Average Global Sea Surface Temperatures
Average Global Sea Surface Temperature, 1880–2015
(USA Environmental Protection Agency)
- The thick orange line shows how “the average sea surface temperature of the world’s oceans” moved between 1880 and 2015.
- The temperatures have been rising since 1970.
- The grey band shows the range of uncertainty in the data.
This rise of sea surface temperature is further evidence that the planet is warming.
Another self-amplifying feedback loop
Unfortunately, when sea surface temperatures rise they can join in another cyclic sequence of cause and effect that tends to raise the temperature further.
- A warming atmosphere tends to warm the surface layers of the ocean.
- This tends to make the surface layers more buoyant.
- This tends to make winds less effective at driving upwelling, the mixing of the cold, nutrient-rich, deeper layers with the surface water.
- This tends to decrease the fertility of the oceans.
- This tends to reduce the population of phytoplankton.
- This tends to decrease the amount of CO2 that the phytoplankton consume via photosynthesis. (Phytoplankton convert light energy from the sun into chemical energy by photosynthesis, consuming CO2 and releasing oxygen in very large quantities. They produce somewhere between 50% and 85% of the oxygen in our air. P
hytoplanktonare important. )
- This tends to increase the CO2 in the atmosphere.
- This tends to warm our atmosphere, completing this cycle.