Chapter 15 Notes
- Over
the past few decades, the global average temperature has increased
noticeably.
- Feedbacks
occur when one change leads to some other change, which can act to either
reinforce or inhibit the original change.
- Positive-
one that enhances an existing trend of a change in climate, in which
small changes can lead to large ones.
An example is the ice-albedo temperature feedback.
- Negative-
one that damps out an existing trend of climate change. An example is the influence of carbon
dioxide on plant photosynthesis rates.
- Air
pollution is composed of airborne solid and liquid aerosols called Particulates,
as well as gases that, when in high concentrations, seriously affect the
lives of people and animals, harm plants, or threaten ecosystems.
- Pollutants
can come from human activities (anthropogenic sources) or from natural
sources such as dust storm and volcanic eruptions.
- Harmful
Pollutants
- Carbon
monoxide
- Lead
- Nitrogen
Dioxide
- Pollutants
can develop from harmless chemical that are emitted into the atmosphere
but then become noxious gases after chemical reactions.
- Sulfur
Dioxide
- Sulfur
Trioxide
- Hydrocarbons
are compounds made of hydrogen and carbon atoms. Examples are methane, butane, and
propane.
- Hydrocarbons
are called Volatile Organic Compounds (VOCs).
- During
the day, hydrocarbons can combine with nitrogen oxides and oxygen to
produce photochemical Smog.
- Ozone
is the main component of Smog, and it is a chemically active molecule.
- Acid
Deposition refers to the falling of acids and acid-forming compounds from
the atmosphere to Earth’s surface.
The acid is represented through the pH scale where 1 is very acidic
and 14 is extremely basic.
- Through
the absorption of ultraviolet (UV) radiation in the stratosphere, ozone
plays a fundamental role in the radiation budget and dynamics of life on
Earth.
- The
Antarctic Ozone Hole was formed through the release of CFCs, in
combination with stratospheric wind and cloud patterns and chemical
reactions with chlorine.
- Large
scale changes in land use, such as urbanization, deforestation, and
agriculture affect the surface of the Earth and can have a direct effect
on regional weather and climate.
- Desertification
refers to the spreading of a desert region because of a combination of
climate change and human impacts on the land. An example is the Aral Sea.
- The
Urban Heat Island effect refers to the increased temperatures of urban
areas compared to a city’s rural surroundings. The buildings in cities have less
evapotranspiration and the buildings trap solar radiation, while the
rural region’s open space reflects solar energy out to space.
- Greenhouse
gases (carbon dioxide, methane, water vapor, and CFCs) act to trap heat in
the Earth’s lower atmosphere, and without it the Earth would be too cold
for most life to exist. However, if
too many gases are released the Earth will get too warm.
- Increased
water vapor amounts can increase cloud cover, however it is difficult to
predict the effect of changes in cloudiness on climate. Different cloud types affect the climate
in different ways.
- Climate
predictions are made using Global Climate Models (GCMs). They can be used to determine how
sensitive climate is to a given process, such as increased carbon dioxide
on global temperature change.
- Global
warming leads to higher sea levels and can have a very large impact on
coastal areas, where more than 50% of the total U.S. population lives.