Friday, August 7, 2015

MIT: western deserts dried out quickly; human impact chicken or egg?

The results of a trophic cascade likely triggered, or at least exacerbated, by humans in North America during the end of the last ice age are being explored in caves in the American West.
David McGee, the Kerr-McGee Career Development Assistant Professor in MIT’s Department of Earth, Atmospheric and Planetary Sciences, says the results suggest that around 8,200 years ago, the climate of the American West began transitioning from a lush landscape to the desert terrain that we know today. On a geological timescale, McGee says the region’s moisture content appears to have dropped rather suddenly — “like falling off a shelf,” he says. This steep drop likely had a dramatic impact on humans living in the region.
“Based upon these data, I would hypothesize that you should see some pretty big changes in how people were living just before and right after 8,000 years ago,” McGee says. “What sort of game were they hunting, what plants were they eating, and where were they choosing to live? Montana’s going to start looking pretty good if the Great Basin is drying out. ”
“One of the big things that was happening at this time worldwide was the collapse of the last vestiges of this big ice sheet in Canada,” McGee says. “An ice sheet is thought to have important effects on where the jet stream goes. By having this ice sheet here, it made it so the jet stream was more likely to bring storms into the American West, and when it collapsed, the region became more like it is today.” [excerpt, Research suggests western U.S. deserts were relatively wet up until 8,200 years ago]
Evidence that humans have eaten or burned themselves out of habitats creating desertification behind them is strewn throughout the continent.

Is it too late for Earth? Have we reached Peak Human?

Should Liberals just say: "to Hell with biodiversity" and join the earth haters in a final orgy of death, consumption and/or prayer?

Coexist or kill them all and let Goddess sort 'em out?

Mary Hoff asks Johan Rockstrom in the Utne Reader: "What would it take? Why do we need to think about protecting Earth’s systems from catastrophic failure?"
The evidence shows that we may have entered a whole new geological epoch, the Anthropocene, where humans constitute the main geological force changing planet Earth. The planetary boundaries framework was developed to address this new reality. The second is the risk of nonlinear change, which comes out of resilience theory and from empirical evidence that particular ecosystems have multiple stable states. But there is a big “but”: And the big but is, have we already gone too far? And that we simply don’t know yet.
From a post by Alex Reshanov at EarthSky:
All this shifting meat consumption is a concern because, despite our middling trophic level, we’re quite good at sucking up resources. According to the study, humans use 25% of the net primary production (that finite amount of [planetary] energy we discussed earlier), and food production accounts for 35-40% of that allocation. Given that agriculture isn’t even our only drain on global resources, the fact that we’re not at the top of the food chain is probably a good thing. [Reshanov, Humans aren't top predators, says report]
At a meeting of the American Geophysical Union, scientists, Brad Werner among them, asked a question: “Is Earth Fucked?”
Why shout out the blunt question on everyone’s mind? Werner explained at the outset of the presentation that it was inspired by friends who are depressed about the future of the planet. “Not so much depressed about all the good science that’s being done all over the world—a lot of it being presented here—about what the future holds,” he clarified, “but by the seeming inability to respond appropriately to it.” Resistance, Werner argued, is the wild card that can force dominant systems such as our current resource-chewing juggernaut onto a more sustainable path. Werner hasn’t completed that part of his model, so we’ll have to wait to find out what happens.--Jonathan Mingle, Slate
Japan's flat economic growth means she is consuming resources at slower rates and other nations haven't figured out how to do it yet.

Legalize automatic weapons and end restrictions on the sale and possession of rocket propelled grenade launchers now.

Let's get it over with. Let the carnage begin.

Rewild the West.

And now, a public service announcement.

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