In the report, the IPCC said "as infrastructure and energy systems develop, in spite of the complexities, there are few, if any, fundamental technological limits to integrating a portfolio of renewable energy technologies to meet a majority share of total energy demand in locations where suitable renewable resources exist or can be supplied".[7] Under favourable circumstances, cost savings in comparison to non-renewable energy use exist.[2] IPCC scenarios "generally indicate that growth in renewable energy will be widespread around the world".[8] The IPCC said that if governments were supportive, and the full range of renewable technologies were deployed, renewable energy could account for almost 80% of the world's energy supply within four decades.[9] Rajendra Pachauri, chairman of the IPCC, said the necessary investment in renewables would cost only about 1% of global GDP annually. This approach could keep greenhouse gas concentrations to less than 450 parts per million, the safe level beyond which climate change becomes catastrophic and irreversible.[9]