The awards name the best environmental performers and reporters from the ASX 200, with winners were judged with data from ASX disclosures and information obtained by CDP.

Rio was singled out for the largest absolute carbon reduction, decreasing scope 1 and 2 emissions by 3.4 million tonnes of carbon dioxide-equivalent.

Only BHP Billiton reduced emissions by more (5.6Mt), but it failed to score sufficient points across the judging metrics.

BHP was a finalist in the largest relative carbon reduction category, but lost out to AMP.

PanAust, which is now Chinese-owned, was awarded the most profitable carbon reduction activity.

The company implemented a number of energy efficiency initiatives at a cost of $A10,000, which resulted in annual savings of $1 million and 7300 tonnes of carbon dioxide-equivalent.

Rio was also a finalist in that category.

Sandfire Resources and Mineral Resources were finalists in the category for the best climate disclosure by a first-time reporter, but were edged out by Super Retail Group.

WorleyParsons won best year-on-year improvement in climate disclosure, while Aurizon Holdings won best year-on-year improvement in climate performance.

Materials averaged a score of 77 out of 100 for climate change reporting.

Data showed that CDP received no response from Evolution Mining, Northern Star Resources, Mount Gibson Iron, Regis Resources, OZ Minerals and Straits Resources, while BC Iron and Sirius Resources declined to participate.