The transition to low-carbon energy systems across the world will have to be faster than seen in 20 years, says a report released globally on Tuesday.Energy productivity has to increase three per cent each year and the share of energy from zero-carbon sources has to rise at least one percentage point, says the report by the Energy Transitions Commission (ETC). Strong public policies will be essential to achieve this. “In addition, the progress implies a major shift in the mix of investment in the energy system: Investment in fossil fuels over the next 15 years could be about $3.7 trillion lower than in a business-as-usual scenario, while investment in low-carbon technologies and more energy-efficient equipment and buildings could increase by $6 trillion and $9 trillion, respectively.”