The Doomsday Scientist

A few days ago I was watching the National Geographic Explorer TV channel and a program was on about global warming/climate change, hosted by Bill Nye (the Science Guy).  I think it was just a year old, so we're talking pretty recently.  Toward the end of the show he interviewed a University of Arizona ecologist named Guy McPherson, who predicted that there will be no more human life on Earth by the year 2030.  Yes, that's what he said...we'll be extinct by then, and it will be due to the cascading effects of human civilization-caused superheating of the planet from built-up carbon dioxide as well as methane gas.  The seas will become lifeless and the oxygen will disappear from the atmosphere.  McPherson didn't explain all of his reasoning to Nye, but I did look him up on Wikipedia and saw his blog page, which goes into much greater detail about his somber conclusion on humanity in the near future...

In looking at the current situation we have with increasing carbon dioxide levels in the atmosphere, McPherson decided to investigate the Great Permian Mass-Extinction of 250 million years ago, when almost all life on Earth was obliterated.  The trigger event for this seems to have been the eruption of massive super-volcanos in what is now Siberia, causing fires over the area and smoke and ashes surrounding the planet.  But the fires then ignited the masses of coal deposits underneath the surface, and Earth went into a long-term greenhouse effect with mass releases into the atmosphere of methane gas, much more potent in its greenhouse effect than CO2.  The oceans and the atmosphere were starved of oxygen and nearly all of the animal and plant species on Earth became extinct.  Now that process back then, as McPherson recognizes, took place over a much longer time span than the global warming going on in our time.  But in both cases, he emphasizes the concept of "self-enforcing feedback loops" that accelerated the process back then and now as well.  For example, global warming melts ice in the far north, but that ice melting exposes holes in the Earth where large methane deposits have been held dormant for millions of years.  Now they are being released into the atmosphere and speeding up the heating.  The more the heating, the faster the methane is exposed and released, which speeds up the heating further...

Guy McPherson does not place much hope in the efforts taken today to restrain carbon emissions, and he thinks a carbon tax is ridiculous.  No, he believes we have already gone too far, and this process leading ultimately to his predicted doom in the too-near future began with human civilization thousands of years ago with the advent of agriculture...

I just heard about this guy last week and already the world's coming to an end?  Uh, please give me a little more time to ingest this!  But McPherson does seem to have his own following, a growing doomsday cult if you will.  His conclusions show to me how someone, if they package their theories in a compelling manner, can pretty much sell anything.  Listen to the folks who are global warming deniers: some of them sound pretty convincing, too.  Look, if we're all perishing in fifteen years anyway, it won't matter, in terms of our habitat on Earth, what I do now with my time or "carbon footprint", and if there is no human-induced climate change, the same is also true.  So in a perverse sort of way, Guy McPherson, with his presentation of impending and certain human extinction, is making the point for folks who want to just forget about climate change and do whatever they want with the environment, for better or...more likely...for worse...

Snowball Earth, Among Other Prehistoric Disasters

I've always been interested in the origins and development of the Earth, both in its geological context and in that of the evolution of life.  I am also a subscriber to Netflix, at least the streaming Netflix which much too often comes up severely lacking with its offerings of movies and shows.  This time around, though, I found on it a four-part television series titled Prehistoric Disasters that explored the Earth's distant past through four key disasters that struck it over the eons.

The four "disasters" were the formation of the Moon through the collision between early Earth and a minor planet, the 25-million year long lapse into a completely ice-packed "snowball" status covering the entire globe some 650 million years ago, the eruption of a supervolcano in what is now Siberia causing a chain of events leading to excessive global warming and mass extinctions 250 million years ago, and the hypothesized collision of an asteroid with Earth about 63 million years ago causing the end of the age of the dinosaurs.  I was especially interested in that strange "snowball Earth"...

Earth throughout its span of existence has gone through an extensive cycle of ice ages, when ice glaciers would flow far south of the polar regions and into more normally temperate climate zones.  But 650 million years ago the ice passed a threshold of latitude and went on to cover the planet with ice, and very thick ice at that (several hundred meters).  The cause: depletion of carbon dioxide in the atmosphere due to loss of this gas as it combined with solid material through excessive weathering from the then-single, huge continental mass lying on the equator and then settled on the sea bottom, far away from the atmosphere.  The advance of the ice sped up the process of global cooling because the ice's reflectivity of sunlight was much higher than the liquid ocean's, sending the sun's heat back out into space instead of absorbing it into the Earth.  Life at that time, for billions of years ongoing as a matter of fact, was composed of unicellular organisms, mainly bacteria.  Nearly all of the species died out, leaving only those few that could adapt through evolution.  After the ice cover eventually receded from the heat generated by massive volcanic eruptions 25 million years later, life began evolving rapidly into more complex forms...but only after the "snowball" period.

By all accounts, the "snowball" period in our planet's past was a singular, nonrepeating event.  That bothers me a little and keeps me from completely accepting it, even though there seems to be empirical evidence that it occurred.  I would have expected at least of handful of other "snowballs", too, in the records.  But if it was truly the only time that Earth was completely encased in thick, thick ice...and for millions of years at that, then to me this has to be the most incredible period of its past.