Air pollution is an underestimated scourge that kills far more people than AIDS and malaria and a shift to cleaner energy could easily halve the toll by 2030, U.N. officials said on Tuesday.

Investments in solar, wind or hydropower would benefit both human health and a drive by almost 200 nations to slow climate change, blamed mainly on a build-up of greenhouse gases in the atmosphere from use of fossil fuels, they said.

The number of people living in extreme poverty could increase by up to 3 billion by 2050 unless urgent action is taken to tackle environmental challenges, a major UN report warned on Thursday.

The 2013 Human Development Report hails better than expected progress on health, wealth and education in dozens of developing countries but says inaction on climate change, deforestation, and air and water pollution could end gains in the world's poorest countries and communities.

The world can significantly slow the pace of climate change with practical efforts to control so-called “short-lived climate pollutants” and by bringing successful Western technologies to the developing world, according to three UC San Diego scientists in the journal Foreign Affairs.

For the last two decades global diplomatic talks on climate change have struggled to make progress. Part of the problem, the scientists say, is that diplomacy has focused almost exclusively on carbon dioxide—a pollutant that is expensive and difficult to control.