Brazil, Russia, India and China, the so-called Brics, are predicted to emerge as major world players by 2050. In this, the second of a four-part World Service series called Brics: The Changing Face of Global Power, the BBC's Peter Day examines how the tables are turning.
Ever more new airlines show that India's economy ready for take-off
Some of the brightest minds in the normally dismal science of economics agree that great big upheaval is on the way.
"We're already seeing the dispersal of economic power and influence, I think, in the world, in the early stages," says Michael Spence, a Nobel prize-winning economist from Stanford University in California.
"Because of the growth of these [Bric] economies, you can see them acting in the WTO and in other places in a way that's much more influential than they used to be, say, 25 or 30 years ago."
In India, the town and the countryside are currently worlds - and centuries - apart.
In the farming village of Tilpat, less than 20km (12 miles) from the government offices and cyber cafes of the capital, Delhi, Badleram takes deep draws on his hookah pipe in the village meeting-place.
As this careworn 70-year-old voices his doubts about the Goldman Sachs international bankers' thesis that India will be rich, the villagers around him nod in agreement.
"India can become great, we have hope that things will improve - but when we look at the present situation, we have doubts," he says.
"We have a very sacred temple in this village. Many important people, even members of parliament, come to it, using this same bad road. They come and go, but the condition of the road remains the same."
But Prahlad Kakkar, a director of commercials for Indian TV, is someone making a living from India's new success and is more optimistic.
"The most interesting thing about India is that 60%, almost 70% of the population of this country is below 40 years old or even 35 years old," Mr Kakkar says.
"And it's going to remain young for a very long time. We are probably evolving as one of the youngest, most dynamic changing societies in... Asia, and therefore in the world."
In fact, with developing countries such as Brazil, Russia, India and China on the rise, a whole new market of trainee consumers is being born.
Billions of new consumers - the overwhelming majority of them drawn from the ranks of people many Western marketing executives habitually dismiss as "the poor".
And, thanks to falling trade barriers and opening economies, they are all finally able to buy into at least part of that dream of abundance the advertisements dangle before them.
Some of the entrepreneurs in Russia are among the most optimistic about this development.
"I really believe in the economic growth and huge potential of this country," says businessman Sergey Vykhodtsev.
"It will be a whole 150 million people market - booming, and prosperity will come here. In five years' time - not more than that."
Economists insist that the poor will not stay poor: that these Brics countries will rise to the top
He believes that this growth will not be restricted to the cities of Moscow and St Petersburg, but right throughout the country.
"The business will be run according to international standards, no question about it," he adds.
"But Russians generally think with the heart, not with the head. That's why I think it will be a little bit different."
The question of "standards" is key to the development of the Brics.
Western investors have tended to be less than rhapsodic about their encounters with the Chinese business culture, emphasising corruption problems.
Campaigning Chinese journalist Hu Shuli, the founder-editor of the financial newspaper Caijing, argues, however, that "if foreign companies compromise with such kinds of corruption, they will be part of the corruption".
"China hates corruption as well. The government, and also the people, have worked very hard to do something against it."
But she admits that reform is needed, even if, "subjectively", the government does not want to be part of corruption.
"Actually, or objectively, because the government has controlled too much economic resources, it helps to be part of the corruption," she added.
Corruption is a huge and headline-making problem in Brazil, along with the ferocious gap between rich and poor found in all four Brics countries. Is that poverty - the squalid, savage poverty of the urban slum - also just a passing historical phase, something Brazil and the other Brics countries might outgrow?
"I think reality is improving in this country," says Norman Gall, a much-travelled American who founded the Fernand Braudel Institute of World Economics in Sao Paulo.
"Life in the favelas where we work has been improving. There's been more infrastructure. There are more schools. People are living better. There are more businesses. The streets have been paved. Streets now are lighted. All of these things work together to make these more civilised societies."
Vast parts of India's cities remain shockingly poor
He compared what was happening to the efforts to clear the slums of London or Berlin in the 19th Century.
"This is a process that has recurred throughout history."
He also argues that the rapidly ageing societies of European and Japan mean the transition of the Brics to global prominence will be relatively painless.
"They have social systems which cannot be sustained, they don't have the manpower to conduct military enterprises," he added.
"So these are fading powers, and I really don't see how they can really obstruct vigorous new powers that are arising. I don't think that this is a problem."
In an increasingly globalising world, rich and poor are living ever closer together, as television and the internet bring down the barriers of time and space. Economists insist that the poor will not stay poor: that these Brics countries will rise to the top.
To the destitute in the slums and the farmers in the countryside, it all seems rather unlikely. But if it actually happens, what will these changes mean for the rest of us?