Gaia – Yes or No ? (12-18 yr old)


Gaia image by Josephine Wall (the presence of Gaia)

My question is, do you believe the arguments outlined below, or not? Read the arguments and make your own post on your own blog or comment on this blog on your decision. 

Enjoy the arguments, make your own decision.

In Greek mythology, Gaia is the ancestral mother of all life: the primal Mother Earth goddess.

The Gaia hypothesis (proposed by James Lovelock) argues that the organic and inorganic components of Planet Earth have ​evolved together as a single living, self-regulating system.

It suggests that this living system automatically controls global temperature, atmospheric content, ocean salinity, and ​other factors, that maintains its own existence and life on our planet. In a phrase, “Life maintains conditions ​suitable for its own survival.” In this respect, the living system of Earth can be thought to be similar to the workings of an individual organism that regulates body temperature, ​blood salinity, etc. So, for instance, even though the luminosity of the Sun – the Earth’s heat ​source – has increased by about 30 percent since life began almost four billion years ago, and lots of other elements continue to change, ​the living system has reacted as a whole to maintain temperatures, and other life determining properties, at levels suitable for life.

(slightly adapted from​)

Look at the Stories before making your decision.


The Stories

Story One – The atmosphere

The atmosphere of the Earth has over the last million years maintained an oxygen level of 20.3-21%. The lower percentage was determined by analysing  ice cores extracted in the Antarctic and Greenland which was formed over 800,000 years ago.

Oxygen is chemically recognised as a very reactive gas, it will react with Nitrogen and Methane over time. Increase the percentage to 25% and lighting a match would start a fire that you would have difficulty extinguishing. Reduce the level to 12% and life as we know it would very difficult (12% is the Oxygen level on our tallest mountains). How has the planet maintained these levels?

Carbon Dioxide levels are rising. There is evidence that this started soon after the industrial revolution in Britain in the 18th Century and has continued to do so in subsequent centuries. There is possible evidence that this rise will caused a ‘greening’ of the environment as Carbon Dioxide becomes  more available for the Earth’s plant life.

Carbon Dioxide is a ‘greenhouse gas’ which prevents the Sun’s heat leaving the planet. However clouds also share that role.There is aso evidence that the oceans provide a ‘sink’ for carbon dioxide where they form carbonates.

An interesting story. Go back millions of years and we have the first living things beginning to populate the land. Fossil evidence indicated these were mosses. They had no challengers, there were no animals, no other plants. They spread, and they spread. Plants breathe in Carbon Dioxide and exhale Oxygen ….there were so many of them that the Carbon Dioxide levels in the atmosphere were destroyed … no greenhouse effect, the Earth’s heat escaped. The result was the Earth’s first ice age. Almost all the  mosses died. Others then moved on to occupy the land, some breathed in Oxygen and exhaled Carbon Dioxide. Life continued.

Trees like the moss in the above story are a major sink for CO2, plant life ‘breathes in’ CO2, uses it to grow and exhales O2. Deforestation would therefore have a negative impact on the environment. Eventually when trees die the carbon they are made of becomes CO2. Growing a lawn does not necessarily have a negative CO2 effect …any idea why?

So are the above phenomena just feedback loops or are they a deliberate intervention by a living planet?


Story Two – The temperature

The average temperature of the Earth has been maintained between 10 and 200C for billions of years while the Sun’s output has increased 10-20% over the same period. With 2016 coming to its end it has been noted by NASA that this has been the hottest year on modern records.


In the above graph the average  ie the 0.0 line is 14.6 0 C

However there have been in the last 650,000 years seven cycles of glacial advance and retreat, with the abrupt end of the last ice age about 7,000 years ago marking the beginning of the modern climate era — and of human civilization. Life has survived all of these external disturbances. Look at this latest NASA video

Where can the heat hide? The main reservoir for any excess heat are the Earth’s oceans. The oceans are also a major source of cloud formation. 

Clouds are sometimes underestimated in terms of thinking about global warming, however clouds are  a tremendously important part of our environment.They can support the greenhouse effect – probably more so than CO2. But they can also counteract global warming by the way in which they move water around and act as reflective shields of the Sun’s energy.

Recent hurricane activity in the Pacific (September 2016) was caused by water movement. Incredible amounts of water, from the warm oceans of the equator, evaporated into the atmosphere, forming clouds, this process lead to the cooling of the ocean and a greatly disturbed atmosphere which then distributes its energy over the nearby environment in the form of hurricane Gaston.

Clouds can also be formed by other means, organic vapours released by organisms such as trees, and livestock appear to play a far more important role in cloud formation than has been suspected.

But it could be argued that hurricanes and associated weather conditions are a way in which the environment (Gaia) is trying to negate the effects of global warming or again are they feedback loops?

Story Three – Salinity

Somehow the salinity (salt content) of Earth’s oceans has been maintained over the last 300 million years. How do we know this? The building blocks of living things, the cells that they and we are made of, cannot survive beyond levels of 6% salt content. However life has survived. There is also evidence from ice samples ( the ones in Antarctica go back to ice created almost 1 million years ago) that salinity levels have remained the same.

We know that the salinity of the blood of whales, mice, humans and most fish, whether dwelling in the sea, on land or in fresh water are the same. So how have the oceans maintained a constant salinity level while millions of tonnes of salts are dumped in them all year round, via rivers, earthquakes, and other natural events?

There is sometimes a complacency in our views on the nature of our oceans. They support the growth of a greater biomass (animals and plant life) than that of the land based environments. There are therefore some thoughts that the biomass contributes in some way to maintaining salinity levels by incorporating salt in their skeletal structures which then become part of the sediment of our oceans.

There are also ideas on ocean ‘cracks’ recirculating sea water and removing excess salt. Another model is CO2  absorption in sea water which reacts with excess salt and deposits insoluble carbonates.

Story Four – Plankton

There are suggestions that increased heat, leads to increased plankton growth then greater production of a compound called Dimethyl Sulphide as the plankton decompose leading to greater sulphur dioxide concentrations in the atmosphere which leads to greater cloud formation  and then leading to greater sunlight reflection. Thus a cooling effect on the oceans.

The final analysis.

Life was first thought to have emerged on planet Earth about 4 billion years ago. Since that time life in it’s variety of forms has continued to survive and evolve, despite dramatic changes in the environment of our planet. At times some forms of life have been extinguished  (dinosaurs are one of many examples) but other forms of life have survived and new ones have developed.  The argument for Gaia is that it is the ‘living’ planet that has provided the conditions for this survival. An alternative argument is that by some lucky event the planet has an environment that can adapt itself to changing circumstances via a variety of feedback loops.


This is the crux post. What do you think?

Do you think that a living, life supporting, Gaia is a realistic possibility?

Do you think that the predicted outcomes are realistic based on the evidence and ideas that you have been presented with? Or do you think that what happens to the the elements mentioned in the stories is just the result of a feedback loop?

What aspects of what you have been presented with would you challenge?

Why do you think that I have presented this as an hypothesis and not a theory?

Thank you for reading. I hope that it has provoked some thinking. It provoked my thinking. I welcome comments.


For those who are making comments. If you give your blogs URL I will reply on your blog. If I don’t have that URL I will reply on this site.


Gaia-Yes or No ? (for 8 -12 yr old)

Some time ago a well known scientist (James Lovelock) suggested that the Earth (our planet) was special. He claimed that the Earth itself was a living thing and had control over its environment. He gave the Earth the name Gaia (a Greek name for the goddess of the Earth) and suggested that the planet’s objective was to support life on it, at all cost.

It has been argued, by those who support this idea, that there is a lot of evidence from investigating the Earth’s history over the last 3 billion years, and the idea is valid. Below are some of those arguments. What do you think?










Permission has been given to use all the images in the above presentation.



For those who are making comments. If you give your blogs URL I will reply on your blog. If I don’t have that URL I will reply on this site.

Do you want to ask further questions then why not ask the Science Master. You can find him at