One of the most fascinating aspects of astronomy is learning exactly when the light from stars that you might have seen last night actually left the source. For example, light that departed from Alpha Centauri at the time when Barack Obama was fighting Hillary Clinton for the Democratic nomination only just now arrived.
Likewise, it appears as if the climate change we’re experiencing today is the result of emissions from 20 or 30 years ago.
One of the most salient—but also, unfortunately, most counterintuitive—aspects of global warming is that it operates on what amounts to a time delay. Behind this summer’s heat are greenhouse gases emitted decades ago. Before many effects of today’s emissions are felt, it will be time for the Summer Olympics of 2048. (Scientists refer to this as the “commitment to warming.”) What’s at stake is where things go from there. It is quite possible that by the end of the century we could, without even really trying, engineer the return of the sort of climate that hasn’t been seen on earth since the Eocene, some fifty million years ago.
Oh. Is that all?