Climate, Crisis and Time

NPR's Ira Flatow interviewed a group of prominent American climate scientists on Friday.  Radio interviews have their disadvantages: they can hop from brief answer on one topic to brief answer on another topic without the necessary length and depth on each.  But they also can have the salutary effect of getting experts to say things plainly and succinctly, especially in answer to pertinent questions we'd all like to ask.

Here's one such exchange, between Flatow and the very prominent climate scientist, Michael Mann:

FLATOW: So we are set on some kind of climate change course that is irreversible at this point?

MANN: Well, we're committed to a certain amount of additional warming of the globe. We've already warmed a little under one degree Celsius. We're probably committed to at least another half a degree Celsius just because of the heating that we've already put in the pipeline. So that means that we don't have a whole lot of wiggle room if we're going to avoid two degree Celsius warming of the globe relative to pre-industrial time, that's three and a half degrees Fahrenheit.

That's what most scientists who study climate change impacts say is sort of where we enter into the red zone, the danger zone, where we start to see some of the most severe impacts of climate change play out.

FLATOW: And what time, what part of the century might that happen?

MANN: Well, we only, as it turns out, have a matter of a few years to bring our global carbon emissions to a peak and begin to ramp them down pretty dramatically if we are going to avoid crossing a threshold in terms of the concentration of CO2 in the atmosphere where we are committed to that warming. So there is still time to avoid that dangerous threshold, but there isn't a whole lot of time. There's an urgency to the problem."

Flatow then goes immediately to the extent of the problem, which emphasizes its urgency:


FLATOW: Are these future projections of four to five degrees Celsius, are they averages for the planet, the entire planet, the land surfaces, just which parts?

MANN: Sure, yeah, in the event where we basically pursue business as usual, where we don't enact any policies to bring down our carbon emissions, we're probably committed to somewhere between four and five degrees Celsius, that's seven to nine degrees Fahrenheit, warming of the globe by the end of this century.

That is just a global average. It turns out that the land warms faster than the ocean. So we'll see more warming than that where we live, on continents. And in the Arctic, we'll probably see twice that much warming. So if you're worried about the shrinking polar icecap, if you're worried about the Greenland ice sheet and the potential destabilization of that ice sheet and the associated sea-level rise that would come from that, we are headed on a course where we will see those things play out if we don't enact some changes now."

As other guests join in, the conversation turns to China and its aggressive, huge but schizophrenic energy policy.  I'll save that part of the interview for another time, or...you can just follow the link to the source.