Billionaire Microsoft co-founder Bill Gates predicts there will be almost no poor countries left in the world by 2035.
Almost all nations will be either lower-middle income or wealthier, and most will have surpassed the 35 countries that are currently defined by the World Bank as low-income, Gates said in his annual letter for the Bill & Melinda Gates Foundation.
Gates and his wife try to dispel what they say are myths about global poverty that hinder development - that poor countries are destined to stay that way, foreign aid is not helpful and saving lives leads to overpopulation.
The first myth, about poverty-stricken countries staying down, has been negated by the jumps in income of countries around the world, the letter says.
Gates points out that since 1960, China's real income per person has gone up eightfold and India's has quadrupled.
"In the next two decades, desperately poor countries will become the exception rather than the rule," Gates wrote. "Billions of people will have been lifted out of extreme poverty."
And in Africa, life expectancy has risen since the 1960s despite the HIV epidemic. Also, more children are going to school and fewer people are hungry.
"I am optimistic enough about this that I am willing to make a prediction," he said. "By 2035, there will be almost no poor countries left in the world."
Gates also rejects claims that foreign aid is wasteful because it is too expensive, because it is stolen by corrupt officials or because countries who receive it become dependent on it.
He says that in Norway, the world's most generous donor of foreign aid, the amount of its budget that goes to foreign aid is only 3 per cent. In the US, it is less than 1 per cent, or about US$30 billion per year.
Measles vaccinations, eradicating smallpox, controlling tuberculosis in China and a plan to eliminate polio in Latin America are all health efforts achieved with aid funding.
Gates writes: "When I look at how many fewer children are dying than 30 years ago, and how many people are living longer and healthier lives, I get quite optimistic about the future."
His wife, Melinda, dispels the myth that saving lives worldwide will lead to overpopulation. She points to countries such as Brazil, where both child mortality and birth rates have declined. When more children survive, she says, parents have smaller families.
"The planet does not thrive when the sickest are allowed to die off, but rather when they are able to improve their lives," she says. "Humans are not machines. We don't reproduce mindlessly. We make decisions based on the circumstances we face."
The Seattle-based Bill & Melinda Gates Foundation is the world's largest charitable foundation. It has made US$28.3 billion in grant payments since its inception 13 years ago.