A 'green investment' analysis was carried out for Mauritius using system dynamics modelling of the complex interactions between the three spheres of development: society, economy and environment. The results presented here are preliminary and form part of a more detailed ongoing study. The main focus of this report is to demonstrate the applicability and versatility of system dynamics modelling to green investment scenario analysis in medium- to long-term cross-sectoral planning for sustainable development. It can also serve as an input into the discussions leading up to Rio+20, where the concept of a green economy will be one of the two principle focuses. Two scenarios have been developed to analyse the allocation of green investments. The first is the 'business as usual' case, which assumes that current socio-economic and environmental trends will continue and that existing policies will take their course. The second scenario looks at the 'green investment' case, simulating additional interventions in three sectors: energy, water and agriculture. The energy sector includes the transport subsector. The green economy scenario assumes that approximately 1.1 per cent of GDP will be invested in these sectors, with 2010 as the base year.