Monday, November 14, 2016

Autumn's Temporary Decline

Many readers count winter, spring, or summer as their favorite season. Others consider autumn  their favorite. Their reasons are abundant and diverse. Many factors contribute to one’s assignment of favorite status to one quarter of the annual calendar. Our ability to rationalize is strengthened and refined. We are able to trace interrelated factors of development and decline and their importance in an overall scheme.

Our 10/28/08 post was entitled Autumn and Early Rains:

In Israel the rains described in Deuteronomy and other passages are literally autumn rains coming at the conclusion of the current year’s harvest, and latter rains coming during the springtime when the newly planted crop is on its way to production. In one dimension of autumn we could describe the coming agricultural and astronomical renewal in store for the earth following a “period of maturity bordering on decline.” Harvest provides a time of rejoicing and thankfulness but the joyful times do not conclude even though lush, verdant fields physically “fail” in autumn. Anticipation of renewal in a new crop the following spring, summer, and autumn rekindles new hope. The beauty of a continually recycling earth is part of the Creator’s genius.

Agriculturally, temperate climates produce a majority of the world’s food. These  climates are dominated by the characteristics of seasonal cycles between tropical and polar regions—neither extremely hot nor extremely cold. Apart from the wonder of food production characteristic of temperate regions, our Creator has also provided esthetic enjoyment related to the change of seasons in these areas. Autumn leaves are especially colorful in southern Canada, northeastern US and a few other world locations. The fascination of behavioral changes in wildlife, from birds and mammals to insects and other species relate to seasonal changes. Temperate climates appeal to many residents because they enjoy meteorological variety throughout the year.

Seasonal changes have a cause and effect relationship with Earth’s 23.5º axis tilt. If the axis were exactly perpendicular to the plane of the planet’s orbit there would be no seasons at all. Earth’s life would be very different. There would be no traditional cropping patterns. Human population would be bunched around the equator. Animal migration would be non-existent. Life as we know it would be altered in multiple deleterious ways from present conditions on our axis-tilted Sun satellite.

The most significant cause and effect relationship of regular and predictable seasonal cycling phenomena is the slowly changing elevation of the mid-day sun above the horizon. In tropical regions the changing angle of the mid-day sun is less significant to the amount of heat tropical populations receive. People living at the equator (0º latitude) would observe the noon sun fluctuating about 67º or more above the horizon all year long. The Sun’s rays would always strike Earth more directly to provide more heat. Weather in the tropic zones is warm all year long. Significant seasonal changes do not occur.  

In contrast, people living at 41º N latitude where your blogger lived and taught science, would see the noon sun at 72º above the horizon at the beginning of summer. (The sun always appears directly south at noon in the northern hemisphere.) At the beginning of autumn the noon sun has gradually declined to about 48º above the horizon. When autumn ends the sun is only about 25º above the horizon. We may understand why autumn is considered a period of decline: The sun’s elevation above the horizon is reduced, solar rays increasingly must be shared over a larger area of land surface, average daily temperature decreases, and length of daylight shortens. We observe that colorful plant greenery fades as crops mature. 

Earth residents, take heart—renewal awaits. On a planet whose axis is tilted to produce seasons, our revolving earth produces seasonal recycling as it has for thousands of millennia. At the beginning of winter, the sun’s elevation slowly increases after a few weeks. The temperature in northern locations begins a gradual rise as daylight starts to lengthen. After a few weeks the earth starts to gain more heat than it loses. By late February and early March residents notice the gradual rise in temperatures which continues into the new growing season. Earth’s wonderful seasonal cycle is renewed!

The repeating cycle of seasons joins with the day/night cycle and numerous other physical and chemical cycles to provide a world described by the Creator as “very good” (Genesis 1:31). Is winter too cold? Is summer too hot? Is snow or rain too heavy at times? Do severe droughts and windstorms sometimes cause discomfort or worse? Is climate change a reality? We reply, “Yes, and it has always been so.” Embedded in these observations are wonderful discoveries for environmental scientists who study the intricacies of life supporting conditions on our planet. Earth’s population has increased over sevenfold since the turn of the 19th century. Planet Earth is a place to thrive.

From January to April 2012 our blog topics focused mainly on some of the important cycles operating on our dynamic planet. Any one of earth’s many cycles is worthy of detailed study by specialists. To the non-scientist, we suggest pursuit of at least a casual overview of nature’s cycles. We recommend perusing our series of posts beginning in January and concluding in April 2012: