Decarbonisation of the global economy is progressing too slowly and while there has been improvement among big developed economies, emerging markets have failed to make reductions, Fitch Ratings warned in a report published on Wednesday.

World CO2 emissions rose by 1.8% last year compared to world gross domestic product growth of 2.9%, the report said.

The ratio of emissions-to-GDP fell by just over 1%, broadly in line with the average annual decline of the previous 25 years and well short of the 8% annual fall required in 2020-2030 to achieve net-zero targets by 2050, the report added.

Fitch noted that while emissions from 10 developed economies fell to their lowest since 1970, emerging markets as a whole failed to make any progress towards decarbonisation -- with CO2 emissions and GDP of 10 emerging markets tracked by Fitch increasing by 4.7% last year.

"The lack of progress in decarbonisation in emerging markets is particularly concerning, given their faster GDP growth and rising share of global energy consumption," Fitch said.

They said one of the reasons for emerging markets’ poor performance was underinvestment in clean energy projects, especially in emerging markets excluding China.