The Home of American Intellectual Conservatism — First Principles

December 11, 2017

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On Climate Change
P. E. Hodgson - 02/13/09

The weather cycles in Peru and Bolivia are quite regular, unless they are interrupted by El Niño, which is unpredictably variable. Mostly the result is torrential rainstorms, warmer seas, and changes in fish populations. Occasionally however an El Niño event causes significant changes to the climate and brings ruin to fishermen and farmers. Thus in 1925 the sea temperature off northern Peru rose over six degrees in ten days. Millions of seabirds perished as the anchovies on which they fed moved to cooler nutrient-rich waters. Cloudbursts turned dry ravines into raging torrents and the city of Trujillo received 396 mm of rain instead of the normal 1.7 mm. Farmlands and irrigation systems were destroyed by a sea of mud, and hundreds of people starved. Many other examples could be given of the devastating effects of El Niño.

It is conjectured that El Niño events played an important role in the decline and fall of ancient civilizations when they were already seriously stressed by other economic and political factors. Particular examples are the Maya civilization in Yucatan and the Moche civilization in Peru. In these cases, the devastation caused by El Niño was the final event that caused the once-flourishing societies to collapse.

The rapid changes in climate associated with El Niño events took place long before the temperature increase associated with global warming and still continue. They are not yet fully understood and make it more difficult to ascribe climate changes to anthropogenic emissions.

Another source of global warming is the variation in the brightness of the sun, already observed over several centuries. The sunlight intensity fell by 4 to 6 percent from the 1950s to the 1980s. Now it is rising again and there has been a 4 percent rise since 1990; it is estimated that this could account for a rise in temperature of 0.4 C by 2100. There are also daily variations of around 0.2 percent, and these could produce significant changes in the climate. In addition, there is a correlation between the temperature and the length of the sunspot cycle. The physical basis for this is suggested by another correlation, namely that between the cosmic ray intensity and the low cloud cover. The miniature Ice Age in the later part of the seventeenth century is known as the Maunder Minimum, which is correlated with the sunspot minimum between 1645 and 1715. The sunspot cycle is a measure of the solar activity, and this in turn affects the cosmic ray intensity. The cosmic rays produce ions in the atmosphere, and these can form condensation nuclei for clouds, which have a strong influence on the earth’s temperature. Detailed studies suggest that solar effects may be responsible for 30 to 57 percent of the observed global warming. Since this varies with the sunspot cycle, it sometimes reinforces and sometimes weakens the effects of global warming. Some fluctuations have been observed and these could be due to varying amounts of aerosols in the atmosphere. [3]

There is evidence that the mini Ice Age in the seventeenth century and the medieval warm period are part of a cycle that occurs over a period of about 1500 years. Supporting evidence is provided by the bands of rock in cores from the Northern Atlantic. These rocks came from Northern Canada, and must have been carried to where they were found by glaciers, indicating periods of cooling and warming. More evidence came from Greenland ice cores which revealed a series of temperature changes, again with a period of about 1500 years. There were also large increases in the dust particles in sediments off the coast of West Africa suggesting dust storms inland, also with the same period. It has been suggested that this cycle is ultimately due to periodic changes in the sun. The resulting changes in solar radiation changes the temperature and this may be detected by changes in the ratios of cosmogenic isotopes in ice cores. All this shows the extreme sensitivity of the climate to very small changes in the intensity of the solar radiation. The same must also be the case for man-made changes in the atmosphere. [4]

A recent study [5] has shown greatly increased frequencies for the more devastating hurricanes like Katrina, which struck New Orleans and the surrounding states in 2005. This increase has been attributed by some scientists to the rising temperatures of the oceans due to global warming. If this is the case, some regions of the earth will be liable to more devastating hurricanes in the future. The cost of the damage due to the hurricane Katrina has been estimated to be around $100 billion.

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