Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Vegetation essential to balancing climate models

01.04.2003


Just as vegetables are essential to balancing the human diet, the inclusion of vegetation may be equally essential to balancing Earth’s climate models.


Satellite image of vegetation types in Africa



Scientists at MIT who were trying to create accurate models of climate change in the southern portion of the Sahara desert found that including a realistic component of vegetation growth and decay was absolutely essential. Without including the vegetation as a variable (rather than a fixed parameter), the models were not able to show the region’s transformation from a fertile expanse of vegetation 6,000 years ago to an arid stretch of mostly sand and mountains today.

“Vegetation is such an important component of the climate system that in this model, including the vegetation was the only way to explain what happened in the past,” said Elfatih Eltahir, an author of the paper describing the research, which appeared in the Jan. 16 issue of the Journal of Geophysical Research.


“Looking at the past climate provides a reasonable way—perhaps the only way—to test models, which must be accurate if they’re going to predict future climate changes,” said Eltahir, a professor of civil and environmental engineering who studies hydroclimatology. “Scientists recognize that the ocean is an important component of the climate system. We are saying that vegetation over land regions is equally important.”

Sometime during the past 6,000 years, the southern boundary of the Sahara desert moved 500 kilometers south, making the desert a much larger portion of northern Africa. The Sahara, the largest desert in the world, covers all of North Africa, from the Atlantic coast to the Red Sea. The “newly” arid area was once covered by lush green grasses and trees and was home to elephants, giraffes and other large wildlife. This includes portions of Sudan, Eltahir’s native country.

The region has been studied considerably by archeologists and paleoclimatologists, who have found fossils in sediment taken from soil cores that prove it was home to a great variety of plants and animals. Cave drawings of many of the animals provide additional proof. Today, only smaller animals, such as antelope, hyena and jackals, live in the desert.

Eltahir and his research team chose this era (the Middle Holocene) for their models, because ice cores taken by climatologists show that the amount of carbon dioxide in the atmosphere was very similar to that of our own time. So CO2 became a fixed parameter in the model.

However solar radiation -- which fluctuates according to slow variations in the geometry of the Earth’s orbit and has considerable impact on Earth’s climate—was very dissimilar. Six thousand years ago, the geometrical aspects of Earth’s orbit were significantly different from today. However, these changes in the Earth’s orbital parameters, though necessary for triggering a retreat of the desert border, were found to be insufficient for fully explaining the extent of the change in the desert’s area. The feedback involving vegetation changes amplified the model’s response to the change in orbital parameters, and brought the model simulations close to the observations of paleoclimatologists.

Another interesting—and rather dire—aspect of the models is the indication that interference with the plants and animals making up the biosphere can induce an altered biosphere which may become fixed at a new and different climate equilibrium. Eltahir’s models suggest that the erosion of that 500 kilometer swath of land from arable to arid was likely to have been sudden, occurring over decades and years, rather than a slow evolution over centuries.

“Sometimes nature reinforces whatever damage you do. We tend to think of nature as healing the damage we humans do. But in this case it seems to be a bit self-destructive,” said Eltahir.

Co-authors on the study are former MIT graduate student Michelle M. Irizarry-Ortiz (lead author), now at the South Florida Water Management District in West Palm Beach, and Guiling Wang of the University of Connecticut. Funding was provided by NASA.

Denise Brehm | MIT News Office
Further information:
http://web.mit.edu/eltahir/www/

More articles from Earth Sciences:

nachricht A promising target in the quest for a 1-million-year-old Antarctic ice core
24.05.2018 | University of Washington

nachricht Tropical Peat Swamps: Restoration of Endangered Carbon Reservoirs
24.05.2018 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>