The Breakthrough Energy Coalition

[Janx]

per NPR listening during drives into meetings this week during the big Paris conference...

It sounds like we are need to get to zero carbon emission by year X or things will be really bad. I'll trust that for the sake of talking about "how do we get there" and given that pollution is bad anyway.

Is it really feasible to get to zero actual carbon emission (nobody anywhere emits carbon)?

Or is it more feasible to reduce emissions, and develop atmospheric scrubbing technology that magically inhales carbon from the atmosphere and febreezes it.

How is the "next" energy technology actually going to have a zero carbon footprint? Somebody has to make it out of something and that something is likely to be dirty (like solar panel making)?

Is solar power (or something) going to get cheap enough where I can build it in my backyard for a few grand and it could power my home in Hotlandia with the AC running 24x7?

 

[tuxgeo]

As to "nobody anywhere emits carbon," we would all have to be dead for that to happen: exhaling carbon dioxide is how we get rid of the carbon we oxidize with our metabolism. (Plants breath in CO2 and breathe out O2; animals breathe in O2 and breathe out CO2.)

The best we could hope for is to approach net-carbon-zero emissions, but that's a shared target including the plants we have growing.

 

[Staffan]

Or is it more feasible to reduce emissions, and develop atmospheric scrubbing technology that magically inhales carbon from the atmosphere and febreezes it.

Unfortunately the laws of thermodynamics, bastards that they are, say that any process that scrubs CO2 will consume at least as much energy as the process that produced the CO2 in the first place.

I think one of the more feasible ways of scrubbing CO2 from the atmosphere, long term, would be to cut down a lot of trees without burning them. Use them to build stuff, or just bury them, and then grow more trees where the old ones stood, and then repeat the process. When growing, a tree extracts CO2 from the atmosphere and turns it into, well, a tree. When burned, or decomposed, the tree turns back into CO2. If you take the lumber out of the cycle, you also take the CO2 out of the cycle.

That's pretty much what oil and other fossil fuels are, after all - the remains of plants and other living stuff that got buried a long time ago, taking them out of the planetary life cycle. Now we're digging it up again and putting them back in.

 

[Umbran]

I think one of the more feasible ways of scrubbing CO2 from the atmosphere, long term, would be to cut down a lot of trees without burning them. Use them to build stuff, or just bury them, and then grow more trees where the old ones stood, and then repeat the process.

Unnecessary. We have clear-cut *loads* of land, removing trees from it. We just need to replant them. Expanding permanent forests creates a carbon sink without having to do anything with the logs.

And, of course, get the people who were doing the marginal agriculture on that land doing something else.

If you take the lumber out of the cycle, you also take the CO2 out of the cycle.

Yes, but note that the burying and building *also* uses energy. We'd be talking about doing so on global industrial scales - that's a lot of energy.

 

[Umbran]

As to "nobody anywhere emits carbon," we would all have to be dead for that to happen: exhaling carbon dioxide is how we get rid of the carbon we oxidize with our metabolism. (Plants breath in CO2 and breathe out O2; animals breathe in O2 and breathe out CO2.)

That's not really carbon emission, though, as far as the environment is concerned.

The best we could hope for is to approach net-carbon-zero emissions, but that's a shared target including the plants we have growing.

To be more clear. The Earth has a normal, natural, "carbon cycle". Plants take in carbon, and make more plant. We eat the plants, and eventually exhale the carbon, or the plants die and decay and carbon is released that way, and then plants take it back in to make more plants. In general, what gets released by biological processes gets taken up by biological processes, and we are balanced and fine. Anything that works within the natural carbon cycle is okay - if we can find a way to economically grow a plant, ferment that plant into alcohol, and burn that alcohol in car engines, and then grow more plants, for example, we are okay - so long as the carbon we release is from something growing that we regrow, we don't have issues.

The problem comes in releasing carbon that was locked away from the cycle long ago. What we need to do is stop burning fossil fuels. If you don't burn fossil fuels, everything else is in the carbon cycle, and you're okay.

Is it possible to stop burning fossil fuels? Yes. There are enough wind, solar, and hydroelectric sources for us to no longer emit carbon in our energy generation. Now, other forms of energy do have their own drawbacks - the batteries in electric cars, for example, pose a chemical pollution problem. But *ANYTHING* you do on the scale of the entire human population will have drawbacks. However, those drawbacks may be more manageable than baking the planet to a crisp.

And, ultimately, we will *have* to stop burning fossil fuels anyway. Even if it didn't cause warming, there's a finite supply - at some point, it would run out.

In theory, one can go one step better, and start removing carbon from the atmosphere, and lock it back into the ground. This is not easy to do in a way that we are sure that it won't leak out in some way or another, and it isn't cheap - in terms of energy, doing this is on the same order as *unburning* the coal and oil.

 

[Staffan]

Unnecessary. We have clear-cut *loads* of land, removing trees from it. We just need to replant them. Expanding permanent forests creates a carbon sink without having to do anything with the logs.

Not really. Old forests are more-or-less carbon neutral - sure, there's a lot of vegetation growing that sucks up CO2, but there's also a lot of vegetation dying and decomposing/being eaten, turning back into CO2.

The talk about rain forests as the "lungs of the Earth" is incorrect. The biggest CO2 consumer/O2 producer consists of algae and stuff in the oceans, where they live brief lives before dying and sinking to the bottom (possibly taking the path through the food chain to get there).

That said, it would certainly be more useful to grow trees and then actually use them for something rather than just burying them. And of course, planting new trees where the old ones stood.

 

[Umbran]

Not really. Old forests are more-or-less carbon neutral - sure, there's a lot of vegetation growing that sucks up CO2, but there's also a lot of vegetation dying and decomposing/being eaten, turning back into CO2.

The *new* forest we plant will suck up carbon.

 

[Janx]

The *new* forest we plant will suck up carbon.

Which is better (more efficient use per square foot or whatever): trees, millions of smaller plants like grass or algae for sucking up carbon?

In a similar note, remember how cow farts are supposed to be bad?

How come all the American Buffalo weren't a problem back then? (which having had this factoid checked recently, outnumbered all the current level of Cows)

 

[tomBitonti]

Interesting: The number of cows seems higher than the previous number of buffalo:

http://www.cattlerange.com/cattle-graphs/all-cattle-numbers.html

(about 90 million in the US in 2015)

And:

http://www.fws.gov/species/species_accounts/bio_buff.html

(estimates of between 30 and 75 million)

This has a discussion of methane production from ruminants:

http://animals.howstuffworks.com/mammals/methane-cow.htm

Thx!

TomB

 

[tomBitonti]

There seems to be a difference between grazing in the wild and grain feeding. From page two of http://animals.howstuffworks.com/mammals/methane-cow1.htm.

Why do cows and other ruminants produce methane?

With the development of large-scale agriculture in the mid-20th century, farming became a big business for some companies. Farms became consolidated into large enterprises with many thousands of animals across large acreages.

Initially, grazing areas were filled with a variety of grasses and flowers that grew naturally, offering a diverse diet for cows and other ruminants. However, in order to improve the efficiency of feeding livestock, many of these pastures became reseeded with perennial ryegrass. With the aid of artificial fertilizers, perennial ryegrass grows quickly and in huge quantities. The downside is that it lacks the nutritious content of other grasses and prevents more nutritious plants from growing. One commentator called it the "fast food" of grasses [Source: Guardian%20Unlimited">Guardian Unlimited].

This simple diet allows many cows to be fed, but it inhibits digestion. A perennial ryegrass diet also results in a significant number of weak and infertile cows, which have to be killed at a young age. This is where the methane comes in. The difficult-to-digest grass ferments in the cows' stomachs, where it interacts with microbes and produces gas. The exact details of the process are still being studied, and more information may allow scientists to reduce cows' methane output.

Thx!
TomB