LONDON, May 31 (Reuters) - Asset managers have so far committed $16 trillion of assets to achieve net-zero greenhouse gas emissions by 2050 or sooner, 39% of their total assets, the latest report from the Net Zero Asset Managers Initiative on Tuesday showed.

The group, launched in late 2020 to encourage asset managers to reach net zero by 2050 and help keep global temperature rises to 1.5 degrees Celsius, now has 273 signatories, including the likes of AXA Investment Managers, Aviva Investors and Columbia Threadneedle.

Signatories must set interim targets for 2030 and review those goals every five years so that the proportion of assets covered by their net zero pledge is increased up to 100%.

The targets try to ensure asset managers secure real reductions in emissions at the companies they invest in.

In its latest report, the group said members manage a total of $61 trillion. Of that, 83 investors managing $42 trillion have set targets so far, with 39% of their assets committed to meet net zero by 2050. That is up 4% from November when the first initial targets were published ahead of the UN Climate Change Conference (COP26) in Glasgow.

Twenty four signatories have tied 100% of their assets to the target, while 19 others have committed more than 75% of the funds they manage.

"While there is some way to go, that $16 trillion of assets are now committed to be managed in line with achieving net zero by 2050, is a more than positive start – although targets must of course still translate into action," Stephanie Pfeifer, CEO at the Institutional Investors Group on Climate Change, said in a press release accompanying the report.

The IIGCC is an investor group seeking to drive members towards net zero.

In its report, the Net Zero Asset Managers Initiative also called the geopolitical backdrop for target setting "increasingly challenging", noting increased politicisation of ESG (environmental, social and governance) issues and changes in the regulatory and policy environments.

Climate campaigners have welcomed the many investor networks established to support decarbonisation efforts, but they say that targets often lack ambition and too little has been translated into action. (Reporting by Tommy Reggiori Wilkes. Editing by Jane Merriman)