Kelly Slater will look to defend his Billabong Pro Pipeline title as surfing's world championship kicks off in Hawaii this week, with the added allure of spots at the Paris 2024 Olympics up for grabs at the end of the 10-stop global tour.The 50-year-old Floridian stunned the surfing world to win the event last year in perfect conditions at the dangerous Pipeline, declaring it the best victory of his unrivalled 30-year career.But Slater faces a tough task this year with surf forecasts suggesting smaller, windier conditions that might better suit some of his rivals, who include a host of hungry newcomers and some returning veterans."He's an 11-time world champion, he's won every event on the schedule, holds every record in the sport and he continues to do mind-blowing surfing, but the truth of the matter is, it's getting harder and harder for him to win," World Surf League commentator Ronnie Blakey said.Reigning world champions Filipe Toledo from Brazil and Australia's Stephanie Gilmore have both in the past admitted to struggling with the giant tubes on offer at Pipeline and will be looking to up their games at the sport's most revered location.Gilmore, who has won a record eight world titles, is up against local wildcard and reigning champion Moana Jones Wong as well as compatriot Macy Callaghan in her first three-woman heat, the loser of which gets sent to an elimination round.In another clash, Brazil's three-times world champion Gabriel Medina, who missed much of last year's tour with depression, takes on local John John Florence, the twice world champion whose 2022 season was ruined by a knee injury.CONTROVERSIAL CUT After a two-stop leg in Hawaii, surfers head to Portugal and then on to Australia for two more