Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Studies Raise Questions about Climate Change

04.02.2002


Image: Courtesy of NASA


Climate prediction just got trickier, according to two new studies appearing in the current issue of the journal Science. Analysis of more than two decades of satellite data shows that more sunlight entered the tropics and more heat escaped to space in the 1990s than a decade earlier. Moreover, current climate models fail to account for the new findings, suggesting that they may contain more uncertainty than previously thought.

For the earth’s climate to remain unchanged, the planet’s energy budget must equal zero—that is, the planet must emit or reflect the same amount of energy that enters as sunlight. But that’s not what Columbia University researcher Junye Chen and colleagues found when they studied thermal radiation emitted by earth (left sphere in image) and reflected sunlight (right sphere in image) over the tropics. Between 1985 and 2000, they found, the amount of energy emitted increased while the amount reflected decreased, with most of the change occurring after 1990. The findings suggest that the movement of air masses over the tropics—the so-called Hadley and Walker circulation cells—increased in strength, causing rising air to become moister and sinking air drier.

In the second study, Bruce Wielicki of NASA’s Langley Research Center and colleagues demonstrated that the earth’s radiative energy budget varies on timescales as short as a decade, making it much more variable than previously thought. Using satellite data covering 22 years, they identified peaks in the amount of energy escaping the atmosphere and seasonal variations in the amount of incoming radiation. "We tracked the changes to a decrease in tropical cloudiness that allowed more sunlight to reach the earth’s surface," Wielicki explains. "But what we want to know is why the clouds would change." Failure to fully account for the effects of clouds is one of the greatest weaknesses of current climate models. Indeed, four major climate models could not reproduce the tropical cloud changes or generate what the researchers call the "more subtle, but still large, decadal changes seen in the radiation data."



The scientists do not yet know what causes this variation in tropical radiation. "We think this is a natural fluctuation," Anthony Del Genio of NASA’s Goddard Institute for Space Studies says, "but there is no way to tell yet." Still, he advises, even before knowing the cause of the variability, researchers should attempt to modify their models in order to accommodate it.

Sarah Graham | Scientific American

More articles from Earth Sciences:

nachricht From volcano's slope, NASA instrument looks sky high and to the future
27.04.2017 | NASA/Goddard Space Flight Center

nachricht Penn researchers quantify the changes that lightning inspires in rock
27.04.2017 | University of Pennsylvania

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Bare bones: Making bones transparent

27.04.2017 | Life Sciences

Study offers new theoretical approach to describing non-equilibrium phase transitions

27.04.2017 | Physics and Astronomy

From volcano's slope, NASA instrument looks sky high and to the future

27.04.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>