A global economic slowdown and the eurozone debt crisis have curbed government investment in renewable energy, experts warned Tuesday. "There are already some signs that government support may be slowing down in Europe," chief economist at the International Energy Agency, Fatih Birol, warned participants in the World Future Energy Summit in Abu Dhabi. Related stories: Report: Environmental threats on the rise EU: Wasting resources may lead to new recession Global warming threatens France's precious truffle More than 26,000 people attended the four-day conference, which also displays top clean energy technologies. Birol named Germany and Spain as countries that have where support for renewables has apparently declined. He said that although the renewable energy sector was growing, its expansion was "far slower" than it should be to meet demand. Wind turbines (Illustration: AFP) "The energy sector needs long-term planning," he said, arguing that "it would be a pity" if governments fail to fully support the development of renewables. In November, the IEA – which promotes stable energy supply among its 28 developed nation members – issued a report saying that if governments implemented promised policy changes, the proportion of energy generated from renewable sources would increase from 13% to 18% by 2035. The percentage of primary energy generated from fossil fuels worldwide would also fall to 75%t from the current 81% level, it said. The European Union is battling a two-year-old debt crisis that has prompted Standard and Poor's to cut the credit ratings of nine eurozone economies and the EU's bailout fund, the European Financial Stability Facility (EFSF). But other experts and officials argued that developing countries have boosted investment in renewables as more advanced economies have cut back. "We talk about a slowdown in the renewable energy sector, but that is mainly in the OECD countries," said Mohamed El-Ashry, Chairman of REN21 policy-network organization. Adnan Amin, the head of Abu Dhabi-based International Renewable Energy Agency (IRENA), said that despite declines in public investment, private investment was still fueling the renewable sector. "Despite a global economic slowdown, investment in renewable energy has grown worldwide," he said, adding that 90% of current investment is coming from private sources. "What is needed is an enabling framework and that is the role of governments," Amin said. Follow Ynetnews on Facebook and Twitter