Part of what alarms his critics is how un-alarmist his conclusions have turned out to be. For example, instead of using policy to change how people will behave in the future, Ausubel prefers exploring technological responses to what he believes people are going to do regardless. His favorite defense of this laissez-faire approach is to explain that, absent any policy dictating that it should happen, energy consumption over the past 100 years has steadily "decarbonized." That is, humankind has moved to fuel sources with progressively better ratios of carbon atoms to hydrogen atoms—wood at 10:1, coal at 2:1, oil at 1:2, natural gas at 1:4 and, eventually (in the future Ausubel envisions) 100 percent hydrogen. He thinks technology inevitably improves things. "That's not to say I don't worry about the downsides of technology," he says. "A lot of my work is about that. But my general interest is new and high-tech ways of dealing with problems."