algae, and crustaceans. (b) The process by which ocean waters have become
more acidic due to the absorption of human-produced carbon dioxide, which
interacts with ocean water to form carbonic acid and lower the ocean’s
pH. Acidity reduces the capacity of key plankton species and shelled animals
to form and maintain shells.
Ozone
Ozone is the triatomic form of oxygen (O 3 ). It is a gaseous atmospheric
constituent. In the troposphere, it is created by photochemical reactions
involving gases resulting both from natural sources and from human activities
(photochemical smog). In high concentrations, tropospheric ozone can be
harmful to a wide range of living organisms. Ozone is a bluish gas that is
harmful to breathe. Tropospheric ozone acts as a greenhouse gas. Nearly 90%
of the earth’s ozone is in the stratosphere and is referred to as the ozone layer.
In the stratosphere, ozone is created by the interaction between solar ultraviolet radiation and molecular oxygen (O 2 ). Stratospheric ozone plays a decisive
role in the stratospheric radiative balance. Since ozone absorbs a band of
ultraviolet radiation called UVB that is particularly harmful to living organisms, the ozone layer prevents most UVB from reaching the ground. Depletion of stratospheric ozone, due to chemical reactions that may be enhanced by
climate change, results in an increased ground-level flux of ultraviolet (UV-)
B radiation.
Ozone “Hole”
A large area of the stratosphere with extremely low amounts of ozone.
Ozone-depleting
substance (ODS)
A family of man-made compounds that include, but are not limited to,
chlorofluorocarbons (CFCs), bromofluorocarbons (halons), methyl chloroform, carbon tetrachloride, methyl bromide, and hydrochlorofluorocarbons
(HCFCs). These compounds have been shown to deplete stratospheric ozone
and therefore are typically referred to as ODSs.
Ozone layer
depletion
Chemical destruction of ozone molecules in the ozone layer. Depletion of this
ozone layer by ozone-depleting substances will lead to higher UVB levels
(a band of ultraviolet radiation), which in turn will cause increased skin
cancers and cataracts and potential damage to some marine organisms, plants,
and plastics.
Particulate matter (PM)
Very small pieces of solid or liquid matter such as particles of soot, dust,
fumes, mists, or aerosols. The physical characteristics of particles, and how
they combine with other particles, are part of the feedback mechanisms of the
atmosphere.
Photosynthesis
The process by which plants take CO 2 from the air (or bicarbonate in water) to
build carbohydrates, releasing O 2 in the process. There are several pathways
of photosynthesis with different responses to atmospheric CO 2
concentrations.
Phytoplankton
Microscopic plants that live in salt and freshwater environments.
Precession
The wobble over thousands of years of the tilt of the earth’s axis with respect
to the plane of the solar system.
Precipitation
Rain, hail, mist, sleet, snow, or any other moisture that falls to the earth.
Radiation
Energy transfer in the form of electromagnetic waves or particles that release
energy when absorbed by an object.
Radiative
forcing
(a) A change in the balance between incoming solar radiation and outgoing
infrared radiation. (b) A measure of the influence of a particular factor (e.g.,
greenhouse gas (GHG), aerosol, or land-use change) on the net change in the
earth’s energy balance.
Salmon
It is the common name for several species of ray-finned fish in the family
Salmonidae. Salmon are native to tributaries of the North Atlantic and Pacific
Ocean. Many species of salmon have been introduced into non-native environments such as the Great Lakes of North America and Patagonia in South
32
L. K. Wang et al.
more acidic due to the absorption of human-produced carbon dioxide, which
interacts with ocean water to form carbonic acid and lower the ocean’s
pH. Acidity reduces the capacity of key plankton species and shelled animals
to form and maintain shells.
Ozone
Ozone is the triatomic form of oxygen (O 3 ). It is a gaseous atmospheric
constituent. In the troposphere, it is created by photochemical reactions
involving gases resulting both from natural sources and from human activities
(photochemical smog). In high concentrations, tropospheric ozone can be
harmful to a wide range of living organisms. Ozone is a bluish gas that is
harmful to breathe. Tropospheric ozone acts as a greenhouse gas. Nearly 90%
of the earth’s ozone is in the stratosphere and is referred to as the ozone layer.
In the stratosphere, ozone is created by the interaction between solar ultraviolet radiation and molecular oxygen (O 2 ). Stratospheric ozone plays a decisive
role in the stratospheric radiative balance. Since ozone absorbs a band of
ultraviolet radiation called UVB that is particularly harmful to living organisms, the ozone layer prevents most UVB from reaching the ground. Depletion of stratospheric ozone, due to chemical reactions that may be enhanced by
climate change, results in an increased ground-level flux of ultraviolet (UV-)
B radiation.
Ozone “Hole”
A large area of the stratosphere with extremely low amounts of ozone.
Ozone-depleting
substance (ODS)
A family of man-made compounds that include, but are not limited to,
chlorofluorocarbons (CFCs), bromofluorocarbons (halons), methyl chloroform, carbon tetrachloride, methyl bromide, and hydrochlorofluorocarbons
(HCFCs). These compounds have been shown to deplete stratospheric ozone
and therefore are typically referred to as ODSs.
Ozone layer
depletion
Chemical destruction of ozone molecules in the ozone layer. Depletion of this
ozone layer by ozone-depleting substances will lead to higher UVB levels
(a band of ultraviolet radiation), which in turn will cause increased skin
cancers and cataracts and potential damage to some marine organisms, plants,
and plastics.
Particulate matter (PM)
Very small pieces of solid or liquid matter such as particles of soot, dust,
fumes, mists, or aerosols. The physical characteristics of particles, and how
they combine with other particles, are part of the feedback mechanisms of the
atmosphere.
Photosynthesis
The process by which plants take CO 2 from the air (or bicarbonate in water) to
build carbohydrates, releasing O 2 in the process. There are several pathways
of photosynthesis with different responses to atmospheric CO 2
concentrations.
Phytoplankton
Microscopic plants that live in salt and freshwater environments.
Precession
The wobble over thousands of years of the tilt of the earth’s axis with respect
to the plane of the solar system.
Precipitation
Rain, hail, mist, sleet, snow, or any other moisture that falls to the earth.
Radiation
Energy transfer in the form of electromagnetic waves or particles that release
energy when absorbed by an object.
Radiative
forcing
(a) A change in the balance between incoming solar radiation and outgoing
infrared radiation. (b) A measure of the influence of a particular factor (e.g.,
greenhouse gas (GHG), aerosol, or land-use change) on the net change in the
earth’s energy balance.
Salmon
It is the common name for several species of ray-finned fish in the family
Salmonidae. Salmon are native to tributaries of the North Atlantic and Pacific
Ocean. Many species of salmon have been introduced into non-native environments such as the Great Lakes of North America and Patagonia in South
32
L. K. Wang et al.