Earth System History by Steven M. Stanley

Changes in Plants With Climate, CO2

by Lewis Loflin

My focus here is on the debate of CO2, warming, and plants in particular food crops. We explore the relationship with past geological changes.

See Part 1 Understanding Earth Science and Climate Change

To recap Part 1: In the geological sense we are in the Phanerozioc Eon (542 MYA), Cenozoic Era (65.5 MYA), the Neogene Period (23 MYA) and the modern Holocene Epoch that goes back 11,700 years.

Here I'm concerned with the Neogene period. This includes the following:

Miocene Epoch 23 - 5.3 MYA. CO2 levels increased from ~200 PPM to 320 PPM. During this time continued cooling and drying. Forests continue to decline, deserts and grasslands expand. That likely led to some rebound in CO2 levels.

Pliocene Epoch 5.3 - 1.8 MYA. Early Pliocene was warm. Winters were warmer, England was subtropical. Modern ice ages began ~3.2 million years ago. By 2.6 MYA the Arctic sea froze over for the first time. Temperatures plummeted even with higher CO2 levels.

Pleistocene Epoch 1.8 - 11,700 MYA. Mostly an ice age. Sea level 400 feet lower, many forests die out.

Some basic science:

Protozoan - single cell animal like eukaryote - has nucleus, etc.

Foraminifers - marine protozoan that form calcite (calcium carbonate) shells. Their remains are used to study climate millions of years ago by carbon and oxygen isotope ratios.

Phytoliths - small bodies of silica in plants. This is a particular issue with grasses.

C3 grasses were replaced by C4 grasses with higher pytoliths. (6-7 MYA) Many mammals went extinct. This was due to shorter teeth wearing down due to silica rich C4 plants.

C4 grasses thrive at lower CO2 levels than C3. Yet when C3 grasses were replaced by C4 was when CO2 increased due to drying and forest die off.

Yet, C4 grasses grow better than C3 under those CO2 levels. CO2 levels increased 15 - 5 MYA from ~200 PPM to 320 PPM. Stanley P460. A contradiction?

C4 grass has 5 times the silica of C3. Warm climate promotes C4 grasses they claim, but higher CO2 favors C3 plants. Mexico dominated by C4, Canada by C3. Stanley 459-460.

C4 plants have a higher ratio of carbon 13 isotope than C3 plants. That is how they tell them apart in the fossil record.

What is going on? Cooler drier climate is what happened even with higher CO2 levels from 23 to 5 MYA.

There is a complex interplay between carbon cycle, drying, and temperatures on grass types. Antarctica not Arctic sea ice drives world climate!

C3 and C4 refer to how the photosynthesis operates.

What does this mean for humanity? I've heard for 50 years how climate change and "global warming" was leading to mass starvation by 1990, then 2000, now 2020, now 2050, etc.

Yet we have record crop yields in 2017-18. Yes I'm a skeptic on these claims. Their efforts at future predictions have failed and continue to fail.

See Grain Production Miracle Debunks Climate Alarmists.


C3 generates less bulk than C4 but feed quality is higher. Thus cat food made mostly of corn has little nutrition value.

C3 - frost tolerant, higher H2O required. (But it turns out at higher CO2 levels plants require less water.)

University of Northern Iowa:

C3 plants - beans, rice, wheat, rye, barley, potatoes, soybeans, spinach, tomatoes, temperate crops, woody trees. All real trees are C3.

C4 - corn, sugarcane, amaranth, hot, dry, mostly grasses.

CAM is another category that includes pineapples.

C4 plants more efficient with water, less efficient with light.

C3 plants have C3 reactions only, in every green cell.

C4 plants have C4 reactions in some cells, C3 in others.

Reduction of CO2 and drying climate promoted C4 and CAM (pineapple, etc) plants.

They claim, "...the alarming possibility that elevated CO2 (may favor) ... C3 photosynthesis."

So growing more wheat, rice, barley, and soybeans is bad?

NASA April 26, 2016:

"The greening represents an increase in leaves on plants and trees equivalent in area to two times the continental United States...carbon dioxide fertilization explains 70% of the greening effect."

Article wonders off subject back to climate change hysteria. That part of the article is speculation.

More good news. NASA June 2, 2016: arctic tundra and wastelands are greening. That means more animal and plant life. They ask, "Will forest biomes migrate with warming climate?" They did in the past and will likely do so now.

Another study in Australia claims even drier regions are greening. Plants can use CO2 more efficiently with less water loss due to transpiration.

Yet The New York Times claims global greening is bad. (July 30, 2018) "Global Greening Sounds Good. In the long run, It's terrible."

Any positive news of climate, food production, etc. is attacked by Progressives hoping to use the issue to foster global governance and wealth redistribution.

To quote, "More photosynthesis doesn't mean more food." But why? We have more greening and more food. He blames transpiration where water and CO2 are pumped back into the atmosphere. Again, so what?

He claims the benefits to crops has been small. Not true according to present world food production. The Times predicted the opposite in the past.

He whines about microbes taking up more nutrients from the soil. They cite a study about Southeast Asia suffering an iron deficiency by 2050. So take an iron supplement. Or bio-engineer plants with higher levels of iron intake.

The rest of the article is propaganda. Not worth my time.

Stick to what is known not speculate on the future based mostly on ideology.

Social justice will not control climate.

Stomata in plants.

Plant Stomata CO2 Climate Record

Stomata are pores that allow the exchange of air to extract CO2. The process uses transpiration or water evaporation to drive the exchange. This is defined as,

The movement of water in a plant is like a one-way street, it is unidirectional and it travels along this route: soil -> roots -> stem -> leaves -> air. The movement of water throughout a plant is driven by the loss of water through it's leaves, or transpiration.

The number of stomata is directly related to CO2 levels in the air. Higher CO2 levels of today accelerates plant growth and use less water.

The number of stomata is proportional to CO2 levels - more CO2, less stomata needed. Stomata in fossil plants is a proxy for CO2 levels when the plant lived.

The claims of 280 PPM CO2 being steady for thousands of years deforestation, etc. is nonsense. This claim came from low-resolution ice cores.

PPM is parts per million. CO2 at 420 PPM is 0.042% of the atmosphere.

Stomata studies show great variation from 260 PPM to 340 PPM with an average of 305 PPM. Yes, humans have added CO2 to the atmosphere of ~115 PPM or 0.0115%. That is ~25% of present levels.

See CO2 Record in Plant Fossils. PDF, not my work.

One great benefit of higher CO2 levels is greater plant growth, but is more beneficial to some plants than others.

Despite the hopes of genocidal crackpots like Paul Ehrlich, Bill McKibben, Amory Lovins, etc. global food production has exploded over the last 50 years. This is due to a warmer climate, higher CO2 levels, and modern technology.


Lewis Frog

Web site Copyright Lewis Loflin, All rights reserved.
If using this material on another site, please provide a link back to my site.