Saving the world's heritage -- minus the US?

An ancient city unearthed from the jungle in Sri Lanka, a chain of coral islands in the Pacific Ocean, and the largest prehistoric settlement in America, are among the latest additions to the World Heritage List, UNESCO's roster of the globe's finest cultural and natural sites.

Yet the upcoming 1983 meeting of the World Heritage Committee may be the last the United States is eligible to attend. All American funding for the program has been ''zeroed out'': Under the terms of the World Heritage convention, a country cannot serve if it fails to contribute for two years in a row.

Says one administration official ruefully: ''The US was the first nation to sign the convention. We may also have the distinction of being the first to be removed from the World Heritage Committee for being in arrears.''

How did the US reach this point?

The World Heritage Program identifies the world's outstanding cultural monuments, parks, and wildlife refuges, then provides a permanent framework for their protection - all to ensure that these legacies, unlike most of the ancient wonders of the world, are passed on to future generations.

But economics and Middle East politics are combining to throw US support for the program into a tailspin.

During its December meeting in Paris, the committee voted on a motion by Jordan to place ''the Old City of Jerusalem and its Walls'' - an earlier and controversial World Heritage Site designee - on an endangered list. The US, arguing among other things that the motion was procedurally improper since Jordan does not now control the Old City, cast the committee's sole dissenting vote.

One UNESCO official who worries over the possible politicization of the project notes, ''World Heritage is UNESCO's least controversial program, but continuing conflict over Jerusalem could change all that.''

Some congressional aides mention ''the Jerusalem issue'' as one reason why American funding of World Heritage ($330,000 in 1981) was eliminated in 1982 and 1983. Others contend a more compelling reason was economic.

''International preservation work has a low priority during budget cuts,'' explains a State Department official. ''Not enough people know about World Heritage to lobby for it.''

Ironically, no nation except France has contributed more sites to the list, now totaling 136. Ten American parks and monuments have been chosen so far, including Mesa Verde, Independence Hall, Everglades, and Yellowstone. The most recent addition - Illinois' Cahokia Mounds State Historic Site, selected during the Paris meeting - is the US's first nonfederal listing.

''It deserves the distinction,'' says Bob Coomer, superintendent of Illinois' historic sites. ''Cahokia is the largest prehistoric settlement north of Mexico City. It's one of America's grandest resources. But it is also one of our most run-down.''

Officials at US sites credit the designation with increasing international visitation and bolstering environmental safeguards. But the greatest impact of the program is felt in developing countries where badly needed preservation funds have shored up dozens of World Heritage Sites, including the Galapagos Islands (Ecuador), Sagarmatha National Park (Nepal), Carthage (Tunisia), and the Lahore Fort (Pakistan).

Despite its fiscal delinquency, the US still intends to take advantage of the program's framework by proposing two new sites for 1983: Smoky Mountains National Park and the historic fortifications in San Juan, Puerto Rico. As with nominations from any country, these will be independently studied before being considered by the World Heritage Committee. Nongovernmental organizations - authorities on cultural and natural properties - will recommend whether they meet the criteria for World Heritage status set down by the 1972 convention.

Says Russell Train, president of the World Wildlife Fund-US and one of the architects of the World Heritage Program: ''The elimination of federal funding represents a real abrogation of US leadership. The US took the lead in promoting the whole concept of the program. The withdrawal of even minimal support represents a serious backward step. Hopefully, next year's budget will take a more positive view toward World Heritage.''