He urged governments to use his policies of “perestroika” (restructuring) and “glasnost” (openness) — which ushered in democratic changes that led against his will to the collapse of the Soviet Union — to address climate change and overconsumption of resources.
Because the Soviet Union and the Warsaw Pact nations were such paragons of environmental stewardship and high standards of living.
From all historical evidence, it appears that crying doom is highly sustainable.