Warmer oceans matter

Some people might argue that oceans aren't warming much and so we've lots of time to mitigate global warming. (See recent article.)

Thing is oceans are warming quickly, and it does matter. It matters to the creatures that live in the oceans for a start. Anyone who has had an aquarium knows that some fish are very sensitive to temperature. Sure, they can swim to where it's cooler if it gets too hot for comfort but there's no guarantee they'll find a source of food there that they like. Many fish have been moving to cooler waters as fishers have known for a while. The fish in the coolest waters don't have any such luck. They've run out of options. Add warming oceans to increasing acidification and marine life is getting a double whammy. (Which reminds me, I must finish that promised article soon.)

It also matters to species like us who live on the surface. That's not just because it affects a major source of food (fish) but because of the ocean-atmosphere connections. Warmer oceans means a warmer ocean surface, which has an impact on surface temperatures on the land as well. Plus there are impacts on ocean currents (with consequences for the atmosphere) and melting ice, which are not insignificant.

"Changing a unit to have a small sounding number doesn't actually change anything"

Deniers tend to downplay ocean warming, calling it "minuscule". Some will quote the change in ocean temperature rather than the change in ocean heat content. As Gavin Schmidt once wrote in a comment on this subject at realclimate.org, when someone else wanted to talk about the energy accumulated as a temperature rise rather than joules:

Changing a unit to have a small sounding number doesn’t actually change anything; neither the significance nor the accuracy. .... – gavin

It takes an awful lot of energy to have a measurable rise in temperature of a body of water measuring 1.3 billion cubic kilometers. We are very fortunate to have such a large body of water to soak up most of the extra energy we've decided to store on earth.

Just think. If instead of warming the ocean, all the extra energy that went into the oceans over the past thirty years or so instead went into warming the atmosphere. Here's a chart of ocean warming again:

Here's a quick calculation. Say since around 1980 there's been approximately 2 x 10²³ joules of energy accumulated in the ocean. (That's just a rough number, but we'll use it for the sake of the exercise.) The atmosphere has a mass of 5 x 10¹⁸ kg and a heat capacity of 1000 J/kg/K. That means that if instead of going into the ocean, that energy had gone into warming the air, then the atmosphere would be around 40°C hotter than it is today - and none of us would be around to realise it.

Of course it didn't happen and it won't and can't. Not only does the ocean absorb most of the extra energy, but there are mechanisms like the water cycle, which moderate the warming.

Still, it's just another way of thinking about what we are doing by warming the globe.

I'll add this graphic from SkepticalScience.com. It's a bit old, being based on the IPCC AR4 report, but it's close enough. It illustrates where all the extra energy is going,

Bob Tisdale pays homage

I see that Bob Tisdale at WUWT (archived here) has written another article on ocean warming. In doing so he paid homage to SkepticalScience by borrowing the title from one of their recent articles. Actually, that was a repost of an article by Richard Allan for NOAA, but I couldn't resist the dig:) Go read it at one or the other websites. It's full of good information.

Bob hasn't added much since his last article on the subject, which I wrote about already. He is still trying (and mostly succeeding) in persuading his readers that the oceans have only warmed a "minuscule" amount. He's wrong of course, as usual.

Bob also seems to think my recent article was "reality impaired" and "nonsensical" but he doesn't say what he found unreal about it or which bits he thought were nonsense. On the contrary, in his latest article, about the only thing new was that he added the chart of ocean heat content, and acknowledged that 90% of the extra energy is going into the oceans. Both of these ideas were a direct take from my article, which contradicts his allegations of nonsensical and unreal. You could call it his homage to HotWhopper. (He also almost, but not quite, thanked me for deleting his address from one of the comments. It's a shame he doesn't share my respect for the privacy of other people.) Oh, and he managed to find a search term that will bring up all his drawings in Google, at least for him, if you're interested. Which I doubt. Not everyone will find the same.

From the WUWT comments

Although this isn't predominately an article about WUWT, I'll still give you a some gems from the comments to Bob's latest article.

mwh wants to wait for a "cooling cycle" before he accepts global warming.

November 30, 2014 at 5:43 am
I find it incredible that after just 10years of data there is an assumption in the warmist camp that we now know what the oceans are doing when it comes to heat. Also I note that a lot of CAGW graphs on the top 2000m use a start date in the 1950s as if the data accurately and continuously goes back to then.
Until we have completed a global warming and cooling cycle we cant possibly know what, how and when the oceans are storing/releasing heat. 60 years maybe…..that would be 2 climate cycles at least. I would think that it is more likely to be centuries before full sense of the data can be made

Alx is a bit slow on the uptake and didn't realise that the title of my article was a reference to Bob Tisdale claiming that ocean warming was caused by the ocean getting hotter.

November 30, 2014 at 8:31 am
I made the unfortunate choice of clicking on a link in the article which brought me to hot whopper. In an earlier response to a comment I suggested alarmists would be soon claiming boiling oceans, but yet was still surprised to see this heading to the article the link brought me to.
“
Why did the water in the kettle boil? Because it got hot!

Yes, that is correct the ocean temperatures rising at a rate of 3 hundredths of a degree centigrade per decade warrants a comparison to a kettle of boiling water. Hot Whopper, apparently a place where common sense is avoided like Ebola. I was tempted to a add a comment telling them to no longer invest in saunas since in 15,000 years the oceans will be boiling, but then thought better of it. Who knows maybe stupid is more contagious than Ebola at Hot Whopper.

 Eugene WR Gallun thinks oceans have been getting hotter, like, forever and ever, and wonders what he's missing.

November 30, 2014 at 1:02 pm
i have a question.
It seems to me that the oceans did not magically start absorbing heat when CO2 rose a few years back. The oceans must have been absorbing heat before CO2 rose. Even if we grant that there has been a rise in surface temperature of a couple degrees with the rise in CO2 — that rise in temperature is very small compared to the previous surface temperature. (Starting surface temp. +_extra CO2 heat of a couple of degrees is still almost the same as the starting surface temperature.)

Therefore most of the heat absorbtion occurring now was occurring before the rise in CO2. So if you measure the heat rise of the oceans now — it must be rising at almost exactly the same rate as it was before the rise in CO2 and the extra heat that CO2 has supposedly generated.

So it seems to me whatever rise is being measured in ocean temperature is “natural” and is a function of the surface temperature and has been occurring for thousands of years — with the new extra CO2 heat adding practically nothing to that rise.

You seem to be attributing all the rise in ocean temperature (as small as it may be) to CO2 heat. But really on a tiny tiny percentage of that tiny tiny rise could possible be caused by CO2 heat.

My question? What am I missing? I drank more Wild Turkey for Thanksgiving than I ate of turkey and seem to have suffered extensive brain damage. So is my idea a turkey that can’t fly???
Eugene WR Gallun

 jimmi_the_dalek is a rare bird at WUWT. I haven't checked his statement about the top 3 metres of ocean, but his conclusion is on the money.

November 30, 2014 at 1:35 pm
Well it is just as well the heat is hiding in the oceans. I remember reading that the top 3 metres of the ocean has as much heat capacity as the whole of the atmosphere. So if enough heat is accumulating that the top 2000 metres is raised by 0.03C/decade, just think what would have occurred if all that heat had ended up in the atmosphere – better hope we don’t get any 1998 style El Nino’s soon.

John Finn is the other rare bird. Again, I haven't checked his calculations but again his conclusion isn't bad. There were only two such rare birds I noticed, out of 149 comments. Or 1.34% of the people commenting. Now that's what I call minuscule.

November 30, 2014 at 4:20 pm
While Bob’s post is undoubtedly correct, it is worth noting that the accumulation of energy in the oceans looks to be reasonably consistent with Hansen’s energy imbalance estimate of 0.85 watts/m2.

If we assume all ‘excess’ energy has gone into the oceans since 2005, i.e. the surface/air temperature has remained unchanged and nothing has gone towards melting ice then the 8.64×10^22 Joules per decade equates to an imbalance of ~0.76 watts per m2. That’s based on a quick calculation made after a couple of pints and a brandy so I could be wrong – but I don’t think I’m too far out.

If correct, though, it does suggest that surface warming could pick up quite strongly again in the future.