A UN-backed investor program designed to pressure Australia to accelerate decarbonization plans will add 18 new money managers including Fidelity International and Morgan Stanley Investment Management, as investor concerns grow over the impact of climate change risks on the country’s debt.

Neuberger Berman and Sumitomo Mitsui Trust Asset Management are also among firms joining the sovereign engagement program coordinated by the Principles for Responsible Investment, the group said in a statement Thursday. The additions expand the initiative from seven investors to 25, with a combined $8 trillion in assets, it said.

The expansion comes as money managers globally grapple with assessing how heat waves, droughts, floods and other extreme weather events will impact investments including sovereign bonds. That’s as more countries look to raise money in debt markets to finance ESG projects.

Australia is the first country the Collaborative Sovereign Engagement on Climate Change initiative is targeting. The nation “has underperformed other OECD countries significantly in terms of climate indicators” while being above average on social and governance factors, said Peter van der Werf, head of engagement at Robeco and an advisory committee member.

The program will consider the results of the Australian pilot over the financial year and may expand its scope to additional countries, the PRI said.

Australia this week was forced to acknowledge climate change may impact its borrowing costs after it was sued for allegedly misleading investors by not disclosing climate risks when selling its debt. A government report issued last week estimated Australia could face economic losses of as much as A$423 billion ($274 billion) in reduced productivity if global action fails to halt extreme climate change.

While Australia has set carbon reduction targets and ramped up its climate policies, they’re still insufficient in meeting Paris Agreement goals, according to Climate Action Tracker.

The engagement program aims to push Australia to close the gap between its current actions and a Paris-aligned emissions reduction trajectory. It also seeks to boost disclosure of the nation’s exposure to climate risks and opportunities, and improve on climate adaptation and resilience against damage from physical climate risks.