One day I’d like to spin this article out into a much longer discussion of the difficult ethical and technical problems when it comes to the environment – in particular climate change caused by carbon emissions. The following is just a starting point.

Malthusianism and the developing world

In 1798, Thomas Malthus argued that technological advances would lead to abundant resources, which would spur exponential population growth such that our resources per person would eventually return to the pre-advance levels.

While this hasn’t come to pass – we are in an increasingly in a similar trap with carbon emissions and the developing world.

In developed countries, population levels have either stabilised or are falling, but in developing countries there are still at least two or three generations of above-replacement-rate population growth left to occur (assuming rates stabilise at the same income and development point they have historically in developed countries).

In large developing countries like Nigeria, Pakistan, Bangladesh and the Philippines – small changes in the fertility rate result in large differences in the stabilised population in two or three generations time. And, consequently, it results in very large differences in the final levels of carbon emissions since these countries will almost certainly decarbonise last.

This leads to a very hard problem – programs that address child mortality in these countries lead to a lot of carbon over the next hundred years. An extremely non-trivial amount of carbon which could easily be the difference between stemming global warming and not.

Some people have suggested that these countries could ‘leap frog’ like they did with telecoms systems but, right now, that looks like wishful thinking. Nigeria has built eight new gas-fired power plants and one new coal-fired power plant in the last ten years.

So, this leaves us in nasty problem where we asked to trade-off between child mortality and potentially catastrophic carbon emissions. Merely stating this problem feels dirty and wrong because you’re insinuating that people have to choose between the two – but what if they do have to choose?

Perhaps there is a way out where western economies decarbonise so much that developing economies can safely ‘have’ those emissions, or perhaps western economies can change tac and help developing economies decarbonise enough now. Sadly, neither of those things are happening now, so the problem isn’t going away.

Non-carbon environmentalism

How to think about all the types of environmentalism that aren’t the reduction of carbon emissions?

For example, the worst case risk of plastic in the ocean is that many more birds and sea creatures will die than is necessary and this will lead to a slow decrease in marine biodiversity and life. Whereas, the worst case risk of continued carbon emissions is a total out-of-control environmental collapse – taking countless whole species down with it.

However, the loss of bio-diversity is an immediate problem occurring right now with known, very bad outcomes – whereas the environmental collapse from global warming is less certain and further into the future. Some scientists and most campaigners are increasingly certain about a so-called ‘tipping point’ is now a certainty – but the scientific consensus is not that this is a foregone conclusion. The most likely scenario is a slowly warming planet with a progressively worse climate and higher sea levels, but rapid collapse is possible.

So, how do you balance your environmental concerns between an immediate bad outcome (plastic pollution) , against an uncertain but possible future utter catastrophe?

Presumably at some point of likelihood of green armageddon, it becomes moral to stop worrying about plastic in the ocean and to only focus on decarbonisation (since global collapse would take out the sea-life soon enough) – but when do we reach that point and will it all be too late by then? Are paper straws and recycling a green luxury that we can ill afford?

Maximum Theoretical Specific Energy

No one knows how to build a battery as good as hydrocarbons.

This problem is less of a trade-off that the first two – and more of a hard technical problem which is rarely considered seriously by those outside the industry (although there are now very interesting battery supply chain ETFs available to retail investors).

There are theoretical limits to the amount of energy that can be stored in a battery (per kilogram of battery) and these limits are a lot lower than what’s available from hydrocarbon products. Traditional lithium-ion batteries can hit 1 mega-joule per kilogram, and theoretical air-oxidising batteries using zinc or elemental aluminium have theoretical limits around 32 mega joules – but these batteries haven’t even been prototyped yet. The problem is that real kerosene (jet fuel) has 38 mega joules per kilogram – which is basically what you need to be able to take off and fly.

Not to mention the problems with power delivery which means that using high energy density fuel cells requires you to carry massive step-up transformers to get the power delivery required for things like aviation. That’s dead weight which isn’t delivering energy. And, kerosene doesn’t have this problem.

For this reason, and despite the launch of a number of electric aviation projects, it’s very hard to see how we can decarbonise aviation in the next ten to twenty years. Aviation is 2.5% of world emissions, scheduled to increase as energy generation, road transportation and home heating decarbonise – but that 2.5% is going to be very hard to shift through ‘electrification’.

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