So it seems traveling by train for longer distances takes around 10x longer than flight but is around 10x less carbon intensive. So yes, traveling by train can be a good choice for activists like Greta Thunberg, but also for regular people. But in another article I read that Greta Thunberg wants to avoid flying to the US and travel by a boat. And that seems unwise. Because cruise ships seem to be even more polluting than planes. So you not just get a trade-off between time spent traveling and pollution, you actually end up with a lose-lose option. Now there is a big difference in what we call a counterfactual - would the charter plane, the cruise boat, or the tourist bus travel if not enough tourists are on board? No it wouldn't, because it is just a seasonal route for a specific group of tourists. On the other hand, if you take a cargo ship as a passenger, it would travel also without you, they don't depend on you, so counterfactually your carbon footprint is almost zero. This is in fact what Greta wants to do – to take a container ship to the US. But over a long time if more people travel like this, this calculation would change, and cargo ships pollute a lot in different ways, not just CO2.

Then there is a cost-benefit analysis that Greta could make, as she could command easily 100k dollars for a lecture in the US. So she could earn somewhere between 1-10m dollars a year of speaking engagements. If the flight ticket costs 500 dollars and she could donate e.g. 50k dollars for carbon offsetting (planting trees) that would be a net positive for the environment many times over. But such a calculation is tricky because signaling value of what we do is very important. And travelling e.g. 10x longer than we otherwise could is a really expensive signal of our commitment to saving the planet. But one negative consequence of her traveling by the boat could be to promote cruise travel and cruise holidays - again the calculation is not straightforward, because you need to subtract the “vacation on land” carbon footprint, but it seems that cruises can be more polluting than planes, and even in multiples.

Another issue is embedded carbon footprint in our consumption. The richer the country the more its citizens consume, often in a silly manner like a low quality fast fashion clothes that you have to throw away in a couple of months. Of course it is nice to recycle all that, but even with recycling, rich countries produce multiples of waste per person more than poorer countries, even within EU. Another issue is globalized character of supply chains - not just long routes, but also labor exploitation that is virtually impossible to trace because of multiple layers of subcontractors based in undemocratic regimes.  

One of the solutions is super-local production thanks to technology like digital fabrication (see Adidas' Speedfactory in Germany as an early precursor) and vertical farms that use 95% less water than conventional farming.  But even more important is a change of mindset or a framework from sustainability paradigm (balancing stocks and flow) into health paradigm (nurturing of life).

So the real issue is not to be sustainable, i.e. grow as many trees as you cut a year, but to plant and grow multiples of trees that you cut because of all the past damage and because of all the uncertainty in our calculations. So an example of a company in this new paradigm would be BioCarbon Engineering - they use drones and repurposed military technology to plant trees 60x faster, by shooting seedpods into ground while using AI and various sensors.

The word “repurposed” is key, they use existing tech that was used previously for killing purposes, but now for something positive - closing a few billion tree gap that we leave annually, and even reversing this gap. So the counterfactual is that the military technology would exist, but would not be used for anything positive. On the other hand, if you created a similar technology using AI for something good, it could be later used for evil purposes and with unintended consequences. So repurposing has a clear benefit – the technology already exists. Also another name for repurposing is exaptation and it is a foundational process in biological evolution, that allowed for non-linear change and jumps. For example, dinosaurs had feathers for warmth and courtship display, but once some dinosaurs fell of tree tops, these feathers were exapted for flight function. So the wings and feathers were not created for flight via adaptation, they adapted for a function of courtship and warmth and were exampled for flight by accident. This is important for innovation – e.g. a melted Hershey’s bar in a pocket of a radar operator caused him to invent a microwave oven.  Therefore, we need to take natural sciences, and e.g. biomimicry seriously, in order to come up with innovations that can help us to save our planet.

The bottom line regarding consumption is that we shall focus on all-win-win solutions, e.g. on locally produced sneakers that use less materials, are cheaper and more durable. This could be possible within next 5-10 years because of exponential technologies. But we should leave the workers in poorer countries to suffer the consequences of relocation - but e.g. retrain them and nurture them to become more artisanal and entrepreneurial workers, but while using high tech tools.

And regarding travel and vacation travel - we should be mindful of the trade-offs but also mindful about the signaling value of what we do on changing the broader culture - to support more train travel seems wise, but to promote more boat travel, and especially cruise travel seems counterproductive.