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Why Do Leaves Change Color?
Some questions, like the one above, seem easy on the surface. But when one digs a little deeper a complexity emerges which leaves us awestruck at the world God has made for us. So, why do leaves change color?
Answer: God wanted to give us beauty in nature.
Question: Ok, but why do leaves change color?
Answer: Because green chlorophyll in the leaf decreases, allowing other natural colors to be seen.
Question: Ok, but why does chlorophyll decrease in autumn?
Answer: Because as daylight shortens and temperatures cool, veins that carry chlorophyll to the leaf are gradually closed. The chlorophyll, used in manufacturing nutrients for the tree, is depleted and not replenished. Thus, the reds, oranges, yellows, and browns of fall emerge.
Question: Ok, but why does the daylight get shorter and the air begin to get chilly?
Answer: Because the earth revolves around the sun in an orbital cycle of 365.25 days, and it has an axial tilt of 23.4 degrees. These and other geometrical aspects produce changing temperatures – seasons – on various parts of the earth at particular times during its orbital path.
Question: But why do leaves change color only in the latter part of the year? Why doesn’t colder weather occur some other time?
Answer: Fall isn’t in the latter part of the year everywhere on earth. Because of axial tilt, the seasons are reversed in the northern and southern hemispheres. Actually, the earth is closer to the sun in the northern hemisphere’s winter, but due to the angle of the axial tilt the rays strike the earth at a more oblique angle. The mathematical equations involved in orbital physics are incredibly precise and complex. But the end result is the seasonal cycle that provides an optimal environment for both plant and animal life to flourish on planet earth.
The bottom line is this: God has made a wondrous home for us to inhabit and enjoy. Beauty is neither natural or random; it is purposefully created. Consider the barren landscape of Mars. While the terrain of another planet is intriguing, Mars is devoid of the “decoration” and complex life properties that are found on earth. Something as “simple” as the changing colors of autumn speaks volumes about our Creator and His gift of life to us.
But as intellectuals delve deeper into the physics of how and why leaves change colors, the complexity is staggering. Design and purpose are obvious to the unbiased viewer. Indeed, how any astronomer or physicist or geneticist can maintain that such a finely tuned universe and the life within it “just happened” is a testimony to the stubbornness of unbelief.
“In the beginning God created the heavens and the earth … Then God said, ‘Let the waters under the heavens be gathered together into one place, and let the dry land appear … Let the earth bring forth grass, the herb that yields seed’ … Then God made two great lights; the greater light to rule the day, and the lesser light to rule the night ... And God saw that it was good” (Gen 1:1, 6, 11, 16, 18). In those simple words we have the foundation statements of how and why leaves change color. With all our advances of knowledge ever since they were written, all we have done is fill out the details.
