Fifty million tons of warm tropical sea water would make a spectacular gift, especially if it included sea life. That's the gift the Kuroshio current gives Japan. Every second.
Fifty million tons of warm water arrive every second in the seas surrounding Japan, bringing warmth and rain and fertile grounds for sea life. The current makes the region viable for agriculture and limits the severity of winters, much like the Gulf Stream that provides warmth to the eastern U.S and to the U.K. 
Did you know such currents are tied to climate? And they vary from year to year. Imagine the complex physics of such a machine. Equatorial warmth, rising and expanding water, deeper waters drawn upward, planetary rotation distributing the upwelling, flow toward cooler climes where, as temperature falls, increasing density causes descent to the depths, and the cycle repeats. El Niño and La Niña are complex weather patterns resulting from variations in ocean temperatures in the Equatorial Pacific. They affect continental weather patterns and the deep ocean current cycles as well. |
| Dead coral reef, bleached by increasing ocean acidity and warming waters. |
Sea life and biomass go with the flow, great quantities of gases are absorbed and processed, and the chemistry of the sea water fluctuates over the millennia.
Recent changes in atmospheric carbon dioxide are contributing to the ocean's dramatic acidification. A third or so of our fossil fuel CO2 emissions are absorbed by the oceans; that's around 10 billion tons per year added to the ocean chemistry. The changing aquatic environment is killing the coral reefs, and not slowly. The current rate of change is now 100 times faster than any changes in ocean acidity in the last 20 million years, raising questions of whether all marine life can adapt to the changes. The scope of impact is under continuing study.
The severity of the issue has prompted suggestions of deliberate climate engineering as a mitigation. What machine might we engineer that could process 50 million tons of water per second and deal with 10,000 million tons of CO2 each year? Curious? Take a look for yourself.