Future growth in world energy demand is a cause for optimism because it will signal economic recovery and progress, Rex W. Tillerson, chairman and chief executive officer of Exxon Mobil Corporation, said today.

ExxonMobil is forecasting the global economy to more than double in size between 2010 and 2040, and during that time energy demand will grow by more than 30 percent. In order to meet that demand, the world needs to invest in and develop all economically competitive sources of energy.

Projections of significant population growth combined with expanding trade, new technologies, and transformative economic opportunities will drive economic expansion and rising standards of living - particularly in the developing world, Tillerson said in a speech to the 20th World Petroleum Congress in Doha, Qatar.

"The energy and economic challenges the world will face in the decades to come require a business and policy climate that enables investment, innovation and international cooperation. Sound policies and government leadership are critical. When governments perform their roles effectively, the results are extraordinary - bringing enormous benefits in terms of investment, enterprise, economic growth and job creation."

Tillerson said that the key to unlocking new economic growth was for industry, governments and society at large to focus on their respective roles and responsibilities.

"By understanding our strengths and proper roles in economic expansion, we can clarify our policy choices, fulfill our core responsibilities and open up economic opportunities for decades to come," he said.

Government has a responsibility to provide a stable and fair legal, tax and regulatory framework; industry needs to invest with discipline to develop energy in a safe and environmentally responsible way; and the public also has a role to play, Tillerson said.

"Citizens and consumers need to understand the importance of energy, the vital role it plays in economic and social development, and how sound policy supports responsible energy development and use. The debates and discussions in society at large need to be informed by the facts and fundamental realities of the challenges before us.'

Tillerson said the state of Qatar is a leading example of what can be done when policies are in place to enable investment and innovation.

"In just over a decade, Qatar has risen to become the world's leading supplier of liquefied natural gas. In the process, the nation has unleashed its own economic growth, supported innovation, spurred job creation and strengthened the energy diversity that allows free markets to maximize the value of national resources for producers and consumers. Qatar is a beacon of energy prosperity."

Tillerson said the current economic challenges will not last forever.

"There is reason for optimism but it is more important than ever that we swiftly take on these challenges with a sound and principled response," he said. "History proves that energy policies that are efficient and market-based are the best path to economic growth and technological progress."