The famous Earthrise photograph inspired an awareness of the complexity and vulnerability of Earth’s climate. Today scientists are studying the interconnected dynamics between the ocean and atmosphere. One way of characterizing chaotic ocean currents is by correlating small scale fluctuations in observations. However since correlation does not imply causation, it was previously unclear how to relate correlation functions to the underlying physics of fluid transport. We have made this relationship clear using an advanced mathematical technique known as a Green’s function. We are now applying correlation functions to estimate transit times in the Denmark Strait Overflow. Improving our characterization of transport in this region may help us understand how the global overturning circulation will respond to climate change.