This is the question addressed in a new book called Waste Wars: Dirty Deals, International Rivalries and the Scandalous Afterlife of Rubbish by Alexander Clapp (2025).
'The combined weight of everything made by humans now outweighs every living thing on Earth!' [ref: Weizmann Institute of Science, Israel, 2020]
Plastics weigh more than twice the weight of all marine and terrestrial animals: buildings and roads outweigh all trees & shrubs!