24/04/2006 (Agence Europe) - 'Major investment, together with energy efficiency improvements, is needed along the entire energy chain to overcome the challenges we are confronting in today's energy markets. Only through timely investment can be build the energy bridges needed for a sustainable future,' said Claude Mandil, Executive Director of the Paris-based International Energy Agency, IEA, in his keynote speech to the 10th International Energy Forum in Doha on 23 April. He warned that a prolonged pattern of under-investment in the oil sector had created constraints in the system that will take several years to resolve, telling producers that if current policies remained in place, global energy demand would grow by 25% by 2015, driven by demand from developing countries. He argued that oil would remain dominant as the single largest fuel in the global primary energy mix but demand for natural gas would increase more rapidly. He said the best option in the short-term was to improve energy efficiency and increasing diversity in the energy mix. Mandil praised progress by the Joint Oil Data Initiative (JODI) in supplying reliable and transparent information on all energy markets.