There is much to be desired in the mainstream media’s coverage of energy politics and climate change, but perhaps the single most important fact that gets consistently overlooked—that is scarcely apprehended by the general public and yet comes to mind for me every time a new pipeline or oil field gets approved—is that greenhouse-driven warming operates on an extremely delayed timescale. As with several aspects of climate science, that timescale is impossible to deduce with perfect accuracy, but NASA climatologist James Hansen estimates that only 60 percent of the final climatic response to a rise in greenhouse gas (GHG) occurs over the course of a century.
This leaves us with the daunting reality that the increasing intensity of heat waves, storms, and ecological disruption that have been associated with rising temperatures can be attributed simply to the elevated levels of greenhouse gases emitted by the mid-20th century, or perhaps even earlier. Even if GHG emissions—which, mind you, have tripled since the mid-sixties—were to halt today, the climate will nonetheless continue to warm for hundreds and by some estimates thousands of years into the future. We have only quite recently reached a CO2 concentration of 400 ppm, (that’s up from under 320 ppm in 1960,) but we do not yet know what a 400 ppm atmosphere really looks like. Whereas we often assume that we are experiencing climate change in real time, we are in fact experiencing a climate augmented by previous generations, while we augment it even further for the next ones. There is, in other words, no automatic system of justice or accountability built into the Earth’s climate.