MONTEREY BAY NATIONAL MARINE SANCTUARY, Calif. – Far from Copenhagen's turbulent climate talks, the sea lions, harbor seals and sea otters reposing along the shoreline and kelp forests of this protected marine area stand to gain from any global deal to cut greenhouse gases. These foragers of the sanctuary's frigid waters, flipping in and out of sight of California's coastal kayakers, may not seem like obvious beneficiaries of a climate treaty crafted in the Danish capital. But reducing carbon emissions worldwide also would help mend a lesser-known environmental problem: ocean acidification. "We're having a change in water chemistry, so 20...