Reflection on “Trees, Cows and Climate Change”: How to Reverse Global Warming

Unitarian Universalist Congregation of the Upper Valley (UUCUV) Sermon Delivered on May 26, 2024.
by Abraham Oort, Ph. D.

POEM – Excerpt from “Love Letter to the Earth”
by Thich Nhat Hanh

At this very moment, the Earth is above you, below you, all around you, and even inside you. The Earth is everywhere.

You may be used to thinking of the Earth as only the ground beneath your feet. But the water, the sea, the sky, and everything around us comes from the Earth. Everything outside us and everything inside us comes from the Earth.

The water in our flesh, our bones, and all the microscopic cells inside our bodies all come from the Earth and are part of the Earth. The Earth is not just the environment we live in. We are the Earth and we are always carrying her within us.

Realizing this, we can see that the Earth is truly alive. We are a living, breathing manifestation of this beautiful and generous planet.

by Abraham Oort, Ph. D.

Good Morning. Thank you, Maureen, for your special introduction.

It is a pleasure to have the opportunity to present a sermon at the UUCUV. My main goal will be to show that the climate situation of global warming is serious but not hopeless– that there is a lot we can do to reverse global warming.

The climate system of the Earth is complex and challenging but it is not difficult to understand. It may be like unraveling a detective story. My intention is to create awareness of what is happening now. My solution to the global crisis may be controversial. But I hope that our dialogue will lead to further discussions of what we can do.

My talk will be on how we are living as a community on Earth. It will be about the simple things we do: How we breathe, how we eat, and how we act. It is about creating the proper balance.

When we breathe, we know that there is a balance but it is a delicate balance between two worlds; the world of trees and plants and the world of people and animals.  We know that all of us have to breathe. We breathe in and we breathe out. It is needed to stay alive. We also know that the trees and plants do the same –but in the opposite direction. We know that trees and plants breathe in carbon dioxide, CO2 , and breathe out oxygen, while we breathe in oxygen and breathe out CO2 .  It gives the beautiful symbiosis between trees and us.

Besides breathing, we also have to eat. While plants and trees depend on the soil and the atmosphere, we depend on plants and minerals from the soil and on meat, if we are omnivores. Eating gives us the energy needed to act, to do our jobs each day– to think, to speak, and to physically act.

My talk will be covering several topics; it may be like a dream. However, I hope you are willing to follow my dream and allow me to be your guide. The first part of the dream will be looking at the Earth in space; shown on this ball. As a reference, I have put a red tape on the Equator to show what we are talking about.

First of all, we see that the Earth is beautiful. We see white clouds that cover the blue oceans and the green, yellowish land. The oceans are huge, covering much of the globe, about 70%. They are several miles deep; the oceans are also very powerful.

We also see the land, it is much smaller, about 30 %. It is the place, where we live. Then we see the ice of Greenland and the sea ice in the Arctic Ocean and, in the Southern Hemisphere, the several miles-thick Antarctic ice cap.

Then there is the atmosphere, it is very thin. It is like the paint on this ball.

And finally, we have the biosphere, the community of trees, plants, animals, and people. The biosphere may be the most beautiful part of the climate system. To understand global warming, we have to study the details and components in the climate system of the Earth.

But, let us first have a look at the source of life on Earth– the sun. The solar radiation heats the earth, and creates the general circulations in the atmosphere and oceans.

For radiative balance, the Earth has to return the same amount of energy it receives from the sun, back into space. Part of this terrestrial radiation gets absorbed by the greenhouse gases in the atmosphere, like carbon dioxide, CO2 , water vapor, and methane. It is a delicate balance. Too little absorption can lead to cooling of the Earth and an ice age, while too much absorption will create global warming.

Besides energy, the high quality of the photons in the solar radiation provides order and organization (negative entropy) in the Earth’s system. It has led to the climatic zones with the equatorial wet zone, the deserts in the subtropics, the mid latitude weather systems with the jet streams, the Gulf Stream in the Atlantic Ocean, and the polar ice caps. In spite of the limited predictability of the weather and climate (with the many positive and negative feedbacks), there has been also an amazing stability and order in much of the Earth. It has led to the enormous complexity of living beings on the planet: the plants, trees, animals, and people with our amazing brains.

Therefore, the Earth is often thought of as a living being: Gaia, or mother Earth. Gaia was the Greek goddess of the Earth. It has protected us for thousands of years by creating the right amount of greenhouse gases in the atmosphere to maintain the surface temperature of the Earth favorable to support life on the planet.

There are two stories I like to tell, about our human history. The first story started 10,000 years ago at the end of the last ice age, when we changed from gatherers/hunters to gardeners, developed agriculture, and domesticated animals — it is called the Agricultural Revolution. We started to create open land by cutting down and burning the ancient trees, in order to plant crops and to raise animals.

It was the beginning of our civilization– we built cities, roads, cathedrals, and pyramids; we developed music and other arts– especially, science and technology. All of these activities required energy and the cutting of trees. The trees released large amounts of carbon dioxide into the atmosphere. But amazingly during the 10,000 years, the CO2 level in the atmosphere didn’t change; it remained practically the same. This phenomenon is sometimes called the GAIA hypothesis. Gaia kept the temperature the same and thereby protected the biosphere for millennia from glaciation into an ice age or from global warming.

The excess in CO2 produced by cutting trees didn’t stay in the atmosphere. It must have gone mainly in re-fertilizing the remaining trees and land surface, and partially in fertilizing the oceans. This led to the observed acidification of the world oceans; the oceans have become more and more acid.

However, the balance has changed during the last few centuries. It happened because we started to use not only trees but also ancient fossil fuels: coal, oil and gas for energy.

Many types of machines were created, leading to more and more CO2 in the atmosphere. This revolution is called the Industrial Revolution. Steam engines, cars, airplanes and other machines were developed.

During the last 60 or 70 years, the CO2 greenhouse gas in the atmosphere started, for the first time, to increase dramatically. As expected, the temperatures also started to rise, as shown by vice-president, Al Gore, in his movie, an Inconvenient Truth. Apparently, the remaining trees could not absorb the excess CO2 anymore. It caused the atmosphere to warm up, and global warming to take place. It led to the recent fires all over the world. In fact, we can say that the Earth is now ON FIRE.

Besides global warming, there are several other problems: Such as the rise in sea level due to the melting of the polar ice caps, the rapid extinction of wild animals, and the loss in biodiversity of plants and trees. And now the climate is even threatening our own human existence.

We have stressed the climate so severely that the climate system is out of balance. The situation is serious, but not hopeless. We know that Gaia and the Earth itself have shown the enormous capacity to maintain a balance during thousands of years, and that this balance can even happen in the future!

We know that both revolutions, the Agricultural and the Industrial Revolutions, are the cause of the present global warming. But which one is more important? This is important since it may tell us what the real cause of global warming has been?

It may tell us also if there is a solution and where we can find it. Are deforestation, the cutting down of trees, and the land use the primary causes of global warming or is it the use of fossil fuels?

Most efforts so far have been to slow down the use of fossil fuels and to harness solar energy. We have installed solar panels, developed electrical cars, and so on. This effort has been beneficial and is a reasonable way to reduce the increase in CO2 but, unfortunately, it will not decrease the present level of CO2 in the atmosphere. It is not enough to reverse global warming.

Recent evidence by Dr. Sailesh Rao of and other scientists have shown that deforestation and land use have been much larger than the use of fossil fuels, by a factor of at least four!

This fact has not been accepted by many scientists and by the world governments. Is this a denial of the Truth? Then there is the huge resistance and financial resources of the animal-based agricultural complex that have influenced and intimidated politicians and scientists all over the world.

However, there is hope when people begin to accept that deforestation and land use are the major cause of global warming. We can look at clues by looking at our own history — what did we do and what then happened with the climate.

As mentioned before, we have cut down and burned trees during thousands of years, creating CO2 in the atmosphere and oceans. We freed up the land to keep animals and to grow food for people and animals. From the six trillion trees (six with 12 zero’s) in the ancient forests 10,000 years ago, less than three trillion remain today, generally of a much lower quality.

At present, one third (33%) of the land area is used to raise animals for meat and it is growing rapidly; 6% of the land is used to grow crops for animals, and 5% to feed the people (Deserts/rocks take up 17%; ice 10%, and only 1% is used for roads, cities, and other human structures). This 33% provides the “organic” meat produced, for example, in our Upper Valley by regeneration. Actually, Didi Pershouse talked about this approach of regeneration of the land in her sermon two weeks ago at the UUCUV. This way of eating is fairly “humane” since the animals have a reasonable life span.

However, if we want to feed the eight billion people in the world using meat, we would need not one but many Earths, that don’t exist in the solar system. We also must realize that 90% of the meat produced is not “organic.” It is produced by raising cows, pigs, chicken, ducks, and turkeys in factories in small cages. It is shocking to realize the number of land animals killed each year for meat. In fact, 92 billion animals are raised and slaughtered each year in factories. This number is more than 10 times the human population of 8 billion people, and is rapidly increasing. Even worse, the conditions in the animal factories are horrendous and cruel– not only for the animals but also for the people who work in the factories.

This situation is unknown to the public–the knowledge is kept secret by laws and is maintained by huge subsidies to keep the meat “cheap.” This is the real inconvenient truth —not the fossil fuel usage– the truth that is hidden from the general public. Sailesh Rao has called this inconvenient truth “The Cow in the Room.” Almost no politician or scientist will mention this truth since it is just too dangerous to do this! But to generate a sustainable world, it is essential that we stop eating animals and change to a whole-food plant-based diet. It will be tough but as individuals, we have the power to do this and change our way of eating. It may be the only way to sustain life for future generations. Even when we adopt this “reality”, it will be difficult for many people to immediately change to a vegan diet. However it will be feasible to gradually change to a plant-based diet. Once people find out that their health and quality of life has increased dramatically by changing their diet, they may adopt a plant-based diet without much difficulty.

Coming back to global warming, we know that one fourth (28%) of the available land is presently covered by trees and grass land. The best way to reverse global warming will be to, at least, double the area of forests in the world and to protect the ancient trees, such as in the Amazon forests. The additional trees will absorb most of the CO2 present in the atmosphere and will decrease CO2 to acceptable levels. In other words, it is needed to rewild the Earth in order for global warming to stop. The result will not only be good for the animals, it will benefit our own health, improve the climate, and resolve many of the other world problems like the extinction of wild animals, world hunger, and global pollution. We don’t need the excessive protein in animal flesh; the nutrition from plants is more than enough to feed us.

We may have to learn to enjoy the energy and satisfaction from eating grains, vegetables, and beans. In fact, it could be the beginning of the golden age.

by Thich Nhat Hanh

When we are in love with someone, there is no separation between ourselves and the person we love. We do whatever we can for them and this brings us great joy and nourishment. That is the relationship each of us can have with the Earth. That is the relationship each of us must have with the Earth if the Earth is to survive, and if we are to survive as well.


1. Campbell, T.C., 2020: The Future of Nutrition. BenBella Books, Inc., Dallas, TX, 305 pp. For the history of the Whole Food Plant-Based Diet, see pp. 7-12

2. Oort, A. H., 2022: Living on Earth–Memoir of a Meteorologist. Planetary Health, Inc., Becket, MA, 229 pp. For the history of Global Warming, see pp. 132-136, and 143-152.

3. Rao, S. K., 2023: The Pinky Promise., Las Vegas, NV, 75 pp. For the transformation to a Climate Healing Civilization, see pp. 59-63


1. Cowspiracy, 2014 (90 min). The film explores the impact of animal agriculture on the environment–examining such environmental concerns as climate change, water use, deforestation, and ocean dead zones. It also investigates the policies of several environmental organizations.

2. Seaspiracy, 2021 (90 min). The film examines human impacts on marine life and advocates for ending the consumption of fish.

3. Oxford Union debate on the proposition, “This House Would Go Vegan” (11 min), 2024. Dr. Sailesh Rao explains the positive environmental effects for the world of going vegan.

4. Eating our way to Extinction, 2024–essential facts (35 min) Featuring commentary from some of the world’s leading scientists. It is a powerful documentary inviting us on a journey into our food system and the negative impact it has on our planet–and on our future as a species.

Abraham Oort, Ph. D., a retired climate scientist, was a member of the observational studies group at the National Oceanic and Atmospheric Administration (NOAA) Geophysical Fluid Dynamics Laboratory in Princeton, NJ. Dr. Oort is a co-author of the text book, Physics of Climate.

Vegan World 2026: The Moonshot of Our Generation

Releasing Our Parents With Love: Mother Earth and Father Sky Await!
Sailesh Rao
No Comments

Post A Comment

Re educate
our world.

Watch, learn and share.

It starts with Education. Eye-opening webinars that lay bare the untruths we are told, and which shine a light on the abuses of our planet and nature all carried out in the name of economic ‘growth’.