The reduction is three times greater than its previous target, but shares fell as investors reacted to the higher spend.
The Anglo-Australian miner brought forward to 2025 its target for a 15% reduction in emissions from 2018 levels, five years faster than it had previously planned.
To meet its goal, Rio will increase the amount of power it gets from renewables, boost research and development spending, and also double spending on growth in minerals critical to the energy transition.
It did not however commit to bigger reductions for its customer emissions, currently targeted at 30% by the end of the decade.
Rio's plans blow past those of rival BHP, which targets reducing its operational emissions by 30% by 2030, but still falls short of Fortescue Metals Group's goals.
It committed earlier this month to achieve net zero emissions by 2040.
