Climates of Hunger

That was the title of a book I read in the late 70s.  Its thesis was that the current warm climate, so conducive to agriculture, is a rarity over the history of the planet.  Most of the record shows the planet in an ice age, with the interglacial periods lasting about ten thousand years.

 

Our current interglacial period started....

...about ten thousand years ago.

 

I still have this book somewhere in my library.

 

Now, from the Foresight Institute, we have some charts:

 

The first one, calculating temperature from oxygen isotope ratios in snow, shows a definite hockey stick:

 

 

A larger scale chart, showing the beginning of the current interglacial period, gives us a nice bit of perspective:

 

 

For longer-term perspective, though, one has to use other ice cores.  Here's one from Vostok, Antarctica:

 

 

And thus, the basic premise of "Climates of Hunger". For most of the history we can access, the planet has been considerably less conducive to agriculture.  And that may be what we're heading for in the next century or two.