The global rating agency said that repeated shock related to sea level rise like damage to assets, loss of life, health issues and forced migration from the sudden events can materially weaken a sovereign's credit profile.
"Thailand, India, China and the US have large port cities that are exposed to sea level rise, but the impact on these sovereigns' economic strength will be limited by the number of ports and their size..." Moody's said.
Domestic transportation networks beyond ports can face disruption from rising sea levels, with knock-on effects on the economy as a whole, it added.
Vulnerability to extreme events related to sea level rise can also undermine investment and heighten susceptibility to event risk, by hindering the ability of governments to borrow and rebuild, increasing losses for banks, Moody's said.
The extent of risk will be determined by the pace of increase in the frequency and severity of natural disasters related to sea level rise, which is currently highly uncertain, and by the effectiveness of adaptation measures, so far largely untested.
While some high income economies, such as Japan (A1 stable) and the Netherlands (Aaa stable) are also exposed, many of them have countermeasures in place, and their credit strengths mean they are unlikely to suffer a material credit impact.
( With inputs from IANS )