What do you think?
Rate this book


152 pages, Paperback
First published May 27, 2016

As I will explain shortly, the glaciers are still due to advance once again and we should expect our planet to be plunged into bitter cold within the next 10,000 years.
A few geologists continue to speak as if they expect Earth to proceed into the next glacial cycle, just as it would have if humans were not around. That glacial period would begin with an ice sheet developing and growing in northern Canada. But why would we allow such an ice sheet to grow, and flow, and eventually crush major cities, when we could prevent it with the greenhouse gases from a single chlorofluorocarbon factory? Humans are now “in charge” of future climate. It is a trivial task to avoid the negative net climate forcing that would push the planet into an ice age (moving conditions toward the left in figure 30). But it is not an easy task to find a way to stop the growth of atmospheric greenhouse gases, most notably carbon dioxide (which moves conditions toward the right in figure 30), as we have been discussing.
Global mean flux of less than 90 mw/m^2 is minuscule in comparison with the mean insolation of about 170 w/m^2...How does this matter? When discussing supervolcanoes, McGuire writes as if humans will forever be as powerless to stop them as our primitive ancestors were. But given the many thousands of years that might elapse between successive eruptions of a supervolcano, a technologically superior civilization should have plenty of time to extract geothermal energy from slowly upwelling magma before it can melt vertical kilometers of crustal rock above it all the way to the surface and erupt. If clever future humans can extract heat as fast as a rising magma plume supplies it, the plume should remain safely capped. Today's humans might have trouble pulling this off, but it should be easier than solving the human-caused global warming that looks set to wipe us out first.