The 120 heads of state and some 50,000 environmentalists, social activists, and business leaders gathered this week in Brazil for the Rio+20 conference on sustainable development deserve credit for trying to save the planet, but they may be missing the point about the best way to do it.

No, I’m not among those Al Gore-bashers who claim that climate change, water scarcity, ocean pollution and other environmental problems are an invention of scientists or those who argue that businesses should not be hampered by more environmental rules.

Environmentalists are right when they say that toxic gases, industrial pollution and the destruction of rain forests are hurting our habitat, and that the problem will get worse if we don’t do anything about it.

The world’s population is projected to grow from 7 billion today to 9 billion by 2050, and the planet will need substantially more water, food and energy in coming years. Something needs to be done to save our clear air, our oceans and our forests. The “grow now, clean up later” economic model is neither fair nor viable.

But reading a new book, Abundance: The future is better than you think, by Peter H. Diamandis and Steven Kotler, I found it hard not to draw the conclusion that the United Nations- sponsored Rio+20 mega-conference is spending too much time trying to punish polluters and too little time on encouraging innovators to come up with new technologies to solve problems.

New technologies have helped the world become a much better place in recent years. When I was a child, the conventional wisdom was that the world would soon run out of food because the world population was growing much faster than food production. There were famines in India, and doomsayers were predicting that the whole world would starve soon.

Instead, along came the Green Revolution of the 1960s that developed new ways of producing high-yielding crops, and India soon became a massive food exporter. Today, life expectancy worldwide has risen from 64 years in the mid 1980s to 68 years today, and infant mortality has dropped by nearly half over the same period.

Which brings me back to the book Abundance, which essentially says that thanks to technology, few resources are truly scarce; they are just inaccessible. If we change our mindset from negative to creative thinking, we can solve virtually all of the planet’s water, energy, and health problems.

Take the case of water: Today, about 1.1 billion people don’t have access to safe drinking water, and some scientists project that 135 million people will die before 2020 because they lack drinking water and sanitation systems.

The planet is full of water — oceans cover two-thirds of its surface — but the problem is that most of it is too salty for consumption, or too concentrated in a few areas, or poorly distributed and mismanaged.

Yet there are dozens of new desalination and nanotech water management technologies that may soon make water abundant for everybody. About 80 percent of the world’s water consumption is for agriculture and a sizable part of it is wasted through holes in leaky pipes, but new information technologies are being used to embed all sorts of sensors into pipes. Scientists believe that a smart grid could save the United States up to 50 percent of its total water use.

In a telephone interview, I asked Diamandis what is missing at the Rio+20 meeting.

Diamandis, who is a co-founder of Singularity University, chairman of the X Prize Foundation and founder of more than a dozen high-tech and space companies, told me that “politicians are very focused on the near term and use linear thinking, with points of view that are based on scarcity and typically based on fear.”

Instead, he said, they should focus on “exponential technologies,’’ or technologies that double in price performance every year. “We now use these technologies to play video games, but we don’t use them to address the world’s biggest problems.’’ he said.

My opinion: I agree. The Rio+20 meeting should be applauded for encouraging conservation, but it should have spent more time promoting innovation.

For instance, the United Nations should do on a large scale what Diamandis’ X Prize Foundation does at the private level: give $10-million dollar prizes to inventors who solve particular problems. That may produce more results than mega U.N.-meetings debating the wording of lengthy declarations calling for the responsible use of the earth’s resources.