Featured Research

from universities, journals, and other organizations

Urban Sprawl Reduces Annual Photosynthetic Production

Date:
February 28, 2000
Source:
NASA Goddard Space Flight Center
Summary:
A study of the impact of urbanization and industrialization over the past seven years using satellites shows that annual photosynthetic productivity can be reduced by as much as 20 days in some areas where urbanization is intense, not unlike turning the lights off in a greenhouse during the growing season.

A study of the impact of urbanization and industrialization over the past seven years using satellites shows that annual photosynthetic productivity can be reduced by as much as 20 days in some areas where urbanization is intense, not unlike turning the lights off in a greenhouse during the growing season.

The study also reveals that urbanization may be creating vast heat islands that can actually lengthen the growing season, but do not improve the productivity of the land.

NASA Goddard Space Flight Center (Greenbelt, Md.) researcher Dr. Marc L. Imhoff presents his findings during a news media briefing at the 2000 American Association for the Advancement of Science (AAAS) Annual Meeting at the Marriott Wardman Park Hotel (Washington, D.C.) on Monday, Feb. 21 at 3 p.m. in the Wilson Room.

According to Imhoff's research, urbanization and industrialization have resulted in the development of mega-cities and urban and suburban sprawl. The environment is altered as a result of replacing land cover with roads, housing, and commercial and industrial structures.

"Human survival depends on the ability of the landscape to produce food," said Imhoff. "Food production can be fundamentally linked to primary production or photosynthesis. If the capacity of the landscape to carryout photosynthesis is substantially reduced - then the ability of the planet to support human life must also be diminished."

Imhoff said data from the mid-1990's from two different satellite systems were combined with land cover maps and census information on population and housing to study the effect of urbanization on photosynthetic production in the United States. Nighttime images from a Department of Defense satellite, which show a dramatic picture of Earth's city lights, were used to determine which areas and how much land have been converted to urban, suburban, or industrial use. Maps showing urban, peri-urban (suburban), and non-urbanized areas were created from the "city-lights" satellite data.

"Using a computer, we combined the city-lights satellite data with another type of satellite data that records a measure of 'greenness' or photosynthetic potential of the landscape over the course of an entire year," Imhoff said. "By merging the satellite data we could examine how urbanization affects the potential of the land surface to carryout photosynthesis by looking at the 'greenness' index inside and outside the urbanized areas for the whole continental United States."

Results show that urbanization can have a measurable but variable impact on photosynthetic productivity. Annual photosynthetic productivity can be reduced by as much as 20 days in areas where housing and commercial land use is very dense.

"However, we also found that in resource limited regions, human activity can increase productivity by altering the environment," he said. "For example, this was the case for arid and semi-arid areas where lawn irrigation and planting changed the ecosystems from shrub lands and desert to deciduous forests."

A most interesting finding according to Imhoff was that urbanization seems to elongate the growing season, yet still reduces the overall productivity of the land. "Vegetation greens up earlier in the spring and takes longer to senesce in the fall, but has lower peak season productivity than similar nearby areas that are not urbanized," he said. "This could be demonstrating a profound urban heat island effect and have implications in climate change, especially in the northern Hemisphere where urban development is most intense."

Analysis of the data also found clear evidence that human beings definitely tend to locate themselves on the most productive land and that those lands are being transformed into less productive types.

"The results of this study should increase our awareness of the importance of land use planning especially in the context of sustainable growth and development," Imhoff stated. "Human survival depends on photosynthesis. If urbanization and industrialization continue, the capacity of the landscape to carry out photosynthesis is substantially reduced. "

For supporting images: http://svs.gsfc.nasa.gov/imagewall/AAAS


Story Source:

The above story is based on materials provided by NASA Goddard Space Flight Center. Note: Materials may be edited for content and length.


Cite This Page:

NASA Goddard Space Flight Center. "Urban Sprawl Reduces Annual Photosynthetic Production." ScienceDaily. ScienceDaily, 28 February 2000. <www.sciencedaily.com/releases/2000/02/000228081039.htm>.
NASA Goddard Space Flight Center. (2000, February 28). Urban Sprawl Reduces Annual Photosynthetic Production. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2000/02/000228081039.htm
NASA Goddard Space Flight Center. "Urban Sprawl Reduces Annual Photosynthetic Production." ScienceDaily. www.sciencedaily.com/releases/2000/02/000228081039.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