Hill Murray Atmospheric Science Practice Quiz

It’s our 42nd and last day of class:27 April 2022
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Today’s topic: global warming action options
Assignments
◆ Lecture quiz for today, due 11:59 PM on Friday,
29 April
◆ Weather Notebook: submit (as one file) to D2L
Assignments dropbox by 11:59 PM on Monday,
2 May
◆ Lab 13, due 11:59 PM Monday, 2 May
04/27/2022
AHS 104 Day 42
1
Review of human-produced
climate change
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Since 1850, climate has warmed
Corresponds with 40% increase in CO2
◆ CO2 increase produced by humans
Computer forecasts are improving
◆ Better able to reproduce climate of last 150
years
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Predictions
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Warming predicted to be 1.5-5°C by 2100
⧫ Greatest in northern latitudes
⧫ Greatest at night and during winter
◆ Higher sea level
◆ Melting of ice sheets and sea ice
◆ More precipitation (but where?)
◆ Less-sure prediction: deserts get hotter and drier (?)
Scientifically questionable predictions
◆ more and stronger hurricanes
◆ more severe weather
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Review (continued)
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Most environmental predictions….
◆ More diseases
◆ Extinction of species
◆ Flooding of coastal cities
◆ Disappearance of ice sheets
…..are based on worst-case scenario
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What should we do????
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Global warming controversy
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What can we do about it?
◆ Mitigation
⧫ Try to make it stop or reverse it
⧫ Big reduction in emissions would require major
lifestyle changes in developed countries
◆ Adaptation
⧫ Try to live with it
⧫ Milder winters a good idea here?
⧫ Some islands already in trouble with sea level
rise
⧫ Will all life be able to adapt?
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Mitigation: Paris Agreement
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Finalized in 2016
◆ Reached at United Nations Climate Change
Summit in Paris
◆ Goal: Countries agree to limit GHG warming to
1.5°C above pre-industrial levels
Signers represent 97% of global emissions
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Why 1.5 degrees Celsius?
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It’s thought that an increase in excess of 2°C, or
3.6°F, will change the climate so dramatically that
neither humans nor natural ecosystems could
easily adapt.
What would 2°C of
warming look like?
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AHS 104 Day 42
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Climate “momentum”
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Even if human beings stopped emitting carbon
dioxide today, global temperatures would continue
to rise for many years (explore this in Lab 13)
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about 0.5°C of warming is “still in the pipeline”
(oceans store a lot of heat)
sea level rise will continue for centuries beyond 2100
because of ice-sheet melting and other causes.
The longer we wait to act, the harder it will be to
attain our goals.
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On some measures, Paris could be
judged a failure
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Emissions in 2019 were about 10% higher than
they were in 2015.
Limiting warming to 1.5°C looks unlikely.
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On the other hand,
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Countries representing
two-thirds of the global
economy have pledged to
reach net-zero carbon
emissions around midcentury
This could limit warming
to 1.8°C by 2100
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Carbon
“footprints”
Ireland
China, U.S. not
out of line per
person
Austria
New Zealand
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How to reach net-zero carbon emissions?
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One approach is renewable energy
“Carbon neutral” energy sources like wind, solar,
nuclear, biofuels, etc. will have to supply our future
energy needs.
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However, there is a long way to go!
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Another mitigation approach:
carbon capture
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Carbon dioxide (CO2)
capture and storage could
play an important role in
reducing greenhouse gas
emissions from power
plants and industry
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Mitigation: Geoengineering
Can planetary-scale “tinkering” help?
◼ One idea: injecting sulfate aerosols into the
stratosphere would cool the planet
◼ Do we have any evidence that aerosols
influence the climate?
◼ Yes, volcanic eruptions cool the climate
temporarily
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Geoengineering
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Such ideas merit increased research and
development, but they are far from ready to be
safely deployed at the scale necessary to combat
climate change, if ever.
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Option 2: Adaptation
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Try to live with it: keep in mind we’ve already
adapted to a 2°F increase
Easier in some places than others?
Projected by 2100
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Ethical issues
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People in developing world have had little role in
carbon emissions so far, but are likely to see
impacts in key areas such as agriculture and
freshwater availability.
Our generation is unlikely to see the most severe
impacts of climate change; it is future generations
who will see the greatest impacts of the carbon we
are emitting today.
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Need to Avoid:
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1. Hubris:
“That which we know is a little thing, that which we do
not know is immense.”
Pierre-Simon Laplace (c. 1814)
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2. Naïve, hysterical extrapolations
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Human ingenuity can solve problems but we don’t want to
make things worse by oversimplifying complex issues and
politicizing science, leading to poor policy choices
3. A rush to prematurely transform infrastructure to
unproven and unreliable energy sources.
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Bottom line:
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The climate system is complex
◆ predictions are associated with deep uncertainty
◆ attributing cause and effect is very difficult
We must proceed with prudence
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Our Home Planet
I hope you enjoyed the course!
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Question 1 (1 point)
Carbon-neutral or net-zero energy sources are sources like
solar power
wind power
hydroelectric power
all of the above
Question 2 (1 point) ✓ Saved
Which of the following is not a geoengineering fix to counter climate change?
change the amount of sunlight reaching Earth’s surface
alter the tilt of the Earth to promote cooler summers
remove carbon dioxide from the atmosphere and store it
Question 3 (1 point)
If we could somehow cease putting carbon dioxide into the atmosphere right now,
the average global temperature would immediately cool
the average global temperature would continue to warm for a time
carbon dioxide has no influence on global temperatures