Comments on: The human footprint

By: Tom Yulsman

Tom Yulsman — Fri, 05 Nov 2010 20:11:00 +0000

John and Steve: The last time you guys went at it — and please understand that I respect you both! — the tit for tat went on for quite some time. Let’s have at it for a bit more but then move on. Fair enough? (I’m sure I’ll soon be writing another provocative piece that you can can come to rhetorical blows over!)

BTW: This post did have a bit of a message, but mostly it was meant to feature an awe-inspiring image. So be inspired!

By: John Zulauf

John Zulauf — Fri, 05 Nov 2010 19:26:58 +0000

@Steve: 1st — I’m still curious as to the source of the “AGW will prevent the next glacial period” claim. There’s still that big yellow thing in the sky, and if it decides to go a bit quieter… 2nd — I’m curious as to the source of the claim that current CO2 level and projections are enough to melt all of the non-floating ice (and as to the timeframe). The most recent information I’ve read is that just Greenland melting (7m) is a multimillenial process, even with worst case temperature rise. Also how many additional doublings of CO2 do you expect with non-renewables eventually running out?

In any case, I’d trade 200m SLR over even a single millenia vs. multiple millenia of 2km ice. You must own a really large snowblower if you don’t thing so… —

As for most of your list of potential disasters, there isn’t good peer reviewed concensus. Many of the most extreme claims come from the advocacy literature (and are self contradictory (i.e. mores storm vs. fewer storms, no more cold winters vs. more extreme winters).

I highly recommend Dr. Pielke Jr. website http://rogerpielkejr.blogspot.com/ where you can find in his archived articles critiques, and re-examination of a large number of these claims.

By: Steve Bloom

Steve Bloom — Fri, 05 Nov 2010 02:44:00 +0000

John, it must be nice to live in a world where you can be so confident that physical reality will arrange itself conveniently for humans, with SLR stopping neatly at 20 meters even though the 500+ ppm CO2 levels that are now pretty much inevitable are enough to melt all of the ice. (The Copenhagen Diagnosis is a good place for more on this.) Then there’s ocean acidification (models wrong yet again — see Tom’s recent post), drought overtaking many of the world’s most productive agricultural areas, increasingly severe storms, etc., etc., etc. Nope, no problem.

By: John Zulauf

John Zulauf — Thu, 04 Nov 2010 21:57:21 +0000

@Steve: re — glaciation, first I’m curious as to your source, second if true, then AGW is a very, very, good thing. I’ll trade 20m of sea level rise for 2km of ice anytime. While it would be expense and difficult to mitigate (mostly by migration) the worst case sea level rise, it’s *way* simpler than melting a glacier.

@Tom: Certainly we have to care for our world. We just disagree as to priorities and risks. Fair enough?

By: Tom Yulsman

Tom Yulsman — Thu, 04 Nov 2010 21:21:39 +0000

Spyder: Fabulous! Which comet is it?

Steve: I’ll take care of the image resolution issue in just a bit. I didn’t take it into Photoshop. I just grabbed the full resolution image from NASA. A mistake, I gather.

By: spyder

spyder — Thu, 04 Nov 2010 21:18:55 +0000

When the image first started to appear i thought you were going to do a piece on this image.

http://photojournal.jpl.nasa.gov/tiff/PIA13570.tif

Really quite stunning on its own, in terms of transportation of materials around the solar system.

By: Steve Bloom

Steve Bloom — Thu, 04 Nov 2010 21:11:32 +0000

Tom, the image seems to be very high-res, including on the front page, which makes for very slow loading.

John will doubtless be shocked when he finds out that the amount of CO2 in the atmosphere is already much higher than needed to block any resumption of glaciation.

By: Tom Yulsman

Tom Yulsman — Thu, 04 Nov 2010 17:10:03 +0000

John: Wow, this is terrific! And thank you for investing so much effort in adding some value to my post. I really appreciate it.

As for your point about what nature can and will do, this is undeniably true. But we humans probably can’t do anything about the next Toba event — or, closer to home, an explosion of the Yellowstone caldera. But we most definitely CAN do something about our own impact on the life support systems of the planet.

The real but exceedingly low probability of a civilization-ending eruption does not diminish in any way the much greater chances that we will cause significant problems for ourselves, including sea level rise. These issues may not be a cataclysmic from a planetary perspective, but they could be very problematic for civilization.

By: John Zulauf

John Zulauf — Thu, 04 Nov 2010 15:56:01 +0000

I remember seeing a scale diagram of low-earth orbit an thinking “that’s very low and very close.” Orbit is closer to me that Portland to Seattle. At the lowest bound it’s a mere 2.5% of the the Earth’s radius (160km orbit vs. a 6370km radius), much less than the difference between a yardstick and a meterstick to scale.

However, the perception belies the true scale. You are looking at two massive things with small relative differences and perceiving small absolute sizes. Mt Everest extends up 5.5% of distance to orbit, and only .14% of the Earth’s diameter (.5mm if the Earth were a regulation basketball). On this “comparison of large things” scale, Everest is vanishing small — the atmosphere, well “it’s wafer thin.”

Humans have had impact on our planet and have a responsibility to care for it to be sure. Our impact is still far less (by orders or magnitude) than what nature can and *will* do (the next glacial period, the next Toba event, the next “dinosaur killer”). Perspective for assessing risk is important and human frontal lobes are bad at this scale.