“It is tough for the BRIC countries to all repeat their remarkable growth rates” of the first decade of this century, said O'Neill, a Bloomberg View columnist and former chairman of Goldman Sachs Asset Management International. “There was a lot of very powerful and fortuitous forces taking place, some of which have now gone.”

The growth slump this year isn't a new normal, though, and O'Neill sees expansion in Brazil and Russia partially recovering, helping the BRICs average about 6 percent growth per annum this decade—still more than double the average for the Group of Seven nations.

Their share of global gross domestic product will “rise sharply,” he said.

O'Neill had previously estimated average annual growth of 6.6 percent for the BRICs this decade, a pace it was close to achieving through last year mainly because China exceeded the 7.5 percent annual average growth he estimated for the first three years, he said.

Unlike Brazil and Russia, China is embracing economic change while India, after the election of Narendra Modi as prime minister and benefiting from low oil prices and a young labor pool, may have brighter prospects this decade than last, O'Neill said.

With China and India spurring growth, the BRICs will remain the most dominant and positive force in the world economy “easily,” said O'Neill.

China, India

China growing at 7 percent will add about $1 trillion nominally to global output every year, O'Neill said. When measured by purchasing power parity, China's growth adds twice as much as the U.S.'s, he said. India expanding at 6 percent will add twice as much as the U.K. in those terms, he said.

“Their consumption is increasingly key for global consumption, and which markets were amongst the world's strongest in 2014? China and India both were up significantly,” he said. “So many investors are herd-like, they probably have already forgotten the BRICs, but it is silly. They are the most important influence in the world.”

A prediction in his book, “The Growth Map,” that the BRICs economies would overtake the U.S. in size this year will be delayed likely until 2017 primarily by the drag from Russia, O'Neill said.

The founding of the BRIC's Development Bank signals the group's influence in global economic affairs will rise, O'Neill said.

By 2035, the BRICs will be as big as the Group of Seven nations while China is in “a reasonable position” to be bigger than the U.S. in 2027 and India may overtake France to become the world's fifth biggest economy by 2017, “certainly before 2020,” he said.

–With assistance from Simon Kennedy in London.

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