“The world’s oceans are both the most important and the most problematic piece of the earth’s climate system. They hold more than 90 percent of the climate’s heat and are its long-term memory. Conditions in the atmosphere swing wildly from day to day and year to year in response to any number of influences—that’s part of what makes untangling weather and climate so difficult. The oceans, on the other hand, change—and respond to changes—over decades to centuries.”