Written by Dr Klaus L.E. Kaiser
The latest news, as per the Canada Journal: Oceans are warming so fast that readings are now off the chart, Report. There you have it: from now on it’s gonna be fried or steamed fish only.
That ought to get your attention: 15×10^22 Joules or more of additional ocean heat energy, all in the last 30 years or so. The fish must just about be jumping out of the water and into the (presumably cooler) frying pan.
Perhaps though, some sobering thoughts may be appropriate. Let’s start with small freshwater lakes. The kind you have all over the Ontario, Quebec, and some States in the U.S., a vast area of rather impermeable granite. Snow melt and rain water there collects in every dimple. If those dimples are large and deep enough not to have their contents evaporate in the summer’s heat, they are called LAKES.
A good part of the year these lakes are covered by a layer of ice, one meter (approx. 3 ft.) deep. In the spring, when it finally gets warmer, that ice slowly starts to melt. Only 100 miles north of the metropolis Toronto (Ontario), that time arrives between mid-April and mid-May. However, even when the ice is gone, it’s not time to go frolicking in the water. For that, you have to wait another month or two, or three, like to the end of July. Then the surface water temperature gets to be pleasant, like 20-25 °C (70+ °F); however that’s very close to the surface only.
When I went to take my NAUI (National Association of Underwater Instructors) open water checkout dive, in the middle of June in Georgian Bay at Tobermory, my quarter inch wet suit with hood, gloves and boots left me with an inch of forehead directly exposed to the water. That was enough to cause excruciating pain upon entering the water, at least until the skin became so numb not to feel it anymore.
Since then, I have snorkeled in various lakes in mid-summer, i.e. the months of July or August, without a wet suit. At that time of year, the surface temperature is quite pleasant but already when treading water you can feel your toes to be in a cooler environment. Diving down to a depth of 15-20 ft., you’ll be surprised how drastically the temperature changes. It’s like stepping naked into a deep freezer. Once you hit the thermocline, perhaps 10-15 ft. below the surface, the water temperature drops right down to 38 °F (4 °C) and it’s pitch dark as well so that in many of the smaller lakes you cannot even see your own hands anymore. In larger freshwater bodies and the oceans things are a bit better.
To begin with, oceans have much less humic materials (from decaying plants) that cause the dark color of the water in most of the shield lakes. Therefore, you can see quite well down to a few hundred feet of depth. Also, with the prevailing large currents there is a constant exchange of tropical warm with colder polar water. Still, at mid-range latitude, the oceans’ surface water is nowhere really warm.
The seminal work by Nathaniel Bowditch (1773-1838), the American Practical Navigator and its later editions shows that approximately 50% of the ocean’s surface water never gets any warmer than 70 °F (21 °C). Of course, in the tropical areas of the oceans, the thermocline (see graph below) is much deeper than in the thousands of small lakes in the Canadian Shield or even in the Great Lakes. For example, in Lake Erie (26,000 km^2) it typically is at a depth of 25 ft., even in mid-summer, while in the tropics in the oceans it is around 1500 ft. (500 m). Still, as Bowditch states, even there in deep bottom waters of the tropics, the temperature can be close to 28 °F (-1.5 °C) as the salinity lowers the freezing point to that temperature.
In order to visualize the thermocline, let’s look at a mid-Pacific temperature profile, as shown in the graph below from the ARGO float project (http://www.argo.ucsd.edu). The black line in the graph shows the temperature vs. depth. At this particular station and time (20.25N 121.4W, May 15 2004), you can see the temperature declining slightly from around 23 °C (74 °F) at the surface to 20 °C (at approximately 100 m) and rapidly declining down to 10 °C or 45 °F at 200 m. The zone with the sharp temperature gradient is called the thermocline.
Ocean Heat Content
Let’s get back now to the true meaning of the multi-magnitude increase of the ocean heat content as given at the top. In order to put that into perspective one needs to calculate the amount of additional heat energy in a liter or gallon of ocean water in terms of temperature.
That is easy to do: The earth’s oceans contain approximately 1,335,000,000 cubic kilometer or 1.3×10^21 liter of water. Assuming the claim of an additional 150 J/liter heat content in ocean water over the last few decades is correct, how does that translate into degrees of temperature?
As one liter of water gets warmer by 1 °C for every 4,200 J of energy, we are talking about (150/4200) = 0.03 °C or 0.05 °F, not exactly something to get excited about. Even if most of that additional heat energy were to be found in the photic zone, i.e. above the thermocline, it would likely extend the thermocline to a slightly deeper depth. As most of the oceans organisms live in that photic zone, it could only help to increase their habitat. If there is any drawback to be found at all, perhaps I can summarize it as follows:
Your fresh in-the ocean-steamed-fish will take a few more billion years to arrive.
Dr. Klaus L.E. Kaiser is author of CONVENIENT MYTHS, the green revolution – perceptions, politics, and facts convenientmyths.com
Dr. Kaiser can be reached at:email@example.com