According to Bloomberg, the worlds’ wealthiest countries are not fulfilling their pledge to provide $US100 billion a year to developing countries for building green technologies as part of the Paris climate accord.

Of the $US111 billion invested to date in clean energy technologies, only $US10 billion was provided by wealthy or so-called First World countries.

While the pledge was made in Copenhagen in 2009, and confirmed at the 2015 Paris Agreement to limit global greenhouse gas emissions, the $US100 billion, to be raised from multiple sources including from the private sector, was intended to be a minimum, with nations expected to set a new goal by 2025.

With UN negotiators meeting in Bonn, Germany this week to try and work out how to implement the Paris accord, which aims to keep global warming at below two degrees Celsius above pre-industrial levels, Standard and Poor's is questioning where the money would come from, citing a need for some countries having to increase their national debt in order to finance their environmental pledges.

"In our view, it is very unlikely that governments would be willing, or able, to risk deteriorating their creditworthiness by stretching their budgets and debt burdens to fund the implementation costs," the analysts at Standard and Poor's found.

But a Bloomberg spokesperson said that developing countries need to improve their own legal frameworks in order to make investments in clean energy more attractive and easier for both institutional and private investors.