The official reason is that the Coalition Government is already doing its bit to curb greenhouse gases by instrumenting its Direct Action policy which has recently passed the Senate, and in these restrictive financial times it would be foolish to make more climate change expenditures when there other things to attend to.
In my opinion, the reasoning put forward by the UN's IPCC for the raising of funds to combat "climate change" is a fallacious one, and the world would be better off if they ceased pushing the "global warming" bandwagon.
The UN insists the world must become carbon neutral by mid or late century if the average rise in global temperature is to be kept within the 2 degree threshold limit predicted by scientists to cause catastrophic environmental results.( www.un.org/climatechange ) We must curb the rise in greenhouse gases so please send your money to our fund on climate change and we will spend it for you, firstly to pay all our bloated UN salaries and finance our fancy 2015 Conferences in Paris and Lima.
The IPCC have got it wrong. CO2 is not an atmospheric pollutant. It is a welcome gas to our atmosphere because it is used by plants, crops and trees to grow. The whole biosphere depends on having an atmosphere rich in CO2 gas. What we don't want is an atmosphere loaded with particulate pollutants and sulphur dioxide etc which can be controlled if you know the chemistry involved. But the IPCC avoids the scientific approach to the problem because its prime purpose is self-enrichment and power to boss countries around, eventually leading to world government run by them! I say POX on the IPCC. It's not going to happen.