Natalia Ruiz started realizing the coronavirus was going to clobber her catering business when she was forced to discard a whole refrigerator of Jabugo ham, smoked salmon and foie gras.

It was roughly one year ago, on the eve of a giant technology conference that usually brings more than 100,000 visitors to Barcelona. Organizers spooked by the virus nixed the summit at the last minute, leaving hundreds of local suppliers in the lurch.

It was one of the first in a flood of event cancellations that soon spread around the world, from Singapore to Chicago, signaling the start of a global downturn. Now, as the global economy starts to emerge from the pandemic, Barcelona and others business destinations like it are wondering: Will thousands of people ever want to pack into a conference center again?

Ruiz, who caters high-end cocktail parties, was able to return the 700 bottles of Rioja and Cava she’d ordered, “but the fish and all these things, you cannot return it,” she said. She donated some of the canapé ingredients to charitable groups and discarded the rest. An entire city full of restaurateurs, florists and others did the same.

Heavily dependent on tourism and business travel, Barcelona has endured a difficult year, and it is not alone in suffering from the cancellation of big trade shows. Conferences and industry events were big business before the coronavirus, generating more than $1 trillion in spending each year on meeting venues, catering, hotels and travel, according to the Events Industry Council.

Barcelona normally draws 12 percent of its economic activity and 9 percent of its employment from tourism and business travel, according to the city council. Orlando, a major conference hub, generates $3 billion of economic activity in a typical year through its convention center.

For Las Vegas, big events like the CES electronics show usually bring hundreds of millions of dollars in revenue. This January, CES was held online, and the city’s visitor traffic was down by 64 percent from a year earlier. The collapse of tourism and conferences has left Las Vegas suffering some of the worst unemployment nationwide, at a rate of around 10 percent.

In Barcelona, the organizers of the annual tech gathering Mobile World Congress are counting on a comeback, and have scheduled their event to resume this year in late June. The industry association that stages the event, GSMA, estimates it will draw less than half of its previous turnout, but local travel-industry executives say they would welcome any signs of life.

“It’s not a matter of the number of attendees. It’s a matter of starting the business and the industry again,” said Christoph Tessmar, director of the Barcelona Convention Bureau.

The economic damage over the past year has been severe. About 70 percent of Barcelona’s hotels are closed. The cruise ships have stopped docking. The massive conference venue that would have hosted the 2020 tech summit was converted into a field hospital for coronavirus patients, though thankfully Barcelona never needed to use it.

Many of the city’s restaurants have gone dark, and the open ones are allowed to serve breakfast and lunch but not dinner — the regional government of Catalonia has ruled they must close by late afternoon.

Workers in most of these sectors have been furloughed, with the government paying 75 percent of their normal wages, but that benefit could run out soon.

“It’s a very sad city, I have to say,” says Bruno Halle, a hotel-industry consultant in Barcelona with Cushman & Wakefield.

To try to persuade people to attend Mobile World Congress, the organizers will require participants to undergo testing before entering the venue. Barcelona tourism officials are working with health authorities to arrange testing in hotels and at the convention center, Tessmar said.

Proof of vaccination will not be required to attend, Barcelona officials said. GSMA declined to comment on that.

Other meeting organizers are also shifting gears. The Tourism Innovation Summit, held in November in Seville, used facial recognition technology to ensure anyone entering the venue had tested negative for the virus, according to Silvia Aviles of event organizer Next Business Exhibitions.

Orlando, which experienced 73 conference cancellations after the pandemic began, has set up a broadcast studio at its main convention center to allow speakers to prerecord their talks if they aren’t comfortable speaking before a live audience, according to Casandra Matej, chief executive of Visit Orlando.

Hybrid events that are part in-person and part online are also becoming more common, said Mark Cooper, chief executive of IACC, an industry association representing conference venues.

IACC’s own July summit for the Americas will operate this way. Instead of gathering 250 people in Dallas as usual, smaller groups will convene in Dallas, Chicago and Toronto, and connect with each other online. “They can mostly travel by car or rail; they don’t have to fly. But they will still be meeting live with their peers,” Cooper said.

Some business travelers aren’t eager to get back on the road. One Silicon Valley executive who usually attends Mobile World Congress said he is likely to skip it this year because he doesn’t think enough travelers will be vaccinated by then, and he isn’t sure that testing is a reliable enough screening tool.

Meanwhile, many companies have realized they can save money by holding meetings online, which could undercut their willingness to fund business travel in the future, conference organizers say.

But some industries are agitating to meet, said Constanti Serrallonga, general manager of Fira de Barcelona, which organizes the city’s trade fairs.

A bridal fashion show that was forced to go virtual last year is keen to reconvene in Barcelona in July because dress suppliers usually win 80 percent of their annual orders at the fair, Serrallonga said.

“This event is absolutely key for this sector, because they need this to sell,” he said.

Integrated Systems Europe, an annual gathering of the audiovisual industry, is also planning to meet in Barcelona in June, and a seafood-industry summit is on the books.

Ruiz said her usual catering clients for Mobile World Congress “don’t know if they are going to come, and if they come they are not going to do a cocktail for 200 or 300 like before, where they pass canapés.”

Instead, they want individual boxes of food, for smaller group meetings, or maybe “cocktails with a few people,” she said. “It’s not really clear. It’s going to be a new way of contact.”