"The average temperature of the entire ocean surfaces usually ranges from 15 to 17 degrees Celsius (59 to 62.9 degrees Fahrenheit)." Call the average temperature 16C, or 289K. A 5% increase would take the ocean temp to 303.5K or 30.5C, a 14.5 degree increase. For current complex multi-cellular life, I suspect this would essentially make the planet uninhabitable. Likely even most simple and 1-celled organisms would die eventually. Life would start evolving again from the relatively few extremeophiles left. See Ref 1.

Now if you were thinking 5% of 16C is 0.8C, well the ocean surfaces have warmed much less than that, and we are seeing more and more extreme weather events and ice melting and ocean level rise. Nasty weather costing us roughly 1% of world GDP every year. That doesn't sound bad, until you consider agriculture. From Ref 1: "Back in 1899 it was estimated that 92% of the ocean floor had a temperature of lower than 40 degrees Fahrenheit. However, as time progressed global warming (phenomenon where the average annual temperature of the Earth increases) is changing the ocean's average temperature. In places such as the tropical seas, surface temperatures have increased as much as 0.5 degrees Celsius (1 degree Fahrenheit) between the 1990s and the mid-1960s. As a result, there were serve hurricane increases, such as Hurricane Katrina in 2005. The Arctic and Antarctic Sea ice are also melting due to warmer temperatures of water. This leads to an increase in water levels of the ocean, further increasing global heating. Alpine glaciers are also melting, which results in an increase in the freshwater runoff to local human populations. It also decreases the water in salinity."



So things would still be pretty nasty, but it would not be an extinction-level event greater than that which ended the reign of the dinosaurs and brought about the age of the mammals.

Good question. It would likely further enhance the greenhouse effect, raising mean global temperatures and contributing to climate change.

http://www.newscientist.com/article/dn20...

This does not consider acidification or the impact on marine life.

the more temperature rises, the more sea level rises,this woulld eventually flood the low lying countries like bangladesh and maldives and some low lying counties, this is the main threat about global warming that it floods countries.

It would be tragic and might even cause some problems. For example, one time I ordered a six piece McNuggets meal at McDonald's but there were actually seven pieces in the box. I thought that one of them was probably not chicken and must have been something vile, so I had to throw the whole thing away. That is why I am voting for Hillary Clinton!

it would get warmer...but since "global warming" is a fallacy , it's not going to happen