there's a controversy about earth it's a
controversy about a process that may
affect the quality of life in the United
States and in every other nation
scientists don't agree on its impact
because it's evidence is complex
disturbing and filled with conflicting
information that process is called
global warming your national and
international initiative is needed to
seek new solutions for ozone depletion
in global warming and acid rain and this
initiative global warming is the phrase
used to describe the heating up of the
Earth's atmosphere why is this an
important issue if the atmosphere heats
up by only a few degrees wind rain and
heat patterns change damaging vital
agricultural areas the impact natural
resources would alter the geopolitical
assets of the earth would shift a
different climate would change the
forestry food and water supply of each
nation dr. Anthony del genio from NASA's
Goddard Institute for Space Studies New
York by the time we get into the middle
of the next century a magnitude of heat
wave or drought that we might have only
experienced once in the 20th century we
might be experiencing once every 10
years in order to acquire the
information necessary to answer global
warming issues a number of scientific
instruments are needed including an
imaging instrument called SAR synthetic
aperture radar SAR as planned as a part
of a mission to Planet Earth NASA's
series of Earth observing satellites in
1981 and 1984 dr. Charles elachi and his
colleagues sent an imaging radar into
space
they received astonishing data the radar
penetrated the dry sands of the Sahara
and discovered ancient riverbeds this is
the most arid region on earth and it
trains once every 40 to 60 years however
when we look at the radar image which is
moving in front of you you see what
seemed to be drainage channels and these
are the remnant rivers which have dried
up because of climatic change at so we
know that as recent as a time of the
pyramids that region was not as drawing
as arid as it is at the present time
radar can see through vegetation as well
as through clouds it's as if we could
take an x-ray of the inaccessible areas
of the earth the belts of rain forests
around the earth are critical
storehouses of vegetation and thus
carbon some researchers believe that
deforestation is causing significant
damage to the Earth's biosphere however
rain forests are difficult to measure
they are difficult to access and the
great bulk of their biomass is hidden by
their canopy of tall trees dr. Joe bway
from nasa's jet propulsion laboratory
scientists know very well today that
atmospheric carbon dioxide is increasing
very significantly and we have
successfully been able to map the areal
extent of deforestation we have never
attempted to measure anything about the
forest itself biomass or its water
properties that will disappear when you
get into the account view pressure the
radar however can penetrate the entire
biomass of in the lower understory you
see as you look behind here that there's
quite a bit of action going on below
this canopy raid art may be tuned to
look at different levels of the biomass
thus electronically penetrating tree
tops that have veiled the rainforests
for so long
at the other extreme of the earth the
icy oceans of the planet are powerful
drivers of global climate the exchange
of heat gases and energy at the polar
regions is immense essentially all of
the uncertainties in predicting future
climate have to do in one way or another
with the hydrologic cycle anything that
involves water and how it changes phase
and goes from one form to another is
something that we need to know
desperately to predict future climate
and for which we don't have adequate
data sets right now sea ice is an
important modifier of the Earth's energy
it insulates the warmer ocean below from
the freezing winter atmosphere in cloud
free seasons it dramatically increases
the amount of solar energy reflected
back to space the heat flux through an
open area of Arctic Ocean is 100 times
more than in an ice-covered area we know
that the polar masses are laced with
cracks that expose ocean areas of the
air however there's a problem at the
poles how do we monitor an area that is
obscured with clouds and in darkness for
six months of the year SAR can
investigate ice concentration and motion
during the long polar night period and
through extensive cloud cover being able
to get that continuous monitoring and
the extent of the ice cover and the age
of the ice and possibly the thickness of
it is a key scientific parameter in that
heat exchange between the ocean and the
atmosphere we know with certainty that
the burning of fossil fuels is causing
significant damage to the Earth's
biosphere the concentration of carbon
dioxide in the air has increased by over
ten percent since nineteen fifty eight
and by nearly twenty five percent since
the Industrial Revolution
heat from the Sun flows past nitrogen
and oxygen molecules but is absorbed by
co2 heat from the earth is also kept in
by co2 creating an atmospheric blanket
the result the greenhouse effect the
increased warming of the earth however
scientists disagree on whether it will
get warmer because global processes are
complex sunshine land masses vegetation
the oceans and the atmosphere are
intricately bound in a climatological
dance the earth is a closed system a
huge global system
NASA's mission to Planet Earth a program
to use satellites for the analysis of
our own environment will address
questions of potentially great impact to
our future is global warming occurring
how fast is it occurring how do man's
actions today relate to our past and
future climate yasar will explore the
dynamics of the earth as a fragile
system in a search for answers to
controversial questions
you