We’re covering a United Nations warning about global food supplies, President Trump’s trip to Ohio and Texas, and a series of fatal stabbings in California. | | By Chris Stanford | | Harvesting in northwestern China. A U.N. report warns that food shortages are likely to affect poorer parts of the world far more than richer ones. China Daily/Reuters | | The report, which was prepared by more than 100 experts from 52 countries, was released in summary form today. It warns that climate change will exacerbate the dangers, as extreme weather threatens to disrupt and shrink the global food supply. | | Food shortages could also increase a flow of immigration that is already redefining politics in North America, Europe and other regions. From 2010 to 2015, the number of migrants from El Salvador, Guatemala and Honduras who traveled to the U.S. increased fivefold, coinciding with an unusually dry period that left many without enough food. | | What’s next: Addressing the crisis would require a major re-evaluation of land use and agriculture as well as consumer behavior, the report suggests. Proposals include increasing the productivity of land and eating less meat. | | A protest on Wednesday in El Paso, which President Trump has described as "one of our nation's most dangerous cities." Ivan Pierre Aguirre for The New York Times | | Mr. Trump visited privately with victims, law enforcement officials and hospital workers in Dayton, Ohio, and in El Paso, where a total of 31 people were killed last weekend. He was greeted by protesters in both cities. | | The Daily: In today’s episode, our correspondents discuss the president’s trip. | | Another angle: Congressional Democrats insisted on Wednesday that any gun-related legislation moving through the Senate be accompanied by a House bill requiring background checks on all gun purchasers. Mr. Trump said he was open to such a measure, which the National Rifle Association and many Republicans oppose. | | Wanda Vázquez, center, was sworn in as governor of Puerto Rico on Wednesday in the capital, San Juan. Erika P. Rodriguez for The New York Times | | Wanda Vázquez, the former secretary of justice, took the oath as the territory’s governor on Wednesday after its Supreme Court ruled that her predecessor, Pedro Pierluisi, was sworn in last week on unconstitutional grounds. | | Mr. Pierluisi’s 120 hours in office made him the shortest-serving governor in modern Puerto Rican history. He had replaced Gov. Ricardo Rosselló, who resigned after huge public protests. | | A man fatally stabbed four people and wounded two others in Southern California on Wednesday in what appeared to be a series of random attacks, the authorities said. | | A 33-year-old suspect was arrested at a convenience store in Santa Ana, about 30 miles southeast of downtown Los Angeles. A security guard at the store was among the dead. | | The details: The police said that they didn’t yet know the motive but that the suspect was also thought to be responsible for several robberies. | | Mary Turner for The New York Times | | Scotland, the setting of the ’90s-era novel-turned-film about addiction, is finding out what happens as opioid abusers hit middle age. | | Overdoses are more common there, by some measures, than in the U.S., and the way Scotland is responding may provide answers for other countries grappling with the same issue. | | PAID POST: A MESSAGE FROM CAMPAIGN MONITOR | Email Marketing 102: Work smarter, not harder. | Working smarter means running beautiful, results-driven email marketing campaigns – without sacrificing any bandwidth along the way. And with Campaign Monitor, you'll have access to a drag-and-drop email builder, a gallery of templates, and personalized customer journeys – all the tools you need to replace ‘harder’ with ‘smarter.' | | Learn More | | | Immigration raids in Mississippi: Almost 700 migrants were arrested in what federal officials said might be the largest worksite enforcement action in a single state. | | Canadian murder suspects: After a two-week hunt, the bodies of two teenagers suspected of killing three people were found in Manitoba, the authorities said. | | New claim against Jeffrey Epstein: The billionaire mogul Leslie Wexner said that his former money manager, who is accused of sex trafficking, “misappropriated vast sums.” | | Filippo Monteforte/Agence France-Presse — Getty Images | | Snapshot: Above, security personnel patrolling the Spanish Steps in Rome this week. Sitting on the steps is subject to a fine of 400 euros, or about $450, under a new ban on a variety of activities “not compatible with the historic and artistic decorum” of the city’s tourist attractions. | | What’s that smell?: The observatory at One World Trade Center, one of New York’s top tourist destinations, has an official fragrance, pumped through the air vents. (It smells of trees, with some citrusy notes.) Reviews are mixed. | | What we’re reading: This article in Cosmopolitan. “Please do not try to convince me after this week that we’re not in a post-apocalyptic future far more dire than ‘Back to the Future II’ imagined,” says our Magazine writer Taffy Brodesser-Akner. “I am consoled only by great stories like this one, by Andrea Stanley, about the A.D.L.’s best weapon against hate, a savant who is like a ‘Minority Report’ precog for white supremacists and anti-Semites.” | | David Malosh for The New York Times. Food Stylist: Simon Andrews. Prop Stylist: Paige Hicks. | | Listen: “All Mirrors,” the first single from Angel Olsen’s fourth album, is a sharp turn into a more theatrical, melodramatic presentation, our critic writes. | | Smarter Living: “There’s a lot wrapped up in the word ‘no’ for women — beginning with the fact that women are expected to say yes (and feel guilty when they don’t),” writes our gender editor, Jessica Bennett. So, following the example of a professor at New York University and two colleagues, she’s starting a “No Club,” and inviting you to join. | | Rubber duck races started in Canada in the 1990s and are now fund-raisers the world over. London claims the title for most ducks — 250,000 in the River Thames in 2008. (Last month, the start of the London race was delayed because real ducks got in the way.) | | Rubber ducks floating down the Chicago River in the Windy City Rubber Ducky Derby in 2017. Scott Olson/Getty Images | | Racing ducks are different from the bathtub variety: They are made with a weighted bottom. | | The toy had its origins in the mid-1800s, about the time the American engineer Charles Goodyear figured out how to make rubber malleable. The first rubber ducks were meant as chew toys and didn’t float. | | The Russian-American sculptor Peter Ganine gets credit for the design of the rubber ducks we know now, patenting his in 1949 and selling 50 million of them. Disney and “Sesame Street” helped. | | That’s it for this briefing. See you next time. | | Thank you Melina Delkic helped compile this briefing. Mark Josephson, Eleanor Stanford and Chris Harcum provided the break from the news. Victoria Shannon wrote today’s Back Story. You can reach the team at briefing@nytimes.com. | | Were you sent this briefing by a friend? Sign up here to get the Morning Briefing. | | |