Record levels of renewable energy have driven the first drop in Australia's annual greenhouse gas emissions since 2015 but if maintained the rate of decline would mean the country's Paris pledge would be met 68 years late.

National greenhouse gas emissions reached 133.1 million tonnes of carbon dioxide equivalent (Mt CO2-e) in July-September 2019, according to Ndevr Environmental Consultants, an environmental auditing company with a track record of accurately estimating a nation's carbon pollution.

AGL's Loy Yang power plant in Victoria: Emissions from brown coal are on the slide. Credit:James Davies

For the 12 months to September, emissions were about 0.2 per cent lower – or 0.6 Mt CO2-e – than the previous year, the first decline in annual pollution since 2015, the consultancy said. The quarterly figures were little changed from the April-June period.

Key to the modest decline was the electricity sector. While still Australia's largest source of carbon emissions, the power industry is likely to have emitted 43.1 Mt-CO2-e for the quarter, or the lowest in data going back to 2002.