The Historical Record of Atmospheric Carbon Dioxide

Written by Patrick Moore et al. (Greenpeace co-founder) on January 8, 2018. Posted in Current News

The public is being cynically misled by the mainstream media and government scientists about ‘ocean acidification.’ All the CO2 in the atmosphere came from inside the Earth. During the early life of the planet, the Earth was much hotter, and there was much more volcanic activity than there is today.

The heat of the core caused carbon and oxygen to combine to form CO2, which became a significant part of
the Earth’s early atmosphere, perhaps the most abundant component until photosynthesis evolved. Most of the CO2
in the oceans comes from the atmosphere, although some is injected directly from ocean vents.

It is widely accepted that the concentration of CO2 was higher in the Earth’s atmosphere before modern-day life
forms evolved during the Cambrian Period, which began 544 million years ago. It was also at that time that a number
of marine species evolved the ability to control calcification, an example of the more-general term “biomineralization.”13

This allowed these species to build hard shells of calcium carbonate (CaCO3) around their soft bodies, thus providing
a type of armour plating. Early shellfish such as clams arose more than 500 million years ago, when atmospheric CO2 was 10 to 15 times higher than it is today.14 Clearly, the pH of the oceans did not cause the extinction of corals or shellfish or they would not be here today.

Why, then, are we told that even at today’s much lower level, CO2 is already causing damage to calcifying species

The most common argument is along the lines of “today’s species of corals and shellfish are not adapted to the level
of CO2 that ancient species were familiar with. Acidification is happening so quickly that species will not be able to
adapt to higher levels of CO2.”

This is nonsensical in that from a biochemical perspective there is no reason to believe these species have lost their ability to calcify at the higher CO2 levels that existed for millions of years in the past. The ancestors of every species alive today survived through millennia during which conditions sometimes changed very rapidly, such as when an asteroid caused the extinction of dinosaurs and many other species 65 million years ago.

While many more species became extinct than are alive today, it must be said that those species that came through these times have proven the most resilient through time and change.

As far as is known, there was only one other period in the Earth’s history when CO2 was nearly as low as it has been
during the past 2.5 million years of the Pleistocene Ice Age. During the late Carboniferous Period and into the Permian and Triassic Periods, CO2 was drawn down from about 4,000 ppm to about 400 ppm, probably owing to the advent of vast areas of forest that pulled CO2 out of the atmosphere and incorporated it into wood and thus into coal (see Figure 1, top of page). #

We know from Antarctic ice cores that CO2 was drawn down to as low as 180 ppm during the Pleistocene, only 30 ppm above the threshold for the survival of plants, at the peak of glacial advances (see Figure 2 below).

These periods of low atmospheric CO2, as is the case at present, are the exception to the much longer periods when CO2 was more than 1,000 ppm, and often much higher. For this reason alone, the possibility that present and future atmospheric CO2 levels will cause significant harm to calcifying marine life should be questioned. However, a number of other factors bring the ocean acidification hypothesis into question.

Figure 2. Cryostratigraphic reconstructions of air temperature and CO2 concentration anomalies from Vostok station, Antarctica, 50-2.5 thousand years BP. CO2 concentration fell to a little above 180 ppmv 18 ka BP.16

Adaptation of Species to Changing Environments

People have a tendency to assume that it takes thousands or millions of years for species to adapt to changes in the environment. This is not the case. Even species with relatively long breeding periods can adapt relatively quickly when challenged by rapidly changing environmental conditions. In fact, it is rapidly changing environmental conditions that foster rapid evolutionary change and adaptation.17

Stephen Jay Gould explains this well in his classic Wonderful Life, which focuses on the Cambrian Explosion and the evolution of vast numbers of species beginning 544 million years ago.18

Most of the invertebrates that have developed the ability to produce calcium carbonate armour are capable of relatively rapid adaptation to changes in their environment due to two distinct factors. Firstly, they reproduce at least annually and sometimes more frequently.

This means their progeny are tested on an annual basis for suitability to a changing environment. Secondly, these species produce thousands to millions of offspring every time they reproduce. This greatly increases the chance that genetic mutations that are better suited to the changes in environmental conditions will occur in some offspring.

A number of studies have demonstrated that change in an organism’s genetic make-up, or genotype, is not the only factor that allows species to adapt to changing environmental conditions. Many marine species inhabit coastal waters for some or all of their lives where they are exposed to much wider ranges of pH, CO2, O2, temperature and salinity than occur in the open ocean.

Two distinct physiological mechanisms exist whereby adaptation to environmental change can occur much more rapidly than by change in the genotype through genetic evolution.

The first of these is phenotypic plasticity, which is the ability of one genotype to produce more than one phenotype when exposed to different environments.19 In other words, a specific genotype can express itself differently due to an ability to respond in different ways to variations in environmental factors.

This helps to explain how individuals of the same species with nearly identical genotypes can successfully inhabit very different environments. Examples of this in humans are the ability to acclimatize to different temperature regimes and different altitudes.

There is no change in the genotype, but there are changes in physiology. The second and more fascinating factor is transgenerational plasticity, which is the ability of parents to pass their adaptations to their offspring.20 One recent study pointed out that “contemporary coastal organisms already experience a wide range of pH and CO2 conditions, most of which are not predicted to occur in the open ocean for hundreds of years – if ever.”21

The authors used what they called “a novel experimental approach that combined bi-weekly sampling of a wild, spawning fish population (Atlantic silverside  Menidia menidia) with standardized offspring CO2 exposure experiments and parallel pH monitoring of a coastal ecosystem.”

The parents and offspring were exposed to CO2 levels of 1,200 ppm and 2,300 ppm compared with today’s ambient level of 400 ppm. The scientists report that “early in the season (April), high CO2 levels significantly … reduced fish survival by 54{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117} (2012) and 33{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117} (2013) and reduced 1 to 10 day post-hatch growth by 17{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117} relative to ambient conditions.” However, they found that “offspring from parents collected later in the season became increasingly CO2-tolerant until, by mid-May, offspring survival was equally high at all CO2 levels.”

This indicates that a coastal species of fish is capable of adapting to high levels of CO2 in a very short time. It also indicates that this same species would not even notice the relatively slow rate at which CO2 is increasing in the atmosphere today. The changes that have occurred to the Earth’s climate over the past 300 years since the peak of the Little Ice Age around 1700 are in no way unusual or unique in history.

During the past 3,000 years, a blink in geological time, there has been a succession of warm periods and cool periods. There is no record of species extinction due to climatic change during these periods.

Read more at fcpp.org

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