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The GLAS is Half Full: Satellites and Changing Tropical Forests

This article is from Issue Climate Change - Vol. 14 No. 1.

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The scientists wanted to know if the information gathered by satellites was as good as the information they would get if they gathered it in person. The scientists in this study wanted to discover whether information gathered by satellites could be used to identify the age of tropical rain forests and to estimate the increase in the amount of biomass in growing rain forests. They also wanted to know if information gathered by satellites could be used to estimate the amount of biomass held by old rain forests.

Welcome to the Climate Change edition

Note to Educators

Journal Lesson Plan

Word Search

Word Scramble

Education Standards Correlations

Reflection Section Answer Guide

Additional Resources for this Article:
Meet the scientists that contributed to this article:

"Science Topics" covered in this article:
  • Earth Science
  • Life Science
  • People and Science
  • Technology and Science

"Thinking About Science Themes" covered in this article:
All life on Earth depends on sunlight to survive. Humans, however, also use light for convenience and to meet modern needs. In recent years, the use of light has increased. Light is used not just for human needs and comfort; it is also for science and technology. In the 1950s and 60s, light began to be used to improve electronic communications. Today, optical fibers are used for most landbased electronic communications. Light is also used in satellite technology to communicate between Earth and space. In 2003, a satellite was launched carrying an instrument called the Geoscience Laser Altimeter (al ti mə tər) System, or GLAS. GLAS sends 40 beams of light every second to Earth’s surface. GLAS provides continuous light beam observations of Earth. When each light beam reaches Earth, it is reflected back to the satellite. By tracking and recording the amount of time each beam of light takes to return to the satellite, GLAS can be used to calculate many properties of Earth’s surface. In this research, the scientists used GLAS to estimate the increase over time in living material, such as branches and leaves, in young and growing tropical rain forests. If this kind of research is successful, scientists will have a more accurate way to understand the world’s rain forests.
Specific "Thinking About Science" Themes:
  • Scientific Topics
  • Uses and Benefits of Science

"Thinking About Environmental Themes" covered in this article:
When a large amount of carbon dioxide, or CO2, is emitted into the air, it gets trapped in the atmosphere and causes the surface of Earth to warm beyond its normal range. This is happening now, partly because of the large amount of fossil fuels being burned for energy. Carbon, one of the elements that makes up CO2, is found in every living thing. As trees grow, for example, they absorb carbon from the atmosphere. Old forests also absorb and hold carbon. Because trees keep carbon on Earth, they help to reduce the rate of global warming. Scientists need to know the location and age of forests to estimate how much carbon they absorb and hold. To do this, scientists must calculate how much living and once-living material, called biomass, is contained within a forest area. They also need to calculate how much the biomass of young forests is increasing as they grow. The amount of carbon absorbed and held by forests is related to the amount of biomass contained in the trees and other vegetation that make up the forests. If a forest has more trees, leaves, and other vegetation, it keeps more carbon on Earth.
Specific "Thinking About the Environment" Themes:
  • Forests ability to hold carbon

NSE Standards covered in this article:
  • Abilities necessary to do scientific inquiry (A)
  • Nature of science (G)
  • Science and technology in society (F)
  • Science as a human endeavor (G)
  • Structure of the earth system (D)
  • Understandings about science and technology (E)
  • Understandings about scientific inquiry (A)