Lego typically makes the majority of its bricks with a plastic known as ABS, which is formed through heating petroleum at a very high heat. This plastic is particularly good for the toy bricks as it is durable and has what it calls “clutch power”, where it can be clipped apart and together easily.
The toy maker has started to look at using more sustainable oils in the process, including creating plastic by heating bio-waste such as cooking oil or food industry waste fat.
The industry remains relatively small. Fossil fuels are used to create around 90pc of all the plastic in the world.
Lego also revealed its operating profits jumped to a record high of 8.1bn kroner (£910m) in the first six months of the year, up 26pc on last year. Its sales were up 14pc, even as the rest of the toy market remained stagnant.
The company said it planned to open around 100 stores this year, taking its total number to 1,100.
Mr Christiansen said Lego’s focus had shifted to the US and European markets amid softness in China, saying: “We are opening slightly fewer stores in China right now because we see that consumers there are holding back a bit.”