Companies should expect a surge in shareholder activism on climate change risk in 2020 as major investors become more confident in taking on directors, according to one of the leaders of global investor movement Climate Action 100+, which represents 400 investors with $US35 trillion ($50 trillion) under management.

The past year saw some of the world's biggest investors, from AXA to PIMCO to AustralianSuper, ratchet up the pressure on major companies to take steps to address climate risk, and Emily Chew, chairwoman of the steering committee of Climate Action 100+, warned this pressure would increase as the effects of climate change became more evident.