Lego drops prototype blocks made of recycled plastic bottles as they "didn't reduce carbon emissions"

Well to be fair they can be, plastic is very recyclable, it's just more expensive than producing virgin plastic, so it's not done :-(

this is correct less than 5% of plastics even get recycled.

Lego already does a great job at reuse, you can just pass it on to the next generation as they last forever anyway.

Yes but lego wants to be carbon neutral

They stated that the new mater lies would not live up to their requirements on longlivity and quality. Abs which is currently used is quite stable and can and is therefore be used for generations.

The new materials would lead to faded and broken Lego bits after some years and degrade the brand perception. Since new stuff would need to be bought then this would be less CO2 efficient.

For other PET products we usually do not have any longlivity requirements. Plastic bottles barely need to survive for a year and therefore the recycling process is still much better than producing new plastic.

In short: It is better to produce 1kg of CO2 once every 30 years than 0.2kg of CO2 every 5 years.

I am sure there is still some typical greenwashing in the calculations, but it makes sense to me that they do not want to reduce their quality standards.

I wasn't able to find a definitive answer to your question. Lego blocks are usually made of ABS plastic, not PET, so I though initially the company was doing a thermal breakdown to the hydrocarbon level, then reformulating it into ABS, which I could absolutely be a CO2/energy intensive process.

However this Lego company linked PDF suggests they're actually making blocks out of PET and not reformulating. This should be a significantly less CO2/energy intensive.

One other thing to consider is how Europeans are approaching "green" initiatives. European methods are generally hyperfocused on CO2 reduction as pollution largely ignoring other types of pollution. As an example, with automobile pollution diesel cars were incentives because they produced less CO2 than gasoline cars for similar distance/work. This ignored the NOX and particulate pollution from diesel which was far worse than gasoline. The statement Lego made here of "didn’t reduce carbon emissions” resonates with that idea.

Back to Lego, even if PET method was only CO2 neutral, using recycled PET could still be a good path to reduce PET plastic from going into landfills or being burned (producing other toxic pollution). However, if CO2 reduction is the only goal, then the program ending isn't surprising.

The vagueness of this statement means that they found it to be 0.2 cents more expensive per tonne and didn't want to take this overwhelming hit to their profit streak.