Bill Gates has a terse response to criticism that the high-tech solutions he advocates for world hunger are too expensive or bad for the environment: Countries can embrace modern seed technology and genetic modification or their citizens will starve.

When he was in high school in the 1960s, people worried there wouldn't be enough food to feed the world, Gates recalled in his fourth annual letter, which was published online Tuesday. But the "green revolution," which transformed agriculture with high-yield crop varieties and other innovations, warded off famine.

Gates is among those who believe another, similar revolution is needed now. The Bill & Melinda Gates Foundation has spent about $2 billion in the past five years to fight poverty and hunger in Africa and Asia, and much of that money has gone toward improving agricultural productivity.

Gates doesn't apologize for his endorsement of modern agriculture or sidestep criticism of genetic modification. He told The Associated Press that he finds it ironic that most people who oppose genetic engineering in plant breeding live in rich nations that he believes are responsible for global climate change that will lead to more starvation and malnutrition for the poor.

Resistance to new technology is "again hurting the people who had nothing to do with climate change happening," Gates said.

Groups resistant to genetic modification and other hallmarks of modern agriculture, such as pesticides and petroleum-based fertilizers, generally object on two grounds — concerns about the environment and the high cost of the seed and chemicals used in modern farming.

Bill Freese, a science policy analyst for the Washington-based Center for Food Safety, said everyone wants to see things get better for hungry people, but genetically modified plants are more likely to make their developers rich than feed the poor. The seed is too expensive and has a high failure rate, he said. Better ways to increase yields would be increasing the fertility of soil by adding organic matter or combining plants growing in the same field to combat pests, he said.

The biggest problem with those alternatives, Freese said, is the same one that Gates cited in high-tech research: A lack of money for development.

In his 24-page letter, the Microsoft Corp. chairman lamented that more money isn't spent on agriculture research and noted that of the $3 billion spent each year on work on the seven most important crops, only 10 percent focuses on problems in poor countries.

"Given the central role that food plays in human welfare and national stability, it is shocking — not to mention short-sighted and potentially dangerous — how little money is spent on agricultural research," he wrote in his letter, calling for wealthier nations to step up.

The Gates Foundation is heavily engaged in political advocacy to get governments to spend more money on agriculture and improve policies on issues such as trade and land ownership. Along with advocacy and seed research, it spends its money on buying and distributing fertilizer, educating farmers and improving their access to world markets.

Gates said most of the seed research paid for by his foundation involves conventional plant breeding. In those cases, DNA research allows scientists to pinpoint which genes are responsible for desirable traits. He compares the work to changes in modern libraries.

"We used to have to use the card catalogue and browse through the books to find the information we needed," he wrote in his letter. "Now, in the same way we know ... the precise page that contains the piece of information we need, we can find out precisely which plant contains what gene conferring a specific characteristic. This will make plant breeding happen at a much faster clip."

But in some cases, researchers have inserted foreign genes, such as with cassava, a plant that when processed makes tapioca. It is a stable in Africa, but has been stricken by two diseases, causing more widespread hunger. Scientists injected genes from the disease-causing viruses into the plant's DNA to create a vaccine-like effect.

While Gates is a strong supporter of such work, he said scientists and government need to proceed with caution.

"I think the right way to think about GMOs is the same way we think about drugs," Gates said in an interview. "Whenever someone creates a new drug, you have to have very smart people looking at lots of trial-based data to make sure the benefits far outweigh any of the dangers.

"You can't be against all drugs, but drugs in general are not safe."

Gates' letter also addressed the foundation's work on combating AIDS and eradicating polio. He noted India recently celebrated its first polio-free anniversary and expressed optimism during an interview that other countries will soon have similar celebrations.

He said good progress is being made toward developing an AIDS vaccine and on AIDS treatment, and he hopes the U.S. will fulfill its pledge to provide $4 billion over three years to The Global Fund for AIDS research. It paid only $1 billion of that pledge in the first year.

Gates expressed in his letter and in person concern that the U.S. and other rich nations continue to support foreign aid during the recession.

"If you ask people should we provide AIDS drugs to people who need them, you get an overwhelming yes. When you ask people, do you believe in foreign aid, you get a very skeptical view," he said. "But the fact is that the biggest single program in foreign aid is providing those AIDS drugs. People need to connect those things."



Bill & Melinda Gates Foundation: http://www.gatesfoundation.org

Center for Food Safety: http://www.centerforfoodsafety.org/


Associated Press writer Donna Blankinship can be reached at http://twitter.com/dgblankinship