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 Greening
in the North
To determine how climate changes affect
vegetation, scientists have developed new ways of measuring
plant growth on a global scale.
The more visible sunlight a plant absorbs, the more the plant
photosynthesizes, using the energy in light to produce food.
The more photosynthesis occurs in a given region, the thicker
the plant cover. Using information collected by satellites,
scientists can track the changes in the amount of light absorbed
by different parts of the earth. When an area absorbs more
visible light and less near-infrared light (which is not useful
for photosynthesis), researchers know that more vegetation
is growing there.
This map shows the persistence of vegetation growth above
thirty degrees north latitude. Persistence is scored on a
scale of low to high based on how consistently the vegetation
in an area increased between 1982 and 1999. Vegetation in
this region has been growing more vigorously over the past
two decades. The greatest changes have been north of forty
degrees north latitude where the length of the growing season
has increased by several days.
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Technology (in this case, satellite
imagery) provides scientists with much new data.
Knowing how to use these data takes creativity
and ingenuity. As the research on greening shows,
scientists sometimes have to find innovative ways
to combine new information with what has been
known for years. No matter how good a researcher’s
instruments are, science remains a form of detective
work.
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glossary terms
