Global ocean temperatureThe atmosphere affects the ocean, and the ocean influences the atmosphere. As the temperature of the air rises, the ocean absorbs some of this heat and also becomes warmer.

What's happening now?
Overall, the world's ocean is warmer now than at any point in the last 50 years. The change is most obvious in the top layer of the ocean, which has grown much warmer since the late 1800s. This top layer is now getting warmer at a rate of 0.56°C (1°F) every 50 years! While one degree might not seem like a lot, think about the change from rain to snow. 

What will happen in the future?
The ocean is expected to continue getting warmer—both in the top layer and in deeper waters. Even if no more greenhouse gases are added, the ocean will continue to absorb existing atmospheric heat and get warmer for many years until it is the same temperature as the air.

Why does it matter?
A warmer ocean contributes to rising sea level due to the thermal expansion of water as we just learned. But, even just small temperature changes can affect climate patterns, cause more powerful tropical storms, and can threaten many kinds of sea life, such as corals and fish that are unable to tolerate warmer waters.  

Hurricane Isabel