New global warming excuse: Forest, plant emissions moderate warming

Counteracting as much as 30% of warming on a regional scale.

The media release is below.


Plants moderate climate warming

As temperatures warm, plants release gases that help form clouds and cool the atmosphere, according to research from IIASA and the University of Helsinki.

The new study, published in Nature Geoscience, identified a negative feedback loop in which higher temperatures lead to an increase in concentrations of natural aerosols that have a cooling effect on the atmosphere.

“Plants, by reacting to changes in temperature, also moderate these changes,” says IIASA and University of Helsinki researcher Pauli Paasonen, who led the study.

Scientists had known that some aerosols – particles that float in the atmosphere – cool the climate as they reflect sunlight and form cloud droplets, which reflect sunlight efficiently. Aerosol particles come from many sources, including human emissions. But the effect of so-called biogenic aerosol – particulate matter that originates from plants – had been less well understood. Plants release gases that, after atmospheric oxidation, tend to stick to aerosol particles, growing them into the larger-sized particles that reflect sunlight and also serve as the basis for cloud droplets. The new study showed that as temperatures warm and plants consequently release more of these gases, the concentrations of particles active in cloud formation increase.

“Everyone knows the scent of the forest,” says Ari Asmi, University of Helsinki researcher who also worked on the study. “That scent is made up of these gases.” While previous research had predicted the feedback effect, until now nobody had been able to prove its existence except for case studies limited to single sites and short time periods. The new study showed that the effect occurs over the long-term in continental size scales.

The effect of enhanced plant gas emissions on climate is small on a global scale – only countering approximately 1 percent of climate warming, the study suggested. “This does not save us from climate warming,” says Paasonen. However, he says, “Aerosol effects on climate are one of the main uncertainties in climate models. Understanding this mechanism could help us reduce those uncertainties and make the models better.”

The study also showed that the effect was much larger on a regional scale, counteracting possibly up to 30% of warming in more rural, forested areas where anthropogenic emissions of aerosols were much lower in comparison to the natural aerosols. That means that especially in places like Finland, Siberia, and Canada this feedback loop may reduce warming substantially.

The researchers collected data at 11 different sites around the world, measuring the concentrations of aerosol particles in the atmosphere, along with the concentrations of plant gases, the temperature, and reanalysis estimates for the height of the boundary layer, which turned out to be a key variable. The boundary layer refers to the layer of air closest to the Earth, in which gases and particles mix effectively. The height of that layer changes with weather. Paasonen says, “One of the reasons that this phenomenon was not discovered earlier was because these estimates for boundary layer height are very difficult to do. Only recently have the reanalysis estimates been improved to where they can be taken as representative of reality.”


4 thoughts on “New global warming excuse: Forest, plant emissions moderate warming”

  1. This study basically says that plants help cool things down. Wow–I never would have thought of that.

  2. 7 Billion people in the world cannot afford to cause global warming.Our planet earth is just one of Billion planets.Global warming or climate change is only for the idiots.Nature can change by itself and no idiot Ph.D or scientists can do anything about it but money to support themselves by promoting false information and propaganda.Why spend Trillion,Trillion dollars to solve the problem that is no existence? Why not produce more food and housing for the world population?

  3. I don’t know that it’s fair to call this an excuse. For one thing, it’s probably true. For another, it emphasizes that the models used to predict harmful warming, and to lay responsibility on human activity, are in error.

  4. A Czech Republic company says it has found an abundant, long-term source of energy in South Texas to help European utilities produce electricity.
    The energy source has nothing to do with the Eagle Ford Shale.
    The source is the hated mesquite wood.
    “We looked all over the world for a stable and big source of biomass. We found the source in Texas,” Zdenek Mayer said. He’s business director and CEO for GreenHeart Energy LLC, the Texas division of GreenHeart Energy, based in Duchcov, Czech Republic.
    GreenHeart Energy LLC has selected San Antonio for its Texas company’s headquarters — for legal, banking and accounting purposes — but most of its activities will occur near and in Corpus Christi.
    GreenHeart Energy, founded in 2008, plans to harvest mesquite in South Texas, chip the wood, and ship it from Corpus Christi in bulk to a German port. Once the chips are in Europe, electricity utilities will burn them to create turbine-turning steam.
    Because burning mesquite chips produces less pollution than the coal the utilities have been burning, the utilities can sell some of their pollution permits back to their governments.
    Mayer listed Poland as the country with the biggest potential for mesquite chips. Utilities in the United Kingdom, Ireland, Holland, Italy, Sweden, Norway and Denmark also are likely customers, Mayer said.
    Mesquite wood has a low moisture content and an energy level, when burned, of somewhere between that of brown and black coal, Mayer said.
    GreenHeart Energy estimates more than 500,000 acres of mesquite exists within 100 miles of Corpus Christi, with a yearly availability of 19 million tons. The company wants to harvest mesquite within only 100 miles of Corpus Christi to control transportation costs.
    Every 35 metric tons of mesquite chips will cost the company about $2 million in payments to landowners, the ports and logistics, Mayer said.
    GreenHeart Energy is negotiating a three-acre lease at Port Corpus Christi, which would give it enough space for 40,000 metric tons of storage.
    The company plans to operate three or four harvesting teams of seven workers each. It also will run a fleet of 12 trucks and employ port workers.
    Mesquite is even renewable. GreenHeart Energy’s harvesting method will leave the root systems intact. Within 10 years of a harvest, the plant will grow back for another harvesting. “This is nature management,” Mayer said.
    Mesquite may look like a tree, but the species is considered a woody plant and not a forest species in the United States.
    Mesquite, instead, is viewed as an invasive species that has taken over grasslands and rangelands, wrote Jim Ansley, professor of rangeland shrub ecology at the Texas A&M AgriLife Research and Extension Center at Vernon, in a letter to Mayer.
    The mesquite species existed only in limited locations in what is now Texas. When settlers and the cattle industry rose in the last half of the 1800s, the species spread rapidly across the state. The number of naturally occurring grassfires was reduced by settlements, preserving grass for cattle consumption.
    Cattle also consumed the seed-containing legume beans on the mesquite plant and spread the seed geographically, especially on cattle drives, by passing the seeds through their droppings. Mesquite in some places became so dense it threatened the grasslands needed for the cattle.
    “These thickets may have potential as a bio-energy feedstock source,” Ansley wrote in the letter. “It sprouts vigorously after above-ground harvest and would be considered a highly sustainable fuel source.”
    GreenHeart Energy LLC plans to be operating in Texas as early as June, Mayer said. The company is being assisted by San Antonio lawyer Bob Braubach, who met GreenHeart executives in February at a Business Opportunities in Mexico and Texas seminar in Prague, the Czech Republic capital.
    Will mesquite wood ever work as a fuel for U.S. utilities? It obviously takes a large amount of energy to harvest, chip and transport the wood chips, but Mayer and Libor Šmída, GreenHeart Energy LLC’s business development manager, said their strategy works for Europe if the pollution credits are considered.
    Cris Eugster, CPS Energy’s executive vice president and chief strategy and technology officer, said he is aware of European utilities, especially in the United Kingdom, turning more to biomass sources.
    “For us, it’s a cost issue,” Eugster said. “Until the costs come down, it’s still a bit out there.”
    Mayer said he is confident that biomass has a big energy future. “There are now a lot of companies looking for biomass in the world,” Mayer said.

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