 IN
FOCUS: NASA Study Confirms the Earth's
Energy is Out of Balance |
Scientists have
concluded more energy is being
absorbed from the sun than is
emitted back to space, throwing the
Earth's energy "out of balance" and
warming the globe.
Scientists from NASA, Columbia
University, New York, and Lawrence
Berkeley National Laboratory,
Berkeley, Calif. used satellites,
data from buoys and computer models
to study the Earth's oceans. They
confirmed the energy imbalance by
using precise measurements of
increasing ocean heat content over
the past 10 years.
Image above:
Clouds
and the Earth's Radiant Energy
System (CERES) measurements show the
reflected solar radiation (left) and
emitted heat radiation (right) for
January 1, 2002. In both images, the
lightest areas represent thick
clouds, which both reflect radiation
from the Sun and block heat rising
from the Earth's surface. Notice the
clouds above the western Pacific
Ocean, where there is strong
uprising of air, and the relative
lack of clouds north and south of
the equator. The animation, created
from daily data, shows how rapidly
these measurements change. Credit:
NASA
The study reveals Earth's energy
imbalance is large by standards of
the planet's history. The imbalance
is 0.85 watts per meter squared.
That will cause an additional
warming of 0.6 degrees Celsius (1
degree Fahrenheit) by the end of
this century.
As the Earth warms it emits more
heat. Eventually the Earth will be
back in balance, if the greenhouse
gas emissions are kept at the same
level of today. Scientists know it
takes the ocean longer to warm than
the land. The lag in the ocean's
response has practical consequences.
It means there is an additional
global warming of about one degree
Fahrenheit that is already in the
pipeline. Even if there were no
further increase of human-made gases
in the air, climate would continue
to warm that much over the next
century.
 Image
right:
Methane is one
greenhouse gas that impacts the
Earth's energy balance. This image
shows the circulation of methane
around the globe.
Photo credit: NASA
Warmer world-wide water temperatures
also affect other things. "Warmer
waters increase the likelihood of
accelerated ice sheet disintegration
and sea level rise during this
century," Hansen said. Since 1993,
sea levels have been measured by
satellite altimeters. Data has shown
they have risen by approximately 3.1
centimeters or 1.26 inches per
decade.
Although 3.1 centimeters is a small
change, the rate of increase is
twice as large as in the preceding
century. There are positive
feedbacks that come into play, as
the area of ice melt increases. The
researchers agree monitoring ice
sheets and sea level is necessary to
best ensure the system is in
balance.
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