Warm

Based on their structures, which of the following molecules are greenhouse gases? (atoms of the same kind are the same color) You can select more than one option if applicable

A & C molecules with different atoms

Which of the following is not a greenhouse gas? You should be able to answer this question, even if you cannot identify the molecule.

N2

Which statement is most correct?

Neither of the statements above are correct

Which option correctly completes the statement? Greenhouse gases __________________ Note for the answer choices: "longwave radiation" refers to the infrared portion of the spectrum, which is what Earth emits. When I use the term "terrestrial" that means it is from the Earth

absorb and re-emit outgoing terrestrial longwave radiation.

Note that this question is worth two points As noted in the day 2 lecture, Earth's axial tilt explains why we experience seasons. Our current axial tilt is 23.4 degrees from perpendicular. The Northern and Southern Hemispheres experience summer and winter at opposite times of the year when one of the hemispheres is tilted toward the Sun and receives more direct sunlight. The images below show four alternative configurations of Earth's axial tilt or orbit around the sun. Below the images is a written description of each of these figures as well. A. Earth's orbit is much more elliptical. The Earth is much closer to the Sun in December than in June. B. The Earth has no axial tilt C. The Earth's axis is tilted at 90 degrees. D. Earth's axis still has a tilt of 23.4 degrees, but Earth rotates in the opposite direction.

Seasons would be very extreme in both hemispheres: Winter would be very cold and dark. Summer would be very hot and experience constant sunlight = C The Northern Hemisphere summer would receive significantly less sunlight than the Southern Hemisphere during its summer season = A The Northern and Southern Hemispheres would receive an equal amount of sunlight year-round. There would be no seasons = B There would be no difference in the amount of incoming sunlight compared to Earth's present orbital configuration. Therefore, this would not change Earth's seasonality. = D

Which one of the following selections does NOT occur after CO2 is emitted into the atmosphere?

Some of the CO2 is converted to carbon monoxide

Which one of the following options accurately describes the water vapor feedback?

Surface temperature increases → Evaporation increases the water vapor content in the air → Greenhouse effect is enhanced ( because water vapor is a greenhouse gas) → the surface warms further.

Go through the steps below to decide if they are initiated by a positive or negative radiative forcing. (first bold statement) they describe a positive or negative feedback in Earth's climate system. (second bold statement) I have also provided a diagram below that may be helpful. You can double-check with the rule of multiplication! The surface of the Earth warms as a result of a [ ???] ["positive", "negative"] radiative forcing This leads to a warmer ocean. As the ocean warms, its ability to take up CO2 from the atmosphere is diminished. This means that more CO2 remains in the atmosphere, rather than being absorbed by the ocean. The increased greenhouse gas concentration warms the surface temperature further This process describes a [ ???] ["positive", "negative"] feedback.

positive positive

Note that this question is worth two points. For each of the couplings below, decide if it is... a POSITIVE coupling a NEGATIVE coupling, or no coupling exists: it is not an accurate direct cause-and-effect relationship. The amount of snow covering the surface increases --> the albedo of the surface increases: positive coupling The amount of snow covering the surface decreases --> the albedo of the surface decreases: negative coupling The amount of energy emitted by the Sun increases --> the concentration of greenhouse gases in the atmosphere decreases: no coupling exists The area covered by bright cloud tops in the atmosphere increases --> the absorption of incoming solar radiation at the surface below decreases negative coupling .

positive coupling positive coupling no coupling exists negative coupling

The figure above shows a slightly modified version of the ice-albedo feedback. In the third (bottom) step, instead of saying "surface albedo", the variable is "Amount of incoming solar radiation absorbed at the surface." Consider the new couplings, and decide if the ice-albedo feedback is still positive, if it is now negative, or if there is not enough information. Surface Temp + -> Snow and Ice cover - -> amount of solar radiation absorbed at the surface + ->

still a positive feedback!

If the Permafrost Feedback described above began with a negative radiative forcing, temperatures in the Arctic would instead initially cool. The Permafrost Feedback would ...

still have the same sign: If your answer to the previous question was "positive feedback", a negative radiative forcing wouldn't change that the feedback is positive If your answer to the previous question was "negative feedback", a negative radiative forcing wouldn't change that the feedback is negative.

If the change in radiative forcing is 4 W/m2, and the change in temperature is 6 oC, what is the climate sensitivity parameter (in oC/(W/m2))?

1.5

You can see that the overall trend is that methane is increasing, but the increase is not a straight line. The rate of change tells us how quickly a variable (in this case, methane concentration) increases or decreases over time. The rate of change in methane concentrations is slowest in which cluster of years?

2000-2005

Note that this question is worth two points Match the radiative forcing scenario with how it would affect the amount of incoming shortwave radiation at the surface of Earth or in Earth's atmosphere. Your choices are An increase in shortwave absorbed A decrease in shortwave absorbed No effect in shortwave absorption You'll use one of the options twice!

A doubling of nitrous oxide concentrations (compared to pre-industrial concentrations) = No effect in shortwave absorption An increase in sulfate aerosol emissions from a new coal-fired power plant = A decrease in shortwave absorbed An increase in black carbon aerosol emissions from a new coal-fired power plant = An increase in shortwave absorbed A low number of sunspots, indicative of a decrease in solar radiative output = A decrease in shortwave absorbed

Imagine the amount of incoming solar radiation drops. With less shortwave radiation reaching Earth, the temperature goes down. As temperatures decrease, the amount of sea ice in the Arctic and Antarctic expands. As a result, more shortwave radiation is reflected away, further cooling the planet. This describes a:

Negative forcing followed by a positive feedback

As we have discussed, the amount of CO2 in our atmosphere is rising due to emissions of CO2. But CO2 also varies seasonally. During which seasons does CO2 start to accumulate in our atmosphere (relative to other seasons)?

Northern Hemisphere fall/winter

Eyjafjallajökull Volcano is glaciated, so it has a large amount of ice and snow cover. The ash from the eruption blanketed the nearby glacier in gray material (though there is a range of albedos from ash, depending on the mineral composition, has an average albedo of 0.5). The ash deposition on the ice led to a local decrease in the surface albedo.

decrease

The graph in the previous question showed that China's total emissions were the highest. So why does the US have higher per-capita emissions?

differences in total population

Imagine the following scenario: The amount of incoming solar radiation remains fixed, and the amount of shortwave radiation absorbed by Earth stays constant. Greenhouse gas concentrations increase rapidly, suddenly decreasing the amount of longwave radiation emitted to space. In this scenario, the amount of shortwave energy entering the system would be [ ???] ["less than", "greater than"] the amount of outgoing longwave radiation leaving the Earth system. To compensate, the temperature at the Earth's surface will [ ???] ["warm", "cool"] until energy balance is restored, and the energy in is equal to the energy out to space.

greater than warm

According to a 2006 paper in the scientific journal Climate Dynamics (Jones, Sparks, and Valdes), the albedo of ash varies, but is, on average, approximately 0.5. Using this information, information about the albedo of forests and vegetation (from lecture), and the images above, did the albedo of the island increase or decrease after the volcanic eruption?

increase

Choose the correct ranking for the following portions of the EM spectrum in terms of frequency, from lowest to highest frequency.

infrared, visible, ultraviolet

The visible-light images above come from NASA's Solar Dynamics Observatory. On the left is an image from 2019; on the right, from 2014. You can observe that 2019 has fewer sunspots. Therefore, 2019 was a year that the Sun was emitting less radiation (compared to 2014).

less

Consider a scenario where the Earth is initially in energy balance and has a steady average global temperature. If the Sun suddenly dimmed and put out less solar radiation, the Earth would no longer be in energy balance: the Energy In would be [ ???] ["less than", "greater than"] the Energy Out of the Earth system. In response, the Earth would [ ??? ] ["warm", "cool"] until energy balance was

less than cool

The intensity of the sun's radiation peaks at approximately 0. 5 micrometers , which is in the visible portion of the electromagnetic spectrum.

micrometers and visible

The Clean Air Act of 1970 (and amendments in 1990) has dramatically reduced sulfate aerosol emissions in the US. This has likely saved and/or lengthened thousands of lives, by reducing Americans' exposure to pollutants. This reduction in sulfate aerosols has also allowed less incoming solar shortwave radiation to reach the Earth's surface.

more

Scientists estimate that it is likely that the global average temperature will increase by 3 oC if CO2 concentrations double (compared to pre-industrial temperatures and concentrations). There is uncertainty within this estimate though. It is extremely unlikely that the temperature would warm by 4 oC in response to a doubling of CO2. It is possible that the temperature would warm by only 1.5 oC in response to a doubling of CO2

possible extremely unlikely

The image above shows, in true color, two of the brightest stars in the night sky: Regulus and Gacrux. The color of a star is related to its temperature--our eyes see the maximum wavelength that the star is emitting. Some stars (like Regulus) appear to be blue while others (like Gacrux) appear red. Fill in the dropdowns to explain this phenomenon. (Refer to the slides on the radiation spectrum to help answer this question) Regulus emits radiation at a shorter peak (maximum) wavelength than Gacrux; Regulus is, therefore, a hotter star.

shorter hotter

Tropospheric ozone forms when...

sunlight hits pollutants (like nitrogen oxides) and sets of ozone-producing chemical reactions.

Recall that climate sensitivity is often reported as how much the world would warm in response to a doubling of CO2 compared to pre-industrial concentrations. The figure below shows the range of climate sensitivity from two sources: The results of a comprehensive study that came out in 2020 (Sherwood et al., 2020, Geophysical Research Letters) are shown in gray. The reported range of values from the 2013 IPCC report is shown in blue. The likely climate sensitivity (66% range) is shown by the rectangles, while the very likely sensitivity (90% range) is shown by the thinner bars.

the IPCC neither water vapor = potentially wrong

The temperature record shown above comes from NASA and was also shown in the lecture slides (Part 1). Inspect the figure closely and note the axes. The temperature anomaly for 2020 was +1.02oC. In 2021 it was +0.84oC These anomalies are compared to a reference value of ...

the average of the global mean temperatures between 1951 and 1980

Consider the following scenarios: Scenario 1: If the temperature increases by 3 °C in response to a 4 W/m2 radiative forcing, the climate sensitivity parameter is 0.75 oC/(W/m2). Scenario 2: Now, if the temperature response is higher (say 6 °C), the sensitivity parameter would also be a higher value. Physically, a higher sensitivity parameter indicates that the positive feedbacks are stronger in this second hypothetical climate system.

.75 stronger

Compare the WA State Emissions to the US Emissions, shown in the pie charts above For both, the transportation category is responsible for most emissions. In 2018, the state of Washington's total gross emissions were approximately 100 million metric tons of CO2. Since transportation makes up 45% of the state's emissions, this means that the state emitted 45 million metric tons of CO2. Transportation makes up 29% of the US's total emissions. In 2019, the US emitted approximately 5 billion metric tons of CO2. How much of that was due to transportation? 1.45 billion All of the possible answers above are greater than the 45 million metric tons that Washington state emits. This is because even though the proportion of emissions due to transit in the US is higher, the total emissions due to transit in Washington State are higher.

1.45 billion Washington State The US

On average, the incoming solar radiation at the top of Earth's atmosphere is ~ 342 W/m2. Because Earth's average albedo is 0.3, the average amount of incoming solar radiation that is reflected away by the Earth is then approximately [ ???] ["103", "342", "445", "239"] W/m2. If the planet's albedo increased, then the average amount of absorbed radiation would [ ???] ["increase", "decrease"] .

103 decrease

If a little less than half (~45%) of the emitted CO2 stays in the atmosphere, where does the remainder go?

About 30% is taken up by the land surface, and 25% by the ocean.

Out of all factors discussed by Dr. Hayhoe, which global warming impact has been shown to increase human mortality directly? (Select one)

Air pollution worsens as temperatures rise.

Carbon Dioxide, Methane, and CFCs all contribute to the anthropogenic greenhouse effect and are all associated with positive radiative forcings (compared to 1750). Rank the three greenhouse gases from smallest total radiative impact to largest.

CFCs, Methane, Carbon Dioxide

Which of the following statements are TRUE regarding ozone in the atmosphere?

Chlorofluorocarbons (CFCs) break down ozone molecules in the stratosphere and are responsible for the ozone hole over the Antarctic Ozone is considered a pollutant in the troposphere (ground level), but blocks harmful UV rays in the stratosphere (upper atmosphere)

Imagine that the intensity of sunlight reaching Earth suddenly increases. How would Earth respond to maintain energy balance?

Earth's temperature would increase until the amount of energy being emitted as longwave radiation again equals to the amount of incoming shortwave

The following statement is FALSE. Select the best explanation from below to refute this statement. The Global Warming Potential (GWP) of nitrous oxide is 298. Therefore, nitrous oxide is contributing more to the unnatural/anthropogenic greenhouse effect than carbon dioxide.

Even though nitrous oxide has a higher GWP, its concentration in the atmosphere is much lower than carbon dioxide. Carbon dioxide, therefore, contributes more to the unnatural greenhouse effect

In 2020, the country of New Zealand emitted 33.5 million tons of CO2 into the atmosphere. In that same year, the country of Ecuador emitted a comparable amount: 31 million tons. However, the per capita emissions from New Zealanders were 7 tonnes per person in 2020, while the per capita emissions from Ecuadorians were only 1.75 tonnes per person. Why are the per-capita emissions for Ecuador so much lower? You don't need to know anything about these countries in particular-only one explanation below makes sense

New Zealand's population is lower than Ecuador's-therefore the emissions in New Zealand are distributed among fewer residents.

Inspect the diagram below, which shows the flux of radiation incident on two pieces of paper (flux = amount of energy that hits a unit surface area per unit time). The flux of radiation that strikes the paper is reduced when the paper is tilted at an angle to the incoming light. The bottom image better represents sunlight hitting the polar latitudes, while the other image is more akin to the tropical latitudes.

bottom (horizontal to the sun)

The graph indicates that between 1880 and 1940, changes in the Sun's strength cannot explain most of the variability in Earth's global average temperature. Since the 1970s, changes in the Sun's strength cannot explain most of the increase in global average temperature.

cannot cannot

The figure above shows a generic feedback loop. There is no information about the components within the loop. Using the rule of multiplication alone, is this a positive or negative feedback?

negative

In the lecture, I showed images of the optical depth and climatic impact of the Mt. Pinatubo eruption in the Philippines. Based on location alone, which volcanic event do you think had a bigger global climatic impact (in terms of short-term temperature drop)?

Pinatubo in the Philippines (latitude of 15 degrees N)

Why is the ozone hole harmful?

The ozone hole allows more UV radiation to reach the surface of the Earth, which is dangerous for human, animal, and plant life

Go through the steps below to decide if they describe a positive or negative feedback in Earth's climate system. I have also provided a diagram below that may be helpful. The surface of the Earth warms as a result of a change in Earth's radiative balance (energy in or out) This leads to warming surface temperatures As the surface warms, evaporation rates increase This can dry out vegetation In places that are prone to fire, an abundance of dry vegetation provides kindling for larger fires Large fires emit carbon to the atmosphere (as the vegetation burns) The concentration of CO2 in the atmosphere increases and the process begins again! The process detailed by the bullet points above describes a positive feedback .

positive feedback

Positive feedbacks are especially dominant in the Arctic. Therefore, in the coming decades, the Arctic is expected to warm more quickly than the rest of the planet.

positive warm

Use the figure below, referred to as the Keeling Curve, to answer the following question. Note, the red line represents monthly average carbon dioxide concentrations while the black line removes the seasonal cycle. (Source: NOAA). Refer to the black (annual) line: Between 1980 and 2000, atmospheric carbon dioxide concentrations increased by about [ ???] ["70", "30", "45"] ppm. From the year 2000 to 2020, they increased by approximately [ ???] ["45", "30", "70"] ppm Therefore the rate of change has increased in the past 20 years, compared to the 20 years prior.

30 45 increased

Note that this question is worth two points Imagine that the Sun decreases in intensity, and at the same time there is an increase in the amount of CO2 in the atmosphere. The decrease in intensity of the Sun represents A negative shortwave radiative forcing . The increase in the amount of CO2 in the atmosphere represents A positive shortwave radiative forcing . Overall, the combined effect of these two changes will leave the Earth's temperature stable .

A positive shortwave radiative forcing A negative shortwave radiative forcing leave the Earth's temperature stable

Now focus on the March 11, 2020 image. The lowest albedo is found in square B . The highest albedo is found in square A .

B A

Hydrofluorocarbons (HFCs) are human-made organic compounds that are commonly used in air conditioning and as refrigerants. One example of a HFC is Tetrafluoroethane (HFC-134a), which... - has a global warming potential of 1430 (over a 100-year timeframe) - stays in the atmosphere for about 14 years after it is emitted. - has a concentration in the atmosphere of 110 parts per trillion This means that Tetrafluoroethane is:

Better at absorbing terrestrial longwave radiation than CO2 on a per-molecule basis (higher radiative efficiency)

Suppose that low clouds always form where sea ice has melted. This would initiate a negative feedback. There is no evidence that this feedback is occurring.

negative no evidence

Go through the steps below to decide if they describe a positive or negative feedback in Earth's climate system. I have also provided a diagram below that may be helpful. You can double-check with the rule of multiplication! A positive radiative forcing leads to warming temperatures in the Arctic. This, in turn, thaws permafrost in the region. Thawed permafrost releases methane and carbon and carbon into the atmosphere. The increased greenhouse gas concentration warms the surface temperature further

positive

The transportation sector is an important source of greenhouse gas emissions. However, its relative importance varies based on location and the other sources of emissions in that region. Choose which percentage matches the relative importance of the transportation sector to the place (one % per place).

Globe = 14% US = 29% Seattle = 58%

In the article, Dr. Kelly McKusker* notes that an increase in 90-degree days will be more painful in humid regions than in dry ones. How does humidity affect how humans experience heat? *Dr. McKusker is an alum of UW Atmospheric Sciences!

High humidity makes it harder for humans to evaporate their sweat as easily -- so it's harder to cool down

In addition to the units degrees C or degrees F, why do scientists estimate the amount of climate change in terms of the unit Joules?

Joules are a measure of energy; a small increase in temperature corresponds to an enormous addition of energy to the climate system.

Note that this question is worth 2 points In 2002, 118 many days per year were expected to reach at least 90 degrees F in Miami, Florida. But by 2082, scientists project that 163 many days per year are expected to reach at least 90 degrees F in Miami, Florida.

118 163

The average summertime temperature in Anchorage, Alaska is 64 °F

climate

Average annual temperatures in Alaska are projected to rise by 2°F to 4°F by 2050

climate change

Since the late 1970s, Alaska's statewide annual average temperature has been increasing at a rate of 0.7 °F

climate change

In what year did China become the highest CO2 emitter in the world?

2005

Ignoring the error ranges (in square brackets), the approximate size of the radiative forcing when you sum carbon dioxide with the other well-mixed greenhouse gases is 2.7 W/m2. This value is higher than the "total anthropogenic" forcing! The reason for this is that negative natural (non-human) forcings offset some of the positive radiative forcings caused by greenhouse gas emissions.

3.3 negative anthropogenic

Why does carbon leakage make it challenging to calculate a country's carbon footprint?

A country may outsource manufacturing to countries with less strict greenhouse gas regulations.

The figure above shows the radiative forcings (in W/m2) used in NASA's GISS global climate model. The time-dependent radiative forcings are relative to the year 1850. The last year in this record is 2015. I have covered up the legend. Consider what you know about the sign of different radiative forcings (are they positive or negative?), the size of those forcing (are they small or large?), and the timescale of the forcings (are they short or long-lived? Are they periodic or persistent?) to match the line color with the radiative forcing. Each option will be used once and only once.

Anthropogenic aerosols (direct and indirect effects) = pink Greenhouse gases = green Natural drivers, including solar variability and volcanic eruptions = blue Total radiative forcing = black

Earth would experience no distinct seasons if.... A. Earth's orbit around the Sun was a perfect circle B. The tilt of Earth's rotational axis was 45o C. There was no tilt to Earth's rotational axis D. The Earth had no moon

C

Again, consider a scenario where the Earth is initially in energy balance and has a steady average global temperature. If Earth's planetary albedo suddenly decreased, then more incoming solar radiation would be absorbed by Earth's surface/atmosphere. The Earth would no longer be in energy balance, so the Earth's temperature would warm until energy balance was restored.

more warm

The aerosol indirect effect leads to a positive shortwave radiative forcing--more incoming sunlight is reflected away. This is because the high concentration of these aerosols gives rise to clouds that are composed of many tiny water droplets, resulting in high-albedo cloud tops.

negative tiny

Note that this question is worth two points For each statement below, indicate whether the relationship is a positive coupling, a negative coupling, or has no coupling (does not accurately describe a cause-and-effect relationship) Decrease in Earth's albedo → increase in absorbed incoming solar radiation [ ???] ["positive coupling", "negative coupling", "no coupling"] . Increase in methane concentrations in the atmosphere → increase in strength of greenhouse effect [ ??? ] ["positive coupling", "negative coupling", "no coupling"] . Increase in methane concentrations in the atmosphere --> increase in CFC concentrations in the atmosphere positive coupling . Increase in sea-ice extent in the Arctic --> increase in planet's albedo positive coupling

negative coupling positive coupling positive coupling positive coupling

Does the following scenario describe a forcing or a feedback? Positive or negative? As the surface temperature of Earth increases, this leads to increased evaporation from the ocean surface. This increased evaporation results in the formation of more clouds in the lower atmosphere. These clouds have a high albedo, so reflect away more solar radiation back to space. Therefore, less incoming solar energy is absorbed and the surface temperature cools.

negative feedback

Does the following scenario describe a forcing or a feedback? Positive or negative? Due to failure in storage tanks, a huge amount of methane was released into Aliso Canyon, CA in 2015/2016, increasing atmospheric concentrations of the greenhouse gas.

positive forcing

Let's consider two radiative forcings that would lead to a warming on Earth's surface: The planet's albedo drops dramatically. This is a positive shortwave radiative forcing. The concentration of methane increases dramatically. This is a positive longwave radiative forcing. Though they are different physical changes, the size of the radiative forcings could be compared in W/m2!

shortwave longwave

On July 4th, 2019, Anchorage International Airport recorded a high of 90 °F, setting an all-time temperature record.

weather