“At the end of the day, the biggest source of uncertainty is still the emissions. It’s the human element in all of this.”
The speaker of those words taken from this month’s Yale Climate Connections “This is Not Cool” video, is Rob DeConto, PhD, of the University of Massachusetts.
He’s speaking specifically about the future of global sea-level rise in a warming world. It’s a point others have made in the context of climate change generally, and also in the context of other projected adverse impacts: How much and how soon? Many physical scientists agree: Despite a plethora of real and imagined uncertainties in the context of climate change, the one that’s perhaps most befuddling and most unresolved is how humans will act and how and when their policy makers in the U.S. and internationally may take action.
The video can serve as a valuable instructional tool for those wanting to better explain or understand global sea-level rise trends and prospects. There are some painful, and even dire, concerns expressed about the potential that Greenland ice sheets could be “entirely lost” if emissions continue at a business-as-usual pace; about the rate of sea-level rise increasing “faster and faster with time”; and about the planet’s ice sheets likely becoming “more active” over coming decades than they have been over recent decades.
But scientist Eric Rignot, PhD, of the NASA Jet Propulsion Laboratory, whose research about three years ago pointed to bleak long-term glacier melt prospects for the western Antarctica, says he holds out hope for some “pretty good news.”
Rignot says that some took from his earlier research that “we’re doomed. There’s nothing we can do about it, so why even bother?”
Not necessarily, Rignot says. “There’s still a lot of things we can do” if the planet can be kept cooler than the 1.5- to 2-degree Centigrade increase targeted in the 2015 Paris climate agreement. Seeking to now provide “a little bit of balance to this concept of unstoppable retreat” of the Antarctic ice sheet, Rignot clings to hope the global community can “actually, possibly, prevent some of the big ice sheets” from inevitably melting.
Again, it all comes back to that precaution from DeConto: the greatest uncertainties involve “the human element” and humans’ continued emissions.