliminated nearly half the trees on the planet.
    If you want somebody to trust your numbers, you should start by demonstrating that you can, indeed, count.

      • I know for sure they did not count the six new Coconut trees I have going, or the dozen date palms.
        So make that headline “Just over three trillion and eightteen”.
        I will update the total again after my new peach trees go in.

      • This may sound dumb, but how do they define a tree. Is it a three foot high sprig or a giant redwood. Not all trees are equal size and I assume they absorb (convert) CO2 at different rates.

      • SP,
        Not a dumb question at all. Even professional foresters can’t all agree on what counts as a tree.
        I think they are all C3 plants, however, so benefit from higher CO2.

      • And I planted 48 bare-root fruit trees just this spring. However, in the past two years I’ve cut down 27 cottonwoods that were creating a mess and shading our pasture and some of those trees were huge. Apparently, I’m still in a tree deficit.

    • It is worse than you think. In the same paragraph, the scientists found a 750% error in the previous satellite-based estimate. But in almost the next sentence, they state that the number of trees has dropped by 46% (not 45% or 47%, mind you) since ‘the start of human civilization.’ They claim impossibly high accuracy in tree counts at a time that they leave basically undefined.
      And this made it through peer review for Nature, one of the highest impact journals in the world?

      • “they state that the number of trees has dropped by 46% (not 45% or 47%, mind you) since ‘the start of human civilization.’ They claim impossibly high accuracy in tree counts at a time that they leave basically undefined.”
        No, they claim “roughly 46%” (which would include 45% and 47%, mind you).

      • Calculating % of tree loss is much easier than counting trees. Especially when using rough estimates. You look at the amount of land cleared for things such as agriculture, roads, subdivisions, lumber harvest, etc. and multiply by the averaged tree density, subtracting from the total area of forested land. So simplistically, if I cut down 5 acres of trees on a 10 acre forested property, then tree loss is roughly 50%. Extrapolate that to the whole world and you get a rough estimate of tree loss.

      • Except that from a CO2 perspective, it doesn’t matter what kind of plants. The percentage lost of one particular plant species is a specious argument.
        A study showed that clear cutting actually helps because the replacement plants are much more vigorous in oxygen production and CO2 intake than old growth forests. Croplands consist of plant life. Even suburbs are well vegetated.
        Mankind doesn’t always clear cut, but when it does, it almost always replaces trees with other plants. Stay thirsty my friends…

      • GOD: Francis, you know all about gardens and nature. What in the world is going on down there? What happened to the dandelions, violets, thistle and stuff I started eons ago? I had a perfect, no-maintenance garden plan. Those plants grow in any type of soil, withstand drought and multiply with abandon. The nectar from the long lasting blossoms attracts butterflies, honey bees and flocks of songbirds. I expected to see a vast garden of colors by now. But all I see are these green rectangles.
        ST. FRANCIS: It’s the tribes that settled there, Lord. The Suburbanites. They started calling your flowers “weeds” and went to great lengths to kill them and replace them with grass.
        GOD: Grass? But it’s so boring. It’s not colorful. It doesn’t attract butterflies, birds and bees, only grubs and sod worms. It’s temperamental with temperatures. Do these Suburbanites really want all that grass growing there?
        ST. FRANCIS: Apparently so, Lord. They go to great pains to grow it and keep it green. They begin each spring by fertilizing grass and poisoning any other plant that crops up in the lawn.
        GOD: The spring rains and warm weather probably make grass grow really fast. That must make the Suburbanites happy.
        ST. FRANCIS: Apparently not, Lord. As soon as it grows a little, they cut it-sometimes twice a week.
        GOD: They cut it? Do they then bale it like hay?
        ST. FRANCIS: Not exactly, Lord. Most of them rake it up and put it in bags.
        GOD: They bag it? Why? Is it a cash crop? Do they sell it?
        ST. FRANCIS: No Sir. Just the opposite. They pay to throw it away.
        GOD: Now let me get this straight. They fertilize grass so it will grow. And when it does grow, they cut it off and pay to throw it away?
        ST. FRANCIS: Yes, Sir.
        GOD: These Suburbanites must be relieved in the summer when we cut back on the rain and turn up the heat. That surely slows the growth and saves them a lot of work.
        ST. FRANCIS: You aren’t going to believe this Lord. When the grass stops growing so fast, they drag out hoses and pay more money to water it so they can continue to mow it and pay to get rid of it.
        GOD: What nonsense. At least they kept some of the trees. That was a sheer stroke of genius, if I do say so myself. The trees grow leaves in the spring to provide beauty and shade in the summer. In the autumn they fall to the ground and form a natural blanket to keep moisture in the soil and protect the trees and bushes. Plus, as they rot, the leaves form compost to enhance the soil. It’s a natural circle of life.
        ST. FRANCIS: You better sit down, Lord. The Suburbanites have drawn a new circle. As soon as the leaves fall, they rake them into great piles and pay to have them hauled away.
        GOD: No. What do they do to protect the shrub and tree roots in the winter and to keep the soil moist and loose?
        ST. FRANCIS: After throwing away the leaves, they go out and buy something which they call mulch. They haul it home and spread it around in place of the leaves.
        GOD: And where do they get this mulch?
        ST. FRANCIS: They cut down trees and grind them up to make the mulch.
        GOD: Enough. I don’t want to think about this anymore. St. Catherine, you’re in charge of the arts. What movie have they scheduled for us tonight?”
        ST. CATHERINE: “Dumb and Dumber”, Lord. It’s a really stupid movie about…..
        GOD: Never mind, I think I just heard the whole story from St. Francis.

      • Viking,
        If C3 plants (such as trees) are replaced with C4 or CAM plants, cutting down trees could have an effect on CO2 drawdown. Corn is a C4 plant, which is why I wasn’t sure if replacing trees with it would lower CO2, but apparently it does, thanks to the rapid growth of crops vs. mature hardwood forest.
        Corn however gets fed to livestock, which raises methane.
        Small grains like rice, oats, wheat and barley are however C3 plants.

      • While Tim is correct, I still say they should have said “Roughly half”. That’s a defensible estimate that can be made from historical tree extent and areas that should be able to support trees but do not due to agriculture, roads, industry, and cities. Saying 46% is a basic violation of significant digits. Even high schoolers are penalized for such an error.

      • Ben,
        I agree, but with ongoing reforestation in North America and Europe, the total might no longer be half. And where the land hasn’t been reforested, crops are growing, eg rice and wheat in China, wheat and potatoes in Europe and corn and wheat in North America.

      • Unbeknownst t most people, there are plant growth regulators that will make turf grass grow extremely slowly and mostly just get denser.
        I cannot figure out why these are not big sellers.
        Ditto with hedges and bushes…nurserymen treat their flowering shrubs and other plants with chemicals like B-Nine (also sold under the name Alar) which reduce internodal distance and make a plant darer green, denser, have more flowers, and have a very uniform appearance.
        other products like Bonsai work in a similar fashion.
        Ever wonder why the Bermuda on a golf course looks different than the stuff on your lawn?

      • From the BBC article cited above-
        “And Dr Martin Lukac from the University of Reading was still not sure we were near an accurate count.
        “The previous estimate of trees in the world was 400 billion. The new estimate is three trillion large trees. There are so many margins of error in this study that the real number could be anything between the two – or even 10 times higher,” he said.”

      • “There are so many margins of error in this study that the real number could be anything between the two – or even 10 times higher,” he said.”
        I love this settled science!

      • Viking,
        The replacement vegetation that comes in when a tree is cut down might have a short term higher CO2 draw, but the CO2 which comprises the tree is likely to be released unless said wood is stuck into a building.
        It is thus not clear at all what the net CO2 effect is overall. If the wood from the chopped down tree is burned, it isn’t going to be negative.

      • possibly a precursor to releasing the rest of the data from the oco-2 project .all the extra trees they missed will account for co2 levels not being as high globally as the mauna loa measurements and the higher concentrations being in completely different areas o what was expected. gotta cover up that confirmation bias somehow.

      • Roughly 46% includes 10%, 20% 50% and 90%…
        An honest scientist would happily give the number in 25% variables, i.e., 25%-50%….
        If you can’t define “roughly,” you can’t offer ANY percentage…

      • Agree – the best thing the supercomputer does is get to the same bad result but it does it REALLY fast and can thus move on to even more bad results.

      • Wondering what data this Supercomputer has been fed as input. Was the whole world covered in trees in the beginning? When was the unset of humanisation on Earth? We still differ of opinion on that. The North Sea for instance was maybe still land covered in trees in those days, with rivers flowing through it. Possibly more of these alluvial areas present around the globe. How did we account for that? Natural flooding killing trees after one of the ice ages. The Netherlands were still covered with sea water twice a day, until we built dikes and planted trees on the land. More of these places present in Mangrove areas. So what an unbelievable difficult base calculation must that have been, hence I take the whole story with a bucket of salt. What is the accuracy? 6 trillion now and last time 1/7 of that. Rather large spread. Not worth the paper it is written on. And what is the aded value……..

        • Rein: “Wondering what data this Supercomputer has been fed as input. Was the whole world covered in trees in the beginning?”
          AFAIK man was certainly on the planet long before the end of the last ice age, when there was an ice cap covering a great deal of the Northern hemisphere land mass (I don’t know about the Southern). So unless trees can grow on glaciers, it seems likely that there wasn’t as much space for them to grow (although there was land available that is now flooded, of course).
          This “roughly” 46% (at least they didn’t specify any decimal places) “since the start of human civilization” just looks like the usual guilt trip BS to me.

    • My sister in Melbin, lives in a veritable forest of trees and other greenery including all sorts of cacti and other plants.
      Every green thing that is visible from their house; they planted themselves in the 45 years since they built their house on a piece of open empty ground on one side of a small stream.
      That includes the forest of Australian native trees (they’re called gum trees mate) that they planted on the other side of the stream; well actually on the other side of the paved walking pathway on the other side of the stream, that now comprises a public city park.
      The tallest of the trees are over 150 feet high, all planted from saplings they dug up out in the outback and brought home to plant.
      Their tallest cactus (or would that be a cactum) is over 50 feet tall; and is named Arizona. It finally flowered after several years of not flowering, while I was there last March. it only flowers at night and the flowers die the next morning.
      So some humans are doing their share of greening the planet.

      • I recently was given a picture of my side yard from 10 years earlier and it was nearly treeless. Now it is covered with red oak. Trees grow like weeds in VA and we only get 30-35″ rain. I can’t harvest fast enough to keep up. Can no longer get broadcast signals because of denseness of forest and I have just 8 acres.

      • Maybe the extra CO2 we are pumping into to the atmosphere has caused us to grow 2.58 trillion new trees since the last study, I am sure the last study was pier reviewed so it had to be correct at 420 billion.

      • When I was growing up, the empty lots in the subdivision I lived in were dominated by cogon grass and the only trees were a ring of 20 or so she-oaks planted by the developer around the “park.” Now there’s hardly any cogon to be found, no she-oaks, and hundreds of broad-leaf trees—in both the park and the yards of the no-longer-empty lots, including 5 in our backyard. Summer temps are tangibly cooler, if only because of the presence of so many shade trees.
        The same thing goes for the urban area where I live now. The open spaces around my old school have been replaced by malls and high-rise buildings, sure. But the fields of cogon grass were also replaced by dozens of trees.

    • the total number of trees has plummeted by roughly 46% since the start of human civilization
      but of course that had no effect on CO2

    • Yep – that is what I took away from that too. If you couldn’t count them accurately, then all the other statements are irrelevant.

    • This paper covered 12,000 years. We were just recovering from an ice age to go into the Younger Dryas, another cold period. there were no trees in polar regions back then and rainforests were grasslands due to the cooler climate. All those trees in 10,000years pays tribute to the tree’s survival skills.

  2. Without the trees, we don’t breath so protect the trees. There is an interesting ride up Route 17 to Ithaca. It winds through ageless mountain that comprise part of the chain of Appalachian Mountains along the east coast of US. Route 17 seems to follow a trail through the mountains that must have been used hundreds of years ago. Beautiful in the Fall but the colors don’t stay long, 2-3 weeks.

    • I grew up about 70 miles from the area you mentioned, in another densely forested area.
      Most of the Twin Tiers was clear-cut a hundred years ago. It all grew back.

    • I was working at a property at the very southern-most terminus of US 17 today.
      Vivante @ Punta Gorda.
      Nice place too.

    • I appreciate these references to where I live and work. I often tell people “anyone who thinks world population is too high has never driven from Binghamton, NY to Erie, PA” – or across the Commonweath of PA on Route 80, for that matter. The great states of NY and PA consist mostly of thousands of square miles of wild, green woods and fields, with plenty of fresh water.

  3. Trees respire as well as photosynthesise.
    As the largest density of trees is Boreal Forest (up by the Arctic) do they increase or decrease the total CO2 in the Northern Hemisphere winter?
    Trees aren’t as simple as they are huggable.

    • M Courtney
      Trees are obviously important for a number of reasons but presumably someone needs to recalculate the carbon budget in the light of this huge revision of the number of trees as they are considered both a source (when burnt) and a sink when growing. So at some point the co2 has been released by felled trees and not fully reabsorbed by those remaining.
      Whether that means we are more or less culpable for past and current levels of co2 I don’t know.
      New carbon budget anyone?

      • Tony,
        The global CO2 budget caused by the whole biosphere can be deduced from the oxygen balance: when trees take in CO2, they release oxygen. When they shed their leaves in fall, much of it returns as CO2 into the atmosphere and that uses oxygen. Rotting trees, stems, eating feed and food by animals and humans also uses oxygen and releases CO2.
        O2 releases/uptake from/to the oceans are only temperature dependent and don’t follow the CO2 path, except for bio-life in the oceans of course.
        Oxygen use from fossil fuel burning is more or less known from sales and burning efficiency of each type of fuel. Oxygen measurements in the atmosphere are available with sufficient accuracy (1:200,000!) since the 1990’s. That shows that the whole biosphere is an increasing sink for CO2 of currently about 1 GtC/year since 1990:
        The new findings don’t change that, only may show that the carbon cycle is larger than estimated, but the net result at the end of the seasonal cycle remains the same…

    • Any two year old child can identify a tree; ANY tree, (cept maybe a Boojum tree in Baja), and they can distinguish any tree from the fake AT&T tree, commonly called a telephone pole.
      But nobody has ever got a computer program to distinguish ANY real tree from any real telephone pole.

      • I have a 20 foot tall lilac bush in my back yard and a locust tree. Please tell me IYO if they’re both trees or if the tree-sized bush is a shrub.
        There are also some other tall bushes and maple trees. What IYO distinguishes a tree from a tall shrub?

      • Bob,
        A tree can be bushy. One defining trait of a tree is a single dominant trunk but that isn’t always dispositive. One of my maples has two, formerly three, trunks that split close to the ground.
        Hence, the issue is whether the lilac bushes are shrubs or trees.

      • I’ve been working on a sign to post on our local cell-phone towers. So far:
        Intrusive species: Native to Santa Clara, CA
        Propagation: Pod Clusters, Line of Sight

        : > )

      • Gloria:
        Your lilac is either a bush or a tree – your locust on the other hand, is a carpenter ant house with leaves.

      • Greg,
        Both trees and shrubs can be bushes, although the latter more often than the former. Bush describes the shape of a tree or shrub, usually the latter. Shrub refers to size rather than shape.
        Please see the material I posted from the Utah State forestry program.
        Luckily my locust or carob tree doesn’t harbor carpenter ants. An old one I cut down still sends up shoots from its roots. And its trunk was grown together from a number of suckers, so in its youth it had been bushy before becoming trunky.

    • I agree with Gloria, without a definition it’s like arguing your salary went up 150% because you are now paid in dimes instead of quarters and get more coins each week.

      • Professional foresters have different definitions, but apparently George knows one when he sees one:
        “So trees, shrubs, and woody vines all have woody, perennial stems. What makes them different from one another? The distinction between trees and shrubs is not always clear. We all know that a large cottonwood is a tree and a creeping juniper is a shrub, but there are many shrub-like trees and tree-like shrubs. Though no scientific definition exists to separate trees and shrubs, a useful definition for a tree is a woody plant having one erect perennial stem (trunk) at least three inches in diameter at a point 4-1/2 feet above the ground, a definitely formed crown of foliage, and a mature height of at least 13 feet. This definition works fine, though some trees may have more than one stem and young trees obviously don’t meet the size criteria. A shrub can then be defined as a woody plant with several perennial stems that may be erect or may lay close to the ground. It will usually have a height less than 13 feet and stems no more than about three inches in diameter.”
        By this standard, my lilac “shrubs” are trees.
        [And my dogwoods are shrubs. .mod]

      • Mod,
        Good point from the reverse angle. A plant which might in the course of nature grow into a tree can be trained to be a bushy shrub.

    • Well I think it is important to monitor the average number of animals per acre or hectare; and have the WWF keep tabs on that number. In this case, an animal would be any kind as big as or bigger than say an ant.

  4. Plant another 1.5 trillion trees, and (if my maths is correct) they will absorb all of our CO2 emissions.
    Anyone have a cheaper solution?

    • It’s possible that the corn fields which have replaced the hardwood forests of eastern North America suck more CO2 out of the air than the native woods would have.

      • It is not only possible, it is a fact and I wish I could site the study but it was about 20 Yrs. ago. (I’ll look for it.) It should be obvious over the short term (corn growing season) but the study showed it was on average the same over the long term as the year over year growth RATE is much faster for corn (and grasses of all types) than for trees, acre for acre. That said, do not forget they also give up some (but not all) of that CO2 to the atmosphere when they die. (As do of course the trees.) Comparable net to net – – ?? depends on what happens to the remains at life cycle end of each, but in most scenarios the grasses win the “CO2 sucking war” by a wide margin and at worst it’s a tie, even if nature (including humans) burns them. So her’s a question for ya’ all, which sucks and keeps more CO2 from the atmosphere (over a years time), the 2 trees in your yard or the grass?

      • Depends…
        The corn carbon cycle is quite short: about everything of it is eaten within a year (or at maximum a few years), as it is mostly feed for animals, which transform most of it (3/4th) back into CO2, only 1/4th remains in the animal, until eaten by humans… Or worse, they use the corn for alcohol into car feed…
        One has to look at the difference of what remains in the roots or humus in a corn field (near zero) and what remains in a forest (piling up over the years)…

      • George,
        For the purposes of comparison with the vanished hardwood forests, and “eastern” cornfield would be in a spot that grew woods before white settlement, rather than grassland.
        So, yes, it would be east of Nebraska’s long grass prairie. Even much of Illinois was prairie before the white man, although Indian land management might have contributed to that. The native hardwood forest extended from west of the Mississippi River (MO, AR, LA) to the Atlantic. It featured both a northern, including Ontario and other Canadian provinces, and southern version.

      • Top two corn states are IA & IL, close together at the top, with IL some years switching more heavily to beans, followed by NE, MN, IN, KS, SD, OH, WI, MO, MI and TX.

      • J. Philip,
        All the leading corn states were at least partially covered by the native hardwood forests cut down or burned by the pioneers. Corn grows where the forest or at least long grass prairie was. Wheat grows on the former short grass prairie.
        In the 1870s someone calculated that an Ohio pioneer would have been way bucks ahead not to have cleared the hardwood forest off his land but to have held onto those trees and sold them for a fortune 50, 60, or 70 years later. Of course, in the meantime, he would have needed to have slashed and burned some of them to feed his family.
        I’m descended from such a family in SW Ohio.

      • Ferdinand
        am I sequestering CO2 from corn if I eat to much and gain extra weight each year. If I continue to gain weight by eating corn should I get some kind of carbon credit?

      • “which sucks and keeps more CO2 from the atmosphere (over a years time)”
        My cousin, Bertha. By a lot.

      • Bob,
        Your deferred carbon taxes will be tacked onto the estate taxes your heirs must pay upon your I hope long deferred demise, when your so public spiritedly sequestered carbon will be released into the atmosphere.

  5. This story in this blog is about 3 times more complete than is reported in my daily newspaper today. The story I read this morning is totally slanted toward the loss of trees by 46%. I am getting the feeling that since we have no true historical record of how many threes were here in the past couple hundred years, the study means nothing. I think, that at least in the U.S., we have planted a heck of a lot of trees.

    • I’m not sure I would agree that it means ‘nothing”, but it is just the first data point. We need more data points using the same method 10, 20, 100 years from now to know what the change is. This study can’t point to any change so far.

      • Does grass and corn also count at a CO2 eater ? Why just slow-growing trees. There is a lot more green out there than just trees eating CO2.

    • The Wall Street Journal story today says “it was hard to accurately count re-growth and reforestation, in part because saplings are small, but the researchers estimated that new trees might reduce the net loss to about 10 billion.” Even with a huge increase in their tree count they still try to weasel towards saying we are losing trees on net. They just can’t admit the truth that they have no frigging clue what is going on in nature.

  6. So there is eight times the sequestration of CO2 by trees than we thought! I have an idea. How about getting cheap fossil fuel energy to the poor nations so they can leave their trees to grow and sequester CO2 like the UK Drax power plant that is burning North Carolina hardwoods to save the planet. Its carbon neutral, don’t you see. Otherwise half of the remaining half will be cut down by 2100 and CO2 will have fewer places to go. Don’t you hate it when they keep finding things out that squelch CO2 policy.

    • O Lord, have mercy, it’s so funny:
      In the viewpoint of the Anti-CO2 cultists as even in this sentence from lukewarmer Antony
      “… because it is trees of course that play an important role in removing the greenhouse gas carbon dioxide from the atmosphere.”,
      the only reason of existance and function of trees seems to be to remove the evil satanic gas CO2 out of the atmosphere to rescue planet Earth from its otherwise inevitable terrible frying death… 😉
      What a grotesque caricature of the real world! It’s the other way round! Without the very limited and valuable trace gas CO2, there would be no trees on Earth, nor any other higher forms of life, as well.
      Never forget: CO2 is THE GAS OF LIFE !!!

      • CO2 is not only the stuff of life, it makes life bigger. In all but a few species, plant growth increases with higher concentrations of CO2. There is a detailed table of increased growth here:
        A quick scan shows up to 146% increase in some species, with a mere 300 ppm added – though that is exceptional. It is also what satellites show in the greening of low precipitation regions such as the Sahel desert and parts of Australia. With the greater availability of CO2 leaf stomata shrink, reducing transpiration and offering better drought resistance. What is there not to like?

  7. All three trillion trees will die soon returning a large part of that sucked up carbon to the environment. If they are not replaced with 3 trillion trees there will be a net deficit of carbon sucking. Fortunately CO2 levels are not much of a concern unless we run out of it by the rogue action of mad as hatters green activists.
    The irony is if we stop producing CO2 we will run out of money and have to resort to burning wood for energy and comfort. When we run out of trees we will run out of people. And isn’t that the objective?
    Who wants to be the last man to die anonymously and alone on a neutered planet for a very misguided idea? (to paraphrase John “Flip Flop” Kerry).

  8. “We’ve nearly halved the number of trees on the planet, and we’ve seen the impacts on climate and human health as a result,”…
    The climate is better now than any time in the last 200+ years. Human health? Life expectance around the world is the highest it has ever been! Is he suggesting that we should cut down more trees, maybe halve the number agian?

  9. “We’ve nearly halved the number of trees on the planet, and we’ve seen the impacts on climate and human health as a result”
    Yes, indeed. Over millennia human health has made great strides forward possibly due to opening up the land to grow crops instead of crawling around in the forests hunting for bugs and leaves and anything else vaguely digestible.
    As for climate, there have certainly been impacts but have they made it better or worse … or just different?

  10. I keep hearing how trees remove CO2 from the atmosphere. While that’s true for an individual tree over its lifetime, isn’t virtually 100% of that carbon released back into the atmosphere as the tree decays after it dies? In my (perhaps simplistic) understanding, trees in the aggregate are carbon neutral over time unless:
    A) The total mass of living trees changes, or
    B) A meaningful percentage of dead tree mass is sequestered for geological timescales
    Living tree mass could change because of net changes in forested area (due to natural or human causes) or because of changes to tree mass per unit area (due to increases in density or average tree size).
    Dead tree carbon could be sequestered if a lot more trees fell into water, perhaps.
    Am I right in assuming that steady state forests are indeed carbon-neutral?

    • It can take a very long time for trees to decay and much of their carbon goes into the fungi which break them down.
      Young trees grow rapidly. Older ones sequester carbon. Thanks to more CO2 plant food in the air, the mass of trees and other vegetation is indeed increasing.
      Humans do cut trees down to turn into lumber and paper, also still to burn, but planting new ones in their place is a net drawdown of CO2.

    • Give or take soil carbon, in the long run you are correct. Trees are carbon neutral on timescales of several centuries. The main carbon sink is ocean calcareous phytoplankton like coccolithophores, and diatoms. When these organisms die, their carbonate exoskeletons sink to the seafloor and form limestone/dolomite over geologic time. Any good discussion of the carbon cycle has estimates. NASA has a nice one on its EarthObservatory website.

      • The process that sequesters carbon by turning dead trees and other vegetation into coal may not be happening at the same scale as in the past, but are you saying that it is not happening at all now? Because, if new coal, peat, or other processes are still sequestering carbon, then trees are not carbon neutral, even over several centuries. Some coal fields are over a billion years old.

      • Louis, the process of coal formation was almost exclusively during a specific period of time known as the carboniferous.
        This was due mostly to the evolution of lignin in plants, and the tens of millions of years before any organisms evolved the means, by way of various enzymes, to degrade and digest lignin (and to a lesser extent various forms of cellulose).
        Because of this, for all those millions of years, every tree that grew sat right where it fell, unless it caught on fire. Nowadays, only certain conditions lead to the formation of beds of pea/lignite.
        Back then it was everywhere, and all the time. Also, back then, trees had about six to ten times more bark as now, and bark is mostly lignin.

      • I would give a more complete explanation, and have several times, but it is now sleepy time.
        Please…read all about it…fascinating science.

      • Also, know that some of, if not all of, the largest coal beds to ever form were long since exposed to the air and oxidized, or caught on fire, or just eroded away.
        It is not like no coal beds ever became exposed.
        Can you imagine a coal bed hundreds and maybe over a thousand feet thick, extending over several large western states, catching on fire?
        (BTW, d’ya think that could affect the climate? Add some CO2? Hmmm?)
        This has happened in various places at various time in the world.
        A lot of those western vistas of buttes and mesas may have this in their history.

      • Coal has been found from the Paleoproterozoic (Huronian), more than two billion years ago. But yes, most of the coal mined on earth dates to the Carboniferous, before fungi evolved to break down wood.

  11. If we produce around 40B tons of CO2 per year,,,,it’s previously reported that 25% of CO2 pumped into the atmosphere (about 9.5B tons) goes back into land (trees, grasses, etc). If there are 8X more trees, then doesn’t this mean the 25% figure is now much much larger?

  12. Irony alert; carbophobes like bioenergy, which is land-intensive, and often involves clear-cutting of trees, in addition to being expensive.

    • But they want to build artificial trees to make up for that. The fact that these stupid things don’t produce oxygen is obviously lost on them. Everything the so-called Greens do turns out to be an attack on the nature they claim to want to preserve.
      Great article to include here.

  13. It would be very interesting to compare the mass of the trees instead of the count. This likely be a better measurement of the CO2 consumption of each type of forest. It would likely further increase the impact of the tropical forests but also the redwood forests in California where trees can’t grow densely because the canopy restricts undergrowth.

    • I noticed that as well. They simply cannot resist the meme. The net figure is important as is the actual reduction in farm land as yields increase – assuming that crops more or less maintain similar net levels of carbon capture.

      • You must ask yourself, Grasshopper, why you seek this knowledge?
        Is it for the blades of grass’ sake, or for your own?
        Will this knowledge make you picnic on the open meadow more pleasant?
        Or will it cause you angst to know the number is less when the sheep are grazing?
        Look inside yourself, and let the blades of grass be grass.

  14. At the last glacial maximum when CO2 and precipitation was much lower, the number of trees would have only been 5% to 10% of these numbers.

    • Good point, as usual.
      Humans cut and burned down a lot of trees during the Holocene, but most were new on the scene, geologically speaking.

  15. More important than trees and plants taking in CO2 is what they do with it. That’s what sustains all life on earth. We would find breathing a lot harder to sustain without the oxygen production. A lot of sea life depends on the oceans taking in CO2, don’t forget. The organism that use calcium carbonate for shells in naturally sequestering large amounts of CO2.

  16. Somewhat related. Can someone provide an estimate of the amount of CO2 that was released during all the forest fires this summer across Canada and the US?

  17. I just checked the front yard. BAM!!
    10 more baby trees. Let’s see
    Oh yeah,
    some algae in the bucket that I left filled after the last rain.
    Does the moss on the trees count?

  18. The northern hemisphere’s vast boreal temperate forests are believed to be the sink and source for the CO2 kinetics in this NOAA graphic.
    In early May, northern hemisphere CO2 levels being a rapid decline to a minimum in late Sept. Then it is believed the leaves turn colors, shut off their CO2 respiration, and start to rot (fungus and bacteria food) on the forest floor, releasing their stored CO2 back to the environment. Of course much of the uptake CO2 went to make sugars that are now stored in the trees’ body and roots (growth).
    Meanwhile… we await any word from the OCO-2 data team on what they are seeing.
    In the same way that the satellite AMSU-derived Lower Troposphere temperature records are quite “inconvenient” to the Church of CAGW orthodoxy, OCO-2’s global view of CO2 sink and source kinetic data is quite likely an inconvenient message for the CAGW crowd.

    • Doesn’t this graphic suggest that CO2 in the northern hemisphere gets removed from the atmosphere before it can raise the mean in the southern? I thought the stuff supposedly lived for decades in the atmosphere, surely mixing globally in the time shown. I mean, how long does it take to mix a dilute source in the northern across the gradient to the southern? Seems something far more dynamic is going on than just rising CO2 from human sources.

      • There is a ~2.2 ppm per annum secular rise on the seasonal CO2 kinetics. The CO2 measures from Antarctic research stations demonstrates that a 2ppm rise during the SH winter, which of course is the NH hemisphere summer. The NH summer is of course the period when the NH CO2 pump handle is moving rapidly downward (sink kinetics dominate oven source kinetics). Furthermore, the NH “pump handle” moves downward faster than it rises.
        You are correct that when one really takes some time to look at the seasonal fluxes in that graphic some keen insights are available. Think about what the source and sink kinetics must be to generate it, you come to realize the NH boreal forests have an incredible sink (CO2 uptake kinetics) capacity. A sink capacity limited only by length of the hemisphere’s average growing season, i.e. the last spring freeze and first autumn freeze as the limits on the boreal CO2 uptake. Expand that window just a little bit, and soon you will have falling CO2 baseline.
        Any OCO-2 product that spans an entire year’s observations must somehow explain how and where these sources and sinks are operating. If NASA does try to fudge the OCO-2 data (to make human CO2 a larger source in the data than warrented) then it would not agree in some important aspect with the ground-based measures.

      • Joel,
        Agree completely, except I’d include NH temperate and tropical forests as well as boreal, and maybe add grass and croplands, too. To say nothing of oceans.

      • Bernie,
        There is some 60 GtC flowing in and out the biosphere over the seasons, where some 70% is situated in the NH. Here the average change over the seasons for the period 1990-2013:
        The opposite CO2 and δ13C changes show that the biosphere is the dominant cause. Even so at the end of the seasonal cycle, there is a remaining ~2 ppmv increase in CO2. There is a lag of ~6 months between ground level from the mid to high latitudes to the height of Mauna Loa in the trade winds of the tropics and up to 2 years with the South Pole:
        The difference between seasonal uptake and release and longer-term uptake is that the first is temperature driven that starts huge, but limited capacity processes in the ocean surface and the biosphere and end near in equilibrium for the same temperature, while the long term uptake is mainly pressure driven: slow, less limited processes in capacity, but limited in speed as well as in the (deep) oceans as in vegetation.

      • Thank you Joel and Ferdinand. I appreciate your taking the time to show me the data and answer my questions. The annual emission of CO2 has grown from just under 3 to just over 5 GT per year over the interval 1995-2004, and yet the slope of CO2 concentration has remained about 2.2 ppm/year. Would I be correct in asserting that the ability of the global biome to absorb CO2 has increased over that interval?

      • Bernie,
        Indeed the biosphere is growing, despite the slashing of rainforests, the earth is greening. Even in (semi-)dry environments: higher CO2 levels need less stomata, which means less water loss…

    • Gymnosperm,
      Look at the dates: only 6 weeks of data in the period that CO2 levels in the NH are lowest. If you look at the NOAA graph sent in the previous message, the NH is average higher in CO2: thus despite far more trees in the NH, the source of the extra CO2 is there…

      • Thank you Ferdinand. I somehow remembered the OCO as a single day but it was more than a month! Work berry fas make boo boo.
        I was discounting the northern hemisphere as it was out of season. Many intensely forested areas of South America, Africa, Australia and Indonesia show impressive CO2 levels. Since I was working fast I didn’t want t take the time to differentially increase the ocean transparency in the tree map, but if you look at the maps separately it is very clear that the highest CO2 concentrations are over land.
        I monitor the soil temperatures in my vineyard. They do not follow air temperature, they follow the sun. Vegetation is certainly a net sink for Carbon, but soil is a net source.

  19. “nearly halved the trees on the planet and seen the results…on human health” Do they mean human’s no longer have a 34 year life expectancy perilously living a semi- nomadic existence with a world population of roughly half a billion? Yes, Gracie, yes we have seen the great progress of humanity and dramatic improvement in health that civilization and science have wrought!

  20. But the total number of trees has plummeted by roughly 46% since the start of human civilization, the study estimates.
    I blamed the $18 trillion debt

  21. Hell, I have several hundred trees on my 2 acres alone – love sitting outside at night and hearing all that CO2 being sucked in.

    • ” love sitting outside at night and hearing all that CO2 being sucked in.”
      Don’t they emit CO2 at night? Still a nice place to sit, I do the same.

  22. So this news might improve IPCC AR5’s Table 6.1 CO2 balance uncertainties (i.e. WAGs) from the current +/- 96%. Maybe the natural sources and sinks really do dominate the 400 ppm global CO2 balance and mankind’s 2 ppm “imbalance” is lost even deeper in the data noise of natural variability.

    • Nicholas, the natural variability after a full seasonal cycle is only +/- 1 ppmv around the trend over the past 55 years, which is recently over 2 ppmv/year net increase with human emissions of around 4.5 ppmv/year.
      The new findings may change the throughput of the biological carbon cycle, but the net result is independently measured via O2 and δ13C changes.

  23. “We’ve nearly halved the number of trees on the planet, and we’ve seen the impacts on climate and human health as a result,”
    Always speculation. Does anyone ever publish an article where the conclusions are actually based on research? I would have said numbers, but since all numbers are now produced by co mputer models we can’t use numbers any longer.

  24. “The first Europeans to penetrate the Amazon rainforests reported cities, roads and fertile fields along the banks of its major rivers. “There was one town that stretched for 15 miles without any space from house to house, which was a marvellous thing to behold,” wrote Gaspar de Carvajal, chronicler of explorer and conquistador Francisco de Orellana in 1542. “The land is as fertile and as normal in appearance as our Spain.”
    Such tales were long dismissed as fantasies, not least because teeming cities were never seen or talked about again. But it now seems the chroniclers were right all along. It is our modern vision of a pristine rainforest wilderness that turns out to be the dream”

  25. Carbon is pollution. More carbon is more pollution. Since the total amount of carbon has now risen according to the latest study numbers, its totally appropriate to say “Its worse than we thought”

  26. Man moves to desert. Man plants trees and other green shrubs. More man show up in desert, soon golf course and more trees….hmmmmm

  27. I’m not sure the actual number of trees is such a relevant number.
    Also, grasses and forbs tend to begin growth earlier in the season and continue till frost, and the soils they grow on generally have greater biomass. Is it possible the worlds grasslands and prairies are more significant than the forested areas with respect to the CO2 budget?

  28. A couple of years ago I put forth an idea, partially in jest, that it could the natural order of things on all planets like Earth for vegetation to suck so much CO2 out of the atmosphere that it eventually turns the entire planet too cold for anything to live. Only planets where the intervention of intelligent species that can manipulate the environment would be saved from this inevitable fate.

    • Hi Tom in Florida,
      The problem with that idea is that there is evidence in the Geologic record that there was Ice ages during the early Archean time period, (when CO2 was 30,000 times the current concentrations). Granted the Sun was a bit dimmer back then, but it kind of punches a hole into the “CO2 controls the Earth’s temperature” theory.
      I read a geological paper a couple of year back that was addressing the conditions on the earth about the time that life started. In that paper they pointed out this discrepancy between CO2 density and temperature in detail. Unfortunately I cannot locate the reference to the paper at this time. I will keep looking though.

      • Think you mean 30% (ie, 300,000 ppm) rather than 30,000 times the current concentration, which implies 12 million parts per million (400 ppm x 30,000).

    • Tom Fl, problem with that is plants will only take it down to where I becomes limiting for plant growth….plant growth will slow to where it reaches a balance
      …oh wait! we did that already!

      • Gloria Swansong,
        The context of the paper I was referencing, was that the atmosphere was much denser back in the Archean , most of which was CO2. They specifically referenced 30,000 times the current CO2.

      • Sorry, Tom, but that’s not possible.
        Even with a denser atmosphere, 12 million parts per million is at best unlikely. The graph I linked shows an early Archaean atmosphere of perhaps 30% CO2. That would mean N2 and other constituents would have to be over 20 million parts per million of present density.
        Sorry, but an early atmosphere more than 32 times as dense as today’s just doesn’t compute. Where did all that nitrogen go?
        Study of Archaean rocks suggests that at most the atmosphere might have been twice as dense then as now, but probably not.

  29. So there was 5,629,629,629,633 trees on the planet before – – – ?? Yes, there is the problem with THAT “46% less” wild a_ _ guess in the dark, and therefore the entire count and therefore the entire study/report. The start of the decline, they say, is; “since the start of human civilization.” Tell me – exactly when was that? At 100,000 humans? At 1 million? At 100 million? And when was that FIRST tree (and every one there after) cut down and was it for a “beneficial” reason or was it just left there to rot? Should the early humans not have cut tress for huts or teepees or – – -? If not, there probably wouldn’t be – – – us.
    Oh, and one (two actually) other question; How many tree nurseries are there in the world and how many tress has “human civilization” cultivated “since the start”?
    Yes, the authors would have been far better off if they had left the “46% less” GUESS out. And to quote a political hack; “WHAT DIFFERENCE DOES IT MAKE NOW?”

  30. “We’ve nearly halved the number of trees on the planet, and we’ve seen the impacts on climate and human health as a result,” Crowther said.

    I do love forests, but what is implied by Crowther, is not true.
    I can’t say much about climate, except it is actually better now in Europe than it was 300 years ago. But human health, impacts or not, did improve tremendously.
    Does Crowther mean all this improvement is due to loss of trees? I doubt it.

    • The sad thing about the life expectancy plot is how close together the developing nations and global lines are, suggesting a much larger sample size in the developing nations data. I.e. there are far more poor people in developing nations and developed nations. Be on the look out for the mass migration to the first world nation you worked hard to build.

  31. Here’s something new: We are driving the earth to the brink. I would say Iran getting nukes would probably be more of a problem than co2.
    “The study is described in the paper “Biotic replacement and mass extinction of the Ediacara biota” published Sept. 2 in the journal Proceedings of the Royal Society B.
    “There is a powerful analogy between the Earth’s first mass extinction and what is happening today,” Darroch observed. “The end-Ediacaran extinction shows that the evolution of new behaviors can fundamentally change the entire planet, and we are the most powerful ‘ecosystem engineers’ ever known.”
    And we were having so much fun with trees. Sorry… 🙁

    • And, climate scientists said in yesterdays article that we can change the ocean currents if we have to to avoid a catastrophe.

  32. “420 trees for every person on the planet”.
    But there are estimated 3/4 of a ton of wood munching termites for every person on the planet. Is 420 trees enough?

  33. In this study is there any distinction between Deciduous Forests/Trees and Conifer Forests/Trees? I didn’t see any reference to that. I assume Deciduous “eats up” more CO2 than Coniferous (except maybe in winter, depending on latitude, etc.).

  34. Does anyone know the CO2 uptake rate for — say, an acre of grass, or an acre of trees, — or an acre of corn?

      • So DB, maybe the giant sucking sound is all the freakin’ birdchoppers that are extracting so much wind energy that they will kill all the corn by CO2 starvation, eh?

    • “Does anyone know the CO2 uptake rate for — say, an acre of grass, or an acre of trees, — or an acre of corn?”

  35. The world is always coming to an end. Endlessly.
    The record for ‘end of world’ predictions is around zero so far.

    • If the choice is between Catastrophic Anthropogenic Climate Armageddon and kudzu, I’m going with the CACA!

      • But Sturgis…this stuff is edible…a delicacy in some places.
        I here they will remake the movie “Soylent Green”, and it will be called “Kudzu Yellow”.

      • OK, Never really knew much about kudzu (thought this was kind of a joke/humorous), except that my in-laws north of Philadelphia, PA grew it every year in front of their front porch. Sometimes it would try to enter the living room through a side window. It was cut down at the end of each season, but reappeared every spring. So I have been educated via the internet about something I knew little about:
        “Kudzu may not have gained much traction as a bovine food source, but it may have a future as a source of alternative fuel for automobiles and airplanes. In fact, researchers are exploring it as a form of ethanol. This green, lush plant’s roots contain large amounts of carbohydrates that can easily be converted to biofuel. These days, corn and soy are largely used to create biofuel, but some people are concerned that depleted supplies of both due to ethanol production could create a food shortage. In fact, the popularity of corn-based ethanol has already made price swings more volatile, affecting farmers, food manufacturers and even charitable organizations that depend on food donations [source 1=”Ruble” language=”:”][/source]. Proponents of kudzunol say that kudzu is the perfect solution for this dilemma; it grows like a weed and it can meet the demand for fuel for combustible engines — without jeopardizing food supplies.”
        “People don’t call kudzu the plant that ate the South for nothing. As we learned earlier, kudzu grows really fast — as much as a foot or two (30 or 61 centimeters) each day. Once it forms a blanket over land or trees, light can’t get through, so the vast majority of the underlying plants or trees eventually die. Only the hardiest plants can survive the suffocating effects of a kudzu infestation. Considering that, imagine the damage kudzu can do to a food or timber crop. Forest economist Coleman Dangerfield estimates that for every acre of timber that kudzu overtakes, landowners lose $48 per acre per year. Another expert, plant ecologist James Miller, calculates that electricity providers spend $1.5 million per year just to control kudzu and keep it off power lines and utility poles [source 1=”Britton” language=”:”][/source]. That’s scary enough, but the weight of kudzu vines can actually uproot trees, elevating the plant from a mere annoyance to an actual source of danger.”
        OK, Then let’s plant them around the bases of each giant wind turbine. That will eventually make them green. But it will only work in places that get enough inches of rain during growing season. Probably not in the desert soutwest.

      • Responding to J. Philip Peterson below:
        Biofuels, even from a weed is a waste of time, energy, and equipment. We have no need for something that simply makes gasoline more expensive and ruins our engines. It’s broken-window economy to do all this work and not end up gaining anything from it. And, in reality, more energy is spent making it than is gained in burning it. But biofuels from corn raises the price of corn and other grains and starves people in other countries to death, which the UN sees as a natural way to lower the world’s population.

  36. This reminds me of the fish in the ocean estimate. From what I gather, until last year the estimate accepted by nearly all scientists with knowledge in the field was that the carrying capacity of the oceans was around 1 billion tons of fish. Using new technology scientists learned that the fish population at depths below about 200 meters is far more dense than previously believed. The new estimate is that the oceans contain 10 billion tons of fish, or 10x more than the previous “settled science consensus”. Who knows how long this new estimate will hold.

  37. Oh, great…another computer model showing results that cannot be verified. Someone tell me what the value is of comparing a rough estimate of the current number of trees to an unverified computer model number from a long time ago.

  38. from the BBC link:
    “The previous estimate of trees in the world was 400 billion. The new estimate is three trillion large trees. There are so many margins of error in this study that the real number could be anything between the two – or even 10 times higher.”- Dr Martin Lukac, University of Reading
    2 Sept: ABC: AP: Seth Borenstein: Lots of Trees to Hug: Study Counts 3 Trillion Trees on Earth
    So if there are so many trees on the planet, the planting of a billion trees wouldn’t do too much to fight climate change on its own, Crowther conceded. But he said that didn’t stop the tree planters group; they just upped their goal. On its website, Plant for the Planet says the objective is now ***18 BILLION.
    Now that’s over many decades, and it might be hard to find space, but it can be done, Crowther said…
    2 Sept: NPR: Nell Greenfield Boyce: Tree Counter Is Astonished By How Many Trees There Are
    Thomas Crowther was inspired to do this tree census a couple of years ago, when he was working at the Yale School of Forestry and Environmental Studies. He had a friend who was working with a group with an ambitious goal: trying to fight global warming by planting a billion trees. A billion trees sounded like a lot. But was it really?
    “They didn’t know if planting a billion trees was going to add 1 percent of the world’s trees, add 50 percent of the world’s trees,” recalls Crowther. “They didn’t even know if it was even possible to fit a billion trees on Earth.”…
    So did all of this news discourage that group that wanted to plant a billion trees?
    “Based on this, they really want to upscale their efforts hugely,” says Crowther, who explains that the new analysis has spurred them on. “Their goal is now to plant ***A TRILLION TREES.”

  39. BTW I heard BBC quote the UN-affiliated youth group had upped their target to 1 trillion trees on radio this morning, without even a giggle. of course, the 3 trillion figure will no doubt be factored in by all the carbon groups, who will update the availability of carbon offsets, etc.

  40. 422 trees for every person on earth? It sounds like the world is overpopulated with trees. Trees will soon deplete the Earth of natural resources required for their massive bodies. If the average tree consumes 1,000 pounds of minerals and water a year, we will be out of minerals and water in 50 years. It’s time to start cutting them down.

  41. Last year one of my 500 year old red oak trees suddenly shuddered and the trunk split in two and it nearly fell on me and my dog as we came over to see what the loud cracking sound was. I suspect the trees are plotting something about the tree/human ratio.

  42. The ‘new’ number of trees is 4 Trillion. The ‘old’ number of trees was 300 Billion. A little arithmetic tells me that the number of trees has INCREASED by 7.5 times. Just how is this a 46% decrease from years ago?

  43. Since the actual global tree population is 3 trillion as opposed to 400 billion, a good case could be made that the 25% increase in tree growth from CO2 fertilization is the tree-equivelant of almost TWICE the original estimate: (3 trillion trees x 25% added CO2 fertilization effect= 750 billion tree-equivelant).
    New bumper sticker: “Hug a tree. Buy an SUV.”
    Why is Glooooooobal Waaaaarming still taken seriously????…

  44. Q: What is the #1 GHG? A: Water vapor
    Q: What is a/the major producer of water vapor? A: Trees and vegetation
    Q: Where has the majority of the growth in trees occurred? A: N Hemisphere
    Q: Which hemisphere has shown the greatest warming? A: N Hemisphere
    Q: Does CO2 difference between the N and S hemisphere? A: Nope
    Imagine that? Trees cause global warming. How ironic.
    Water Vapor Confirmed as Major Player in Climate Change
    Studies have revealed that about 10 percent of the moisture found in the atmosphere is released by plants through transpiration. The remaining 90 percent is mainly supplied by evaporation from oceans, seas, and other bodies of water (lakes, rivers, streams).

  45. ““We’ve nearly halved the number of trees on the planet, and we’ve seen the impacts on climate and human health as a result,”
    Is he referring to the tremendous improvements in human health in the last 10,000 years because of Anthropogenic Medine?

  46. My bet is that the temperature variation is much less for climates with near saturated air than climates with very dry air. That would be solid evidence that H2O, not CO2 is the driving GHG. I also bet that regions with saturated air rarely have temperatures go much above the temperature associated with saturation, ie the Equatorial area would have stable rain forest temperatures and wild swings in the deserts. Basically H20 would continue to trap heat and warm until the air is saturated, at which time is would have less ability to continue warming. (yes I know that warmer air hold more water so their is a feedback, but not enough to be a self perpetuating cycle).

    • CO2isLife– As Willis has so adroitly shown through his research, increased ocean evaporation/cloud cover is the mechanism that keeps global temps so stable over eons of time.
      Any tiny amount of logarithmic CO2 forcing is mostly offset by the added cloud cover/increased albedo caused by increased ocean evaporation.
      During global cooling periods, there is less ocean evaporation, fewer clouds, lower albedo, which allows more TSI to hit the earth’s surface, thus preventing snowball earth.
      The CAGW hypothesis is 100.00% dependent upon ocean evaporation causing a “catastrophic runaway feedback loop” from an added H2O GHG effect, which is absolutely impossible. Our very existence proves this catastrophic runaway H2O feedback loop doesn’t exist.

  47. ““We’ve nearly halved the number of trees on the planet, and we’ve seen the impacts on climate and human health as a result,” Crowther said.
    There is absolutely no evidence for this statement. It is simply impossible to detect or define. Just sheer propaganda. There is no way a negative impact on human health, which has improved greatly over the years, can be detected by losing trees. Maybe he is indication a positive impact, but that would not get him more funding, would it?

  48. Ya wanna know about trees ?, take a 4 hour walk(one way) away from the parking lot in the U.P. of Michigan.
    You come back with blisters, the last 2-3 miles are just …desperation.
    18 mile round-trip !!
    Oh, most of the trip was under the canopy of trees.

  49. I was listening to Adelaide radio this week talking about what vegetation used to be here in South Australia before European settlement. Surprise, surprise, most of the plains and low hills were mostly grassland only, with forest predominantly in the mountains. We have vegetated almost all of greater Adelaide with trees that were never there before. We have roughly 11 trees per person just in the city and greater metropolitan areas. This does not include any of the native and plantation forests. Plenty of trees here matey! I wonder how many other places are the same?

    • Well, I guess, there were trees in the Adelaide region BEFORE the aborigines arrived there around 40’000 years ago. These indigenous hunter/gatherers liked to hunt by ignition of wild fires in wood lands and had so likely some influence in the extinction of Australias megafauna as well…
      Thus, not only our modern technical civilisation, can have a destructive influence on the landscape…

  50. Of course then there is irrigation… vast areas that were desert scrub before are now green, places like perth, ord river, alice springs and Los Angeles. When we build cities in deserts we plant and irrigate trees and begin to sequester CO2 in places there was little sequestration before. Bet this urban effect isn’t considered.

  51. I saw some estimates a number of years ago about trees in Australia. The original Aborigines kept huge areas cleared by fire, to promote grassland for herbivores such as kangaroos. Very successful farming practice. A very high percentage of that land is now forested. According to scientists in Australia, there are more trees now than two hundred years ago. Similar stats elsewhere for Europe and North America.
    However that is changing. Timber is a sustainable energy source, and is being cut down to be used for fuel by Watermelons, particularly Europe and the UK. Now if we got rid of the crazy “Global Warming” obsession, we could go back to having more trees.
    And living in the Australian bush, I don’t know where they got there numbers from, but there are a lot more trees per person around here than that.

  52. Tim Folkerts says,
    ‘ No, they claim “roughly 46%” …”
    The article in Nature as posted by the magazine on the internet says exactly,
    “…the number of trees worldwide has dropped by 46%…”

  53. But, but, but, . . . Regardless of any estimates of the number of trees, the amount of CO2 in the atmosphere has increased by something like 40 percent in just the last century or so, and the carbon isotope ratios show that the extra carbon probably came from fossil fuels.
    Jim Shea

    • “the amount of CO2 in the atmosphere has increased by something like 40 percent” …
      CORRECTION!… an increase in CO2 IN THE ATMOSPHERE from 0.028% (280 ppm) to 0.040% (400 ppm) is an increase of 0.0120% (120 ppm) …

      • You are talking ‘percentage points’, not percent. Percentage points are in relation to the whole, percent is in relation to the item under discussion alone.

  54. Geoengineered Forest Fire Incineration, Dark Ice, And Methane Extinction
    Dane Wiggington
    Record forest fires are raging around the globe, climate engineering is a primary factor fueling the planetary burning. All over the northern hemisphere boreal forests are going up in flames and smoke, further loading the atmosphere with Co2 and soot. This in turn triggers multiple climate feedback loops which causes much more rapid warming than what is already occuring.

    • Fred, Dane
      The linked article is 100% psychotic drivel. What climate geoengineering? Do you mean the CO2 increase which is greening previously desert areas and holding more water on land? If warming and CO2 “trigger multiple feedback loops” then how did the dinosaurs not all burn to death in global temperatures 10C higher and CO2 of 2000-3000 ppm?
      Actually the important climate feedbacks are negative. That is why life has existed on earth for 4 billion years.

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