Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Geoengineering the climate would reduce vital rains

04.11.2013
Although a significant build-up in greenhouse gases in the atmosphere would alter worldwide precipitation patterns, a widely discussed technological approach to reducing future global warming would also interfere with rainfall and snowfall, new research shows.

The international study finds that a massive increase in greenhouse gases and warming of the planet would spur a nearly 7 percent global increase in precipitation, on average, compared to preindustrial conditions.


Monsoon rainfall wets Beijing streets and passersby in 2011. New research indicates geoengineering to reduce global warming would also reduce average global precipitation. Credit: Sierra F.

But, trying to resolve the problem through “geoengineering” could result in important seasonal rainfalls, known as monsoonal rains, in North America, East Asia, and other regions dropping by 5-7 percent compared to preindustrial conditions. Globally, average precipitation could decrease by about 4.5 percent.

“Geoengineering the planet doesn’t cure the problem,” said Simone Tilmes of the National Center for Atmospheric Research (NCAR) in Boulder, Colo., and lead author of the new study. “Even if one of these techniques could keep global temperatures approximately balanced, precipitation would not return to normal conditions.”

As concerns have mounted about climate change, scientists have studied geoengineering approaches to reduce future warming. Some of these would capture carbon dioxide before it enters the atmosphere. Others would attempt to shade the atmosphere by injecting sulfate particles into the stratosphere or even launching mirrors into orbit with the goal of reducing global surface temperatures.

The new study focuses on the second set of approaches, those that would shade the planet. It warns however, that Earth’s climate would not return to its preindustrial state even if the warming itself were successfully mitigated.

“It’s very much a pick-your-poison type of problem,” said John Fasullo, also of NCAR and a study co-author. “If you don’t like warming, you can reduce the amount of sunlight reaching the surface and cool climate. But if you do that, large reductions in rainfall are unavoidable. There’s no win-win option here.”

The study appears in an online issue of the Journal of Geophysical Research: Atmospheres, published this week by the American Geophysical Union. It was written by an international team of scientists from NCAR and 14 other organizations, and was funded in part by the National Science Foundation (NSF), which sponsors NCAR. The team used, among other tools, the NCAR-based Community Earth System Model, which is funded by NSF and the Department of Energy.

Future carbon dioxide, with or without geoengineering

The research team turned to 12 of the world’s leading climate models to simulate global precipitation patterns if the atmospheric level of carbon dioxide, a leading greenhouse gas, reached four times the level of the preindustrial era. They then simulated the effect of reduced incoming solar radiation on the global precipitation patterns.

The scientists chose the artificial scenario of a quadrupling of carbon dioxide levels, which is on the high side of projections for the end of this century, in order to clearly draw out the potential impacts of geoengineering.

In line with other research, they found that an increase in carbon dioxide levels would significantly increase global average precipitation, although there would likely be significant regional variations and even prolonged droughts in some areas.

Much of the reason for the increased rainfall and snowfall has to do with greater evaporation, pumping more moisture into the atmosphere as a result of more heat being trapped near the surface.

The team then took the research one step further, examining what would happen if a geoengineering approach partially reflected incoming solar radiation high in the atmosphere.

The researchers found that precipitation amount and frequency, especially for heavy rain events, would decrease significantly. The effects were greater over land than over the ocean, and particularly pronounced during months of heavy, monsoonal rains. Monsoonal rains in the model simulations dropped by an average of 7 percent in North America, 6 percent in East Asia and South America, and 5 percent in South Africa. In India, however, the decrease was just 2 percent. Heavy precipitation further dropped in Western Europe and North America in summer.

A drier atmosphere

The researchers found two primary reasons for the reduced precipitation.

One reason has to do with evaporation. As Earth is shaded and less solar heat reaches the surface, less water vapor is pumped into the atmosphere through evaporation.

The other reason has to do with plants. With more carbon dioxide in the atmosphere, plants partially close their stomata, the openings that allow them to take in carbon dioxide while releasing oxygen and water into the atmosphere. Partially shut stomata release less water, so the cooled atmosphere would also become even drier over land.

Tilmes stressed that the authors did not address such questions as how certain crops would respond to a combination of higher carbon dioxide and reduced rainfall.

“More research could show both the positive and negative consequences for society of such changes in the environment,” she said. “What we do know is that our climate system is very complex, that human activity is making Earth warmer, and that any technological fix we might try to shade the planet could have unforeseen consequences.”

Journalists and public information officers (PIOs) of educational and scientific institutions who have registered with AGU can download a PDF copy of this early view article by clicking on this link: http://onlinelibrary.wiley.com/doi/10.1002/jgrd.50868/abstract

Or, you may order a copy of the final paper by emailing your request to Thomas Sumner at tsumner@agu.org. Please provide your name, the name of your publication, and your phone number.

Neither the paper nor this press release is under embargo.

Title

“The hydrological impact of geoengineering in the Geoengineering Model Intercomparison Project”

Authors:

Olivier Boucher and Michael Schulz
Laboratoire de Météorologie Dynamique, IPSL, CNRS/UPMC, Paris, France
Jason N. S. Cole
Canadian Centre for Climate Modeling and Analysis, Environment Canada, Toronto, Ontario, Canada
Charles L. Curry
School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia, Canada
Andy Jones and Jim Haywood
Met Office Hadley Centre, Exeter, UK
Peter J. Irvine
Institute for Advanced Sustainability Studies, Potsdam, Germany;
Duoying Ji and John C. Moore
State Key Laboratory of Earth Surface Processes and Resource Ecology, College of Global Change and Earth System Science, Beijing Normal University, Beijing, China.
Diana B. Karam
Laboratoire des Sciences du Climat et l’Environnement, CEA, CNRS, UVSQ, Gif-sur-Yvette, France;
Ben Kravitz, Philip J. Rasch, Balwinder Singh and Jin-Ho Yoon
Pacific Northwest National Laboratory, Richland, Washington, USA
Ulrike Niemeier and Hauke Schmidt
Max Planck Institute for Meteorology, Hamburg, Germany
Alan Robock
Department of Environmental Sciences, Rutgers University, New Brunswick, New Jersey, USA
Shuting Yang
Danish Meteorological Institute, Copenhagen, Denmark
Shingo Watanabe
Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan
Contact information for the authors:
Simone Tilmes, Phone: +1 (303) 497-1445, Email: tilmes@ucar.edu
John Fasullo, Phone: +1 (303) 497-1712, Email: fasullo@ucar.edu
AGU Contact:
Thomas Sumner
+1 (202) 777-7516
tsumner@agu.org
NCAR/UCAR Contacts:
David Hosansky,
+1 (303) 497-8611
hosansky@ucar.edu
Zhenya Gallon
+1 (303) 497-8607
zhenya@ucar.edu

Peter Weiss | American Geophysical Union
Further information:
http://www.agu.org

More articles from Earth Sciences:

nachricht NASA eyes Pineapple Express soaking California
24.02.2017 | NASA/Goddard Space Flight Center

nachricht 'Quartz' crystals at the Earth's core power its magnetic field
23.02.2017 | Tokyo Institute of Technology

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>