Global greening

The Greening of the Earth from 1982-2011. The numbers below the color bar are the percentage changes in total biomass, per unit area of land, between 1982 and 2011. Constructed from satellite data. Source: Zhu Z and Myneni RB (2014), A greener Earth (?) Global vegetation monitoring and modelling, Avignon, France, February 3 to 7, 2014.

The Earth has been getting greener over the past few decades, both in the tamed and the untamed regions. The greening has been observed from both satellites in space and from field studies on the ground. The total biomass on land has increased by about 15% since the 1980's. This "Global Greening" is believed to be primarily due to a man-made increase in atmospheric CO2, although it has been suggested that global warming may also contribute to the growth of global biomass.

We are witnessing the “Greening of the Earth” as higher levels of CO2, due to human emissions from the use of fossil fuels, promote increased growth of plants around the world. This has been confirmed by scientists with CSIRO in Australia, in Germany, and in North America. Only half of the CO2 we are emitting from the use of fossil fuels is showing up in the atmosphere. The balance is going somewhere else and the best science says most of it is going into an increase in global plant biomass. - Patrick Moore

Plant Growth and Climate Models

Greening of the Earth and its drivers, Nature Climate Change, 25 April 2016

Global environmental change is rapidly altering the dynamics of terrestrial vegetation...Yet how global vegetation is responding to the changing environment is not well established. Here we use three long-term satellite leaf area index (LAI) records and ten global ecosystem models to investigate four key drivers of LAI trends during 1982–2009. We show a persistent and widespread increase of growing season integrated LAI (greening) over 25% to 50% of the global vegetated area, whereas less than 4% of the globe shows decreasing LAI (browning). Factorial simulations with multiple global ecosystem models suggest that CO2 fertilization effects explain 70% of the observed greening trend, followed by nitrogen deposition (9%), climate change (8%) and land cover change (LCC) (4%). CO2 fertilization effects explain most of the greening trends in the tropics, whereas climate change resulted in greening of the high latitudes and the Tibetan Plateau.

From the IPCC Fourth Assessment Report, Working Group I Report "The Physical Science Basis", Section 7.3.2.2.3, Residual land sink, pp 520:

An intriguing possibility is that rising CO2 levels could stimulate this uptake by accelerating photosynthesis, with ecosystem respiration lagging behind. Atmospheric CO2 concentration has increased by about 1.5 ppm (0.4%) yr–1, suggesting incremental stimulation of photosynthesis of about 0.25% (e.g., next year’s photosynthesis should be 1.0025 times this year’s) (Lin et al., 1999; Farquhar et al., 2001).

This "residual land sink", which means all plants and animals on the land of Earth, translates to an average 1% increase in global photosynthesis every four years, or 10% over 40 years, without including the compounding.

Impact of mesophyll diffusion on estimated global land CO₂ fertilization

Here we demonstrate that current carbon cycle models underestimate the long-term responsiveness of global terrestrial productivity to CO2 fertilization. This underestimation of CO2 fertilization is caused by an inherent model structural deficiency related to lack of explicit representation of CO2 diffusion inside leaves, which results in an overestimation of CO2 available at the carboxylation site. The magnitude of CO2 fertilization underestimation matches the long-term positive growth bias in the historical atmospheric CO2 predicted by Earth system models.
In C3 plants, CO2 concentrations drop considerably along mesophyll diffusion pathways from substomatal cavities to chloroplasts where CO2 assimilation occurs. Global carbon cycle models have not explicitly represented this internal drawdown and therefore overestimate CO2 available for carboxylation and underestimate photosynthetic responsiveness to atmospheric CO2. An explicit consideration of mesophyll diffusion increases the modeled cumulative CO2 fertilization effect (CFE) for global gross primary production (GPP) from 915 to 1,057 PgC for the period of 1901–2010. This increase represents a 16% correction, which is large enough to explain the persistent overestimation of growth rates of historical atmospheric CO2 by Earth system models... This finding implies that the contemporary terrestrial biosphere is more CO2 limited than previously thought.

Matt Ridley on How Fossil Fuels are Greening the Planet

...a curious global trend that is just starting to receive attention. Over the past three decades, our planet has gotten greener! Even stranger, the greening of the planet in recent decades appears to be happening because of, not despite, our reliance on fossil fuels.

Study shows increase of CO₂ in the atmosphere is lower than predicted because of plants (October 14, 2014)

A team of researchers in the U.S. claims that climate models used to predict the rise in CO2 concentrations in the atmosphere are approximately 17 percent too high because they incorrectly approximate how much CO2 plants pull from the atmosphere... the team describes how they studied the ability of plants to absorb increased amounts of CO2 and discovered that they are capable of pulling more out of the atmosphere than has been previously thought and the difference is approximately equal to the error difference reported by simulation models.
Plants, as most people learn in grade-school, use light as part of the photosynthesis process to convert the suns' energy into energy the plant can use to grow—oxygen is then emitted as a byproduct. What's not really clear is how plants in general respond to the presence of more CO2 in the air. Prior research has shown that some plants grow bigger, which tends to cause them to take in more CO2.
Recently, it's come to light that climate models have on average been off a little bit in predicting how much CO2 is being added to the atmosphere by man-made processes. More specifically, over the years, 1901 to 2010, that error rate has been found to be on average 17 percent too high...
In this new effort, the researchers took a new look at the photosynthesis process and how it might be altered in the presence of increasingly higher concentrations of CO2. They found that as CO2 levels rose, plants altered the way they processed the gas, saving more of it to use as a fertilizer, which allowed the plants to grow bigger or to become more robust, which in the end meant more CO2 was taken out of the atmosphere... their research showed that when plants were exposed to the same higher levels of CO2 as actually occurred over the past century, they were able to absorb on average 16 percent more CO2, which very nearly coincides with the 17 percent error difference earth scientists have found with their climate models.
...their results indicate that climate models need to be modified to take proper account of the behavior of plants as CO2 levels rise. 

Increased CO₂ in the atmosphere has altered photosynthesis of plants over the 20th century (December 7, 2015)

Researchers at Umeå University and the Swedish University of Agricultural Sciences have discovered that increasing levels of CO2 in the atmosphere have shifted photosynthetic metabolism in plants over the 20th century. This is the first study worldwide that deduces biochemical regulation of plant metabolism from historical specimens. The findings are now published in the leading journal PNAS and will have an impact on new models of future CO2 concentration in the atmosphere.

Detecting long-term metabolic shifts using isotopomers: CO₂-driven suppression of photorespiration in C₃ plants over the 20th century

Terrestrial vegetation currently absorbs approximately a third of anthropogenic CO2 emissions, mitigating the rise of atmospheric CO2. However, terrestrial net primary production is highly sensitive to atmospheric CO2 levels and associated climatic changes. In C3 plants, which dominate terrestrial vegetation, net photosynthesis depends on the ratio between photorespiration and gross photosynthesis. This metabolic flux ratio depends strongly on CO2 levels, but changes in this ratio over the past CO2 rise have not been analyzed experimentally. ...the intramolecular deuterium distribution (deuterium isotopomers) of photosynthetic C3 glucose contains a signal... By tracing this isotopomer signal... we detect a consistent reduction in the photorespiration/photosynthesis ratio in response to the ∼100-ppm CO2 increase between ∼1900 and 2013. 
...isotopomers of plant archives contain metabolic information covering centuries. Our data provide direct quantitative information on the “CO2 fertilization” effect over decades, thus addressing a major uncertainty in Earth system models.

Patrick Moore Lecture

(Edited down. Subtitles are added by the editor, they were not originally in the lecture.)

Should We Celebrate CO2?
Dr Patrick Moore, Global Warming Policy Foundation
2015 Annual GWPF Lecture – London 14 October 2015

...But there is certainty beyond any doubt that CO₂ is the building block for all life on Earth and that without its presence in the global atmosphere at a sufficient concentration this would be a dead planet. Yet today our children and our publics are taught that CO₂ is a toxic pollutant that will destroy life and bring civilization to its knees. Tonight I hope to turn this dangerous human-caused propaganda on its head. Tonight I will demonstrate that human emissions of CO₂ have already saved life on our planet from a very untimely end. That in the absence of our emitting some of the carbon back into the atmosphere from whence it came in the first place, most or perhaps all life on Earth would begin to die less than two million years from today.

When Greenpeace began we had a strong humanitarian orientation, to save civilization from destruction by all-out nuclear war. Over the years the “peace” in Greenpeace was gradually lost and my organization, along with much of the environmental movement, drifted into a belief that humans are the enemies of the earth. I believe in a humanitarian environmentalism because we are part of nature, not separate from it. The first principle of ecology is that we are all part of the same ecosystem, as Barbara Ward put it, “One human family on spaceship Earth”, and to preach otherwise teaches that the world would be better off without us. As we shall see later in the presentation there is very good reason to see humans as essential to the survival of life on this planet.

In the mid 1980s I found myself the only director of Greenpeace International with a formal education in science. ...When I left Greenpeace I vowed to develop an environmental policy that was based on science and logic rather than sensationalism, misinformation, anti-humanism and fear.

The Keeling curve of CO₂ concentration in the Earth’s atmosphere since 1959 is the supposed smoking gun of catastrophic climate change. We presume CO₂ was at 280 ppm at the beginning of the Industrial Revolution, before human activity could have caused a significant impact. I accept that most of the rise from 280 to 400 ppm is caused by human CO₂ emissions with the possibility that some of it is due to outgassing from warming of the oceans.

Let’s begin with our knowledge of the long-term history of the Earth’s temperature and of CO₂ in the Earth’s atmosphere. Our best inference from various proxies back indicate that CO₂ was higher for the first 4 billion years of Earth’s history than it has been since the Cambrian Period until today. I will focus on the past 540 million years since modern life forms evolved. It is glaringly obvious that temperature and CO₂ are in an inverse correlation at least as often as they are in any semblance of correlation. Two clear examples of reverse correlation occurred 150 million years and 50 million years ago. At the end of the Jurassic temperature fell dramatically while CO₂ spiked. During the Eocene Thermal Maximum, temperature was likely higher than any time in the past 550 million years while CO₂ had been on a downward track for 100 million years. This evidence alone sufficient to warrant deep speculation of any claimed lock-step causal relationship between CO₂ and temperature.

The Devonian Period beginning 400 million years ago marked the culmination of the invasion of life onto the land. Plants evolved to produce lignin, which in combination with cellulose, created wood which in turn for the first time allowed plants to grow tall, in competition with each other for sunlight. As vast forests spread across the land living biomass increased by orders of magnitude, pulling down carbon as CO₂ from the atmosphere to make wood. Lignin is very difficult to break down and no decomposer species possessed the enzymes to digest it. Trees died atop one another until they were 100 metres or more in depth. This was the making of the great coal beds around the world as this huge store of sequestered carbon continued to build for 90 million years. Then, fortunately for the future of life, white rot fungi evolved to produce the enzymes that can digest lignin and coincident with that the coal-making era came to an end.

Carbon Dioxide Photosynthetic Limit

There was no guarantee that fungi or any other decomposer species would develop the complex of enzymes required to digest lignin. If they had not, CO₂, which had already been drawn down for the first time in Earth’s history to levels similar to todays, would have continued to decline as trees continued to grow and die. That is until CO₂ approached the threshold of 150 ppm below which plants begin first to starve, then stop growing altogether, and then die. Not just woody plants but all plants. This would bring about the extinction of most, if not all, terrestrial species, as animals, insects, and other invertebrates starved for lack of food. And that would be that. The human species would never have existed. This was only the first time that there was a distinct possibility that life would come close to extinguishing itself, due to a shortage of CO₂, which is essential for life on Earth.

A well-documented record of global temperature over the past 65 million years shows that we have been in a major cooling period since the Eocene Thermal Maximum 50 million years ago. The Earth was an average 16C warmer then, with most of the increased warmth at the higher latitudes. The entire planet, including the Arctic and Antarctica were ice-free and the land there was covered in forest. The ancestors of every species on Earth today survived through what may have been the warmest time in the history of life. It makes one wonder about dire predictions that even a 2C rise in temperature from pre-industrial times would cause mass extinctions and the destruction of civilization. Glaciers began to form in Antarctica 30 million years ago and in the northern hemisphere 3 million years ago. Today, even in this interglacial period of the Pleistocene Ice Age, we are experiencing one of the coldest climates in the Earth’s history.

It is sobering to consider the magnitude of climate change during the past 20,000 years, since the peak of the last major glaciation. At that time there were 3.3 kilometres of ice on top of what is today the city of Montreal, a city of more than 3 million people. 95% of Canada was covered in a sheet of ice. Even as far south as Chicago there was nearly a kilometre of ice. If the Milankovitch cycle continues to prevail, and there is little reason aside from our CO₂ emissions to think otherwise, this will happen gradually again during the next 80,000 years. Will our CO₂ emissions stave off another glaciation as James Lovelock has suggested?.

Global Greening

Coming to the core of my presentation, CO₂ is the currency of life and the most important building block for all life on Earth. All life is carbon-based, including our own. Surely the carbon cycle and its central role in the creation of life should be taught to our children rather than the demonization of CO₂, that “carbon” is a “pollutant” that threatens the continuation of life. We know for a fact that CO₂ is essential for life and that it must be at a certain level in the atmosphere for the survival of plants, which are the primary food for all the other species alive today. Should we not encourage our citizens, students, teachers, politicians, scientists, and other leaders to celebrate CO₂ as the giver of life that it is?

It is a proven fact that plants, including trees and all our food crops, are capable of growing much faster at higher levels of CO₂ than present in the atmosphere today. Even at the today’s concentration of 400 ppm plants are relatively starved for nutrition. The optimum level of CO₂ for plant growth is about 5 times higher, 2000 ppm, yet the alarmists warn it is already too high. They must be challenged every day by every person who knows the truth in this matter. CO₂ is the giver of life and we should celebrate CO₂ rather than denigrate it as is the fashion today.

We are witnessing the “Greening of the Earth” as higher levels of CO₂, due to human emissions from the use of fossil fuels, promote increased growth of plants around the world. This has been confirmed by scientists with CSIRO in Australia, in Germany, and in North America. Only half of the CO₂ we are emitting from the use of fossil fuels is showing up in the atmosphere. The balance is going somewhere else and the best science says most of it is going into an increase in global plant biomass. And what could be wrong with that, as forests and agricultural crops become more productive?

All the CO₂ in the atmosphere has been created by outgassing from the Earth’s core during massive volcanic eruptions. This was much more prevalent in the early history of the Earth when the core was hotter than it is today. During the past 150 million years there has not been enough addition of CO₂ to the atmosphere to offset the gradual losses due to burial in sediments.

Let’s look at where all the carbon is in the world, and how it is moving around.

Lost Carbon

Today, at just over 400 ppm, there are 850 billion tons of carbon as CO₂ in the atmosphere. By comparison, when modern life-forms evolved over 500 million years ago there was nearly 15,000 billion tons of carbon in the atmosphere, 17 times today’s level. Plants and soils combined contain more than 2,000 billion tons of carbon, more that twice as much as the entire global atmosphere. The oceans contain 38,000 billion tons of carbon, as dissolved CO₂, 45 times as much as in the atmosphere. Fossil fuels, which are made from plants that pulled CO₂ from the atmosphere account for 5,000 – 10,000 billion tons of carbon, 6 – 12 times as much carbon as is in the atmosphere.

But the truly stunning number is the amount of carbon that has been sequestered from the atmosphere and turned into carbonaceous rocks. 100,000,000 billion tons, that’s one quadrillion tons of carbon, have been turned into stone by marine species that learned to make armour-plating for themselves by combining calcium and carbon into calcium carbonate. Limestone, chalk, and marble are all of life origin and amount to 99.9% of all the carbon ever present in the global atmosphere. The white cliffs of Dover are made of the calcium carbonate skeletons of coccolithophores, tiny marine phytoplankton.

The vast majority of the carbon dioxide that originated in the atmosphere has been sequestered and stored quite permanently in carbonaceous rocks where it cannot be used as food by plants.

Beginning 540 million years ago at the beginning of the Cambrian Period many marine species of invertebrates evolved the ability to control calcification and to build armour plating to protect their soft bodies. Shellfish such as clams and snails, corals, coccolithofores (phytoplankton) and foraminifera (zooplankton) began to combine carbon dioxide with calcium and thus to remove carbon from the life cycle as the shells sank into sediments; 100,000,000 billion tons of carbonaceous sediment. It is ironic that life itself, by devising a protective suit of armour, determined its own eventual demise by continuously removing CO₂ from the atmosphere. This is carbon sequestration and storage writ large. These are the carbonaceous sediments that form the shale deposits from which we are fracking gas and oil today.

The past 150 million years has seen a steady drawing down of CO₂ from the atmosphere. There are many components to this but what matters is the net effect, a removal on average of 37,000 tons of carbon from the atmosphere every year for 150 million years. The amount of CO₂ in the atmosphere was reduced by about 90% during this period. This means that volcanic emissions of CO₂ have been outweighed by the loss of carbon to calcium carbonate sediments on a multi-million year basis.

Ice Age Extinctions

If this trend continues CO₂ will inevitably fall to levels that threaten the survival of plants, which require a minimum of 150 ppm to survive. If plants die all the animals, insects, and other invertebrates that depend on plants for their survival will also die.

How long will it be at the present level of CO₂ depletion until most or all of life on Earth is threatened with extinction by lack of CO₂ in the atmosphere?

During this Pleistocene Ice Age, CO₂ tends to reach a minimum level when the successive glaciations reach their peak. During the last glaciation, which peaked 18,000 years ago, CO₂ bottomed out at 180 ppm, extremely likely the lowest level CO₂ has been in the history of the Earth. This is only 30 ppm above the level that plants begin to die. Paleontological research has demonstrated that even at 180 ppm there was a severe restriction of growth as plants began to starve. With the onset of the warmer interglacial period CO₂ rebounded to 280 ppm. But even today, with human emissions causing CO₂ to reach 400 ppm plants are still restricted in their growth rate, which would be much higher if CO₂ were at 1000-2000 ppm.

The curious timing of the industrial revolution

Here is the shocking news. If humans had not begun to unlock some of the carbon stored as fossil fuels, all of which had been in the atmosphere as CO₂ before sequestration by plants and animals, life on Earth would have soon been starved of this essential nutrient and would begin to die. Given the present trends of glaciations and interglacial periods this would likely have occurred less than 2 million years from today, a blink in nature’s eye, 0.05% of the 3.5 billion-year history of life.

No other species could have accomplished the task of putting some of the carbon back into the atmosphere that was taken out and locked in the Earth’s crust by plants and animals over the millennia. This is why I honour James Lovelock in my lecture this evening. Jim was for many years of the belief that humans are the one-and-only rogue species on Gaia, destined to cause catastrophic global warming. I enjoy the Gaia hypothesis but I am not religious about it and for me this was too much like original sin. It was as if humans were the only evil species on the Earth.

But James Lovelock has seen the light and realized that humans may be part of Gaia’s plan, and he has good reason to do so. And I honour him because it takes courage to change your mind after investing so much of your reputation on the opposite opinion. Rather than seeing humans as the enemies of Gaia, Lovelock now sees that we may be working with Gaia to “stave of another ice age”, or major glaciation. This is much more plausible than the climate doom-and gloom scenario because our release of CO₂ back into the atmosphere has definitely reversed the steady downward slide of this essential food for life, and hopefully may reduce the chance that the climate will slide into another period of major glaciation. We can be certain that higher levels of CO₂ will result in increased plant growth and biomass. We really don’t know whether or not higher levels of CO₂ will prevent or reduce the eventual slide into another major glaciation. Personally I am not hopeful for this because the long-term history just doesn’t support a strong correlation between CO₂ and temperature.

It does boggle the mind in the face of our knowledge that the level of CO₂ has been steadily falling that human CO₂ emissions are not universally acclaimed as a miracle of salvation. From direct observation we already know that the extreme predictions of CO₂’s impact on global temperature are highly unlikely given that about one-third of all our CO₂ emissions have been discharged during the past 18 years and there has been no statistically significant warming. And even if there were some additional warming that would surely be preferable to the extermination of all or most species on the planet.

You heard it here. “Human emissions of carbon dioxide have saved life on Earth from inevitable starvation and extinction due to lack of CO₂”. To use the analogy of the Atomic Clock, if the Earth were 24 hours old we were at 38 seconds to midnight when we reversed the trend towards the End Times. If that isn’t good news I don’t know what is.

I issue a challenge to anyone to provide a compelling argument that counters my analysis of the historical record and the prediction of CO₂ starvation based on the 150 million year trend. Ad hominem arguments about “deniers” need not apply. I submit that much of society has been collectively misled into believing that global CO₂ and temperature are too high when the opposite is true for both. Does anyone deny that below 150 ppm CO₂ that plants will die? Does anyone deny that the Earth has been in a 50 million-year cooling period and that this Pleistocene Ice Age is one of the coldest periods in the history of the planet?

If we assume human emissions have to date added some 200 billion tons of CO₂ to the atmosphere, even if we ceased using fossil fuels today we have already bought another 5 million years for life on earth. But we will not stop using fossil fuels to power our civilization so it is likely that we can forestall plant starvation for lack of CO₂ by at least 65 million years. Even when the fossil fuels have become scarce we have the quadrillion tons of carbon in carbonaceous rocks, which we can transform into lime and CO₂ for the manufacture of cement. And we already know how to do that with solar energy or nuclear energy. This alone, regardless of fossil fuel consumption, will more than offset the loss of CO₂ due to calcium carbonate burial in marine sediments. Without a doubt the human species has made it possible to prolong the survival of life on Earth for more than 100 million years. We are not the enemy of nature but its salvation.

To conclude, carbon dioxide from burning fossil fuels is the stuff of life, the staff of life, the currency of life, indeed the backbone of life on Earth.