Massive tsunamis.  Sinking cities.  Mass hunger, limited food, uninhabitable climates and the devastation of the earth’s most productive biomes.  These are what Mark Lynas predicts for an earth that is just an average of 6 degrees Celsius warmer, in his new book Six Degrees.  What is so scary is that, according to the UN Intergovernmental Panel on Climate Change (IPCC), a six degree increase in global temperature is possible within the next century (albeit, it is on the high end of estimates).

In a slew of research, Lynas charts, apocalyptically, the path the earth will take if current trends in carbon dioxide emissions continue.  One degree at a time, gradually, the natural mechanisms that keep the world’s climate in place, the subtle changes in tropical temperatures, ocean temperatures, rainfall and polar melting will send the weather into overdrive.  Massive hurricanes like Hurricane Katrina will be small compared to the “hyperstorms” expected by mid-century.  Wide food shortages are to be expected, as the world’s agricultural centers in North America and South Asia will become dryer and less arable, and many agricultural operations will be aborted by soil acidity from rising oceans.  Mountain glaciers, which serve as hearts to great river arteries which provide water to the some of the world’s biggest cities–Lima, Peru and Karachi, Pakistan among them–will melt, leaving millions of people without drinking water and looking for somewhere to live.  As the polar ice caps melt, faster each decade due to a positive ice albedo feedback, ocean levels will rise, and costal cities–most of the world’s cities–will be in a situation similar to New Orleans the past century.  Capable of saving the city, yes, but incapable of preventing a storm from breeching the levies.

The scariest prospect of a warmer future is the massive migrations that will be taking place, and accompanied with food shortages, the political extremism that is bound to occur.  Millions of Africans, looking for food after their already paltry agricultural supply goes dry, will want entry into more developed nations, whose technology might have their people living large for many years to come.  Of course, more immigration means more discrimination, more marginalization.  “Climate revolutionaries” will blame industrial nations for their role in causing their suffering, and some of these climate revolutionaries in some of the worst hit nations–India and Pakistan to be precise–will be armed with nuclear weapons and will be under political pressure to use them.

Six Degrees is indeed apocalyptic, but it does not seem entirely exaggerated.  With even one degree of warming, something that almost unanimously scientists agree will be reached by mid-century, changes in climate will make ocean waters rise, and storms will intensify.  Warmer oceans do not absorb oxygen as well, and thus the oceans, the home of millions of phytoplankton (source of one half of all the world’s primary photosynthesizing biomass) will become devoid of a necessary ingredient to life.  With carbon dioxide-absorbing phytoplankton dying, it is only a matter of time before carbon dioxide in the atmosphere increases, and the cycle starts to feed on itself.

But, on the bright side, best case humans will be living on Mars by then, and everyone will be able to generate their own food using Star Trek-style replicators, and everything will be dandy.  Of course, worst case, as people start tearing apart every building looking for food, there’s little chance scientists and teachers and even governments will be able to operate, meaning the progress of technology will slow to a stop and we’ll enter the dark ages.  But at least we’ll be alive, right?  Well, given the exponential destruction of species in tropical rainforests and the extent to which our food chain is becoming killed from the bottom up, that doesn’t even seem to be very likely.

What is scary to me is that in my lifetime, I might actually see some of the greatest cities this world has ever known swallowed up by the oceans.  In the meantime, the world will be consumed by political extremism and worse, religious fanaticism.

It’s dangerous to jump to conclusions, and worse of all, to throw millions of dollars into solving the wrong problem (we don’t even know if it can be solved).  But major science is needed right now to develop clean energy alternatives that are cost competitive with fossil fuels, which futurist Ray Kurzweil sees happening in the next 20 years.  Carbon fuel sources have to be replaced eventually, and ways of sucking up the excess carbon dioxide have to be developed.

I think that this book should be read by anyone interested in the long-term, and short-term, effects of climate change.  Even if it seems a bit exaggerated, it is certainly worth contemplating what could happen to the planet–and the human species–if current warming trends continue.

And as for the politics of the matter, I don’t really get if it’s worth debating who is causing the problem.  Even if the problem isn’t caused by humans, isn’t it still worth trying to solve?  Our very species, after all, may be at stake.