Download What is the Global Warming?

Global Warming
What is the
Global
Warming?
Magdalena Anguelova
Ph.D. Student
Advisor: Prof. Ferris Webster
5 min.
Global Warming
A 100-year Old Question

In 1896 the Swedish chemist Svante Arrhenius
asked:
“Is the mean temperature of the
ground in any way influenced
by the presence of heatabsorbing gases in the
atmosphere?”
Philosophical Magazine
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Global Warming
A 100-year Old Question

In 1896 the Swedish chemist Svante Arrhenius
asked:
The global warming
question was opened.
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Global Warming
A 100-year Old Question
Uncertainty

Well, more than 100 years later
we still have not answered this
question.

Moreover, it is a hotly
debated issue.
10 years have passed since this presentation was made. Today
(2011), we have constrained some of this uncertainty.
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Global Warming
What is Global Warming?
Global warming is a
greenhouse effect in
excess of the natural
greenhouse effect.
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Global Warming
Greenhouse gases

An increasing amount of greenhouse gases in
the atmosphere causes the excessive warming.

The change in greenhouse gas
concentrations can be:
» Natural;
» Man-induced.
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Global Warming
Human Impact

Humans have always
changed their
surroundings to some
degree.
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Global Warming
Human Impact

However, in the last century our
activities have altered the global
environment as never before.
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Global Warming
Gas Emissions

Our daily life adds to the
naturally occurring
greenhouse gases:
Nitrous oxide (N2O)
Carbon dioxide (CO2)
Methane (CH4)
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Global Warming
Gas Emissions
30%

The changes since the
industrial revolution
are:
Nitrous oxide (N2O)
15%
Carbon dioxide (CO2)
Methane (CH4)
100%
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Global Warming
Adding More

Even worse -- we add unnatural long-lived
(100’s of years) greenhouse gases:
» ChloroFluoroCarbons (CFCs),
» and Surface Ozone (O3)
– this is “bad” ozone,
– different from the one in the
UV-protective ozone layer
high in the stratosphere.
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Global Warming
The Statistics

U.S. CO2 emissions, 1995.

Greenhouse gas
concentrations
are projected to
double preindustrial levels by
the middle of the
next century.
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Global Warming
The Effect

The global heat budget is
balanced in the long run:
Incoming sunlight
=
Earth’s Reflected + Earth’s Emitted

An increased amount of greenhouse gases,
however, may disrupt the planet’s heat
budget.
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Global Warming
Troubled Heat Budget

If the amount of CO2 doubles, the outgoing radiation
from Earth would decrease.

To restore the balance, an
increase in the mean surface
temperature of the Earth is
required.
Climate Changes
Temperature
Precipitation

By 2100 Earth would be 2 6oF warmer, hence...
Sea Level Rise
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Global Warming
The Role of the Ocean

A chain of processes removes atmospheric CO2
and stores it in the ocean depths:
» Atmosphere-ocean gas
exchange;
» Phytoplankton
photosynthesis;
» Ocean circulation;
» Biological pump.
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Global Warming
The Removed CO2

The ocean is the greatest
reservoir for CO2.

The net carbon uptake by
the ocean is about 34%
of the carbon put into the
atmosphere.
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Global Warming
Keeling Curve

Atmospheric CO2 concentration,
Mauna Loa, HI.

It became an icon of the
global warming problem
.

No doubt, the amount of
greenhouse gases increases.
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Global Warming
Why the Uncertainty Then?
Our uncertainty stems from
these questions:

Is the warming solely man-induced?

Or is this a natural variation in climate?

What is the climate change rate?
» Slow -- centuries to millennia?
» Fast -- decades?
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Global Warming
Natural Climate Variability

The Earth’s climate has
always been changing.

Greenhouse gas
concentrations have changed
accordingly.

No doubt, the climate will continue to
change.
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Global Warming
Slow Climate Change

If natural climate change is slow:
» We can find ways to
deal with the maninduced warming;
» Ecosystems have an
opportunity to adjust.
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Global Warming
Fast Climate Change

If natural climate change is fast:
» The man-induced warming may
initiate even more rapid
warming;
» Ecosystems will be
drastically affected.
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Global Warming
Study, Study, Study...
Thus, we need to



...know past climate
changes well.
...understand present
climate better.
...predict future climate
changes accurately.
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Global Warming
Actions
Everything helps:

Observations:
» Ice and sediment cores;
» Ship measurements;
» Satellite monitoring.

Computers:
» Ocean-atmosphere models;
» Chemical-physical-biological
models;
» Socio-economic models.
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Global Warming
Global Warming Concern
The End
We have a lot of work
to do!
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