A general view of Shanghai's financial district of Pudong ais seen from the Shanghai World Financial Center amid heavy smog in Shanghai, China, December 25, 2015. REUTERS/Aly Song

LONDON (Reuters) - Almost half of the world’s top 500 investors are doing nothing to address climate change through their investments, a study showed on Monday.

A report by the Asset Owners Disclosure Project (AODP), a not-for-profit organization aimed at improving the management of climate change, found that just under a fifth of the top investors - or 97 managing a total of $9.4 trillion in assets - were taking tangible steps to mitigate global warming

These include investing in low polluting assets or encouraging the companies they invest in to be greener.

A further 157 investors managing a total of $14.2 trillion were taking “first steps” towards addressing climate change, while 246 managing $14 trillion were doing nothing at all, the report said.

“Climate change risk is now a mainstream issue for institutional investors and last year has seen many significantly step up their action to manage this,” AODP Chief Executive Julian Poulter said in a statement.

“However ... it is shocking that nearly half the world’s biggest investors are doing nothing at all to mitigate climate risk,” he said, adding pensions funds and insurers that ignore climate change were “gambling with the savings and financial security of hundreds of millions of people”.

The AODP rates the world’s 500 biggest pension funds, insurers, sovereign wealth funds, foundations and endowments, which collectively manage $38 trillion in assets, on their success at managing climate risk within their portfolios.

Based on direct disclosures and publicly available information, they are graded from ‘AAA’ to ‘D’ while those taking no action are rated ‘X’.

Best-performing was Britain’s Environment Agency Pension Fund, with $3.96 billion in assets.