Rather than pumping harmful emissions underground, carbon capture scientists at the University of Sydney and University of Toronto say they have developed an alternative process to create widely used chemicals.

According to research published in the online journal Nature Synthesis, the acid-based electrochemical method can be used to create ethylene and ethanol - both commonly derived from oil.

Critics say carbon capture is being used to extend the life of highly polluting industries.

But Fengwang Li from the University of Sydney's School of Chemical and Biomolecular Engineering told AAP carbon capture provides a "second choice" for creating widely used chemicals used in everything from packaging to pharmaceuticals.

"We can use direct air capture or direct ocean capture technology and by doing so we are addressing the historical emissions of the past 200 years," he said.

Rather than serving as an excuse for fossil fuel companies, carbon capture would help them to transform, he added.

The study's lead author, CSIRO Energy research scientist Yong Zhao, said by converting carbon, the reliance on oil extraction to create ethylene could be reduced.

Dr Li said the new method would also reduce the cost of carbon capture and create value in the form of a new chemical product.

But using pharmaceutical molecules for making medicine, for example, may be seven to 10 years away.

Still, the experimental study resulted in a two-fold improvement in energy efficiency compared with the team's previous benchmark work.

"If we want our process to be deployed at scale and used by industry, we need to double efficiency again and improve stability," Dr Li said.

The research was backed by Canada and China as well as the Australian Research Council.

Australian Associated Press