Senators John Kerry (D-Mass.) and Joseph Lieberman (I-Conn.) introduced their long-awaited climate bill in the Senate this week, where it faces uncertain prospects. Rather than speculating about the bill's future, let's take a far longer view for a moment. What would America's First Congress have said about climate change?
You've heard all the dire scenarios before: by 2100, unabated climate change would likely mean widespread floods, droughts, and heat waves, with cities under water due to sea level rise. But how is any person or nation expected to factor consequences 90 years from now into decisions that must be made today? Not to mention consequences that may not occur until several hundred years from now.
Most scientific analyses of climate change don't go beyond 2100, which ignores the likelihood of further warming even without continuing carbon pollution - due to momentum and feedbacks in the climate system.
A new study [subs. req'd] published in the Proceedings of the National Academies of Science (PNAS) this week takes the longer perspective. Scientists Steven Sherwood and Matthew Huber of the University of New South Wales and Purdue University estimate a nontrivial chance that by 2300, if most or all fossil fuel reserves are burned, warming could bring heat waves that would literally be unsurvivable outdoors or without air conditioning. Shade, fans and water would not be enough for people to cope.
Widespread areas would experience such conditions, including lands home to the majority of the world's population today, effectively rendering them uninhabitable.
In other research [subs. req'd], while scientists project sea levels to rise three to six feet this century, the warming likely to occur during the same period threatens to lock in several times more over the next few hundred years, as ice sheets continue to disintegrate.
But if 2100 is hard to grasp, how do we even begin to contemplate these longer-term risks?
Back to the future
For me, it actually helps to look backwards. The time of the American Revolution is about as far behind us as the 23rd century is ahead of us. It happened a long time ago - but not so long that we have any trouble remembering it in our history books, parks and museums. Now imagine that warming progresses backward in time from the present, instead of forward. How would history have been different?
George Washington and his troops would never have frozen during the winter at Valley Forge. Their biggest problem? Probably yellow fever. And they might have had to soak in the Delaware River just to survive a hot day or two - provided they could dodge the alligators.
Now let's take just one more leap of imagination. Suppose the 18th century climate was exactly as history books describe it - but that Benjamin Franklin, among his other scientific achievements, somehow figured out the relationship between carbon dioxide and climate change. Say that in 1789 he went before the First Congress to describe a world that would warm beyond recognition by 2010 if coal burning were to proceed unabated.
Would they have listened to him?
It might be useful to consider that scenario as we watch the current Congress debate what to do about emissions today.