The world3 model is available as a library in the open source package modelica: https://build.openmodelica.org/Documentation/SystemDynamics....

You can download the free openmodelica package and run world3 yourself: https://www.openmodelica.org/

A news article about Gaya Herrington's analysis is here: https://www.theguardian.com/environment/2021/jul/25/gaya-her...