The world remains heavily dependent on fossil fuel but a new report issued by the UN Environment Program on Monday highlighted an emerging trend that points to the increasing investments on renewable energy by key economies across the globe.

By the end of 2011, the world's total investment in clean energy jumped by 17 percent to $US257 billion, registering an actual retreat of 37 percent from the amounts poured in developing renewable energy in the previous year, the UN report said.

In a conference call held in Geneva yesterday, Environment Program chief Achim Steiner told reporters that figures collected by the agency have so far suggested that clean energy forms have been gaining sufficient traction in the past years that soon enough the sector will reach considerable maturity.

"These trends are real, they are substantive and they are transformative," The Associated Press reported Mr Steiner as saying during the news briefing.

The agency's report indicated too that solar and geothermal energies appear to have attracted investment initiatives from countries around the world, with the former mostly focused on by developed economies such as Australia, Germany and Italy.

On the other hand, poor countries from the African continent have started tapping other renewable sources of energy apart from hydropower, which aside from the conventional electricity sources of coal and fossil fuel has been the preferred power-generating supply in the region, the report said.

The UN report has also underscored the growing presence of solar energy in many affluent nations, which mainly contributed to the $US147 billion investment surge seen in the segment in the past year.

Mr Steiner said that China and the United States spent more than $50 billion each in 2011, which contributed to the 52 percent soar of solar energy investments from some of the major economies around the world.

The UN report noted that Germany, Italy and India also upped their spending on solar energy initiatives that last year resulted to the significant drop on the price of rooftop photovoltaic installations in these countries.

In fact, electricity generated by solar panels now offer competitive retail price in these specific nations as compared to the commercial source of electricity, the report said.

Also, the UN report has lamented that wind power spending in the past year declined by 12 percent to $US84 billion last year, no thanks to policy adjustments rolled out in the year by some European governments.

China too has seen considerable dips in wind mill installations last year as compared to the levels posted in the previous years, the report said.

While the world has been picking up on renewable sources of energy since scientists called attention to the fact that coal and fossil fuel have been largely responsible for much of the carbon emission in the planet, only an estimated 17 percent of global energy consumption has been attributed to clean energy as of 2010, Mr Steiner said.

That means more than 80 percent of the world's power requirements still heavily depend on pollution-causing energy sources, the UN report said.