Earlier quoted context omitted.
Most of your partial solutions depend on 'mere engineering' on a scale that has never been attempted before.
Sure but I think climate change is just one of many variables that show how our global society is fragile - the direction of my proposal would go a long way towards making it much more robust, isolation from climate change is just one problem solved by it. It becomes easy to quarantine/filter access preventing biological contamination. Even on city level you can have isolated blocks further limiting the impact of cat…
Thousands of underground gas bubbles poised to 'explode' in Arctic
141–150 of 384 posts
Re: Thousands of underground gas bubbles poised to 'explode' in Arctic
#142Earlier quoted context omitted.
When you look at the many different potential sources of, "Fucked... goodbye..." the trend is very clear. We're juggling apocalypses and just waiting to find one that will stick. Will it be ocean acidification first? Ocean levels rising? Catastrophic weather patterns? Famine? Drought? War touched off by rapid changed? Mass extinctions? They're all in play, each with the potential to end us.
Is this why we have not yet found signs of intelligent life in the universe? Every time a civilization is advanced enough to really screw up (their) planet, inevitably, they do? Fermi Paradox redux.
Re: Thousands of underground gas bubbles poised to 'explode' in Arctic
#143Earlier quoted context omitted.
If we can't figure out an engineering solution to this problem then it's game over. It always amazes me how much people and governments focus on prevention when it comes to climate change, knowing full well it's far too late to change anything by reducing carbon emissions. If we can't sequester these 'surplus' gases from the atmosphere then I guess you could say we don't have a chance in hell, pun intended, of surviv…
Yeah, exponentials are tricky. By the time danger is clear, it's too late to do anything about it. But hey, at least this will probably be self-limiting. Disruption will arguably reduce population and industrialization, and so CO2 emissions will drop.
Re: Thousands of underground gas bubbles poised to 'explode' in Arctic
#144Re: Thousands of underground gas bubbles poised to 'explode' in Arctic
#145Earlier quoted context omitted.
Methane has a short ~5-10 year half life in the atmosphere. So, releasing 50x current methane levels over 100 years does not triple current methane levels.
Where did you get that? Every link I've ever seen indicates that the half-life is 7-9 years. Regardless of what the half-life is, what you say is true about the concentration of methane. It is so much better at trapping heat than carbon dioxide, though, that even over a 100 year time frame, it will warm the earth 34 times more than carbon dioxide would. ( https://www.epa.gov/ghgemissions/understanding-global-warmin..…
So if you use 34x that 1,000ppb is only 39,000 vs 124,000 meaning it's significantly less important overall contribution. It would need to reach ~4,347ppb to cause as much impact as CO2 has which is in nobody's projections that I have seen.
PS: "Methane has a large effect (24 times as strong as carbon dioxide per unit mole) for a brief period (having an estimated lifetime of 8.9±0.6 years in the atmosphere)" https://en.wikipedia.org/wiki/Atmospheric_methane So, if it's lifetime is ~8.3-9.5 years it's half life is around 1/2 that. However, I have also seen a lot of other numbers tossed around and most people want to make it seem much more important even if it's been rising very slowly.
Re: Thousands of underground gas bubbles poised to 'explode' in Arctic
#146Earlier quoted context omitted.
Artificial sulfate aerosols look like they could quickly damp positive feedbacks though of course they're no permanent fix and won't do anything to counteract ocean acidification. There are more permanent fixes possible in theory (large scale accelerated silicate weathering) but their feasibility hinges, IMO, on some rather optimistic assumptions about the future trajectory of robotics. Metaphorically speaking, we no…
Can you elaborate on the optimistic assumptions in robotics that may enable accelerated silicate weathering? Or could you point me to some readings on the matter?
Naturally occurring silicates of magnesium, calcium, sodium, and potassium are thermodynamically prone to weather to carbonates in ambient conditions, when water absorbs CO2 and passes over rocks. In the case of magnesium and calcium in particular, the weathering leads to stable solids that will not spontaneously release CO2 again. A schematic example with calcium silicate:
CO2 + CaSiO3 -> SiO2 + CaCO3
Gaseous carbon dioxide and solid calcium silicate become solid silicon dioxide and calcium carbonate. Silicate weathering has multiple advantages over other carbon dioxide removal/sequestration schemes:• The end state is naturally stable. You don't have to worry about the leakiness of underground containment.
• It restores the pH balance of the oceans as well as reducing radiative forcing (warming) effects.
• It deals equally well with point and distributed sources of CO2 (coal plants, automobile tailpipes).
• It can be located anywhere on Earth. It does not need to be adjacent to CO2 sources.
• It does not require concentrated CO2 streams, but works with ambient atmospheric concentrations.
Natural silicate weathering reactions dominate Earth's CO2 balance in the very long term. But they are strongly kinetically hindered in nature. After a freshly exposed rock surface has weathered to a depth of a few microns, the cation-depleted "rind" drastically slows the weathering of the remaining interior. Without human intervention, it'll take about 100,000 years for natural silicate weathering to restore the pre-industrial baseline of atmospheric CO2 concentrations. There are different ways to improve the kinetics:
• Crush bulk rock to a fine sand texture, so full interior weathering finishes much faster (still takes years-to-decades, but no longer takes geological time scales).
• Place crushed rock in near-shore ocean environments where mechanical wave erosion keeps removing rinds.
• Place crushed rock in acidic tropical agricultural soils where it weathers faster due to low pH and elevated temperature. This also improves soil quality for growing crops.
It's not explicitly included in the scholarly literature, but I say that advanced robotics are necessary because the required scale of intervention is staggering, bigger than any engineering endeavor in history.
For example, the Columbia Plateau in the United States contains basalt whose alkali and alkaline earth content could bind about 20% of its own mass in CO2, after complete weathering:
https://crustal.usgs.gov/geochemical_reference_standards/bas...
To neutralize the CO2 that humans emitted in 2015, about 36 billion tons (https://en.wikipedia.org/wiki/List_of_countries_by_carbon_di...), would require mining and pulverizing about 180 billion tons of Columbia Plateau basalt. That's about 60 cubic kilometers. We're in no danger of running out of plateau -- it contains more than 170,000 km^3.
As for energy estimates, the Bond Work Index for crushing basalt such that 80% of particles pass a 100 micron screen is in the neighborhood of 17-20 kWh per ton:
https://www.911metallurgist.com/blog/table-of-bond-work-inde...
I'll add a factor of 2 for overhead to estimate the whole process energy expenditure. That would mean that using Columbia Plateau basalt, you'd expend 40 kWh per ton of basalt, about 200 kWh per ton of CO2 removed from the atmosphere. That is, energetically speaking, really good compared to schemes that try to run "combustion-in-reverse" to regenerate hydrocarbons from CO2. It's efficient enough that you could actually use coal fired power to drive the whole process and it would still be a net CO2 sink. But at 200 kWh per ton-CO2-scrubbed, it would take 7.2 billion megawatt hours to neutralize humanity's 2015 CO2 emissions. That's an annualized power of 821 gigawatts -- nearly twice the average electrical power generated in the United States.
The scale is so vast that I can only imagine advanced robotic manufacturing, mining, and energy generation being up to the task. However you want to modify my baseline scenario -- smaller projects scattered around the Earth instead of one mega-project, being pickier about processing only the best rocks -- I think that the scale is still daunting. But I think it may still be possible because I see automation advancing a lot in the 21st century if we don't precipitate a civilization-ending crisis first.
Re: Thousands of underground gas bubbles poised to 'explode' in Arctic
#147Earlier quoted context omitted.
Methane has a short ~5-10 year half life in the atmosphere. So, releasing 50x current methane levels over 100 years does not triple current methane levels.
Seven years. And after that you get carbon dioxide (& water)
Re: Thousands of underground gas bubbles poised to 'explode' in Arctic
#148Re: Thousands of underground gas bubbles poised to 'explode' in Arctic
#149Earlier quoted context omitted.
Is this why we have not yet found signs of intelligent life in the universe? Every time a civilization is advanced enough to really screw up (their) planet, inevitably, they do? Fermi Paradox redux.
I think it's a good possible resolution, yeah, generally referred to as 'The Great Filter Hypothesis'.
In fact, it could be at the point of single cell --> multi-cellular organisms or at the point of sexual dimorphism or developing general intelligence and ability to use tools, etc.
I guess it's also possible there are multiple Great Filters...
Re: Thousands of underground gas bubbles poised to 'explode' in Arctic
#150Earlier quoted context omitted.
But as a member of the .01% I'd rather only build new infrastructure where I can guarantee only myself and select others will be able to utilize it. I wouldn't want to waste my money on something that might be ended up being used by the public.
Can't tell if this was sarcasm or a serious statement.