A big swell is predicted for Oahu’s South Shore this weekend, which can be frustrating for surfers who have to work, such as Matthias Keller, who will be volunteering all Saturday morning on the shore fronting the Publics surf break in Waikiki, setting up and helping to lead the Surfrider Foundation’s annual beach cleanup and educational event celebrating International Surfing Day, which it founded in 2005.

“I will bring my board,” said Keller, 28, who has volunteered with Surfrider’s Oahu chapter since his student days at the University of Hawaii in 2010. “I usually don’t surf before a cleanup, but given the swell, I’m jonesing to get out for maybe a wave or two.”

This year there’s a new excuse to get wet: a global paddle-out organized by PURE, a nonprofit subsidiary of the World Surf League, which is partnering with Surfrider to raise awareness of and inspire actions to curb pollution and climate change.

Not to be confused with the positive surf terms thrashing, ripping or shredding, the campaign is called “Stop Trashing Waves.” According to a 2016 World Economic Forum report, if the disposal of plastics into the environment continues at current rates, by 2050 the seas will contain more plastics than fish by weight.

“Climate change and plastic pollution are areas in which our events have a footprint,” said Reece Pacheco, executive director of PURE, referring to the worldwide circuit of professional surf contests organized by WSL, which has pledged to go carbon neutral by purchasing carbon offsets and to eliminate all single-use plastics from its events by the end of 2019.

“But all surfers fly and drive; all use plastic. … We need everybody,” Pacheco said, urging surfers and ocean lovers to make their own pledges at worldsurf league.com/pure and to join or organize their own paddle-out. People have scheduled paddle-outs from the Falklands to Fiji, he said.

In Fiji, where she spends summers as a surf guide, Maui’s Paige Alms, WSL two-time big wave champion, will be paddling out, she said by phone from Tavarua.

“If it rains you see trash in the ocean in Fiji, like everywhere,” said Alms, who is one of several PURE ambassadors, including fellow Hawaii surfers Kai Lenny, John John Florence and Carissa Moore.

“The point of the paddle- out is, it’s a sign of honoring somebody, often deceased,” Keller said, “but this is also a way of honoring and making a connection to the ocean while its ecosystems are still alive.”

“The ocean has a voice but not everyone chooses to listen,” Alms said, adding that she was using her platform as an athlete to make it heard.

The event starts with 9:30 a.m. registration at the Barefoot Beach Cafe in Kapiolani Park between the Waikiki Aquarium and Queen’s Surf, and goes till noon, when lunch will be provided to cleaners. Bring your own reusable bottle, gloves and sunscreen; free samples of reef-safe sunscreens will be given out while supplies last. For more information, go to surfrider.org/isd.