I WAS texting a museum director friend in Asia recently. We were discussing whether a trip to this year’s “artworld Olympics,” the Venice Biennale, justified the carbon release.I felt ambivalent. The main exhibition is curated by Koyo Kouoh, whose 2016 edition of Ireland’s Biennale, EVA International, on the 1916 Easter Rising centennial I had admired. Kouoh died of cancer earlier this year. Her posthumously realised Venice Biennale, titled In Minor Keys, seemed a final opportunity to appreciate the subtle, intelligent work of Africa’s leading curator.