[Manuel_D]

Pollution's impact has drastically been reduced over the last half century or so. Pollution is mostly an issue of where waste is released to avoid impact on populations. For example Canada gets a lot of flak for its mountains of sulfur blocks from oil sand processing, but that's an example of limiting impact. The earth is big and there's a lot of desolate places to put waste, it's just the expense of moving it there.

The main challenges are pollutants that can't easily be contained and have adverse effects even when diluted globally. Mercury is one example, DDT, and chlorofluorocarbons are others. We've mostly found ways to contain or replace those.

Of course, the big one is carbon dioxide. But it's not an impossible problem: the Haber Bosch process doesn't inherently emit carbon, it's the hydrogen production that emits carbon dioxide. This can be replaced with thermal water splitting from nuclear power or electrolysis. No doubt it'll take a lot of investment in new energy sources, but it's not impossible.

[modo_mario]

>We've mostly found ways to contain or replace those.

Highly toxic ones or in the case for the CFC's & co ones with a rather fast disproportionate effect and alternatives available. We make these choices relatively quickly and properly whenever they're proportionally easy. From leaded fuel to measures to prevent smog. I don't see the same push for lesser but more omnipresent ones like plastic. Whilst we contain the vast majority of it to landfills I find it rather disturbing how much of it has found it's way out there. Meanwhile recycling is used as a deceptive sham reason to retain it's use in current form and burning it is added to the green energy stats. It boggles the mind

> This can be replaced with thermal water splitting from nuclear power

How so?

>or electrolysis

If i remember well and correct me if i'm wrong the last study i saw on this projected this would need electricity prices that were ridiculously low. Under 0.03$/kwh i think. We'd much sooner use the hydrogen in power to gas plants as a form of energy storage but even that lacks wide scale commercial viability in the forseeable future. Given we're not in some post scarcity society when it comes to energy in the forseeable future i don't see many ditching our conventional methods quickly whilst also cutting down on....nearly all the rest. (Steel production also has a similar output, etc)

So I imagine if we cut down on that in an attempt to be sustainable fertilisers would become a lot lot more expensive putting pressure on our food supply. This in the context of a world poplation that will keep growing, in the meantime we have other issues that relate to food security. For example in Germany flying insect populations dropped about 75% since 1990. We're not exactly jumping to quit what's causing that too.

[Manuel_D]

> > This can be replaced with thermal water splitting from nuclear power

> How so?

If you hear water above ~800 Celsius it'll split into hydrogen and oxygen. A catalyst can make this happen at lower temperatures. Nuclear power can heat water, run it through this catalyst, to produce hydrogen.

Electrolysis is no doubt more expensive than steam reformation, but the point is that alternatives do exist and can be done if enough investments are made.

"Sustainable fertilizers" fundamentally needs some source of nitrogen. The amount we can get from manure is nowhere near sufficient, so carbon neutral replacements to steam reformation are needed. In short, electrolysis and thermal water splitting are the answer to the question, "how do we get sustainable fertilizers?"