Final Exam HW Questions
If the amount of carbon stored in the atmosphere is 1000 Gt and the photosynthesis rate is 50 Gt/year, how long would carbon stay in the atmosphere if photosynthesis is the only process removing it?
20 years
One adaptation option for sea level rise is coastal retreat, i.e., moving inland to escape the rising water levels. For a coastline with simple geometry, we can estimate the required retreat using trigonometry and a triangle. In the triangle above, the triangle side labeled "opposite" is the sea level rise, and triangle side labeled "hypotenuse" is the required retreat. If the angle theta Θ is 0.20 degrees and the sea level rise is 1 meter - What is the required retreat?
286 meters
According to economic discounting and assuming all dollars are adjusted for inflation - Which of the following statements is **TRUE**?
A dollar today is worth more than a dollar in the future.
Where does the carbon dioxide that is emitted by ATOC1060 students end up over their lifetimes?
About 50% of the carbon dioxide remains in the atmosphere, the other half goes into the ocean and the land
Which of the following is an example of climate change adaptation?
Following Hurricane Sandy, the city of New York decided to turn low-lying residential areas into city parks.
Why is the Stefan-Boltzmann law important for explaining the greenhouse effect?
Greenhouse gases in the atmosphere emit infrared radiation towards the surface, which warms the surface.
Which of the following is required for a gas in the atmosphere to be a greenhouse gas?
Having rotation and/or bending modes enabling absorption of longwave radiation
The figure above shows maps of dS/dH for New York City, New York (left) and Reykjavik, Iceland (right). What can you conclude based on these maps?
New York and Reykjavik will experience similar sea level rise associated with decreasing Antarctic Ice Sheet ice thickness.
Which of the following can be explained by natural climate variability alone?
None of the other answers can be explained by natural variability alone
Which of the following statements about polar bears living in the wild is TRUE?
Not all polar bear subpopulations are declining right now due to global warming.
How large is the observed 20th century global warming?
Observed 20th century global warming is about 40x smaller than Earth's natural greenhouse effect.
According to Milankovitch theory (Earth's orbital patterns), which of the following is thought to be the most important factor for initiation of a glacial period?
Summer temperatures at northern mid-latitudes
According to 2017 National Climate Assessment, Executive Summary - by how much is global sea level expected to rise by the end of this century?
0.3-1.2 meters, 1-4 feet
Based on the following CU-Boulder research group's satellite observations http://sealevel.colorado.edu/ - By how much has global sea level risen since 1995? See especially this graph where MSL = mean sea level: http://sealevel.colorado.edu/files/2018_rel1/sl_ns_global.pdf
3 inches
Uranium 238 (238U) decays to become Lead 206 (206Pb) with a half-life of 4.5 billion years. How long will it take for 75% of 238U in a rock sample to become 206Pb?
9 billion years
In 2014 - the University of Colorado issued a press release about a new report on climate change in Colorado - https://www.colorado.edu/today/2014/08/05/new-report-highlights-how-climate-change-may-affect-water-colorado. According to the press release - which of the following was a finding of the report?
A 6-degree (Fahrenheit) increase in temperatures would make conditions in Denver similar to Albuquerque, New Mexico today.
It's 2100. Atmospheric carbon dioxide concentrations are 1000 ppm. Which of the following changes to Earth's climate is most reversible on timescales less than 10 years?
Arctic sea ice loss.
What would happen to atmospheric carbon dioxide concentrations if current emissions due to fossil fuel burning increased by 50%?
Atmospheric carbon dioxide concentrations would continue to increase, but at a faster rate
How do we know that human burning of fossil fuels caused atmospheric carbon dioxide to increase over the last 50 years?
Atmospheric carbon isotope ratios indicate we are burning old dead plants.
Which observation provides the best evidence that increases in atmospheric carbon dioxide concentrations over the last 50 years are anthropogenic (i.e., human-caused)?
Burning fossil fuels (old plants) has lowered the 13C/12C ratio of atmospheric carbon dioxide.
Rank (from largest to smallest) the following greenhouse gases in order of their influence on the increased radiative forcing from 1750 to today:
Carbon dioxide, methane, CFCs
Why is the snow in California more vulnerable to 5 °C global warming than the snow in Colorado?
Colorado has a higher mean elevation than California.
Which of the following is an example of climate change mitigation?
France requires that all cars be powered by solar energy
In 2020, a new climate treaty is signed with two outcomes. First, all countries of the world decrease emissions of carbon dioxide from all anthropogenic activities. Second, global emissions of carbon dioxide from anthropogenic activities remain positive. What is the impact of the treaty on atmospheric carbon dioxide concentrations?
Global atmospheric carbon dioxide concentrations continue to increase.
The figure above shows maps of dS/dH for New York City, New York (left) and Reykjavik, Iceland (right). What can you conclude based on these maps?
If the thickness of the Greenland Ice Sheet decreases, sea level will decrease in Reykjavik, but increase in New York.
Assume that Squaw Valley is expected to warm 5 °C in all months by 2050. What will happen to the snow conditions at Squaw Valley according to the graph above?
In 2050, snow will start accumulating in late December instead of November.
Which of the following is most likely to occur in Colorado by mid-century (2050) in "business-as-usual" climate model projections?
Increased risk for water shortage at the end of summer
In 2020, an international treaty is signed to place mirrors in space to reflect incoming solar radiation. The goal of the treaty is to reduce global warming while still permitting fossil fuel burning over the next 50 years. What is most likely to happen if the space mirror system is implemented and fossil fuel burning continues?
Increases in ocean acidity over the next 50 years
It is the year 2100. Greenhouse gas concentrations are 1000 ppm. There is no summer sea ice in the Arctic and melting of the Greenland and West Antarctica has raised global sea level by 10 feet. When compared to today, the ocean is more acidic and surface air temperatures are warmer. Suddenly, engineers invent a machine to restore carbon dioxide concentrations to 400 ppm. They try to restore the climate of 2100 back to the climate today (2018). Which change to the climate is irreversible, i.e., cannot be changed back to present-day in a human lifetime by reducing atmospheric carbon dioxide concentrations from 1000 ppm to 400 ppm?
Land ice loss
What are the two main processes that contribute to sea level rise in a warming world?
Land ice melt and ocean thermal expansion
In December, the central tropical Pacific Ocean is anomalously warm indicative of El Nino conditions. What is expected for northern Australia during January?
Less rain than the climatological average
According to the 2017 National Climate Assessment Figure ES.4 - Which of the following occurs in "business-as-usual scenario" (RCP8.5 scenario) climate projections for the late 21st century?
More warming in Canada than in Mexico
Polar bears live in four different sea ice habitat zones: Seasonal Ice, Polar Basin Divergent Ice, Polar Basin Convergent Ice, and Archipelago Ice. In which habitat zones are polar bears **least** threatened by global warming?
Polar Basin Convergent Ice and Archipelago Ice
Which of the following is an anomaly?
September Arctic sea ice extent in 2014 was 1.24 million square kilometers below the 1981-2010 average.
Which of the following statements about the Kyoto Protocol is *TRUE*?
The Montreal Protocol is 4x more effective of a climate treaty than the Kyoto Protocol.
What does the "2.6" and "8.5" stand for in the RCP8.5 ("business as usual") and RCP2.6 ("mitigation on steroids") future emission scenarios used in CMIP5?
The radiative forcing at year 2100 measured in W/m^2
It's 2100. Colorado is warmer than it is today. What has changed in 2100 for an afternoon thunderstorm? Assume the storm in 2100 has the same dynamics as the storm today.
The storm in 2100 produces more rain than the storm today.
What best describes the dominant control on climate over the last 544 million years on million-year timescales?
Variations in atmospheric carbon dioxide concentrations driven by the carbonate-silicate geochemical cycle
Which of the following describes a positive feedback?
When Betty studies for exams, her grades improve, which increases her motivation to study for exams.
Assume that Copper Mountain is expected to warm by 5 °C in all months of the year by 2050. What will the 2050 snow conditions be at Copper according to the graph above?
When compared to 1999 (black curve), snow reductions in 2050 will be larger in May than in January.
Steroid use in baseball and greenhouse gas increases in climate have parallels. A baseball player is more likely to hit a home run than strike out when he is on steroids. What is the closest equivalent statement for climate?
When greenhouse gases increase, record high temperatures occur more often than record low temperatures.
Which statement best describes coral bleaching?
When ocean temperatures are anomalously high, coral expels the algae living in its tissues and turns white.
Which of the following statements is true on million-year timescales?
an increase in silicate weathering and carbonate precipitation causes no change in atmospheric oxygen and a decrease in atmospheric carbon dioxide.
Maintaining constant anthropogenic carbon dioxide emissions at 2017 levels during the 21st century will cause_____
atmospheric carbon dioxide concentrations to increase during the 21st century.
Which of the following statements is true? a. India was the largest greenhouse gas emitter on the planet in 2016. b. Greenhouse gas emissions from 2005-2012 exceeded the "business as usual" scenario (RCP8.5) used in the last IPCC. c. New York City is doing nothing to prepare for climate change. d. The Kyoto Protocol, if it had been ratified by the United States, would have maintained carbon dioxide concentrations at 450 ppm until 2100.
b. Greenhouse gas emissions from 2005-2012 exceeded the "business as usual" scenario (RCP8.5) used in the last IPCC.
Which of the following statements is **TRUE**? a. According to the Stefan-Boltzmann law, colder objects emit more radiation than warmer objects. b. Removing all greenhouse gases in the atmosphere would cool the global average surface temperature to -18 degrees C (0 degrees F). c. Isotopes of the same element have the same number of neutrons but a different number of protons. d. Water vapor has a longer residence time in the atmosphere than carbon dioxide.
b. Removing all greenhouse gases in the atmosphere would cool the global average surface temperature to -18 degrees C (0 degrees F).
Which of the following is an impact of more carbon dioxide diffusing from the atmosphere into the surface ocean?
decreasing carbonate ion concentrations in the surface ocean, making it harder to form carbonate shells
Why are global mean temperature higher in the 2000s than they were in the 1900s?
greenhouse gas concentrations were higher in 2000s than in 1900s.
Climate model projections have three sources of uncertainty: 1) internal climate variability, 2) model uncertainty, and 3) scenario (future greenhouse gas and aerosol emission) uncertainty. According to the current generation of climate model projections - What is the largest source of uncertainty for early 21st century projections?
internal climate variability uncertainty
It's 2100. We increased atmospheric carbon dioxide concentrations to 1000 ppm. Engineers invent a machine to reduce carbon dioxide concentrations to 400 ppm. Which of the following things that have happened over the 21st century due to increased greenhouse gases are reversible on human timescales?
sea ice loss
