Featured Research

from universities, journals, and other organizations

Geoengineering Could Slow Down Global Water Cycle

Date:
May 28, 2008
Source:
DOE/Lawrence Livermore National Laboratory
Summary:
As fossil fuel emissions continue to climb, reducing the amount of sunlight hitting the Earth would definitely have a cooling effect on surface temperatures.

A schematic representation of various geoengineering and carbon storage proposals.
Credit: Diagram by Kathleen Smith/LLNL

As fossil fuel emissions continue to climb, reducing the amount of sunlight hitting the Earth would definitely have a cooling effect on surface temperatures.

However, a new study from Lawrence Livermore National Laboratory, led by atmospheric scientist Govindasamy Bala, shows that this intentional manipulation of solar radiation also could lead to a less intense global water cycle. Decreasing surface temperatures through "geoengineering" also could mean less rainfall.

The reduction in sunlight can be accomplished by geoengineering schemes. There are two classes: the so-called "sunshade" geoengineering scheme, which would mitigate climate change by intentionally manipulating the solar radiation on the earth's surface; the other category removes atmospheric CO2 and sequesters it into the terrestrial vegetation, oceans or deep geologic formations.

In the new climate modeling study, which appears in the May 27-30 early online edition of the Proceedings of the National Academy of Sciences, Bala and his colleagues Karl Taylor and Philip Duffy demonstrate that the sunshade geoengineering scheme could slow down the global water cycle.

The sunshade schemes include placing reflectors in space, injecting sulfate or other reflective particles into the stratosphere, or enhancing the reflectivity of clouds by injecting cloud condensation nuclei in the troposphere. When CO2 is doubled as predicted in the future, a 2 percent reduction in sunlight is sufficient to counter the surface warming.

This new research investigated the sensitivity of the global mean precipitation to greenhouse and solar forcings separately to help understand the global water cycle in a geoengineered world.

While the surface temperature response is the same for CO2 and solar forcings, the rainfall response can be very different.

"We found that while climate sensitivity can be the same for different forcing mechanisms, the hydrological sensitivity is very different," Bala said.

The global mean rainfall increased approximately 4 percent for a doubling of CO2 and decreases by 6 percent for a reduction in sunlight in his modeling study.

"Because the global water cycle is more sensitive to changes in solar radiation than to increases in CO2, geoengineering could lead to a decline in the intensity of the global water cycle" Bala said.

A recent study showed that there was a substantial decrease in rainfall over land and a record decrease in runoff and discharge into the ocean following the eruption of Mount Pinatubo in 1991. The ash emitted from Pinatubo masked some of the sunlight reaching the earth and therefore decreased surface temperatures slightly, but it also slowed down the global hydrologic cycle.

"Any research in geoengineering should explore the response of different components of the climate system to forcing mechanisms," Bala said.

For instance, Bala said, sunshade geoengineering would not limit the amount of CO2 emissions. CO2 effects on ocean chemistry, specifically, could have harmful consequences for marine biota because of ocean acidification, which is not mitigated by geoengineering schemes.

"While geoengineering schemes would mitigate the surface warming, we still have to face the consequences of CO2 emissions on marine life, agriculture and the water cycle," Bala said.


Story Source:

The above story is based on materials provided by DOE/Lawrence Livermore National Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

DOE/Lawrence Livermore National Laboratory. "Geoengineering Could Slow Down Global Water Cycle." ScienceDaily. ScienceDaily, 28 May 2008. <www.sciencedaily.com/releases/2008/05/080527155519.htm>.
DOE/Lawrence Livermore National Laboratory. (2008, May 28). Geoengineering Could Slow Down Global Water Cycle. ScienceDaily. Retrieved October 1, 2014 from www.sciencedaily.com/releases/2008/05/080527155519.htm
DOE/Lawrence Livermore National Laboratory. "Geoengineering Could Slow Down Global Water Cycle." ScienceDaily. www.sciencedaily.com/releases/2008/05/080527155519.htm (accessed October 1, 2014).

Share This



More Earth & Climate News

Wednesday, October 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Earth Has Lost Half Its Vertebrate Wildlife Since 1970: WWF

Earth Has Lost Half Its Vertebrate Wildlife Since 1970: WWF

Newsy (Sep. 30, 2014) A new study published by the World Wide Fund for Nature found that more than half of the world's wildlife population has declined since 1970. Video provided by Newsy
Powered by NewsLook.com
Seismic Activity Halts Recovery at Japan Volcano

Seismic Activity Halts Recovery at Japan Volcano

AP (Sep. 30, 2014) Rescuers were forced to suspend plans to recover at least two dozen bodies from near the summit of Mount Ontake in central Japan on Tuesday after increased seismic activity raised concern about the possibility of another eruption. (Sept. 30) Video provided by AP
Powered by NewsLook.com
Dolphins Might Use Earth's Magnetic Field As A GPS

Dolphins Might Use Earth's Magnetic Field As A GPS

Newsy (Sep. 30, 2014) A study released Monday suggests dolphins might be able to sense the Earth's magnetic field and possibly use it as a means of navigation. Video provided by Newsy
Powered by NewsLook.com
How To Battle Stink Bug Season

How To Battle Stink Bug Season

Newsy (Sep. 30, 2014) Homeowners in 33 states grapple with stink bugs moving indoors at this time of year. Here are a few tips to avoid stink bug infestations. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins