Featured Research

from universities, journals, and other organizations

Earth Is Becoming A Greener Greenhouse

Date:
September 5, 2001
Source:
American Geophysical Union
Summary:
Over the past 21 years, parts of the northern hemisphere have become much greener than they used to be. Researchers using satellite data have confirmed that plant life above 40 degrees north latitude (New York, Madrid, Ankara, Beijing) has been growing more vigorously since 1981 due to rising temperatures and buildup of greenhouse gases, and Eurasia seems to be greening more than North America, as existing vegetation is more lush for longer periods of time.

WASHINGTON - Over the past 21 years, parts of the northern hemisphere have become much greener than they used to be. Researchers using satellite data have confirmed that plant life above 40 degrees north latitude (New York, Madrid, Ankara, Beijing) has been growing more vigorously since 1981 due to rising temperatures and buildup of greenhouse gases, and Eurasia seems to be greening more than North America, as existing vegetation is more lush for longer periods of time.

These results will appear in the September 16 issue of the Journal of Geophysical Research - Atmospheres, published by the American Geophysical Union. The authors are Liming Zhou, Robert Kaufmann, Nikolai Shabanov and Ranga Myneni of Boston University, and Daniel Slayback and Compton Tucker of NASA's Goddard Space Flight Center, Greenbelt, Maryland.

"When we looked at temperature and satellite vegetation data, we saw that year to year changes in growth and duration of the growing season of northern vegetation are tightly linked to year to year changes in temperature," Zhou said. The area of vegetation has not extended, but the existing vegetation has increased in density.

The authors also looked at the differences in vegetation growth between North America and Eurasia, because the patterns and magnitudes of warming are different on the two continents. The greenness data from satellites were strongly correlated to temperature data from thousands of meteorological stations on both continents. The Eurasian greening was especially persistent over a broad contiguous swath of land from central Europe through Siberia to far-east Russia, where most of the vegetation is forests and woodlands. North America, in comparison, shows a fragmented pattern of change notable only in the forests of the east and grasslands of the upper Midwest.

Dramatic changes in the timing of both the appearance and fall of leaves are recorded in these two decades of satellite data. The authors report a growing season that is now almost 18 days longer, on average, in Eurasia, with spring arriving a week early and autumn delayed by 10 days. In North America, the growing season appears to be as much as 12 days longer.

The researchers used a temperature data set developed from the Global Historical Climate Network (HCN). Dr. James Hansen of NASA's Goddard Institute for Space Studies in New York, who developed this data set, said, "The data were compiled from several thousand meteorological stations in the United States and around the world. The stations also include many rural sites where the data are collected by cooperative private observers."

Myneni suggested that these results are indicative of a greener greenhouse. "This is an important finding because of possible implications to the global carbon cycle," he said. Carbon dioxide is a main greenhouse gas and is thought to play a major role in rising global temperatures. Further, Myneni said, under the Kyoto protocol, most of the developed countries in the north can use certain vegetation carbon sinks to meet their greenhouse gas emissions reduction commitments. If the northern forests are greening, they may already be absorbing carbon. Myneni said, "As to how much and for how long, that needs more research."

Tucker developed the Normalized Difference Vegetation Index (NDVI) product to help determine the "greening" of plant life. The NDVI uses red and near-infrared solar radiation reflected back to sensors of the Advanced Very High Resolution Radiometers (AVHRR) aboard the National Oceanic and Atmospheric Administration (NOAA) series of polar-orbiting satellites. These data are records of sensor observations of every patch of land on Earth, at least once a day, continuously from July 1981. Processing of such massive amounts of data is a time consuming task, even on modern computers, and requires special methods to correct for atmospheric obscuration of Earth's surface. The NDVI developed from processed data shows greening and browning of plants as they relate to seasonal changes and conditions such as drought or abundant rainfall.

This work was made possible through funding by the NASA Earth Science Enterprise's Pathfinder Data Sets and Associated Science Program.


Story Source:

The above story is based on materials provided by American Geophysical Union. Note: Materials may be edited for content and length.


Cite This Page:

American Geophysical Union. "Earth Is Becoming A Greener Greenhouse." ScienceDaily. ScienceDaily, 5 September 2001. <www.sciencedaily.com/releases/2001/09/010905072142.htm>.
American Geophysical Union. (2001, September 5). Earth Is Becoming A Greener Greenhouse. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2001/09/010905072142.htm
American Geophysical Union. "Earth Is Becoming A Greener Greenhouse." ScienceDaily. www.sciencedaily.com/releases/2001/09/010905072142.htm (accessed July 30, 2014).

Share This




More Earth & Climate News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com
In Virginia, the Rise of a New Space Coast

In Virginia, the Rise of a New Space Coast

AP (July 30, 2014) Every summer, tourists make the pilgrimage to Chincoteague Island, Va. to see wild ponies cross the Assateague Channel. But, it's the rockets sending to supplies to the International Space Station that are making this a year-round destination. (July 30) Video provided by AP
Powered by NewsLook.com
Climate Change Could Cost Billions, According To White House

Climate Change Could Cost Billions, According To White House

Newsy (July 29, 2014) A report from the White House warns not curbing greenhouse gas emissions could cost the U.S. billions. Video provided by Newsy
Powered by NewsLook.com
Climate Change Could Cost Billions According To White House

Climate Change Could Cost Billions According To White House

Newsy (July 29, 2014) A report from the White House warns not curbing greenhouse gas emissions could cost the U.S. billions. 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:
from the past week

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