The World Conservation Congress kicks off today with more than 9,100 registered attendees from nearly every country — enough to make it a record-setting event for the International Union for Conservation of Nature and the largest environmental conference ever in the United States.

Randall Tanaka, executive director of the WCC National Host Committee, said attendance has been steadily building. The number of delegates has surged by more than 80 percent from the roughly 5,000 that were slated to come just three weeks ago, when Tanaka said attendance had been depressed by visa issues and global economic and security concerns.

Tanaka said organizers also are closing the gap on a funding shortfall. A month ago, they were up to $1 million short of their obligation to host the 10-day summit. Latest projections are about $500,000 short, Tanaka said.

“We’ve done a good job catching up. Funding and attendees are still coming in,” he said.

While the city and state will pay roughly $11 million to $12 million to host and provide security for the summit, total economic impacts are now expected to exceed an earlier $62 million projection. The gathering is also expected to fill thousands of hotel rooms during what is typically an off-season for Hawaii’s tourist industry. Attendees also are likely to spend days and money on neighbor islands in pre- and post-conference visits.

Amy Fraenkel of Montreal said she spent 10 days vacationing on Kauai and Hawaii island before the conference, which she plans to attend through Tuesday.

“I think and hope that a lot of other delegates will get to explore Hawaii,” said Fraenkel, who is part of a delegation of seven traveling with the Secretariat of the Convention of Biological Diversity.

IUCN’s surge in registrants is “heartening, and reflects the deep interest, globally and locally, that exists to protect the environment,” said George Szigeti, president and CEO of the Hawaii Tourism Authority.

President Barack Obama’s arrival to announce the quadrupling of the remote Papahanaumokuakea National Marine Monument, which will become the world’s largest marine sanctuary, also likely added to the boost in participants, said Stewart Sarkozy-Banoczy, a Washington-D.C.-based attendee with the Global Island Partnership.

“The fact that there is a large announcement being made shines a spotlight on the event,” Sarkozy-Banoczy said. “Hawaii is a draw, but it’s also a place that people say, ‘You’re going on a junket.’ It takes a while to get approvals.”

Obama’s potential presence at the conference was also a draw for locals like Roberta Brashear-Kaulfers, a member of the Sierra Club Hawaii Chapter and the organization’s national council. Instead, Obama appeared Wednesday evening at the Pacific Islands Conference of Leaders and the East-West Sustainability Summit, which parallel the IUCN event.

Although disappointed she likely wouldn’t see Obama, Brashear-Kaulfers said, “Whoever they have speaking at the opening will be significant,” and that she planned to attend through Labor Day.

Tanaka said attendance at today’s opening ceremony is expected to exceed 4,000, with the possibility of accommodating up to 6,000 — the venue limit. After the opening, the event will head back to its home base at the Hawai‘i Convention Center, where it will continue through Sept. 10.

“I think attendance is just going to get bigger,” said Pohai Ryan, executive director of the Native Hawaiian Hospitality Association, who was exhibiting a cultural app at the event Wednesday. “We’ve seen a lot of people coming in from all over the world. As word gets out about how exciting this conference is, we think we’ll see more local people coming to check it out.”