Download Introduction to The Earth`s Atmosphere

Weather, Climate, and Climate Change
The earth's atmosphere is a very thin layer wrapped
around a very large planet.
Two gases make up the bulk of the earth's atmosphere:
nitrogen (N2), which comprises 78% of the
atmosphere, and oxygen (O2), which accounts for 21
%. Various trace gases make up the remainder.
Trace gases (1%)
Based on temperature, the atmosphere is divided into
four layers: the troposphere, stratosphere,
mesosphere, and thermosphere.
Energy is transferred between the earth's surface and the
atmosphere via conduction, convection, and radiation.
URBAN HEAT ISLANDS!!!
Weather and Climate
The earth's climate is generally defined as the average weather
over a long period of time.
How does climate differ from weather?
Weather - is the current atmospheric conditions, including
temperature, rainfall, wind, and humidity at a given place.
Climate - is the general weather conditions over a long period of
time. Climates are usually classified by annual temperature and
precipitation values, (Arid, Humid, Polar, Tropical)
Ocean currents and global winds play a significant role in
transferring heat around the planet.
Paleoclimates (Ancient Climates)
Studying past climates and climate changes help us to
better understand our current climate and what may happen
in the future. Several techniques are used for measuring
past climates, including:
Extracting deep ice cores from glaciers and the polar ice
caps, examining growth rings on trees, coral reef cores,
sediment cores can all reveal clues to past climates.
Tree Ring (Giant Sequoia)
Core
Coral Core
Sediment
Ice Core
• Examining fossil and pollen records
Neogloboquadrina
pachyderma – coils to
the left when ocean
water is cooler
Vostok Ice Core – deep ice core drilled into
Antarctica (10,230 feet)
What Does the Paleoclimate Data Suggest From
Vostok?
What About the Historical Record?
Why the Increasing Trend in Temperature?
(highest level recorded in Vostok over the past 400,000 years ~325
ppm)
What Causes Climate Change?
- Greenhouse Gases – Gases present in the
atmosphere that absorb infrared radiation given
off by the Earth’s Surface causing atmospheric
temperature to rise.
They include: Carbon Dioxide (CO2), Methane
(CH4), Water Vapor, CFC’s
- Ice House gases – Gases or particulates in the
atmosphere that reflect sunlight back into space,
causing temperatures to decrease.
They include: Sulfur Dioxide (SO2) and Dust
The Greenhouse Effect – Incoming short wave, visible
light radiation from the sun penetrates the atmosphere
and heats the Earth’s surface. The surface then reradiates this energy as long wave, infrared radiation
which is absorbed by gases in the atmosphere, causing
temperatures to rise. Thus the Earth’s atmosphere
acts like the glass in a greenhouse.
What Can Result if the Earth’s Temperature Rises?
Climate Shift – Change in the location and area
of world Biomes.
Sea-Level Rise – Melting glacial ice will add water
to the ocean, and the increase in ocean
temperature will also cause thermal expansion of
the oceans.
East Coast ~20,000 years ago (400 foot drop in sea level)
Complete Melting of the West Antarctic Ice Sheet (~17 foot sea
level rise)
Complete Melting of the East Antarctic Ice Sheet (~170 foot sea
level rise)
Climate Change and NY State
Summer Temperatures
Average temperatures have risen in the Northeast
1.5 degrees F since 1970. In NY, winters are 4
degrees F warmer since 1970. Avg. temps are
expected to rise by 4-9 degrees F by 2080.
Precipitation may increase by 5-15% by 2080,
mostly during winter months as rain.
Forests – loss of Spruce/Fir Forests
Winter Recreation – less snow
Energy – increased demand for cooling
Agriculture – longer growing season, periodic
drought, new crop potential, heat stress for dairy
cows.
Global Cooling – Melting glacial ice may interrupt
warm ocean currents causing changes in local
climates. Cool, low density fresh water may cap
warm, more dense salt water in the Gulf Stream.
This may lead to cooling the climate of Europe.
THE KYOTO PROTOCOL
As part of the United Nations Framework Convention on Climate
Change, the Kyoto Protocol is a binding agreement that is directed at
reducing greenhouse gas emissions worldwide. The agreement was
adopted on December 11, 1997 in Kyoto, Japan, and creates a 5.2
percent total reduction in the amount of greenhouse gases emitted by
industrialized nations that signed the agreement. The time period for
the reductions takes place between 2008 and 2012, and is based on
levels of greenhouse gases produced in 1990. Industrialized nations
bound by the protocol have specific target emission standards, and
developing nations are excluded from emission controls. Currently 163
countries have ratified the protocol. The United States, which is the
world’s largest contributor of greenhouse gas emissions, signed the
Kyoto Protocol in 1998, but withdrew its signature in 2001. The
President and Congress felt that both developing and industrialized
nations should reduce their emissions, and did not want to sign into an
international agreement that might harm the economy.
Bali Conference/ United Nations Climate Change Talks –
December 2007 – talks aimed at reducing industrial nations carbon
emissions by 20 to 40% by 2020, and the world emissions by 50% in
2050. The Lieberman/Warner Climate bill to address it was killed by
the Senate. New Zealand (2025), Norway (2050) and Costa Rica
(2021) declare they will be carbon neutral.
Global Warming and Disease- changes in climate could also lead
to the spread of disease to new areas. Migration and increasing
populations of insects, higher temperatures, increased moisture.
Ozone Depletion
Ozone – Ozone is an unstable form of oxygen (O3)
that naturally exists high in the stratosphere. When
high energy, ultraviolet radiation from the sun strikes the
ozone molecule, it absorbs the radiation, and therefore
acts as a shield that prevents deadly UV radiation from
striking the Earth’s surface. This is called the ozone
layer.
Ozone Destruction – Human created gases used as
refrigerants like chlorofluorocarbons (CFC’s),
commonly known as Freon and Methyl Bromide a soil
fumigant, have escaped into the atmosphere and have
risen up into the stratosphere. It is there that the Sun’s
radiation destroys the CFC molecule, therefore
freeing up reactive chlorine molecules. The chlorine
then bonds with the free oxygen atoms that make up the
ozone layer, and therefore decreases the amount of
ozone in the stratosphere.
The Ozone Hole – The loss of ozone over the poles
has created very thin or no areas of ozone. The
formation of the ozone hole is linked to the formation of
polar stratospheric clouds.
2006
2010
Negative Effects of Stratospheric Ozone Depletion
– the loss of ozone causes more UV radiation to reach
the Earth’s surface. This can damage cells leading to
cancer. In humans the result is an increased risk of
Melanoma, or skin cancer.
THE MONTREAL PROTOCOL
On September 16, 1987, The Montreal Protocol on Substances
that Deplete the Ozone Layer was adopted at a conference in
Montreal, Canada, which was attended by more than 29 countries.
This international agreement between industrial and developing nations
sets reductions and phase-out timelines for stratospheric ozonedestroying compounds. Human-created gases such as
chlorofluorocarbons (CFCs), halons, carbon tetrachloride,
hydrochlorofluorocarbons (HCFCs), methyl chloroform,
Hydrobromofluorocarbons (HBFCs), and methyl bromide have all
been targeted for elimination. The results of this international
agreement have been recently observed by scientists monitoring the
ozone layer. Researchers from NASA and the World Meteorological
Organization have recorded a reduction in the concentration of ozonedestroying chemicals in the atmosphere, and a decline in the size of the
Antarctic ozone hole over the past 10 years. The Montreal Protocol is
now being hailed as a successful example of the importance of
international agreements in reducing environmental degradation.
El Niño and the Southern Oscillation (ENSO
event) – A change in the temperature of equatorial
ocean water off the western coast of South America
that effects world climate.
The Southern Oscillation – Changes in precipitation
patterns of the South Pacific that are related to moving
atmospheric pressure centers.
“Normal” conditions – The Trade Winds drive warm
equatorial surface water of the Pacific Ocean
westward. This causes cool, nutrient rich ocean water
to rise up along the western edge of South America in
a process known as upwelling.
El Nino Conditions – Trade Winds decrease causing
a build-up of warm water off the coast of South
America.
La Niña Conditions – Increasing velocity of Trade
winds causes excess upwelling
Effects of El Nino
Reduced upwelling can affect the productivity of
the coastal ocean, reducing fish populations.
The Southern Oscillation affects global wind and
precipitation patterns, resulting in droughts or
floods. Changing precipitation patterns may also
cause the spread of disease.
El Nino and Global Warming
Coral Bleaching – a recent phenomenon believed to be
the result of climate change and pollution.
Coral and Coral Reef Systems – corals are small
marine organisms that live in large colonies located
in warm shallow seawater. Corals build protective
shells out of calcium carbonate, which lead to the
formation of large structures known as coral reefs.
Coral reef systems are often referred to as
the “rainforest of the sea”, due to the high
amount of biodiversity they support.
Coral Bleaching – recent phenomenon where
corals begin to lose their colors and appear
bleached. The bleaching is the result of the die off
of the symbiotic algae that reside within the coral.
Coral bleaching has been observed in many coral
reef systems worldwide.
Carysfort Reef System, Florida Keys
Causes of Coral Bleaching – coral bleaching is
believed to be the result of many different
environmental stresses, which include:
- changing water temperature
- increased exposure to UV
radiation
- sediment pollution
- water pollution (toxic chemicals,
oils, wastewater, infectious agents)
Ocean Acidification – decrease in the pH
value of the water in the ocean from carbon
dioxide dissolving into the water. Carbonic
Acid forming from excess carbon dioxide.