They may earn only about £2,000 a year but they are 400 million-strong, scattered across the globe and have just bought themselves a fridge.

Meet Generation A, who soon could become the most important economic force on Earth.

Aged between 30 and 40, their per capita income is rising fast and their numbers are forecast to hit one billion within the next two decades. And it is a group whose consumerist aspirations (the “A”) are not about to stop with that fridge.

The emergence of Generation A coincides with a tipping-point reached this year, in which the world's urban population equals its rural population for the first time. The concept of Generation A has been developed by analysts at Macquarie to explain and track many of the “mega trends” holding the global economy in their sway.

The entire future business of investment, Macquarie analysts argue, would make sense only through reference to the activities and spending patterns of Generation A.

Soaring prices of hard and soft commodities, energy and transport are symptoms of what the economist Stewart Ferns describes as a “silent revolution” - an inexorable shift of economic power from the old developed world (Generation Z) to the growing, aspirational middle classes of emerging markets in Asia, Africa and Latin America.

“The increasing per capita income and the huge lifestyle changes of the stereotype we are calling Generation A is what is going to drive the global economy over the next decades,” he said - and as Generation A increases in wealth and numbers, the financial map of the world would have to be changed, along with all the tools used by investors to understand it all.

Generation A's increasing share of global income would irreversibly change world demographics, Mr Ferns said, pointing to the looming demand explosion that will occur when large numbers of people - particularly in China - hit the “magic” annual income levels that cause consumption to soar.

Analysts believe that the figure is reached when a country's per capita GDP reaches $3,000.

The shape of things to come? Generation A's next immediate purchases include not only a wide range of meats and processed foods to put in their new fridge, but a car to go to the shops in and a mobile phone.

Soon Generation A will be thinking about a first holiday, looking for decent financial services, considering healthcare needs and wondering about investing in higher education.

Explore Economics

• Pre-Budget Report 2009

• Budget 2009

• World Economic Forum

• The Times MPC

Times Recommends

• Lies and cover-up at MG Rover exposed by report
• High oil prices push manufacturing costs up
• Primark founder steps down as chief executive