To understand and prevent anthropogenic climatic change by sea activities check the impact of naval warfare during WWI & WWII
A recent paper by Shuai-Lei Yao et al (June 2017) explains: Global warming can be directly linked to ocean surface temperature changes, which is characterized by two weak slowdowns in the mid-twentieth century and early twenty-first century and two strong accelerations in the early and late twentieth century. But instead of considering the possible impact man’s ocean activities during the last 150 years, they merely acknowledge that “the cooling in the mid-twentieth century and distinct intensity differences between the slowdowns and accelerations remain unclear” (Nature, 2017).
Once naval war changed the sea structure the surface temperature is likely to change on multi-decadal timescales, which is with regard to the 20th Century closely related to post WWI warming 1918 to 1939, and the post WWII cooling 1940 to 1970. These two periods show how easy human activities can change climate, and that the often heard claim of “natural variability” is merely a long-standing mystery. When Marius Årthun et al (June 2017) observe that “the North Atlantic is the key provider of a predictable northern climate” they should extent their interest in the impact of human ocean activities. Even the newly appointed U.S. Energy Secretary Rick Perry considers ocean waters as control knob in climatic matters (CNBC-interview). At least some progress is made toward acknowledging that climate prediction resides in the ocean.