Engineering of the lunar biosphere began in 2173 (Gregorian calendar). After a protracted bidding war which resulted in 353 casualties, the engineering contract was awarded to Quad Bionetics of New Sydney, Australia.
The first stage was the construction of mass producer engines hundreds of meters below the surface in order to increase the density of the lunar body. In 2177 (Gregorian calendar), human error led to a density overflow causing massive tidal waves on Earth which led to more than 450 million casualties.
All lunar biospheric engineering was halted until 2250 (Robotic calendar) when the Council for a New Tomorrow began the effort anew. Apex BioCore Design of Phoenix, USA, was given the task of correcting the gravitational damage caused by the previous attempt to engineer the moon, while Generic Organization Robotics of Berne, Switzerland, was charged with custom building a team of scientific engineering robots to further develop the lunar biosphere.
Since then, long-term biospheric processing has been on-going, principally through layer ionization which is expected to continue until at least 2900, after which it is hoped ecopoiesis can commence. Currently, the most noticeable change to the lunar environment is an increase in surface gravity (approximately one quarter of Terran gravity), though strangely this has had more of an effect on solid matter than liquid or gaseous.