From data in the links provided below, it appears that current temperature rise of the world ocean would be enough to raise a volume of water more than 100 times greater than Sydney Harbour from freezing to boiling point every day.
World Ocean Heat Content
Graph Credit: Adapted from S. Levitus et al., Geophys. Res. Letts.; © AGU 2012
For those who imagine that the stability of global air temperature at record high levels over the last decade means we can keep cooking the planet, think again - the heat is going into the oceans.
Science Magazine states
"Global warming contrarians remind the public that the world has not warmed all that much, if at all, during the past decade or so. But that's the atmosphere. Oceanographers with their thermometers in Earth's biggest reservoir of heat—the world's ocean—report in a paper to be published in Geophysical Research Letters that greenhouse warming has in fact been proceeding apace the past decade, not to mention the past half century. Ninety-three percent of the heat trapped by increasing greenhouse gases goes into warming the ocean, not the atmosphere. So taking the ocean's temperature is the most comprehensive way to monitor global warming. A group of National Oceanic and Atmospheric Administration scientists has revised and updated their decade-old compilation of temperature measurements from the upper 2000 meters of the world's ocean. Its store of heat (red line with error bars in graph above) steadily increased over the past 20 years. And the upper ocean has warmed so much in the past 50 years that its added heat would be enough to warm the lower atmosphere by about 36°C (thankfully a physically impossible feat).
This data is from an article since published in Geophysical Research Letters
GEOPHYSICAL RESEARCH LETTERS, VOL. 39, L10603, 5 PP., 2012
World ocean heat content and thermosteric sea level change (0–2000 m), 1955–2010 by S. Levitus National Oceanographic Data Center, NOAA, Silver Spring, Maryland, USA et al
Key Point: The rise in world ocean heat content since 1955 is due to the increase in atmospheric greenhouse gasses
- updated estimates of the change of ocean heat content and the thermosteric [heat induced] component of sea level change of the 0–700 and 0–2000 m layers of the World Ocean for 1955–2010.
- estimates are based on historical data not previously available, additional modern data, and bathythermograph data corrected for instrumental biases.
- heat content of the World Ocean for the 0–2000 m layer increased by ... 0.09°C.
- Ocean accounts for approximately 93% of the warming of the earth system since 1955.
A discussion of this material is at http://www.skepticalscience.com/Brea...ill_A_LOT.html
This post notes that the ocean is very big, and claims (with an apparent mathematical error) that the tiny temperature increase found by such studies has been enough to boil Sydney Harbour dry twice a day. Checking the numbers (see below) suggests the real magnitude is far worse.
How come? This massive heat increase is due to humans adding CO2 to the atmosphere, which lets light enter from the sun but does not let heat escape. CO2 is like a transparent blanket. "NOTHING ELSE FITS THE EVIDENCE... When the first analyses of Ocean Heat Content calculated from old temperature data from the oceans were first published in the early 2000's, they were described as the 'Smoking Gun'. Because they were. They are the primary observational evidence for Global Warming and the human nature of it."
The graph of World Ocean Heat Content above shows a very clear and obvious direction upwards. The average temperature of the ocean at any given time is hotter than at earlier times. The ocean is the main repository of heat on the earth surface, containing about 1.3 bilion teralitres of water, and is responsible for an estimated 93% of global warming. Unlike the atmosphere, which has been in a hot lull since the turn of the millennium, the ocean temperature has continued its remorseless increase. So showing that the "missing heat" from the last decade can in fact be seen in the main repository is correct analysis of the whole system.
0.1 degrees is small. But the ocean is very big. All of that extra heat, with its continued upward trend, has to have come from somewhere. Energy cannot be created or destroyed. As the scientific paper and summaries explain, the only plausible explanation for this obvious heating trend is the extra blanket we have added to the air through CO2 emissions.
The Sydney Harbour example is just a vivid way of showing how big this heat increase really is. The Harbour seems big, but it is tiny compared to the whole ocean. If all the extra heat measured in the whole ocean had been concentrated in a body of water the size of Sydney Harbour (known as a Sydharb in Australian water circles), 0.1 degrees over the whole ocean would reportedly be enough for 100 degrees every twelve hours.
Lets look at the calculations
0.1 Degrees for 1.3 billion teralitres over 50 years (world ocean)
= 100 Degrees for 1.3 million teralitres over 50 years
= 100 Degrees for 26,000 teralitres over 1 year
=~ 100 Degrees for 40 teralitres over 12 hours
In fact Sydney Harbour only contains 0.56 teralitres. So it seems there is a mathematical error in the Skeptical Science source I cited above, and the amount of measured ocean warming could bring to boiling point [edit to change - not boil dry] more than 100 Sydharbs every day, starting from freezing point [edit to change - not starting from ice]. While the GRL data only covers the top two km of the ocean, assuming no heat change for the deep ocean would only cut this estimate by half, to 50 Sydney Harbours per day.
Readers are welcome to check my calculations here. Once we understand the orders of magnitude, the steady continued rise in ocean temperature translates to a massive system heat increase, that has to go somewhere. We are accelerating the addition of the CO2 blanket, and now there are feedback loops from Arctic methane, etc. This illustration suggests we will hit climate tipping points faster than we realize.