Sunday, October 13, 2013

The Nature and Extent of Global Warming, Affecting Our Entire Planet

Global Warming is Affecting Our Entire Planet

Article by S. Tom Bond, Retired Chemistry Professor & Resident Farmer, Lewis County, WV

Most are aware that global warming has not increased as fast recently as it did a few years ago. Global warming deniers made sure of that, while frequently saying global warming has slowed down, implying the heating process had decreased. Not so! The energy is being held in, prevented from escaping from the earth, the same as before, and as the relentless increase in carbon dioxide continues, somewhat more every single day.

The heat retained is going to warm other things than the air. For the transfer of heat from one object to another, the first object (the air which has been heated by infrared radiation) has to be warmer. The greater the difference, the faster the heat transfer. The air is not warming as fast, because it is now transferring much of the heat energy to other bodies that must be warmed simultaneously (because there is no insulation between them).

Chief among the places the retained heat goes is the ocean. As one goes down in the ocean the water becomes colder, because cold water is more dense. Water cooled at the poles sinks under the rest of the ocean, and the coldest water is near the bottom all over the world. The data in the World Ocean Database includes nine million temperature profiles.

The proportions of where the heat goes is shown here.

 (J is for joules, which is a measure of heat energy.) Only 2% of the heat is stored in the atmosphere by raising its temperature, the rest goes to the other sources shown.
This article discusses the heating of the ocean in the last 30 years. The National Oceanic and Atmospheric Administration (NOAA) regularly posts information on the amount of heat stored in the ocean. In terms of energy it is equivalent to exploding a Hiroshima size atom bomb in the ocean every second for thirty years!
That article approaches the subject in more detail, including the el Nino – la Nina cycle, one of several mechanisms mixing the warmer water into the deep, and how climate deniers (devoid of elementary physics knowledge) have tried to distort the facts. Caution! The article is nerdy!

The graph referred to in the second reference is published by the Intergovernmental Panel on Climate Change, see here. The graph shows that 0. 45 x 1022 J of energy is going to melting ice at present, in glaciers in Greenland in Antarctica, and in the Arctic sea ice. Some 14.2 x 1022 J goes into the oceans. Some 0.75 x 1022 J goes into warming land and 0.5 x 1022 J into warming the atmosphere. The relative proportions are: 89.3% to the ocean, 2.8 % to melting ice, 4.7% to warming land, and 3.1% to warming the atmosphere.
Carbon dioxide readily dissolves in the ocean making it more acidic because the CO2 reacts with H2O to form carbonic acid. In some areas, it is now so acidic that sea shell formation from calcium carbonate, including coral, cannot form. But that is another sad story.

There have been two articles in Science, the journal of the American Association for the Advancement of Science, one of the top scientific journals in the world, relating to melting Antarctic ice. One is in the 19th of July issue and the other in the 13th of September issue. Previously it was believed the principal ice loss from the floating ice tongues that extend out from the glaciers inland was the “calving” of icebergs – some of them miles across. It is now known that an even larger ice loss comes from melting on the underside of these seaward extensions of the glaciers. The thickness of the ice can be measured by radar, since reflections occur both from the surface of the ice and the level it reaches the water or land below the ice. Also remote subs are sent under the ice for pictures and holes are bored in it (by hot water, interestingly) and instruments lowered. These devices allow scientists to measure temperature, salinity, and plot the ice undersurface against the sea water below (ice excludes salt when it freezes).  

The authors of 13th of September article in Science were primarily interested in the mechanism of glacier extensions into the ocean. They found an average melt rate of 33 meters (108 feet) per year on the underside of the 1300 to 1600 foot thick West Antarctic Pine Island Glacier and found a system of channels with water as much as 2.5 Fahrenheit degrees warmer than the melting point of the ice.

The authors of the July article were concerned with quantifying the melt from all glaciers around Antarctica. Their result was 3125 gigatons or  3.125 x 1015 metric tons which compares with 1.089 x 1015 metric tons lost by “calving,” ice bergs breaking away from the other edges, established by others. They found temperatures below the shelves as much as 5.4 Fahrenheit degrees above the melting point of the ice. The most rapid melting was in East Antarctica, South of Africa.

So here in simple terms is what happens. Infrared and other radiation from the sun enters the atmosphere, and is reflected back into space. There is a balance between incoming and outgoing radiation which determines air temperature. When carbon dioxide, methane and certain other gases enter the atmosphere in greater quantities than the long established balance, the outgoing radiation is decreased, and the air becomes warmer, which is called the green house effect. A certain amount of green house effect is necessary to keep the planet warm enough to keep water liquid and our earth inhabitable. The balance is very sensitive, however.

When additional green house gases enter the atmosphere, even a few parts per million, the air warms. This is what most of us are familiar with at this point, due to a simplified discussion in the news media. However, the air also warms the surface of the land and the ocean. A slight increase in air temperature makes a slow increase in sea temperature, but the water requires much more heat to warm it than air does, much more because of the greater volume of the ocean and the greater heat capacity if water, compared to air. The ocean is vast, it is warmer on the surface, normally somewhat below the temperature of air above it in the tropics and middle latitudes, and somewhat warmer in the arctic. Warming of the ocean, which is much studied, explains why increases in the temperature of the air has slowed, the extra heat is now mostly going into the oceans, warming them.

Now a third phenomenon has begun. The slightly warmer ocean water has begun to melt the extensions of Antarctic glaciers as well as the Arctic floating ice. The ice has far greater heat capacity (heat needed to melt it) than water, so it is taking heat from the ocean water in contact with it, retarding the temperature change of the ocean water. Antarctica was formed some 96 million years ago, and has been freezing water that has evaporated from warmer areas of the planet, so a vast amount of ice has accumulated even in the seaward extension of the glaciers there.

Thus, the condition of our earth is in the balance and the dangers for our future are real and profound.