TREES HAVE BEEN CONTROLLING CO2 FOR 380 MY
I read recently that the world’s most wealthy man. Elon Musk will donate $100 million to combat global warming He appended a proviso to this gift which states that the money be spent on the most efficacious method of sequestering carbon dioxide. Musk, a “high tech”guy, may have been thinking of some “technical” method. But the Earth and Mother Nature have been naturally sequestering carbon for millions of years. Our Earth is a “living gas belching” planet . These gases (much of it CO2, a “greenhouse” gas ) continued to accumulate during earth’s early history and kept the early planet warm.
In the Devonian Period (420-360 million years ago) terrestrial green plants evolved and expanded over the earth’s surface. These photosynthetic plants remove CO2 from the atmosphere and use it to form and store carbohydrates in the leaves, stems, and roots of plants. Since the long ago Devonian time, the normal out-gassing of carbon dioxide from volcanoes (and other sources) were controlled and modulated by green plants and later by global forests and their uncounted millions of trees.
In fact, tree planting to control CO2 Is the way to control excessive CO2. Our present global forests, even today, much reduced by forest fires, logging, urban sprawl, agricultural expansion and disease are still the most effective means of removing gaseous carbon. It is claimed that modern global forests remove about one third of all the anthropogenic (human derived) carbon we produce each year (an amount often estimated at about 51billion tonnes per year).
We must shun some of the outlandish and dangerous ideas of the “geo-engineers” (like seeding the oceans or dumping solar reflectors upper atmosphere) these technical “solutions” always (based on the laws of conservation of energy) create more pollution and use more earth heating energy than they save.
On the other hand earth history and Mother Nature reveals to us that if we were able to triple the forested area of the globe, we would be well on the way to solving our overheating and global carbon dioxide problem. The positive aspect of this method is that we could accomplish this goal while we continue to use but slowly modulate the use of certain fossil fuels. Over the longer term we must slowly and in a measured way reduce our dependence on these sources of fossil energy. We will always need these resources as sources of chemicals, fertilizers and synthetics. Some claim they are actually too valuable to burn. We need not upend our economies and way of life so drastically, as is envisioned by some.
Climate change is not an impending crisis or an immediate threat. Some would like to equate it to the impact of the Chixulub meteor, which stuck the Earth some 66 million years ago and changed the climate instantly then wiped out the dinosaurs along with three quarters of the earth’s land species. Climate warming is an on going, natural, gradual, Earth process which would proceed even without human action. It is true that humans have exacerbated the process by cutting down forests, digging up fossil carbon and burning this fuel in the atmosphere to release ancient carbon dioxide which had been sequestered for millions of years. Reforestation is the best solution to a measured and reasonable means of the amelioration the ill effects of human actions on global climate.
Along that line of thought, it would be well to mention here that a Canadian start-up company called Flash Forest, has developed a system to plant trees using aerial drones. Especially equipped Flash-Forest-drones can fire a seed packet or pod into the ground from the air, and in this manner plant as many as 100,000 trees per day. This is a vast improvement over hand-planting seedlings, which in reasonable level terrane is a method capable of setting perhaps only 1500 per day. Also the cost per-tree using drones is a small fraction of what it would cost by manual planting .
So if Mr. Elon Musk reads this: Elon, please look up Flash Forest for the best returns on your generous offer!
Some further thoughts on the transformative evolution of green plants in the Devonian follow.
Outgassing from volcanic activity produces carbon dioxide (and other gases). This natural and continuing process led to a build up of CO2 and was responsible for the fact that the early earth was much warmer than at present. In those times of the past, the continents were raw rock and earth there were no green plants or trees to absorb carbon dioxide gas.
It was in the early part of the Devonian Period (420-360 mya) that land plants (such as mosses, ferns, and horsetails ) evolved and spread over the earth’s surface. This event radically altered earth temperatures. Green plants absorb carbon dioxide (photosynthesis) and sequester it as carbohydrates ( sugars, starches, cellulose). With lower CO2 levels in the atmosphere less earth radiation was absorbed and the earth cooled.
During the Devonian, as a result of this transformative cooling event, global ocean temperatures began to fall, (as much as 40F) causing ocean water temperatures at the equator to fall to around 80 to 85 F, this probably as a result of the expansion of green terrestrial plants on the continental masses.
An even more significant event for control of carbon dioxide occurred during the Devonian. The evolution of the tree. Trees are very much more effective in storing CO2.
During the Devonian Period land plants speed and evolved into ever more complex forms which absorbed and held even more carbon dioxide. In the Early Devonian when the first low-growing horsetails, ferns and mosses were common, plants continued to evolve. In the latter part of the Devonian, or around 383 million years ago actual tree-like plants arose. They belonged to a genus known as: Archeopteris a very successful new comer which evolved, and spread widely over the earth’s surface. These tree-like, spore-bearing Archeopteris plants grew to 40 meters tall (131 feet) with draping boughs and fern like leaves . Archeopteris created dense forests which spread world wide during the Late Devonian and on into the early Carboniferous, (or from about 383 mya to 323 mya). These forests had a great impact on earth temperatures, for as they expanded they withdrew and stored vast quantities carbon dioxide which resulted in a much cooler earth atmosphere.
This was a watershed event in earth history, for while low growing herbaceous plants such as ferns and mosses absorb quantities of CO2 from the atmosphere and generate oxygen. But when these plants die, their leaves and roots quickly decay and release that same carbon right back into the air and the soil.
The impact of small, low growing. herbaceous plants was brief and seasonal. Trees on the other hand, produce much more mass (or biomass). They generate bulky wood, tall woody trunks , branches, woody twigs and enormous quantities of leaves as well a large underground root structures. As long as s tree is alive, it holds on to the carbon it absorbed from the air and soil. When, the tree dies, often after hundreds of years, it too decays it only slowly releases the carbon dioxide back into the air, but much much more slowly.
But forests also cool the earth’s surface directly. Trees absorb solar radiation and convert that energy into chemical bonds so forests are cooler. Forests, by reducing the “long wave” earth radiation (this is the radiant energy that CO2 absorbs) cools the earth directly and cools by absorbing CO2 and thus are doubly effective.
For these reasons forests are probably the most effective temperature modulators of a warming earth. They absorb ( but do not reradiate) both solar radiation and as well as carbon dioxide. (Our modern forests absorb as much as one third of the tons and tons of carbon dioxide that modern society releases into the air from fossil fuels If we could triple the area of forests and modulate our use of fossil fuels on the earth, we can close the gap between the carbon we release from our trucks autos, homes, power plants and industries and that which is absorbed by forests.
By the end of the Devonian and early Carboniferous so much carbon dioxide had been removed from the atmosphere by trees that the earth cooled to a level at which many shallow water, warm-water marine species (bony fish and eurypterids) died off during the resulting cooling. (This is called the “end of Devonian extinction episode”)
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