thoughts on runaway climate change

This morning on the subway, I was so deep in thought about climate change that I missed my stop. Specifically, I can't stop thinking about a Letterman video I watched a couple of days ago and a graph I saw this morning.

First, the Letterman video. The basic message, presented with classic Letterman deadpanning, is, "We're Doomed."

While I appreciate the attention given to global climate change, and I do enjoy the humor, I generally prefer a more optimistic approach to problem solving...

...But then I saw this graph, from the Global Carbon Project, showing the updated trend of global carbon emissions from fossil fuels:

(As reported on Climate Progress and Climate Feedback.)

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Update: the data in this graph just made the front page of CNN: Carbon Dioxide Output Jumps to Record Level.
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The data in this graph is terrifying, and it's not just because the trend is going the wrong way (increasing as opposed to decreasing). It's terrifying because actual emissions are outpacing assumed emissions even under the IPCC's "worst case scenario" (actual growth has been 3.5% per year since 2000 as opposed to projected 2.7%). Even without these "extra" emissions, though, the effects of climate change are already being seen much earlier than anticipated by climate models (example: the faster than expected melting of Arctic sea ice). This is principally because the climate models underestimate the effects of certain feedback mechanisms that accelerate warming. A classic example is the fact that as Arctic sea ice melts, it reveals more dark ocean, which absorbs solar radiation more than reflective white ice; this absorption causes the earth to warm faster, which melts more ice, revealing more dark ocean, further perpetuating the cycle.

So then back to Letterman's "It's too late" argument. Though the optimist in me rejects the conclusion, there are days (like today) in which the cynical side of me looks at the data, recognizes how little progress we have made in the fight against global climate change, considers the challenges ahead towards even just slowing the growth in greenhouse gas emissions (not to mention reducing them!), and thinks, How are ever going to do this?

Lastly, the following animation, "Wake Up, Freak Out - then Get a Grip," does a good job describing the "tipping point" of the earth's climate system, beyond which catastrophic changes are inevitable:

(Note: I think the second half of the video is a little too apocalyptic, which I think undermines his conclusion that it's not too late, but nonetheless the first half is quite good.)