Ozone Depletion Deforestation

Comments

Transcription

Ozone Depletion Deforestation
Ozone Depletion
Deforestation
OZONE is a 3-atom oxygen form of oxygen found
in both the troposphere and the stratosphere.
Ozone in the stratosphere occurs naturally and
shields the earth’s surface from harmful
ultraviolet radiation. Ozone in the troposphere is
a pollutant associated with automobile exhaust.
Ozone can be destroyed in the stratosphere by
CFCs, a chemical used in air conditioners, and
aerosol spray cans.
Stratospheric Ozone “Hole”
Fig.1-6 from text
Because of peculiar meteorological
conditions, ozone destruction caused by
chlorine compounds is particularly severe
over Antarctica in spring, giving rise to an
“Ozone Hole”
Ozone depletion in mid-latitudes
Misconceptions (4)
“The ozone hole is causing
global warming.”
No, it is not! But the
elimination of anthropogenic
CFCs that cause the ozone
depletion would also help to
reduce the global warming
since CFCs is a powerful
greenhouse gas.
Facts about DEFORESTATION
• Deforestation occurs at a rate of 150,000 square km per year
worldwide (every 2.5 years, an area equivalent to the state of
California disappears).
• Tropical forests once occupied 16 million square kilometers of
the earth's surface, but now cover only 9 million.
• It is estimated that Latin America and Asia have already lost
40% of their original forest; Africa a little more than half.
• In many countries the rate of deforestation is accelerating.
For example, most of the forested areas of Bangladesh, India,
the Philippines, Sri Lanka and parts of Brazil's rain forest
could be gone by the end of the century.
• Only in the Congo Basin and some of the more isolated areas
of the Amazon Basin does the forest remain largely intact.
Implications of DEFORESTATION
Species loss--The majority of earth’s species live in
the tropics. The majority of the species in the
tropics have very limited ranges, increasing the
importance of small patches of land for overall
biodiversity.
Local climate change--The loss of rain forest alters
precipitation and cloud patterns.
Global carbon cycle--The burning of the forests
releases carbon dioxide into the atmosphere,
contributing to the increase in greenhouse gas
concentrations.
Summary
Contemporary Global Change
due to the Human Impact
•Ecosystem Destruction
•Ozone Destruction
•Global Warming
Weather Data from North Pole Station
Sunlight or
Solar Radiation
Infrared
Radiation
Air Temperature
Air Pressure
Winds
Goes Satellite
weather
observer
(pre-launch)
Unlocking “Stored” Climate Change
• Modern Instrumental
Record
• Tree Rings
• Ice Cores
• Sediment cores
• Rock formations/types
Record: 1000 ~ Present day
“Length” of growing season
Good versus stressed years
Major fires
Unlocking “Stored” Climate Change
• Modern Instrumental
Record
• Tree Rings
• Ice Cores
• Sediment cores
• Rock formations/types
Record: ~ 1Mya to ~ 20th cent
Inert gases (CO2, CH4, N2O,…)
Particulates (soot, ash, etc)
Temperature??
Unlocking “Stored” Climate Change
• Modern Instrumental
Record
• Tree Rings
• Ice Cores
• Sediment cores
• Rock formations/types
Record: ~ 200 Mya
Microfossils (ocean T),
Volcanic glass
Organic detritus
Magnetic pole location
Detecting Change With Proxies
Scientifically, the best way to detect change is to
directly measure it.
Unfortunately for the timescales of interest in climate
science, we weren’t always able (interested in?) to
measure quantities such as temperature, precipitation,
wind speed, direction, greenhouse gas levels, etc.
But, obviously we want to know what these properties
were and how they changed in the past to test our
understanding of how climate changes.
The study of past climate is known as paleoclimate
science.
Detecting Change With Proxies
Another property/qty that is a function of
property of interest.
Think approximate
The measured property is a PROXY for the one of interest.
Water Cycle – Water Isotope T Proxy
18O/16O
18O/16O
18O/16O
high
low
lower
18O/16O
lower
even

Similar documents