Energy and Human Ambitions on a Finite Planet, 2021a

9 Climate Change 162
forcing is 3 × 10 22 J per year. How much would the temperature of
the top 10 m of ocean rise in one year at this level?
29. If we somehow maintained a steady 2 × 10 22 J/yr of unbalanced
input indefinitely, how long would it take to:
a) raise the entire ocean temperature by 1 ◦ C?
b) melt all the ice?
c) raise the entire atmosphere’s temperature by 1 ◦ C?
d) heat up the top 100 m of earth’s l<strong>and</strong> area?
The sum of all these is how long it would take to get all of these
tasks done, even though they would be happening in parallel.
i In practice, this is not how things will
go. The ocean will heat up more near the
surface, allowing air to get hotter <strong>and</strong> ice to
melt faster while the deep ocean stubbornly
resists warming for centuries.
30. On a planet 60% covered in ocean, <strong>and</strong> 5% covered ina3kmthick
ice sheet on top of l<strong>and</strong>, how much would the sea level rise if all
the ice melted?
31. On a planet two-thirds covered in ocean, <strong>and</strong> 1% covered by an
ice sheet melting at a rate of 1 meter per year, how fast would sea
level be rising?
32. How might you express the tradeoffs between the available fossil
fuel resource <strong>and</strong> climate change? In other words, if it turns out
that we don’t have nearly as much fossil fuel as we think, what
does this mean for climate change vs. our economic/geopolitical
stability <strong>and</strong> viability? On the other h<strong>and</strong>, if we have centuries
of fossil fuels left, what does that mean? Which scenario is least
disruptive?
33. If it were certain that the only way to provide a comfortable existence
to future generations involved substantial cutbacks toward a
lifestyle having far fewer energy <strong>and</strong> material comforts today, do
you think humanity would voluntarily do so? Can we leave treats
on the shelf, within easy reach? If so, is it only uncertainty that
prevents us? If not, what do you see as the barriers?
© 2021 T. W. Murphy, Jr.; Creative Commons Attribution-NonCommercial 4.0 International Lic.;
Freely available at: https://escholarship.org/uc/energy_ambitions.