A reduction in non-CO2 greenhouse gases will be required to abate climate change, the researchers said. Cutting releases of methane and nitrous oxide, two gases that pound-for-pound trap more heat than does CO2, should be considered alongside the challenge of reducing fossil fuel use.
The researchers' analysis, "Ruminants, Climate Change, and Climate Policy," is being published today as an opinion commentary in Nature Climate Change, a professional journal.
William Ripple, a professor in the College of Forestry at Oregon State University, and co-authors from Scotland, Austria, Australia and the United States, reached their conclusions on the basis of a synthesis of scientific knowledge on greenhouse gases, climate change and food and environmental issues. They drew from a variety of sources including the Food and Agricultural Organization, the United Nations Framework Convention on Climate Change (UNFCCC) and recent peer-reviewed publications.
"Because the Earth's climate may be near a tipping point to major climate change, multiple approaches are needed for mitigation," said Ripple. "We clearly need to reduce the burning of fossil fuels to cut CO2 emissions. But that addresses only part of the problem. We also need to reduce non-CO2 greenhouse gases to lessen the likelihood of us crossing this climatic threshold."
Methane is the second most abundant greenhouse gas, and a recent report estimated that in the United States methane releases from all sources could be much higher than previously thought. Among the largest human-related sources of methane are ruminant animals (cattle, sheep, goats, and buffalo) and fossil fuel extraction and combustion.
One of the most effective ways to cut methane, the researchers wrote, is to reduce global populations of ruminant livestock, especially cattle. Ruminants are estimated to comprise the largest single human-related source of methane. By reflecting the latest estimates of greenhouse gas emissions on the basis of a life-cycle or a "farm to fork" analysis, the researchers observed that greenhouse gas emissions from cattle and sheep production are 19 to 48 times higher (on the basis of pounds of food produced) than they are from producing protein-rich plant foods such as beans, grains, or soy products.
Unlike non-ruminant animals such as pigs and poultry, ruminants produce copious amounts of methane in their digestive systems. Although CO2 is the most abundant greenhouse gas, the international community could achieve a more rapid reduction in the causes of global warming by lowering methane emissions through a reduction in the number of ruminants, the authors said, than by cutting CO2 alone.
The authors also observed that, on a global basis, ruminant livestock production is having a growing impact on the environment:•Globally, the number of ruminant livestock has increased by 50 percent in the last 50 years, and there are now about 3.6 billion ruminant livestock on the planet.
•A third of all arable land is used to grow feed crops for livestock.
In addition to reducing direct methane emissions from ruminants, cutting ruminant numbers would deliver a significant reduction in the greenhouse gas emissions associated with the production of feed crops for livestock, they added.
"Reducing demand for ruminant products could help to achieve substantial greenhouse gas reductions in the near-term," said co-author Helmut Haberl of the Institute of Social Ecology in Austria, "but implementation of demand changes represent a considerable political challenge."
Among agricultural approaches to climate change, reducing demand for meat from ruminants offers greater greenhouse gas reduction potential than do other steps such as increasing livestock feeding efficiency or crop yields per acre. Nevertheless, they wrote, policies to achieve both types of reductions "have the best chance of providing rapid and lasting climate benefits."
Such steps could have other benefits as well, said co-author Pete Smith of the University of Aberdeen in Scotland. "Cutting the number of ruminant livestock could have additional benefits for food security, human health and environmental conservation involving water quality, wildlife habitat and biodiversity," he explained.
Agricultural researchers are also studying methane reduction through improved animal genetics and methods to inhibit production of the gas during digestion.
International climate negotiations such as the UNFCCC have not given "adequate attention" to greenhouse gas reductions from ruminants, they added. The Kyoto Protocol, for example, does not target ruminant emissions from developing countries, which are among the fastest-growing ruminant producers.
In addition to Smith and Haberl, co-authors include Stephen A. Montzka of the U.S. National Oceanic and Atmospheric Administration, Clive McAlpine of the University of Queensland in Australia and Douglas Boucher of the Union of Concerned Scientists in Washington D.C.
Bill Ripple | EurekAlert!
Machine learning helps predict worldwide plant-conservation priorities
04.12.2018 | Ohio State University
From the Arctic to the tropics: researchers present a unique database on Earth’s vegetation
20.11.2018 | Martin-Luther-Universität Halle-Wittenberg
What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.
Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...
Scientists at the University of Stuttgart and the Karlsruhe Institute of Technology (KIT) succeed in important further development on the way to quantum Computers.
Quantum computers one day should be able to solve certain computing problems much faster than a classical computer. One of the most promising approaches is...
New Project SNAPSTER: Novel luminescent materials by encapsulating phosphorescent metal clusters with organic liquid crystals
Nowadays energy conversion in lighting and optoelectronic devices requires the use of rare earth oxides.
Scientists have discovered the first synthetic material that becomes thicker - at the molecular level - as it is stretched.
Researchers led by Dr Devesh Mistry from the University of Leeds discovered a new non-porous material that has unique and inherent "auxetic" stretching...
Scientists from the Theory Department of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science (CFEL) in Hamburg have shown through theoretical calculations and computer simulations that the force between electrons and lattice distortions in an atomically thin two-dimensional superconductor can be controlled with virtual photons. This could aid the development of new superconductors for energy-saving devices and many other technical applications.
The vacuum is not empty. It may sound like magic to laypeople but it has occupied physicists since the birth of quantum mechanics.
10.12.2018 | Event News
06.12.2018 | Event News
03.12.2018 | Event News
10.12.2018 | Physics and Astronomy
10.12.2018 | Life Sciences
10.12.2018 | Information Technology