climate change

Issues like climate change and sustainability were a major theme in this year's Aspen Ideas Festival, which concluded in early July.

Aspen sang this year with pleas for the next president to make climate change --and the protection of dwindling resources -- the centerpiece of his foreign policy, thus fusing in a very concrete way America's national interest with that of the wider world. There was clearly a yearning for a new, more elevated brand of American patriotism that co-opted these global issues as national security interests - which indeed they are. Americans have always been a people of the frontier, and just as civil rights constituted a new frontier of enlightened patriotism in the 1960s, tackling environmental challenges looks like the new frontier of this and future decades.

New research into the ancient climate of the Sahara shows that the region went from lush and wet to dry and desolate within a few thousand years.

The classic evidence for a wet Sahara comes from the Tassili frescoes, a series of fifty Algerian cave paintings that depict humans living with crocodiles, buffalo, giraffes, and other animals that do not thrive in arid climates. Ten thousand years ago, it appears, our ancestors could have grown rice in the Sahara, or spent their weekends Jet-Skiing at their North African lake-houses. For millennia, they had no reason to fear their water running out, or their settlements' being reclaimed by desert sands, or of water running out. What the new reports about this bizarre climatological period don't much emphasize, though, is that the Sahara was wet during a period of comparative global heat, and that it became parched only as the planet chilled.