United Press International: Sea levels are rising much faster than when the Thames Barrier was designed, and British officials are looking ahead to new consider flood defenses. The barrier was designed in the 1970s and completed in 1982. At the time, average sea level rise around the world was 1.8 millimeters or .07 inches a year. In the past 15 years, sea-level rise has speeded up to 3.1 millimeters or .12 inches annually — and it could accelerate with global warming. While experts say the barrier can …