This post addresses questions of interest namely:
- To what extent is the temperature of the surface of the sea simply a reflection of a variable rate of mixing of the volumes of cold water from high latitudes and the deep ocean into the warmer waters of low and mid latitudes?
- To what extent is the variation in surface temperature due to a change in cloud cover?
- To what extent is the variation in surface temperature due to a ‘greenhouse effect’ as the carbon dioxide content of the atmosphere increases?
At the outset we can dismiss the notion that a greenhouse effect drives surface temperature. The Southern Hemisphere has not warmed in December for seven decades. In logic (science) one instance of failure is sufficient to reject a hypothesis. If one persists with a failed hypothesis one is engaged in a religious observance rather than science.
Figures 1 a,b,c and d are tendered in support of this observation
Figure 1 a, b, c and d. data source Kalnay et al reanalysis here. The arrow in 1d is horizontal.
It is plain from the data in figure 1 c that temperature evolves differently according to the month of the year, that it increases and decreases and the rate of change is highly variable.
If we are to understand climate change, it is the highly variable evolution of surface temperature from month to month that we need to explain.
EVOLUTION OF TEMPERATURE ACCORDING TO LOCATION AND TIME
To investigate the mixing of cold with warm water and temperature change due to cloud effects, it is useful to look at raw data that describes the surface temperature of the ocean at a moment in time.
The Earth can be divided into discrete zones according to latitude and longitude. Figure 2 represents one of these zones at 30-40° north latitude. Plainly, there are zones in the North Pacific Ocean where temperature has declined over the last seventy years.
For this analysis the globe can be divided into twelve zones according to longitude in each of four latitude bands namely 30-40° south, 0-30° south, 0-30° north and 30-40° north. In zones dominated by land data is not reported. The upshot is that there are twenty nine zones with large bodies of water to consider.
Figure 3 shows sea surface temperature on the 17th of September 2016. Superimposed are numbers indicating whole of period change for both January and July, the two months that are known to exhibit the greatest variability. Note that it is the change in the Excel calculated trend line that is reported here rather than simply the difference in the temperature between the first and last month.
For clarity the data is presented again in table 1.
If we consider increases of 0.9° C and more as notably extreme, it is in the southern hemisphere in the 0-30° latitude band and the 30-40° south latitude bands that extreme warming is observed. Look for the numbers in white on the map and the cells in yellow in in table 1.. Change smaller than 0.2°C is marked in green and enclosed with a border.
Generalising we can say that temperature advance is more a southern than a northern hemisphere phenomenon. Between the equator and 30° south the increase in January is notable. At 30-40° south the increase in June is notable. The Pacific is both peaceful and more stable in its temperature than the Indian and Atlantic Oceans. Some areas of the Pacific are cooler today than they were seventy years ago.
Why does temperature change exhibit such diversity?
WIND AS DRIVER
The lowest surface atmospheric pressure occurs in the Antarctic circumpolar trough that is located over the Southern Ocean on the margins of the Antarctic continent. There is no counterpart to this extreme trough in surface pressure in the northern hemisphere where moderately low surface pressure is found over the continents in summer and the sea in winter. Accordingly, across the entire globe, including the tropics, air moves towards the south east, spiralling towards the Antarctic circumpolar trough. Locally, counter currents exist with the movement of the air in other directions but this north- west to south- east flow is the dominant pattern. Part of the counter flow is moist air that moves from the equator into mid and high latitudes, especially in the northern hemisphere, bringing moisture and warmth to cold locations far from the equator. This is a counter flow to the trade winds and without this flow high latitudes would be both colder and drier. Counter flows are in part monsoonal in nature but they also derive from the fact that on a local scale, air circulates about cells of low and high surface pressure.
The strongest winds on the planet are the westerlies of the southern hemisphere. These are also the most variable winds due to the ever changing relationship between surface atmospheric pressure in the mid latitudes and the Antarctic circumpolar trough. This westerly flow has become progressively more extreme over the last seventy years. Oscillations in the flow are consistent with change in the ‘Antarctic Oscillation index’. This change, that is globally influential, is driven by the changing intensity of cyclonic activity in the Antarctic circumpolar trough.
With the notable exception of the Indian Ocean, currents circulate in a clockwise direction in the Northern Hemisphere and anticlockwise in the Southern Hemisphere. Currents are forced by the planetary winds. Since the strongest of these winds are the westerlies of the Southern Ocean, this is where the movement of the ocean is most vigorous. The West Wind Drift of the southern ocean is interrupted by the near conjunction of the South American land mass and the Antarctic Peninsula. A certain amount of up-welling occurs in coastal waters promoting strong fisheries on the Eastern margins of the Oceans, particularly off the coast of Chile. A failure in this up-welling involves a collapse in the fishery. The intensity of up-welling changes the pattern of surface temperature and as we see in table 1 the effect is very much greater in the Pacific.
Notable is the northward extension of warm waters to provide a more equable climate to the western margins of the ocean basins in the northern hemisphere. Because these flows are anomalously warm as they reach the eastern margins of the ocean basins, so the western margins of both North America and Europe are warmer than they would be in the absence of these warm waters. The Gulf Stream is an instance but the Eastern Pacific is equally an example. There is no comparable situation in the southern hemisphere because the northward flow of cold Antarctic waters on the western margins of the southern continents is deterministic.
Limiting this tendency to equable temperatures on the eastern margins of the major oceans, cold water from high latitudes is driven towards the tropics. This is particularly the case in the Pacific (the largest basin) and more particularly in the southern hemisphere. Anomalously cold water is therefore found in the region of the Galapagos Islands and also from Cape Town to Sierra Leonie. Cold water coursing along the coast towards the equator tends to promote precipitation over the ocean rather than the land,and the desertification of adjacent land.
In complete contrast, the Western coast of Western Australia is warmed by a southerly flowing current. The Indian Ocean is atypical in that it circulates weakly in an anticlockwise direction with anomalously cool water moving northwards along the East coast of Africa penetrating to the Persian Gulf and the coast of India. Perhaps it is the strength of the monsoonal influence in this part of the world that dictates this contrary circulation. Accordingly the relative backwater that is the Indian Ocean has produced the steepest increase in sea surface temperature over the last seven decades. There is an increase of 1.3°C between Africa and Australia in the 0-30° latitude band in the month of January. The Atlantic south of the equator, also exhibits a temperature increase of about 1°C with an increase of 1.3°C on the west coast of the African continent, again in the southern hemisphere.
The pattern of warming and cooling is of interest because it comes about via the joint influence of the change in cloud cover, change in the rate of admixing of cold waters from high latitudes and the up-welling of cold water from the ocean deep. Plainly the rate of temperature increase in the Pacific has been moderated and even reversed by comparison with the Indian and Atlantic Oceans.
As already noted, the increase in the temperature of waters south of the equator is greater than the increase in the temperature of the waters of the northern hemisphere in comparable latitudes. This increase has occurred despite the obvious cooling influence due to the West Wind Drift that is so apparent in the Pacific. This exaggerated surface temperature increase is consistent with the marked increase in surface pressure, geopotential height and upper air temperature in the low and mid latitudes of the southern hemisphere. A southward expansion of the zone of high surface pressure in the mid latitudes of the southern hemisphere can be described as an expansion of the Hadley Cell. So the heavy temperature increase in these latitudes is unequivocally due to a decline in cloud cover.
But there are large areas across the Pacific and Atlantic Oceans that have experienced smaller increases in temperature and others zones where a decline in temperature has occurred due to the admixture of cold water with the intensification of the planetary winds that has occurred over time. In June there is significant cooling at 30-40° north probably due to enhanced interaction with the Arctic Ocean. The corollary is a decline in ice coverage in the Arctic. This cooling follows from the acceleration of the westerly winds in high latitudes, and especially so in the southern hemisphere.
SEA SURFACE TEMPERATURE, ATMOSPHERIC PRESSURE AND CLOUD
The relationship between surface pressure and sea surface temperature is documented in figure 4.
The root cause of the increase in surface pressure in the low and mid latitudes of the southern hemisphere is the decline in surface pressure in the region of the circumpolar trough that surrounds Antarctica. This is in turn related to the increase in the ozone content and the temperature of the stratosphere. As Gordon Dobson observed in the 1920s, following on from the work of the pioneering French meteorologist deBort in the last decade of the 19th century, surface pressure is a reflection of the ozone content of the upper portion of the atmospheric column. As surface pressure falls away the tropopause is found at ever lower elevations. Differences in air density between air masses rich and poor in their ozone content gives rise to jet streams that manifest as polar cyclones at the surface. As the vorticity of polar cyclones within the Antarctic circumpolar trough varies, so surface pressure changes across the rest of the globe via mass exchange. A fall in pressure in the Antarctic trough signals a shift in atmospheric mass to latitudes north of about 50° south. It is this shift in mass that is associated with the rising air temperature and diminishing cloud cover in the low and mid latitudes of both hemispheres. Declining cloud cover is associated with rising air temperatures in the cloud zone reflected in increasing geopotential height at 500 hPa. This particular association is frequently the subject of comment in meteorological circles. Ozone is ubiquitous; ozone gathers infrared energy from the Earth itself and heats the air, its efficiency in this respect increasing with surface pressure. It provides more energy to the troposphere than it does to the stratosphere. In this way the extent of cloud cover depends upon the changing flux of ozone in the air.
To understand the evolution of climate we must discard propositions that are devoid of value and re-learn that which was pioneered more than a century ago.
Of major importance to the evolution of surface temperature are ocean currents that depend upon the planetary winds for their motion.
The origin, temperature and humidity of moving air changes according to the flux in the ozone content of the air in centres of low surface pressure. Change is initiated in the stratosphere in high latitudes chiefly in winter. This is ultimately what drives climate change at the surface with a very different pattern of temperature change according to the month of the year. Man is a minnow of little consequence in the grand scheme of things.
In general the pattern of evolution in surface temperature in the near coastal areas of those parts of the Earth favourable to human settlement is dictated by the interception and storage of solar energy by the oceans as mediated by cloud cover. Temperature change at particular locations is mediated by the movement in the waters of the oceans that represent most of the surface of the planet. The oceans are the chief organ for energy storage by virtue of transparency to solar radiation. Energy storage occurs below the surface. Our ability to monitor the temperature of the ocean below the surface is limited. Until we can assess temperatures below the surface there is no valid way to monitor the energy relationships that determine the evolution of temperature above the surface. One should not put too much reliance on surface temperature as an indication of the state of the system over intervals shorter than a decade.
The anthropogenic argument is not a product of observation or deduction but a form of hysteria. Its origin is in the dis-tempered gut of modern man, reeling from the pace of change and the pressures of urban living. Perhaps it is due to a feeling of helplessness in a world in which there is more regulation, more complexity, greater inter-dependence and perhaps a feeling of chronic uncertainty due to the fact that ever increasing numbers enjoy less of the fruits of their toil, governments are piling up debt and seem to be out of touch with the needs of the common man.
In a planet that is too cool for both comfort and productivity man should not worry when the surface warms slightly, a frequent and highly beneficial circumstance in the evolution of the Earth. When we start shedding clothes in winter because we need to cool down, that will be the time to worry.
Worry induces a search for remedies and mankind becomes susceptible to the wiles of multitudes of carpetbagging rent seekers, keen to exploit the situation. That, unfortunately is the situation. Too many carpetbaggers have staked a claim on the general revenue. Central banks fund ever increasing deficits creating spending power where none is earned. This is irresponsibility on a grand scale. The economic system appears to be lurching towards a catastrophic collapse.