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Energy to Surpass the Commitments of Copenhagen

In spite of commitments to limiting the global average temperature increase to no more than 2 degrees Celsius above pre-industrial levels, the latest assessment of the UN is that Intended Nationally Determined Contributions to the 2015 United Nations Climate Change Conference will miss that goal by at least .7 degrees.

It is anticipated that by the end of this year the global average temperature will have risen half way towards the 2 degree limit and two thirds of the way towards 1.5 degrees, which is the maximum many vulnerable developing countries have been pushing for.  

Prior to 1998 global temperatures were rising at a rate of about 0.21 degrees each decade but from 1998 to 2012 the observed rate was only 0.04 degrees.

This slowdown or “hiatus” has been attributed to the movement of heat to deeper water in the eastern Pacific Ocean as a consequence of stronger than normal trade winds.

Were we capable of perpetuating the conditions that lead to the hiatus, as in fact we are with the technology herein proposed, or even bettering that, 1.5 degrees or better is readily achievable. 

The trade winds stacked warm water in the eastern Pacific driving the thermocline down to a depth of about 300 meters. Once these winds subsided however, in 2013, this stacked water sloshed back to the east and to the surface with the result 2014 and 2015 have successively been the warmest years ever recorded.

 

Very little of this heat was mixed and diluted in the ocean abyss below the thermocline and as a result when it came back to the surface it drove temperatures off the coast of British Columbia 3 degrees higher than normal.

The oceans are the repository of 93 percent of the heat of global warming. Since warm water rises, most of this heat sits near the surface while the temperature at depth approaches the freezing point of water. This differential makes the oceans, particularly tropical waters, the largest battery on the planet.

When heat flows from a warm source to a cold sink through a heat engine, just as when electrons flow from the negative to the positive terminal of a battery, energy is produced.

It is estimated the oceans have the capacity to produce 14 terawatts of primary energy through ocean thermal energy conversion or OTEC, or about the same amount of energy as is currently derived annually from fossil fuels.

NOAA estimates the ocean battery is being charged at a rate of about 330 terawatts each year and since there is no draw down of this charge we are experiencing the escalating consequences of global warming.

Due to the low thermodynamic efficiency of a heat engine operating within the temperature range offered by the oceans, OTEC requires the movement of about 20 times more heat to the deep than the14 terawatts of power the oceans are capable of producing.

In other words, virtually all of the heat the ocean battery is currently accumulating is either converted to work or moved to deep water with this process. 

In support of this premise, in the late 1970s a team from the Applied Physics Laboratory of Johns Hopkins University estimated that the surface water temperature of the oceans, and therefore the lower atmosphere, would be reduced by 1 degree Celsius each decade through the production of 5 terawatts of OTEC power.

The relocation of this heat to the deep would be benign due to the large thermal capacity of water. It is estimated that in spite of all the heat they are absorbing, at depths from 500 to 2000 meters the oceans are warming by about .002 degrees Celsius every year, and in the top 500 meters they are gaining .005 degrees.

The benefit of this ocean heat absorption is noted by Levitus, who pointed out that if all of the heat the oceans absorbed to a depth of 2000 meters from 1955–2008, which raised their temperature by an average of .09 degrees Celsius, was instantly transferred to the lower 10 kilometers of the atmosphere that layer would be warmed 36 degrees Celsius.

It is obvious therefore that the objective of Copenhagen can be bettered by producing the energy the world demands with technology that moves the heat of global warming to deep water through heat engines.

Jim Baird's picture

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