Comment by mapontosevenths
3 days ago
Carbon Dioxide is a greenhouse gas, which makes the world warmer on average. It also lowers the PH levels of the oceans.
If the oceans die, its very likely that many or even most humans will also. As a human I am pretty strongly opposed to dying, but thats just, like, my opinion man.
The major problem with hydrocarbons today is that we are releasing carbon dioxide stored hundreds of millions of years ago.
If, theoretically, you could produce hydrocarbons from the carbon dioxide that is currently in our atmosphere, then it could be a substantial reduction in net carbon dioxide being added; and it would be compatible with the fuel infrastructure of today.
What must have been the composition of the atmosphere all those hundreds of millions of years ago for all that carbon dioxide to have been removed from the atmosphere and sequestered as biological matter, to then be buried and reacted to form vast quantities of hydrocarbons.
The bind moggles.
Your mind should boggle. It's all pretty amazing.
2.5 billion years ago the earth would have been uninhabitable to most modern life. Single celled life evolved in those conditions and began creating glucose and oxygen from CO2 and water. When those primitive lifeforms died some of them became oil and the CO2 was sequestered.
Over time the CO2 levels dropped until about 20 million years ago the CO2 levels fell to about 300ppm. That's when life as we know it really took off. Yes, it took BILLIONS of years to get there.
Humans have only existed for about 200k years. During that time our CO2 levels have mostly been below about 280ppm. The are now at 429ppm and are rising exponentially. [0]
[0] https://www.co2.earth/daily-co2
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It's possible to synthesise hydrocarbon analogues of petroluem-based fuels. The problem to date has been that this isn't cost-competitive with petroleum, though the difference is narrower than you might expect. Most famously, a Google X Project attempted this and succeeded technically, but the economics were unfavourable: Project Foghorn: <https://x.company/projects/foghorn/>. Both Germany and South Africa have performed synfuel production (from coal) at industrial scale since the 1930s / 1950s, respectively. Using non-fossil carbon is largely the same chemistry; the process does in fact scale.
Fischer-Tropsch and Sabatier process can both operate with scavenged CO2. There's been some work since the 1990s utilising seawater as a CO2 source, with CO2 capture being far more efficient than from atmospheric sources.
Whilst hydrocarbons have numerous downsides (whether sourced from fossil or renewable sources), they are also quite convenient, exceedingly well-proven, and tremendously useful. In some applications, particularly marine and aviation transport, there are few if any viable alternatives.
I've commented on this numerous times at HN over the years: <https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...>.
I hadn't heard of Fischer-Tropsch. Looks like it usually works based on gassification of biomass or existing fossil fuels, so it seems at first glance that it has the same negative externalities as just burning the source material doesn't it?
The Sabatier process looks like it might have much less of that! Very cool stuff. I would love to see a future in which we use uninhabitable, non-arable, desert land to generate cheap synfuel that we can ship wherever needed.
Fischer-Tropsch is based on the reaction of carbon monoxide with dihydrogen (free hydrogen). This mixture is known as syngas.
While now the cheapest way is to make syngas from methane or from coal, it is possible to make syngas from carbon dioxide that reacts with electrolytic hydrogen.
It is also possible to make equivalent precursors of synthetic hydrocarbons by the electrolysis of carbon dioxide in water.
For these 2 methods, you do not need any fossil fuels, but only electrical energy for electrolysis.
Where the energetic efficiency is still very low is when you want to use clean air as the source of CO2, instead of using a concentrated source of CO2. With very cheap energy, i.e. solar energy that is used at the point of capture, it should still be possible to devise a method of capture for CO2 from the air. Many such methods are known, their only problem being a high energy consumption per the amount of captured CO2, so they are impractical with energy that must be bought from the grid, but I do not see why they could not work when coupled directly with solar panels.
FT can work with pretty much any source of carbon and hydrogen.
The latter might come from an existing hydrocarbon (as with so-called "blue", "grey", "black", or "brown" hydrogen), or from electrolysis, which is not carbon-neutral. If the latter is powered by a carbon-neutral source (surplus renewables, nuclear), it's "green", and carbon-neutral.
CO2 can also be obtained from numerous sources. One prospect suggested when US peak oil was a concern, in the 1960s, was limestone. More recently, the US Naval Research Lab, as well as Google's Project Foghorn, looked at separating CO2 (in the form of carbonic and carbolic acid) from seawater, which is far less energy intensive than direct removal from the atmosphere. I'd looked up the history of research and industrial applications circa 2014, noted here:
<https://web.archive.org/web/20170719101136/https://www.reddi...>
<https://web.archive.org/web/20230601122020/https://old.reddi...>
The US Navy has an interest largely for its carrier fleet. Whilst the carriers themselves are nuclear powered, their aircraft are not, and fuel provisioning for the aircraft fleets is a major logistical hurdle as well as a strategic vulnerability. No need to target the carriers themselves (heavily defended) if the supply tankers can be sunk, something present US adversaries might consider. One prospect would be to effectively recommission older carriers as fuel-synthesis platforms, capable of producing aviation fuel from seawater in situ and not having to transit between fuel depots and the fleet itself. Given the additional costs of transit and strategic significance, the economics should be somewhat more favourable than for civilian use. This was the subject of a number of papers published in the 2010s by the US Naval Research Laboratory (listed above). Earlier research based on other carbon sources was performed at MIT and Brookhaven National Laboratory in the 1970s and 1960s, respectively.
Take The Great Barrier Reef for example.
There’s more of it now than in the reefs recorded history.
Well, 2022 data:
https://www.aims.gov.au/information-centre/news-and-stories/...
Bad news, there has been a fourth great bleaching event going on since January of 23. This time 80+% of all reefs have been impacted and the consensus seems to be that its unlikely there will be any reefs left at all before too long.
https://www.theguardian.com/environment/2025/oct/13/coral-re...
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"The picture is complex. Recovery here, fresh losses there.
While the recovery we reported last year was welcome news, there are challenges ahead. The spectre of global annual coral bleaching will soon become a reality."
This article also mentions that a recent large recovery was due to el nino conditions
"Great Barrier Reef was reeling from successive disturbances, ranging from marine heatwaves and coral bleaching to crown-of-thorns starfish outbreaks and cyclone damage, with widespread death of many corals especially during the heatwaves of 2016 and 2017.
Since then, the Reef has rebounded. Generally cooler La Niña conditions mean hard corals have recovered significant ground, regrowing from very low levels after a decade of cumulative disturbances to record high levels in 2022 across two-thirds of the reef."
Not sure if you were trying to imply some long term recovery or that global warming didn't hurt it because the article says heatwaves were part of a many other conditions that caused massive damage
No one ever attract public support and funding by saying:
Don’t Panic.
Everything is O.K.
—-
Edited to add: Rate limited so can’t reply without creating more alt accounts than I’m willing to, so:
@Timon3 - that’s actually a really good point, and I follow at least a few folk that could be categorised as such at least some of the time.
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Factually correct, but you also missed the joke.
It was only kinda a joke. It's a joke in the same way that uncle on Facebook makes jokes. You know the one.