Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Changes to land cover may enhance global warming in Amazon, reduce it in midlatitudes


New simulations of 21st-century climate show that human-produced changes in land cover could produce additional warming in the Amazon region comparable to that caused by greenhouse gases, while counteracting greenhouse warming by 25% to 50% in some midlatitude areas. The simulations from the National Center for Atmospheric Research (NCAR) show the importance of including land cover in computer-model depictions of global change. The results will be published in the December 9 issue of Science.

Lead author Johannes Feddema (University of Kansas) carried out the modeling work with six coauthors from NCAR while on sabbatical at the center. The team linked NCAR’s Land Surface Model with the global-scale Parallel Climate Model, developed by scientists at NCAR and the U.S. Department of Energy under DOE sponsorship. This marks the first time a simulation of 21st-century warming includes not only interactive ocean and atmosphere components but also changes in land cover caused by agriculture, deforestation, and other human activities.

"The choices humans make about future land use could have a significant impact on regional and seasonal climates," says Feddema.

Taken together, the impacts of greenhouse gases around the globe should far outweigh the regional effects of land-cover change, according to Feddema. However, the regions with extensive agriculture and deforestation also tend to be highly populated, so the effects of land-cover change are often focused where people live.

"Compared to global warming, land use is a relatively small influence. However, there are regions where it’s really important," he says.

To bracket a range of possibilities, the group examined two contrasting scenarios for greenhouse emissions and land cover put forth by the Intergovernmental Panel on Climate Change. The more pessimistic scenario assumed that emissions will increase steadily, while the more optimistic scenario assumes rapid gains in energy efficiency.

The results for the first scenario show that deforestation adds 2°C (3.6°F) or more to surface temperature across the Amazon by 2100. Cooling occurs in the nearby Pacific and Atlantic waters with a weakening of the large-scale Hadley circulation that drives tropical and subtropical climate. In turn, moisture penetrates further north and produces a cooling, moistening influence across the U.S. Southwest during that region’s summer monsoon.

While deforestation acts to warm the tropics by replacing forests with less productive pasture, converting midlatitude forests and grasses to cropland tends to act as a cooling influence, because the crops tend to reflect more sunlight and release more moisture into the air. Feddema and colleagues found that expanded agriculture tends to counteract global warming by as much as 50% across parts of North America, Europe, and Asia. In Canada and Russia, boreal forests add to regional warming as they spread north over time.

Although the two IPCC scenarios studied agree on the impacts of land use in some regions, they produce contrasting results in others. The next step for Feddema and colleagues is to utilize the NCAR-based Community Climate System Model, which will provide higher-resolution results. They also hope to incorporate the effects of urban areas on regional climate.

"Our results suggest that more research efforts should be devoted to producing viable scenarios of land-cover change in the future," says coauthor Linda Mearns, director of the NCAR Institute for the Study of Society and Environment. "We very much hope that other climate modeling centers perform experiments similar to ours."

"The purpose of our project is to include human processes more directly in global climate models," adds Feddema. "This is the first step."

The simulations were supported by the DOE, the National Science Foundation, and the University of Kansas. NSF is NCAR’s primary sponsor. Opinions, findings, conclusions, or recommendations expressed in this publication do not necessarily reflect the views of NSF.

Anatta | EurekAlert!
Further information:

More articles from Earth Sciences:

nachricht Receding glaciers in Bolivia leave communities at risk
20.10.2016 | European Geosciences Union

nachricht UM researchers study vast carbon residue of ocean life
19.10.2016 | University of Miami Rosenstiel School of Marine & Atmospheric Science

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Innovative technique for shaping light could solve bandwidth crunch

20.10.2016 | Physics and Astronomy

Finding the lightest superdeformed triaxial atomic nucleus

20.10.2016 | Physics and Astronomy

NASA's MAVEN mission observes ups and downs of water escape from Mars

20.10.2016 | Physics and Astronomy

More VideoLinks >>>