Climbing forces measure the total "push" or "pull" on a person or gear. Climbing equipment is rating for a specific force in kilo-newtons. Petzl has measured the forces involved in lead falls (link) and found that a lead climber typically experiences 2.5-4kN during a fall. Climbing slings are rated to at least 22kN. Carabiners are rated to at least 21kN.