The bigger picture of climate change

 

  Climate changes.  But there’s far more to it than greenhouse gases. Ocean circulation is a big deal.  Here’s why.  The ability to store heat (‘specific heat’) of water is 5 times that of air.  Atmospheric pressure is 14.7 lbs. per square inch.  That is, one square inch area and all the air from sea level to the ionosphere in height weighs 14.7 lbs. That’s also the weight of a 32 foot column of water (1 X 1").  So in heat storage terms a column of water about 6 feet high stores as much heat as air as high as the atmosphere. 78% of the earth is covered by water. Thus the upper 8 feet of the oceans, lakes, etc. stores as much heat as the entire atmosphere does.

            Think what this means.  A big change in atmospheric temperature makes almost no change in the oceans. During the ice ages, deep ocean water was almost the same temperature. Beyond the continental shelves, oceans are uniformly 14,000 to 18,000 feet deep (exceptions are trenches and ocean ridges).  Only the upper 150 meters ever changes temperature.  Below the oxygen mimimum zone (just a little deeper), there is almost no light, 38 degree water, almost no dissolved oxygen to rot dead plants & critters floating to the bottom.

            Greenland is warming and cold freshwater flows off the island, which stores 1/3 the fresh water in the world.  When that sinking freshwater hits the ocean, it is denser than even deep ocean water and displaces the North Atlantic Deep Water (NADW) to well up in the Grand Banks with nutrients such that ocean life has a feeding frenzy.  It also wells up near in the tropics offshore Africa where Sahara winds in the summer blow over the water and makes our hurricanes.  If you don’t get melting glaciers in Greenland, ice pack surrounds the island, there’s no NADW displacement and what little upwelling there is moves south of the equator setting up an La Nina condition in the Atlantic. The effect even caries over to the Indian and Pacific oceans The La Nina means drought from mid-USA to Central America like the dust bowl of the 30s.  As this progresses we get another ice age. But today, we live in a time of inter-glacial melting where the world constantly warms.  Ice cores from 3 million years of Greenland ice show that when an ice age starts it rapidly accelerates, often over a hundred  years or so. ¾ the arable land is lost.

            Why an ice age?  The increase of a large white polar ice cap has a reflectivity of almost 100% which further accelerates temperature decline.  How cold?  About 35F degrees is usual. If the cloudiness of skies increases as well (cloud tops have a reflectivity of 98%) the earth cools stunningly fast.  Bottom line: cloud cover and ocean circulation is an overwhelmingly large effect than CO2. 

            There’s more.  Solar radiation seems to rise and fall by about 1%.  The cause is as yet unknown.  But the fall from the 1300s to the 1800s caused a drop of as much as 10F degrees during the “Little Ice Age” of Europe and Asia. Volcanic eruptions have been shown to radically cool and disrupt crop production for 5-10 years causing mass famines.  Combined with  the nutation of the earth’s axis, these may serve to start another ice age.  We’re not sure. 24 of the last 26 ice ages correspond to nutation. Nutation is like a top that stops its smooth rotation to shudder in a few wobbles.  In the earth’s case our nutating axis tips from 22 to 24 degrees disrupting climate. Bottom line: We don’t understand all of this, but all these effects are very large compared to the 2 degrees of “global warming” due to industry that politicians love to pontificate about.