Test 1

Greenhouse gases are A. Shortwave radiation absorbers B. Longwave radiation absorbers C. Shortwave radiation reflectors D. Longwave radiation reflectors

B. Longwave radiation absorbers

Photosynthesis A. adds CO2 to the atmosphere and removes O2 from the atmosphere B. adds O2 to the atmosphere and removes CO2 from the atmosphere C. adds both CO2 and O2 to the atmosphere D. removes both CO2 and O2 to the atmosphere

B. adds O2 to the atmosphere and removes CO2 from the atmosphere

Which of the following is a greenhouse gas? A. carbon monoxide B. carbon dioxide C. nitrogen D. argon

B. carbon dioxide

The water vapor feedback (involving temperature, water vapor and the greenhouse effect) is a NEGATIVE feedback. True False

False

UV rays represent a portion of longwave radiation. True False

False

The Intergovernmental Panel on Climate Change is a group of politicians from many countries charged with devising a climate change treaty. True False

False; IPCC consists of scientists explaining climate change, not policy makers involved in international agreements.

Mars has a "runaway" greenhouse effect compared to other planets. True False

False; Venus

Is a small temperature rise such a big deal?

Global temperatures have risen about 1 degree Fahrenheit in the last century. Local temperatures vary by much more than that every day, but this can be important when looking at climate rather than weather.

A closer look at the radiation emitted by the sun

Most of the sun's radiation is visible light, not UV

The percent of solar radiation reflected off a surface is called a) inverse square b) albedo c) emittance d) absorptivity

b) albedo

Consider UV (ultraviolet), visible (VIS), and infrared (IR ) radiation. Which has the shortest wavelength? The highest energy? a) visible, UV b) IR, visible c) UV, UV d) IR, UV

c) UV, UV

Because of the enhanced greenhouse effect, more energy enters the earth system than leaves to space. Where has most of the extra heat accumulated? a) atmosphere b) forests c) oceans d) ice sheets

c) oceans

A scientific journal article whose methods have been approved by other scientists is called a) expert certified b) peer endorsed c) peer reviewed d) substantiated

c) peer reviewed

As the planet warms, the release of methane from __________ would accelerate warming. a) tropical rainforests b) tropical oceans c) permafrost d) the stratosphere

c) permafrost

Match these components of the climate system with their name that contains the term "sphere". cryosphere atmosphere hydrosphere biosphere air plants and animals oceans snow and ice

cryosphere- snow and ice atmosphere- air hydrosphere- oceans biosphere- plants and animals

S0 The solar constant (for Earth)

S0=1366 W/m2 •Amount of insolation at the top of the atmosphere -Insolation=INcoming SOLar radiATION S0=1366 W/m2 This is equivalent to about 13 100W incandescent light bulbs LASP (at CU) measures the solar constant!

Visible Light

Sun, Rainbow

What is climate?

The average weather over a period that may be a few months, a season, or a few years

Is the plant really heating up?

The change in surface temperature for the period 2000-2009 relative to 1951-1980 was calculated by NASA's Goddard Institute for Space Studies using data from surface weather stations for land areas and satellite-derived temperature estimates for the oceans. Gray areas denote places where temperatures were not recorded. The warmth was especially prominent at high northern latitudes, as predicted by computer models. (NASA Earth Observatory) 2015 was warmest year on record for global surface temp 2014 was the warmest prior to last year Ice on land and sea is decreasing, especially in the Arctic. The growing season is increasing in many locations Animals including birds and mosquitoes are being pushed into new locations

Years when El Nino is occurring tend to have a higher global temperature. True False

True

Coupling

The links between any two components of a system, couplings can be positive or negative

What about the Ozone Hole?

The ozone hole and global warming are two different problems. International agreements are in place which should eliminate this problem in this century. Agreements to address climate change will be much more difficult to achieve.

What is weather?

The state of the atmosphere at a given time and place. Snow, tornado, hail, hurricane, thunderstorm

Methane

Warming Tundra and Melting Permafrost Feedback Therefore, it is a positive feedback

Wien's Law (tells us the peak of the Plank function)

Wavelength of maximum radiation flux (wavelength is inversely proportional to Temperature) (higher temperature, smaller wavelength (λ) 1.Sun T = 5778 K (visible, short) 2.Earth T= 288 K (infrared, long)

Ice Albedo Feedback Cont.

Whether you initially increase or decrease Temperature (Ts), you sill amplify this initial change by going through two negatives and one positive coupling. This will always be a positive feedback!!! The ice albedo feedback amplifies the warming in high latitudes by a factor of three or four!

Which is the strongest argument that Earth is warming? a) There have been record high temperatures this year. b) Global temperatures are usually higher when major volcanoes occur. c) The ozone hole is getting worse. d) Annual temperatures, averaged over whole years, have been increasing for decades

d) Annual temperatures, averaged over whole years, have been increasing for decades

The rising air in the Hadley cell occurs near the a) Deserts b) Poles c) Ice Sheets d) Equator

d) Equator

Circular ocean currents are called a) eddies b) jetstreams c) hydrospheres d) gyres

d) gyres

Because of the enhanced greenhouse effect, more energy enters the earth system than leaves to space. Where has most of the extra heat accumulated? a) atmosphere b) ice sheets c) forests d) oceans

d) oceans

Popular Science magazines

written by journalists

The Water Vapor Feedback

•Initially increase temperature in a system •= increased water vapor due to evaporation •= increased greenhouse gases •= increased temperature Therefore it is a positive feedback

Atmospheric greenhouse gases

•The increase in carbon dioxide (CO2) has contributed to about 72% of the enhanced greenhouse effect to date.

Ice Albedo Feedback

(-1)X(+1)X(-1)=(+1) Therefore this is POSITIVE Feedback! Cold to hot This is STILL an example of a POSITIVE Feedback because it reinforces the initial decrease in heat. -This could lead to a runaway ice age! Some people get confused and think, "oh, it's getting colder, so it must be a negative feedback." This is not true! Remember definitions of positive and negative feedbacks.

Negative Coupling

-Negative coupling represented by a circle, change in one component stimulates a change of the opposite direction in the linked component Temp-O Sea Ice Extent If the surface temperature on Earth INCREASES, Sea ice extent will DECREASE Albedo-O Temp If albedo INCREASES, temperature will DECREASE (more sunlight will be reflected to space, never being absorbed at the sfc).

Feedback loops, understanding diagrams

1 positive coupling (arrow), 1 negative coupling (circle), so a negative feedback (+1)X(-1)=(-1)

The atmosphere is mostly made up of nitrogen (N2) and A. water vapor (H20) B. argon (Ar) C. oxygen (O2) D. ozone (O3)

C. oxygen (O2)

Infrared Light

Earth

Southern Hemisphere locations have coldest conditions during the months of December through February. True False

False

A single cold weather event does not tell us much about whether the Earth's climate is warming. True False

True

Positive Coupling

-Positive coupling represented by an arrow, a change in one component is a stimulus that leads to a change of the same direction in the linked component Temp->Water Vapor concentration If the surface temperature on Earth INCREASES, Water vapor concentrations in the atmosphere will also INCREASE due to increased rates of evaporation off of the oceans and other surfaces. Greenhouse Effect->Temp If the greenhouse effect becomes stronger (due to increased greenhouse gases), then temperature will increase.

The Scientific Method

1. Observe: Closely observe the physical world around you 2. Question: Recognize a question or problem 3. Hypothesize: Make an educated guess- a hypothesis- to answer that question 4. Predict: Predict consequences that can be observed if the hypothesis is correct. The consequences should be absent if the hypothesis is not correct. 5. Test Predictions: Do experiments to see if the consequences you predicted are present. 6. Draw a conclusion: Formulate the simplest general rule that organizes the hypothesis, predicted effects, and experimental findings

Climate Literacy: Guiding Principles

1. The Sun is the primary source of energy for Earth's climate system 2. Climate is regulated by complex interactions among components of the Earth system 3. Life on Earth depends on, is shaped by, and affects climate. 4. Climate varies over space and time through both natural and human-made processes 5. Our understanding of the climate system is improved through observations, theoretical studies, and modeling. 6. Human activities are affecting the climate system. 7. Climate change will have consequences for the Earth system and human lives.

The *Enhanced Greenhouse Effect Causes Global Warming!*Where enhanced means amplified

A small change in the amount of greenhouse gases can lead to a big temperature change!

The solar constant relates to A.the amount of energy leaving the sun's surface B.the amount of energy reaching the Earth's surface C.the amount of energy reaching the top of the Earth's atmosphere

C. the amount of energy reaching the top of the Earth's atmosphere

Opposing Climatic Effects of Clouds

Cloudy days are relatively cool: Shortwaves from sun bounce off of clouds Cloudy nights are relatively warm: Longwaves from ground reflect back to ground off of clouds

Don't many experts claim that the science is uncertain?

Considerable uncertainty about •exactly how much it will warm •how much warming will occur in different locations •how rainfall will change in different locations but it is generally accepted that the planet is warming due to human activity

How hot will it get?

Considerable uncertainty about exactly how much it will warm. This uncertainty is due to •The complexity of the climate •Different amounts of heating in different regions Uncertainty about how human actions will change (especially burning of fossil fuels)

Anthropogenic practices add more carbon dioxide into the atmosphere every year. However, the buildup of atmospheric CO2 is slowed by significant amounts taken up by A. oceans B. plants and soils C. ice and snow D. both A and B E. all of the above

D. both A and B

The inverse square law relates the amount if solar energy reaching a planet based on its distance from the sun. A planet that is twice the distance from the sun compared to the Earth-sun distance would receive A.twice as much solar radiation as the Earth B.four times as much solar radiation as the Earth C.one half as much solar radiation as the Earth D.one fourth as much solar radiation as the Earth

D. one fourth as much solar radiation as the Earth

The ice-albedo feedback always results in warmer global temperatures. True False

False

The scientific method is not considered complete until the results are published in a peer-reviewed publication. True False

False

What can we do about it?

Human actions to address the emissions of carbon dioxide and other human causes of global warming are called MITIGATION. What is the cost of various mitigation strategies? How fast can they be implemented? How do these costs compare with the costs (impacts) of doing nothing?

How could humans change the whole world's climate?

Humans add billions of carbon dioxide to the atmosphere every year. Carbon dioxide and other "greenhouse gases" essentially trap much of the sun's energy in the lowest atmosphere

Cloud reflectivity feedback

Increase Temperature, increase water vapor, increase clouds (this is unknown by how much), increase albedo, decrease temperature Therefore, this is a negative feedback, but scientists are still working on quantifying this. Stabilizing effect

Inverse Square Law

Intensity=1/Distance^2 the intensity of the light decreases as the inverse square of the distance

The Stefan-Boltzmann Law Cont.

Let's assume that the sun is a blackbody Isun= εσ(6000K)4 = 7.3 X 107 W/m2 What about a star twice as hot as the sun? Istar= εσ(2 X 6000K)4 = 1.12X109 W/m2 = 16 Isun The amount of energy released per unit area per unit time by the hot star is nearly 16 times greater than that released by the sun

Clouds

Many different types •The effect (overall cooling or warming) depends on the type of cloud, the cloud temperature, height, and optical thickness

Planetary Energy BalanceFormula

Shortwave Radiation •Emission from the sun •Inverse square law •Albedo (reflectivity) Longwave Radiation •Emission from earth (Stefan Boltzman) α = Albedo = 0.30 S = 1366 W/m2 σ = 5.67 X 10-8 W m-2 K-4 T = Earth Temperature (K)

Selective absorbers and the atmospheric greenhouse effect

Sunlight warms the earth's surface only during the day, whereas the surface constantly emits infrared radiation upward during the day and at night. (a) Near the surface without water vapor, CO2, and other greenhouse gases, the earth's surface would constantly emit infrared radiation (IR) energy; incoming energy from the sun would be equal to outgoing IR energy from the earth's surface. Since the earth would receive no IR energy from its lower atmosphere (no atmospheric greenhouse effect), the earth's average surface temperature would be a frigid -18C(0F). (b) With greenhouse gases, the earth's surface receives energy from the sun and infrared energy from its atmosphere. Incoming energy still equals outgoing energy, but the added IR energy from the greenhouse gases raises the earth's average surface temperature about 33C, to a comfortable 15C(59F).

Is global warming necessarily a bad thing? How many people might be hurt or killed? Will agriculture suffer? How will the changes impact wildlife? How will the economy be affected? Will rising seas really put cities such as New York and London under water?

These questions address the impacts of climate change

How do rainforests fit into the picture?

Trees hold vast amounts of carbon which are released due to deforestation which has occurred especially in the tropics. Deforestation has accounted for about 10-15% of the extra CO2 in the atmosphere.

As atmospheric CO2 concentrations increase, photosynthesis rates increase. True False

True

Climates in the sub-tropics, between the low latitudes (tropics) and middle latitudes (like our climate) are the region most likely to exhibit desert conditions. True False

True

Electromagnetic radiation can travel through space where no gas molecules exist (i.e. in a vacuum). True False

True

Venus has a runaway greenhouse effect because of high CO2 concentration in its atmosphere True False

True

Which of these best describes how greenhouse gases "trap" heat on the planet? a) Greenhouse gases like CO2 and water vapor absorb longwave radiation and then emit longwave radiation back towards the surface. b) Greenhouse gases like CO2 and water vapor reflect longwave radiation back towards the surface. c)Greenhouse gases like CO2 and water vapor raise the planet's albedo by reflecting more sunlight. d) Greenhouse gases like CO2 and water vapor absorb shortwave radiation and then emit longwave radiation back towards the surface.

a) Greenhouse gases like CO2 and water vapor absorb longwave radiation and then emit longwave radiation back towards the surface.

Which is the most accurate description of the greenhouse effect? a) It is a natural process that is enhanced by human activity. b) It is caused exclusively by human activity. c) It does not exist. It is a hoax. d) It is a natural process occurring without human activity.

a) It is a natural process that is enhanced by human activity.

According to the change in global temperatures since 1951-1980, what region has warmed the most? a) oceans (as opposed to land) b) high northern latitudes (near North Pole) c) near the equator d) high southern latitudes (near South Pole)

b) high northern latitudes (near North Pole)

Which global location is characterized by abundant precipitation all year? a) near the north pole b) in the tropics (near the equator) c) in the sub-tropics (near the 30 degrees north latitude) d) near the south pole

b) in the tropics (near the equator)

A hotter object emits radiation predominantly at a) at the same wavelengths, but fewer photons. b) shorter wavelengths c) longer wavelengths

b) shorter wavelengths

Infrared flux/temperature feedback

•1. Increase the temperature of Earth •2. Increase the amount of heat given off to space at the top of the atmosphere [Stefan Boltzmann law (outgoing=σT4)] •3. Decrease the temperature of Earth •This is a NEGATIVE Feedback In other words, the hotter our planet gets, the more radiation it will give off to space at the top of the atmosphere, keeping temperatures relatively stable.

Greenhouse Effect

•A greenhouse has a similar effect to the atmosphere on the incoming solar radiation and the emitted thermal radiation

Cloud Radiative Forcing- varies around the globe

•Annual mean net cloud radiative forcing as observed by the CERES instrument on the NASA Terra satellite.

A positive feedback with respect to global temperature would A. amplify warming or amplify cooling B. slow warming or slow cooling C. amplify warming or slow cooling

A. amplify warming or amplify cooling

The albedo describes A. the proportion of energy (e.g. sunlight) reflected by a surface B. the proportion of energy absorbed

A. the proportion of energy (e.g. sunlight) reflected by a surface

The Natural Greenhouse Effect

Selective absorbers in the atmosphere allow shortwave radiation to pass through the atmosphere, but absorb some of the longwave radiation emitted by the earth (these selective absorbers are often called greenhouse gases)

Opposing Climatic Effects of Clouds

•Stratus clouds generally cool the earth because their primary influence is to reflect incoming solar radiation. •Cirrus clouds generally warm the earth because they contribute more to the greenhouse effect than to the planetary albedo. (Ice crystals in cirrus clouds allow much sunlight through, but absorb IR)

The Stefan-Boltzmann Law

•The amount of radiation emitted by a blackbody is a very sensitive function of its temperature •Intensity of light (I) emitted by a blackbody is related to the fourth power of the body's absolute temperature (T) •ε=emissivity, a number between 0 and 1 describing how good of a blackbody the object is I=εσT4 σ=5.67X10-8W/m2/K4

The Scientific Experiment

•Aristotle was proved wrong, he claimed that heavy objects fall faster than light objects -Galileo experimented by dropping heavy and light objects from the Leaning Tower of Pisa and they fell at equal speeds -One experiment that can be reproduced outweighs everything •Scientists must accept their findings, even if they wanted them to be different •Science is kept honest by knowing that statements will be tested before being believed Rather than philosophize about nature, Galileo went an important step further—he experimented! "The test of all knowledge is experiment. Experiment is the sole judge of scientific truth." Richard Feynman "No number of experiments can prove me right; a single experiment can prove me wrong." Albert Einstein

The Enhanced Greenhouse Effect

•The enhanced greenhouse gas effect. Under natural conditions (a) the net solar radiation coming in (S=240 watts per square meter) is balanced by thermal radiation (L) leaving the top of the atmosphere; average surface temperature (Ts) is 15°C. If the carbon dioxide concentration is suddenly doubled (b), L is decreased by 4 watts per square meter. Balance is restored if nothing else changes (c) apart from the temperature of the surface and lower atmosphere, which rises by 1.2°C. If feedbacks are also taken into account (d), the average temperature of the surface rises by about 3°C.

How the earth keeps warm

•The radiation balance of planet Earth. The net incoming solar radiation is balanced on average by outgoing thermal radiation from the earth

Feedback Loops

•a "round trip", a linkage of two or more system components that forms a round-trip flow of information •Then, we multiply the +'s (arrows) and -'s (circles) and see if it is a net positive or negative feedback

Negative Feedback Loops

•diminish the effects of disturbances- a stabilizer

Mass Media

•prepared by journalists -Written -TV -Radio -Blogs- anyone -Social Media (Twitter, Facebook)

Albedo

•reflectivity. The percent of radiation reflected by a surface •What is the Earth's albedo? 30%. •Fresh snow: 75-95% •Sand 15-45% •Thick clouds: 60-90% •Grass: 10-30% Water:10% α=albedo αearth=0.3

Radiative Forcing

•the change in average net radiation at the top of the troposphere (the lower atmosphere) which occurs because of a change in the concentration in of a greenhouse gas or because of some other change in the overall climate system' -A positive radiative forcing warms the surface -A negative radiative forcing cools the surface -We usually represent this in units of W/m2

Journal Articles- Primary sources

•written by scientists - full explanation of background, motivation, methods, results, and conclusions -Peer Review Process

Climate Literacy: Intergovernmental Panel on Climate Change (IPCC)

The Intergovernmental Panel on Climate Change (IPCC) is the leading international body for the assessment of climate change. It was established by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) in 1988 to provide the world with a clear scientific view on the current state of knowledge in climate change and its potential environmental and socio-economic impacts. The IPCC is a scientific body under the auspices of the United Nations (UN). It reviews and assesses the most recent scientific, technical and socio-economic information produced worldwide relevant to the understanding of climate change. It does not conduct any research nor does it monitor climate related data or parameters. Thousands of scientists from all over the world contribute to the work of the IPCC on a voluntary basis. The IPCC generates comprehensive assessments of the current state of knowledge about the climate system and climate change, including impacts and economic costs/benefits of action or inaction on climate change. 1st Assessment report: 1990 2nd Assessment report: 1995 This report provided information for the international agreement known as the Kyoto Protocol 3rd Assessment report: 2001 4th Assessment report: 2005 5th Assessment report: 2013-14

Positive Feedback Loops

•amplify perturbations or forcings- an amplifier

A warmer surface emits more energy. The amount of energy is proportional to A. Temperature (in the Celsius scale) B. Temperature (in Celsius) squared C. Temperature (in the Kelvin scale) D. Temperature in Kelvins squared E. Temperature in Kelvins to the fourth power

E. Temperature in Kelvins to the fourth power

Many aerosols have a cooling effect on the planet. Why? A. They prevent melting of the ice sheets. B. They absorb solar radiation and emit longwave radiation towards the surface. C. They radiate longwave radiation to space. D. They produce clouds. E. They reflect solar radiation.

E. They reflect solar radiation.

Increase CO2, Increase Photosynthesis rates

Effect of changes in CO2 concentration on the photosynthetic rate of typical plants. Photosynthetic rates are relative to the value for today's atmospheric CO2 level. This results in a negative feedback loop.

Radiation

Electromagnetic waves can carry energy through a vacuum, from the sun to Earth at the speed of light (c).