Research shows global photosynthesis on the rise
“Virtually all life on our planet depends on photosynthesis,” said UC Merced Professor Elliott Campbell, who led the research. “Keeping tabs on global plant growth should be a central goal for the human race.”
Photosynthesis is the process through which plants use sunlight to convert carbon dioxide (CO2) into carbohydrates to fuel their growth and other activities.
Yet, researchers lack a clear picture of global trends in photosynthesis over the past few centuries. Some human activities might have stimulated plant growth, while others might have hampered photosynthesis. Conflicting results from different experiments have stoked scientific debate for years.
But maybe not for long. Campbell and an interdisciplinary, international team of scientists discovered a chemical record of global photosynthesis spanning hundreds of years.
“Previous studies covered small physical areas or short periods of time,” Campbell said. “We set out to find a long-term record for the whole planet.”
The researchers estimate that the sum of all plant photosynthesis on Earth grew by 30 percent over the 200-year record they captured.
“Studies have already demonstrated unprecedented changes in climate and greenhouse gases during the industrial era,” Campbell said. “Now we have evidence that there is also a fundamental shift in the Earth’s plants.”
The Net Effect
The research did not identify the cause of the increased photosynthesis, but computer models have shown several processes that could, together, create such a large change in global plant growth.
The leading candidates are rising atmospheric CO2 levels, a result of emissions from human activities; longer growing seasons, a result of climate change caused by CO2 emissions; and nitrogen pollution, another result of fossil fuel combustion and agriculture.
The human activities that underlie the growth in photosynthesis have both positive and negative consequences.
“The rising CO2 level stimulates crops yields,” said Campbell, who’s with the School of Engineering and the Sierra Nevada Research Institute. “But it also benefits weeds and invasive species. Most importantly, CO2 emissions cause climate change, which will increase flooding of coastal cities, extreme weather and ocean acidification.”
Another effect of the rise in photosynthesis is that it can cause plants to remove CO2 from the air and store it in ecosystems. Unfortunately, CO2 emissions from fossil fuel burning overwhelm any uptake by plants.
“The increase in photosynthesis has not been large enough to compensate for the burning of fossil fuels,” said paper co-author Joe Berry, from the Carnegie Institution for Science. “Nature’s brakes have already been overwhelmed. So now it’s up to us to figure out how to reduce the CO2 concentration in the atmosphere.”
Secrets in the Snow
The researchers discovered the record of global photosynthesis by analyzing Antarctic snow data captured by the National Oceanic and Atmospheric Administration (NOAA).
Gases trapped in different layers of Antarctic snow allow scientists to study global atmospheres of the past. The key was finding a gas stored in the ice that provides a record of the Earth’s plant growth.
Previous studies have found that carbonyl sulfide (COS) serves this function. COS is a cousin of CO2, and plants remove COS from the air through a process that is related to the way they uptake CO2.
While photosynthesis is closely related to the atmospheric COS level, other processes in oceans, ecosystems and industry can change COS level also.
To account for all these processes, Campbell coordinated analysis between members of the research team, including Ulli Seibt from UCLA; Steve Smith of the Pacific Northwest National Laboratory; Steve Montzka of NOAA; Thomas Launois of Institut National de la Recherche Agronomique; Sauveur Belviso of Laboratoire des Sciences du Climat et de l’Environnement; Laurent Bopp of Laboratoire de Météorologie Dynamique; and Marko Laine of the Finnish Meteorological Institute. Their work was funded by the U.S. Department of Energy, NOAA, the Academy of Finland, H2020 and the European Research Council.
Future research, the researchers said, will include studying current changes in photosynthesis using the ongoing COS measurements made by NOAA.
“Part of predicting the future state of our atmosphere depends on understanding natural mechanisms and how they are changing over time,” said Montzka, a research chemist with NOAA. “We are making measurements and observations, and if we don’t continue to do that, we won’t have the fundamental information needed to answer important questions related to future atmospheric changes.”
Chris Field, a climate scientist at Stanford University who was not involved in the study, said the new results “provide another line of evidence confirming the dynamic nature of Earth’s ecosystems and the large magnitude of the changes caused by human actions.”
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Large historical growth in global terrestrial gross primary production
J. E. Campbell, J. A. Berry, U. Seibt, S. J. Smith, S. A. Montzka, T. Launois, S. Belviso, L. Bopp & M. Laine
Growth in terrestrial gross primary production (GPP)—the amount of carbon dioxide that is ‘fixed’ into organic material through the photosynthesis of land plants—may provide a negative feedback for climate change1, 2. It remains uncertain, however, to what extent biogeochemical processes can suppress global GPP growth3. As a consequence, modelling estimates of terrestrial carbon storage, and of feedbacks between the carbon cycle and climate, remain poorly constrained4. Here we present a global, measurement-based estimate of GPP growth during the twentieth century that is based on long-term atmospheric carbonyl sulfide (COS) records, derived from ice-core, firn and ambient air samples5. We interpret these records using a model that simulates changes in COS concentration according to changes in its sources and sinks—including a large sink that is related to GPP. We find that the observation-based COS record is most consistent with simulations of climate and the carbon cycle that assume large GPP growth during the twentieth century (31% ± 5% growth; mean ± 95% confidence interval). Although this COS analysis does not directly constrain models of future GPP growth, it does provide a global-scale benchmark for historical carbon-cycle simulations.
http://www.nature.com/nature/journal/v544/n7648/full/nature22030.html
From the article: “climate change caused by CO2 emissions” – well, that is a theory. But, it has no supporting Laws, Axioms, Postulates, or formulas. It’s a vacuous theory with no science to apply.
Contrast that with the known truths that Carbon Dioxide is:
– the base of the food chain for all carbon based life forms
– the only singular throttle in the Carbon Cycle of life
– the source of all carbon in all organic material
Well, whaddayaknow, areas in the Arctic ocean seeing less sea-ice are producing large amounts of chlorophyll…..
The Mauna Loa CO2 data shows a yearly pattern, CO2 going down a bit during NH summer and back up during NH winter.
If CO2 is increasing the total mass of plant life on planet, would this yearly drop and recovery increase in size?
MarkW,
Indeed the near-ground seasonal amplitude it is increasing, mainly in the high latitudes, as that is where average growth season temperatures and thus seasonal plant growth increased most:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/seasonal_CO2_MLO_BRW.jpg
Maybe even more if earlier years were compared. Here the data are from 1974 on, as from that year on regular δ13C measurements were taken, which show the opposite pattern as for CO2. That proves that the main seasonal changes are from vegetation, not from the oceans.
On hemispheric (Mauna Loa) and global level the changes are too small in the graph, but still may be significant.
BTW, MLO = Mauna Loa and BRW = Barrow, at the coast of the North Slope, Alaska on a small penisula into the Arctic Ocean.
Decades ago, when the earth was cooling some idiot should have suggested that we use geo-engineering to warm the planet. They might have suggested CO2 because not only would it warm the planet and prevent the next ice age, but it would also benefit plant growth.
Now we have a great climate and plants are doing well and we are getting idiots wanting us to cool the planet and kill off plants by simulation the effect of massive volcanoe eruptions.
What is not mentioned is that increasing CO2 promotes weed growth, particularly vines, over more desirable flora and that changes in plant chemistry due to increased CO2 decreases the nutritional content of many important food sources.
I didn’t think of that! Co2 is making Americans Fat? The expanding waist lines are directly proportional to the increase in co2. So that’s where the sinks are !!
I thought the sinks were in the bathroom?
Actually, the claim that weeds will benefit more was addressed.
As to the claim about nutrition, that study was refuted over a decade ago.
Slipstick,
As far as I remember, only leave vegetables did contain less nitrogen compounds (less proteins), but seeds, fruits,… didn’t change. With more nitrogen fertilisers the “problem” for feed/food even for leaves was over…
My new shirt Motto:
“Save Gaia’s Plant KingDom”
“End the CO2 Drought!”
it would be CRIMINAL to reduce CO2.
Unless our liberal “friends” want to eat less themselves and so compensate for less food?
“Plant photosynthesis was stable for hundreds of years before the industrial revolution, but grew rapidly in the 20th century,”
So thanks to man-made CO2, those damned triffids are going to take over.
We’re doomed.
Although [ after 40 years climate modelling ] this COS analysis does not directly constrain models of future GPP growth, it does provide a global-scale benchmark for historical carbon-cycle simulations.
There’s another 40 years. Next comes ‘ocean acidification’.
venus says:
April 6, 2017 at 12:48 pm
it would be CRIMINAL to reduce CO2
Exactly.
From the article:
The researchers estimate that the sum of all plant photosynthesis on Earth grew by 30 percent over the 200-year record they captured.
The whole biosphere benefits from it, and from it humans.
This would mean that about 1/3 of all food that we have comes from it, without the extra CO2 2 billion of people would starve.
Researches estimate that the increase of photosynthesis lead to an increase of sexual activity across the 200-year record they captured.
However, the increase of research in the field of climatology has offset the former increase, due to their preferrence to intellectual masturbation VS the real thing.
/SARC