Has anyone dug into the numbers related to AGW in connection to the heat content of the oceans? I’ve seen the graph on this wiki page in several places, and I did a calculation suggesting that the heat capacity of the oceans is about 5e24J/(deg C). Since the graph suggests an increase in heat content of about 1e22J/yr, this calculation implies we’ll get about 1 degree of warming in 500 years.
Is my calculation wrong? If so, why? Has anyone else looked into this?
assumes that all the surplus heat due to human activity goes into the oceans, and none into the atmosphere, and then
estimates the change in ocean temperature as opposed to any change in atmospheric temperatures.
But when people worry about AGW it usually isn’t primarily ocean temperatures they’re worried about, it’s land temperatures where people live and grow crops, and the mechanism they worry about isn’t that human activities make the oceans hotter and everything else follows along, it’s that human activities warm the atmosphere which changes human comfort and crop yields and so forth.
So, assuming the consensus view on AGW generally, what your calculation suggests is that we should expect to see the atmosphere warming faster than the oceans. (That might have interesting consequences for things like winds but I don’t know enough about this stuff for my guesses to be worth much.)
Let’s not debate the larger AGW question, just the specific one about ocean temperature. Based on the estimated rate of ocean heat accumulation taken from the graph, as well as my calculation about the heat capacity of the ocean, it appears that we will get 1 degree of ocean warming in 500 years. True or false? If false, what’s wrong with the calculation?
Heat content of the oceans is complicated because you can’t treat the oceans as a single reservoir—they have layers and these layers do not mix well. In particular, any warming of the oceans is confined to the upper layers.
You can find lots of discussion e.g. here, or, more specifically, here.
Assuming that the simplifications you’ve made are OK—which is a question for which you’d need an actual climate scientist or oceanographer—there’s nothing wrong with the calculation. I just don’t see why it’s a calculation whose answer we should be very interested in. Are you doing it just out of curiosity or is it intended to tell us something important about the impact of AGW?
Has anyone dug into the numbers related to AGW in connection to the heat content of the oceans? I’ve seen the graph on this wiki page in several places, and I did a calculation suggesting that the heat capacity of the oceans is about 5e24J/(deg C). Since the graph suggests an increase in heat content of about 1e22J/yr, this calculation implies we’ll get about 1 degree of warming in 500 years.
Is my calculation wrong? If so, why? Has anyone else looked into this?
It looks to me as if your calculation
assumes that all the surplus heat due to human activity goes into the oceans, and none into the atmosphere, and then
estimates the change in ocean temperature as opposed to any change in atmospheric temperatures.
But when people worry about AGW it usually isn’t primarily ocean temperatures they’re worried about, it’s land temperatures where people live and grow crops, and the mechanism they worry about isn’t that human activities make the oceans hotter and everything else follows along, it’s that human activities warm the atmosphere which changes human comfort and crop yields and so forth.
So, assuming the consensus view on AGW generally, what your calculation suggests is that we should expect to see the atmosphere warming faster than the oceans. (That might have interesting consequences for things like winds but I don’t know enough about this stuff for my guesses to be worth much.)
Let’s not debate the larger AGW question, just the specific one about ocean temperature. Based on the estimated rate of ocean heat accumulation taken from the graph, as well as my calculation about the heat capacity of the ocean, it appears that we will get 1 degree of ocean warming in 500 years. True or false? If false, what’s wrong with the calculation?
Heat content of the oceans is complicated because you can’t treat the oceans as a single reservoir—they have layers and these layers do not mix well. In particular, any warming of the oceans is confined to the upper layers.
You can find lots of discussion e.g. here, or, more specifically, here.
Assuming that the simplifications you’ve made are OK—which is a question for which you’d need an actual climate scientist or oceanographer—there’s nothing wrong with the calculation. I just don’t see why it’s a calculation whose answer we should be very interested in. Are you doing it just out of curiosity or is it intended to tell us something important about the impact of AGW?
Unevenly distributed. Most of the warming happens near the poles, the tropics change less.
And near the surface more than deeper.