Investment in green energy projects globally has hit its lowest figure in four years for the first quarter of 2013, according to a report in Bloomberg New Energy Finance.

Investment across the first three months of 2013 was recorded at $40.6bn, down 38% from spend in the previous quarter. This decline marks a 22% drop from green energy spending for the same quarter in 2012.

The reduction in investment figures has been blamed on political uncertainty across major green investing economies, including Germany, the wider EU and the US, while cooling markets like Brazil and China have also been less forthcoming in their support for green projects.

The news comes as some concern to industry analysts, many of whom continue to call for greater investment in the green sector to help reduce CO2 emissions and improve energy efficiency outcomes.

With international targets to be met over the coming decades for emissions-level reductions and energy efficiency gains, the apparent partial withdrawal of funding could inhibit progress.

But while less is being spent on green energy, the figures don’t take account of more efficient, affordable technologies being used. In particular, a reduction in capital and operating costs for photovoltaic panels has made it much more cost-effective to generate solar energy.

For every 100% gain in solar capacity (i.e. for every doubling of photovoltaic panel coverage), the costs of solar power fall by around 20%, providing massive incentives for public and private sector partners to engage in the development of this green, renewable energy source.

However, with BP switching off their investment in the US renewables market, and many other major energy providers pulling back on their commitments to the sector, some are concerned bigger potential investors are being put off renewables, with potentially devastating consequences for long-term energy needs.

Daniel Yergin, an energy expert who has authored several major books on green energy policy, said that a shift away from renewables and other green technologies now could have lasting implications on the environment and the energy industry in future.

“The need to secure a stable energy future has never been greater – both politically and for the environment. If governments and industry start rolling back investment at this stage, it could take years to recover towards a more sustainable energy mix, jeopardizing international emissions targets and the need to switch to cleaner sources of power.”

Green energy funding rose by a total of 5% in 2011, but started to decline in 2012 down from $302bn to $269bn. While even the reduced spending levels are amongst the most significant amounts ever to be invested in green energy, the trend remains a cause for concern for champions of green technologies.

The news comes at a time when President Obama is trying to step up US efforts in the green sector, proposing a multi-billion-dollar 8% rise in his Energy Department budget. Germany, Japan and China too are taking steps towards increasing their involvement in green energy sources as more governments look for ways of tackling their own future energy needs.