What is Global Warming?
-Mitch B., Lake Toxaway
Answered by Justin Caudell
Mitch, I could certainly understand with all the hype recently on why you would like more
information on Global Warming. I have run into people just like you over the past couple months
after Al Gore’s movie “An Inconvenient Truth” came out asking the same question.
We’ll begin with an analysis of Earth's atmosphere before Global Warming. Like learned in
Earth Science class, our planet contains certain gases called greenhouse gases containing of
mostly water vapor and carbon dioxide. These gases act to keep the lower layers of the
atmosphere warmer than what they otherwise would be without those gases in order to keep the
Earth’s climate warm and habitable.
Global Warming is the expected slow, gradual warming of the lower layers of the Earth’s lower
atmosphere by the slowly increasing concentrations of man-made greenhouse gases, primarily
from the burning of fossil fuels: petroleum, coal, and natural gas. These gases trap infrared
radiation, which is the heat radiation that cools the Earth.
In order for the Earth to remain at a constant temperature, the Earth must lose as much
energy through infrared radiation as it gains from the sun. This concept is called energy balance.
The burning of fossil fuels produces carbon dioxide as one of the by-products. As of 2003, the
concentration of carbon dioxide was over 50% higher than it was before the start of the industrial
revolution in the late 1800's, which is when the burning of fossil fuels really took off.
Presence of Global Warming so far
Although controversial, there seems to be pretty good evidence that globally-averaged
temperatures have risen about 0.5 degrees Celsius (about 1 deg. F) in the last 100 years. But it
is not known how much of this is due to man-made greenhouse gases, or to natural processes.
The Earth sometimes goes through natural climate fluctuations without any help from mankind. It
is reasonable to assume, however, that some portion of the warming in the last century is man-
made based on some scientific research.
Future of Global Warming
It currently unsure what affect Global Warming will have for the future, and there is much
debate in the climate research community over the very question. The consensus of opinion is
that a warming of about 0.2 degrees Celsius (about 0.4 deg. F) every 10 years is expected for
the next 100 years and possible more. The reason why there is so much uncertainty, though, is
because weather acts to rid the surface of the earth of excess heat.
The processes by which this happens are very complex, and usually involve water. For
instance, clouds on a whole act to cool the Earth. How clouds will change with Global Warming
will be critical though, as they could either amplify the warming, or reduce it.
The evaporation of water removes a huge amount of heat from the Earth’s surface, and this
heat is deposited high in the atmosphere when rain clouds form. It is expected that Global
Warming will be accompanied by small changes in rain systems. If those rain systems become
more efficient at converting water vapor into precipitation, this would act to offset global warming.
This is just one of the uncertainties in predicting how much Global Warming there will be.
There are also other uncertainties relating to possible changes in sea ice, snow cover,
vegetation amount and type, and how much of the extra carbon dioxide will be absorbed by
vegetation or by the ocean.
Research is being compiled daily by scientists and meteorologists to see if there is a Global
Warming problem and how to tackle the problem if one exists.