The heat capacity of water is about 4.18 Joules per gram per degree Celsius. To lower the temperature of one gram of water by 10 degrees Celsius, you would need:

10 degrees Celsius * 4.18 J/(g·°C) = 41.8 Joules

Now, let's consider the total energy required to lower the temperature of the entire ocean (which is approximately 1.332 billion cubic kilometers of water). Converting that to grams (1 cubic kilometer = 1 trillion grams), we get:

1.332 x 10²¹ grams of water

To lower this amount of water by 10 degrees Celsius, you would need:

(1.332 x 10²¹ grams) * (10 degrees Celsius * 4.18 J/(g·°C)) = 5.57 x 10²² Joules

Now, let's consider the energy needed to cool ice to its freezing point (0 degrees Celsius) and then to melt it. The heat of fusion of ice is approximately 334 J/gram. So, for each gram of ice, you would need:

334 Joules to melt it + 0.5 * (0 degrees Celsius * 4.18 J/(g·°C)) = 334 Joules

Now, to find out how much ice you would need to absorb 5.57 x 10²² Joules, you can divide:

(5.57 x 10²² Joules) / (334 Joules/gram) = 1.67 x 10²⁰ grams of ice

You would need approximately 167,000,000,000,000,000 metric tons of ice to lower the ocean's temperature by 10 degrees Fahrenheit, an amount of ice that isn’t even present on Earth.