Read the following materials
attached pdf below
and chapter 2 lecture in the link below
http://forecast.uchicago.edu/lectures.html
You are expected to submit a summary of a current climate / environmental-related article from the mainstream press, along with your personal evaluation / reflection. Using a recent news article from a reliable source, please feel encouraged to explore topics that include extreme weather (e.g. winter storms, drought), climate change, energy (e.g. decreases in crude oil price, fracking, coal mining, nuclear power plants, alternative energy, etc), adaptation of animal behavior to recent climate change (including mammals, insects, fish, etc), policy related topics (international climate change conferences), and more. Due by February 10th.Guidelines of this assignment are:
- Article summary: Your own summary – do not copy from an original source (1 page).
- Reflection: Your own discussion about the topic(s) of the article. Please apply your knowledge from this course and incorporate it into your discussion (1 page)
- Maximum pages: 2
- Font type and size: Times New Roman/Times, 12-point size, double spaced
- Data : include source data
- Figures and Tables: include source data
- List of at least 3 reference(s)
the article you use must be related to the course topic in chapter 2 or the materials below and must be different from assignment 1
Greenhouse Effect continued…
We are still here.
Climate change
The knobs that control earth’s climate:
• Atmospheric composi-on (greenhouse effect)
• Amount of solar radia-on (luminosity)
• What parts of Earth get radia-on (orbit)
• Atmospheric and ocean circula-on
• Earth’s albedo (frac-on of solar energy reflected off earth’s
surface)
• Volcanoes
• Plate tectonics
How much radiation we get depends on the angle at
which the Sun’s rays hit the Earth, which:
• varies with latitude
• varies with the season
• varies with orbital parameters . . .
The same amount of
sunlight is spread over a
larger area at high
latitudes
SunEarth
For more learning module, go to:
http://www.windows2universe.org/earth/climate/sun_radiation_at_earth.html
Solar irradiance (the power per unit area received from the Sun) varies
with latitude because of the curvature of the Earth’s surface. When you
travel from lower latitude (e.g. equator) to higher latitude (e.g.
Massachusetts, 42N), you will notice that, in the middle of the day, the sun
is not directly shining above you. Instead, the angle of the solar insolation
is much smaller in the higher latitude than in the lower latitude (see figure
as well as previous slide). Since each ray of light carries the same amount
of energy (342 W/m2), if the solar angle is smaller, this energy must be
split across a wider area. Therefore, higher latitudes receive less solar
irradiance than the lower latitudes. This partly explains why you feel that
sunlight is stronger in Miami, Florida than in Quebec City in Canada!
Earth’s orbit
Also, solar irradiance varies seasonally. Why we experience seasons?
Seasonality occurs because the Earth’s axis is tilted 23.5° as it revolves around
the Sun. This tilt causes the northern and southern hemispheres to tilt
alternately toward and away from the Sun, and this motion causes seasonal
changes in solar radiation received in each hemisphere. Therefore, from our
Earth perspectives, incoming solar radiation varies with seasons.
The figure shows the tilt of Earth’s axis in its annual orbit around the sun causes
the northern and southern hemispheres to lean directly toward and then away
from the Sun at different times of the year.
Earth’s orbit
This change in relative position causes seasonal shifts between the
hemispheres in the amount of solar radiation received at Earth’s surface.
Especially, from our Earthbound perspective, this orbital motion causes a shift
of the overhead Sun through the tropics from a latitude of 23.5°N on June 21
to 23.5°S on December 21. This change in the Sun’s angle results in large
seasonal changes in the amounts of solar radiation (W/m2) received on Earth.
This figure shows the latitudinal solar radiation energy received from January
(J) to December (D). The high energy zone shifts as seasons migrate. During
northern hemisphere spring/summer (April – August), the high energy zone
shifts from equator to ~40N. The opposite happens during the southern
hemisphere spring/summer.
Earth’s orbit – eccentricity
Further, Earth’s actual orbit is not a perfect circle. It has a slightly eccentric or
elliptical shaped. This shape of Earth’s orbit around the Sun has varied in the
past, becoming at times more circular and at other times more elliptical
(eccentric). This change in orbital shape also contributes to changes in
seasonality, and is called eccentricity.
Eccentricity:
Obliquity:
Precession:
Orbital effects
Cause slight adjustments
in timing and location of
radiation.
Combined, these cause
Milankovitch cycles
The figures here summarize other important orbital effects that contribute to
climate change on Earth (Eccentricity, Obliquity, and Precession). These are known
as Milankovitch Cycles, named after Serbian astrophysicist, Milutin Milankovic,
who found their cyclicity. They are important climate forcings to understand longer
time scales (e.g. thousands to millions of years). However, long term climate
change is beyond the scope of this course and, therefore, will not be included in
future Tests.
Each of the successive time scales reveal short oscillations embedded within longer
ones, just as cycles of daytime heating and nighttime cooling are embedded in the
longer seasonal cycle of summer warmth and winter cold. Referring to past
variability and understanding the factors contributing to those variability =
paleoclimatology. In this course, we focus on relatively short response time
periods that affect us more recently and in our near future.
Response times of Climate Components
This table shows examples of different climate components with various response
times.
(continue)
August Arctic Ocean Ice Extent
Source: NSIDC
(con%nued)
Now, we revisit the figure showing sea ice extent in the Arc%c. It is obvious that
the decrease in sea ice extension occurred within just the past few decades.
What is the forcing (climate knobs) for this, and is this a slow or fast response?
The Atmosphere
Gas Name Chemical Formula Percent Volume
Nitrogen N2 78.08%
Oxygen O2 20.95%
*Water H2O 0 to 4%
Argon Ar 0.93%
*Carbon Dioxide CO2 0.0390%
Neon Ne 0.0018%
Helium He 0.0005%
*Methane CH4 0.00017%
Hydrogen H2 0.00005%
*Nitrous Oxide N2O 0.00003%
*Ozone O3 0.000004%
*affected by people
We learned that the three major components of the atmosphere are nitrogen,
oxygen, and argon, which compose over 99.9 % of the Earth’s entire
atmosphere, but none are a greenhouse gas. In contrast, the most important
greenhouse gases, which are water vapor (H2O), carbon dioxide (CO2), and
methane (CH4), make up only a fraction of the atmospheric composition.
CO2 emissions by country
Very interesting map as the area of each country represents the amount of CO2
emissions (updated in 2008). This figure indicates that the US, EU countries, India,
China, South Korea, and Japan are particularly responsible for the large amount of
CO2 added to the atmosphere. https://www.grida.no/resources/5437
Both CO2 and CH4 trap part of Earth’s back radiation, keep the heat in the
atmosphere, and make Earth warmer than it would otherwise be. And this
warming in turn activates the positive feedback effect of water vapor (H2O). Due to
the importance of this positive feedback, water vapor is considered to be the most
concerning greenhouse gas.
CO2 is also important when we consider future climate change as human emissions
of CO2 are driving climate change. This figure shows major countries emitting CO2
since 1950 in billions tons. The U.S. is THE largest contributor of the CO2 emission.
Methane (CH4) is a second important atmospheric greenhouse gas. It has many
sources, including swampy lowland bogs, rice paddies, the stomachs and bowels of
cows, digesting vegetation, termites, and the decay of organic matter in an oxygen-
free (anaerobic) environment.
https://www.grida.no/resources/5437
Greenhouse Gas Concentra.ons
Industrial Revolution
1750-1850 AD
Carbon dioxide and other greenhouse gas (e.g. CO2, CH4, N2O) variability
between 0 to 2005 AC. Please take notice of the abrupt increasing that
occurred between 18th to mid-19th – at the time of the Industrial Revolution!
Industrial Revolution
▪ The Industrial Revolution was a period from 1750 to 1850 where changes in
agriculture, manufacturing, mining, transportation, and technology had a
profound effect on the social, economic and cultural conditions of the times.
▪ It began in the United Kingdom, then subsequently spread throughout
Western Europe, North America, Japan, and eventually the rest of the world.
▪ The Industrial Revolution marks a major turning point in history; almost
every aspect of daily life was influenced in some way.
▪ Most notably, average income and population began to exhibit
unprecedented sustained growth.
▪ In the two centuries following 1800, the world’s average per capita income
increased over tenfold, while the world’s population increased over sixfold
▪ Major innovations: steam power, iron making, textiles
The shapes of the
blackbody
spectra of Earth
and the sun
Percentage of
radiation
absorbed through
the atmosphere
Absorption
Spectra of
Greenhouse Gases
To fully understand the greenhouse effect, we need to understand, once more, about
blackbody radia9on. As we learned earlier, the radia9on emi a characteris9c wavelength distribu9on that depends on the body’s absolute
temperature (the Earth’s blackbody radia9on = infrared wavelength).
In the lowest figure “Percentage of radia9on absorbed through the atmosphere”,
absorp9on of 100% means that no radia9on penetrates the atmosphere. CO2, O3,
N2O, CH4, H2O are the media that absorb associated wavelength energy – and we
now know that these media are called greenhouse gases! As you see, part of the
shortwave radia9on from the Sun is almost 100% absorbed by ozone (O3) and oxygen
molecules (O2) in the stratospheric ozone layer!
Supplemental reading: What is Ozone? NASA Goddard Space Flight Center,
h Greenhouse Effect continued…
We are still here. Climate change
The knobs that control earth’s climate: surface) We talked about climate knobs that effectively control our climate system. Air Pollution
Smog trapped below Image from NASA Although the atmosphere is a renewable resource, the atmosphere is very EOS, December 2014 The Atmosphere Oxygen O2 20.95%
*Water H2O 0 to 4%
Argon Ar 0.93%
*Carbon Dioxide CO2 0.0390%
Neon Ne 0.0018%
Helium He 0.0005%
*Methane CH4 0.00017%
Hydrogen H2 0.00005%
*Nitrous Oxide N2O 0.00003%
*Ozone O3 0.000004%
*affected by people The most important greenhouse gases are water vapor (H2O), carbon Climate change The Sun as a source of Energy • Nuclear Fusion to Helium releasing – 3.9 X 1026 W (watt)!
– Average distance to the – Surface temp. is 5800 K Nuclear Fusion: At the core of the Sun, tremendous amounts of nuclear power The Sun is a natural fusion reactor, which produces magnificent amounts of For more information about nuclear fusion, pleas visit: Diagram showing the different parts of the Sun. The three parts of the Further reading about the Sun: Video link: NASA -Introduction to the Electromagnetic Spectrum Energy travels by means of light through space in the form of waves called Energy travels by means of light through space in the form of waves. Photon – These waves span many orders of magnitude in size, or wavelength, and this Absorption Spectra of Greenhouse Gases Energy from the Sun moves through space in a wide range of wave forms that The shapes of the spectra of Earth Percentage of absorbed through Absorption Spectra If a chunk of matter oscillates and can interact with light at all possible Thus, Earth not only absorbs energy, it emits the energy back to the space.
In the middle figure, “the shapes of the blackbody spectra of Earth and the The lowest figure, “percentage of radiation absorbed through the atmosphere” Blackbody (Planck) Curve
Sun’s planetary temperature Earth’s planetary temperature The wavelength distribution of blackbody radiation can be described Example Test 1 question: A. blackbody The answer is A!
• Atmospheric composition (greenhouse effect)
• Amount of solar radiation (luminosity)
• What parts of Earth get radiation (orbit)
• Atmospheric and ocean circulation
• Earth’s albedo (fraction of solar energy reflected off earth’s
• Volcanoes
• Plate tectonics
Rather than to understand the chaotic and complicated systems that interact
with the climate system as a whole, a better way to understand climate is to
focus on components (climate knobs) that strongly affect the climate system.
Here, let’s learn about the first climate knobs.
clouds by a thermal
inversion across
upstate New York
Johnson Space Center
fluid and definitely not stable. It is the most dynamic of all of Earth’s systems.
We, as human beings, both use and abuse the atmosphere. It is treated as a
gigantic waste disposal system for emissions from our vehicles and industries.
How people affect the atmosphere and influence global climate has become a
major environmental concern for many around the world.
Gas Name Chemical Formula Percent Volume
Nitrogen N2 78.08%
dioxide (CO2), and methane (CH4), and they consist of only a fraction of the
entire atmosphere’s composition. While water vapor can range to above 3%
in the moist tropics, it is less than 1% of the atmosphere in a dry/cold
environment. All of these greenhouse gases make up, on average, less than
1% of the atmosphere, and are referred to as trace gases. Although small,
these gases are important in how they can impact and alter the Earth’s
energy budget. Here, green-colored gases are human influenced
greenhouse gases. While we are primarily talking about trace gases, it is
important to note that not all trace gases are greenhouse gases.
The knobs that control earth’s climate:
• Atmospheric composition (greenhouse effect)
• Amount of solar radiation (luminosity)
• What parts of Earth get radiation (orbit)
• Atmospheric and ocean circulation
• Earth’s albedo (fraction of solar energy reflected off earth’s
surface)
• Volcanoes
• Plate tectonics
The sun is the ultimate source of energy in our solar system. Almost all energy originates
from the Sun.
– Hydrogen is converted
tremendous energy
Earth is ~150 X 106 km
(kelvin)
are generated by a reaction known as nuclear fusion. Nuclear fusion is the
process by which two or more smaller atomic nuclei combine to form a larger
one, with an accompanying release of energy. Fusion is a process where a simple
hydrogen nuclei containing one proton fuses to produce helium. Fusion is a clean
energy producing process and can be used as an alternative energy source in the
future. However, the process is currently too expensive to be widely
commercialized.
energy and it’s clean energy!
https://energyeducation.ca/encyclopedia/Nuclear_fusion_in_the_Sun
atmosphere, from the surface of the Sun outward are the photosphere,
chromosphere, and corona. (Credit: NASA)
https://imagine.gsfc.nasa.gov/science/objects/sun1.html
https://youtu.be/lwfJPc-rSXw
electromagnetic radiation. These waves span many orders of magnitude in size,
or wavelength, and this range of wave sizes is known as the electromagnetic
spectrum.
an elementary particle – carries this energy in the form of a wave. This is called
electromagnetic radiation.
range of wave sizes is known as the electromagnetic spectrum.
vary by wavelength (electromagnetic spectrum). However, the energy that
drives Earth’s climate system occupies only a narrow range of this spectrum.
Much of the incoming radiation energy from the Sun is scattered, reflected, or
absorbed by the atmosphere. By the time it reaches the surface of the Earth, it
mostly consists of visible radiation at wavelengths between 0.4 and 0.7
micrometers. Also, some ultraviolet radiation enters Earth’s atmosphere. Both
are sometimes referred to as shortwave radiation (blue band in figure).
Infrared radiation is a longer wavelength than visible and ultraviolet radiation
and referred to as longwave radiation (red band in figure).
blackbody
and the sun
radiation
the atmosphere
of Greenhouse Gases
frequencies, it is called a blackbody. The light (energy) that is emitted by a
blackbody is called blackbody radiation. Most solids and liquids at the surface
of the Earth are blackbodies. Blackbody radiation is made up of a characteristic
distribution of frequencies of infrared light (red band in figures).
Sun” show the band of wavelength the Sun shines with surface temperature
5800 kelvin (K) (blue band) and Earth shines in infrared light (red band) with
mean surface temperature 255 K (= -18 C°, -0.4 F).
explains the basics of greenhouse effect. We will come back to this later!
5800 K or 5526 C
Incoming solar radiation =
shortwave radiation
255 K or -18 C
Earth’s outgoing radiation =
longwave radiation
mathematically by a relation called the Planck function, thus called
blackbody curve or Planck curve. The important message from this figure is
the spectrum of blackbody radiation is dependent on the temperature of the
object. A higher temperature blackbody radiates higher energy in a shorter
wavelength than a lower temperature object.
An idealized object that absorbs all incident
electromagnetic radiation and emits the maximum
amount of radiation possible at every wavelength for its
temperature is a(n):
B. isotherm
C. celsius
D. albedo
E. kelvin