The nut grafs in this Q-and-A piece are on page 2:
Is there some minimum EROI we need to have?Anybody who's followed the issue knows that Canada's tar sands are on the borderline of that 6:1 at best. It's more than global warming/climate change issues of this relatively dirty oil that's the problem. It's the amount of energy needed to extract them, and what sources are used for that energy, and then, how does THAT affect climate change as a sidebar.
Since everything we make depends on energy, you can't simply pay more and more and get enough to run society. At some energy return on investment—I'm guessing 5:1 or 6:1—it doesn't work anymore.
What happens when the EROI gets too low? What’s achievable at different EROIs?
If you've got an EROI of 1.1:1, you can pump the oil out of the ground and look at it. If you've got 1.2:1, you can refine it and look at it. At 1.3:1, you can move it to where you want it and look at it. We looked at the minimum EROI you need to drive a truck, and you need at least 3:1 at the wellhead. Now, if you want to put anything in the truck, like grain, you need to have an EROI of 5:1. And that includes the depreciation for the truck. But if you want to include the depreciation for the truck driver and the oil worker and the farmer, then you've got to support the families. And then you need an EROI of 7:1. And if you want education, you need 8:1 or 9:1. And if you want health care, you need 10:1 or 11:1.
But, it's more than "just" climate change. Author Mason Inman, in those nut grafs, also ties it to quality of life, and somewhat, if you will, to quantity of life.
On some things, increased efficiency will continue to help. But, recycling, like when that truck breaks down? That takes energy itself.
Meanwhile, in news more directly related to climate change greens have long touted the possibility of oceanic phytoplankton "eating" a fair share of our burgeoning carbon dioxide emissions.
Climate-related geoengineers then came up with the idea of seeding patches of ocean with microscopic iron to stimulate phytoplankton growth.
Then, nature provided a ready-made experiment.
Ash from the recently erupted Icelandic volcano Eyjafjallajökull provided enough iron to stimulate 2010 plankton growth in the North Atlantic the size of France or Texas.
But, the effect was short-lived and for a specific reason.
Unfortunately or fortunately, perhaps, the specificity of the reason could lead to further experimentation elsewhere.
The reason why it was short-lived is that the additional plankton quickly gobbled up oceanic nitrates.
So, the reason an experiment could be tried elsewhere is that our Big Ag produces a nitrate-laden "dead zone" every year just beyond the mouth of the Mississippi. On the other hand, what if this works and a huge bloom causes other problems? What if some of the plankton evolve into freshwater forms and start colonizing the river?
And, in the Southern Ocean, phytoplankton have reached their limits, it seems.