An environmental catastrophe....

....................is likely in our future.  As a betting man, I would wager a large sum that it won't be man-made:

     In about 2200 B.C., a major volcanic eruption somewhere far to the north spewed enormous quantities of fine ash into the atmosphere.  If historic eruptions are any yardstick, the debris veiled the sun for months on end, bringing unseasonal cold.  Unfortunately for Ur's lords, the eruption coincided with the beginning of a 278-year drought cycle that affected huge areas of the eastern Mediterranean world and is clearly visible in ice cores from the Greenland ice sheet and the high Andes.  With catastrophic abruptness, the moist Mediterranean westerlies faltered.  Winter rainfall plummeted.  The Euphrates and Tigris floods, starved of rain and snowfall in the distant Anatolian highlands, failed as well.
     The drought turned the once-fertile northern Habur plains by the Euphrates into a near desert.

-Brian Fagan,  The Long Summer:  How Climate Changed Civilization