Regenerate by Daniel Baertschi, Ananda Fitzsimmons and Patrick Love

REGENERATE

COMPILATION BY LA BUTINEUSE

A MANIFESTO FOR REGENERATIVE AGRICULTURE

DANIEL BAERTSCHI

THE FORGOTTEN ROLE OF WATER IN THE CLIMATE CRISIS

ANANDA FITZSIMMONS

INSIGHTS FROM THE IPCC SPECIAL REPORT

A MANIFESTO FOR REGENERATIVE AGRICULTURE

Daniel Baertschi

Feeding the earth

A Manifesto for Regenerative Agriculture

To my wife Kathrin, who constantly encourages and supports me.

To my parents, who paved the way for me.

For my children, who are passionate about nature.

“Good farmers, who take seriously their duties as stewards of Creation and of their land’s inheritors, contribute to the welfare of society in more ways than society usually acknowledges, or even knows. These farmers produce valuable goods, of course; but they also conserve soil, they conserve water, they conserve wildlife, they conserve open space, they conserve scenery.” (Wendell Berry, 2009, Bringing it to the Table: On Farming and Good)

Wendell Berry is an American essayist, poet, novelist, environmental activist, cultural critic and farmer. He lives and works with his wife Tanya on the farm they share in Port Royal, Kentucky (United States).

Foreword

The fact that you are reading this book shows one thing: food means something to you. Of course, we all eat to live, but few of us consider the effort required to put food on our plates. The subject is too complex, the processes too opaque. The sheer number of brands, the often-confusing labeling and the seemingly infinite number of products on shop shelves is overwhelming.

Eating is much more than just calories and nutrients. It is about pleasure, a deep connection to our culture, sharing and meeting people. Eating is part of our identity and thus an important part of our lives.

For many of us, an abundance of food means we have never experienced real hunger. We are faced with the challenge of choosing what is best for us from an overflowing range of products and of consuming them in moderation. This is anything but obvious. Only by working carefully with nature will we be able to eat in harmony with our planet.

Despite technical progress, soil remains the source of our food. The earth produces enough food for everyone if it is used properly and if we consume a balanced diet favoring plant-based foods, and in reasonable quantities. Healthy soil is the basis for healthy plants, animals – and people.

All over the world, there is an alarming decrease in available agricultural land. Erosion and desertification are increasing dramatically. Every year, droughts and floods destroy fields and consequently millions of tonnes of food crops. In many countries, farmers have abandoned their lands because of war and conflict.

How – and why – did we get here? Is regenerative agriculture a solution? As you read this book, you will see that change is needed, and that everyone can contribute to it. After closing this book, you will be able to make better choices about what you eat. Our health depends on our personal choices, as well as the health of our planet.

Let’s heal our earth by eating healthy!

Introduction

For decades, I have wondered what agriculture would look like if it wisely used the natural resources and conditions of each place, and produced food in harmony with nature. Growing up on a pioneering organic farm in the Emmental region of Switzerland, I had direct and immediate experience, from childhood, of the complexity and demands of farming to answer this question. Following a traumatic personal experience, my parents converted the family farm to organic farming in the early 1970s at a time when agriculture was expanding rapidly in the country. A neighbour farmer used a licensed chemical pesticide against house longhorn beetle infesting his barn. The product was sprayed on the beams – directly above the hay. Some of the product got into the hay, which was consumed by the cows. This farmer supplied milk to the village dairy, which produced Emmental cheese, and some of the cheese was exported to the United States, where health authorities discovered residues of the chemical agent. The cheese was confiscated and the entire shipment destroyed. The farmer concerned had to dump his milk into a slurry pit and to wait a year before he was allowed to deliver to the cheese factory again. This incident prompted my parents to take a critical look at the benefits of technical and chemical progress. They turned to organic farming.

The experience changed my parents’ outlook, and consequently my own. I became concerned at an early age about what a healthy agriculture and food system could look like. Over the years, working in the fields and stables, I tried to find practical solutions to this question. I had benefited from quality food produced on our farm, and I consider it a privilege to have grown up eating organic food. Freshly picked salad on the table, meat and milk from

our own animals, vegetables in all their varieties, preserves and sweet cider from the cellar – it was all natural, normal and obvious to me.

All the discussions about organic farming around the family table, in the fields and in the barn are unforgettable memories. As a child and teenager, you want to follow your own path and make your own opinion, which is what I did. Like my parents, I became a farmer. I also studied agricultural economics. I worked as a consultant and manager in Switzerland and elsewhere, becoming involved in a variety of fields, from development cooperation, occupational safety, and the management of a nature museum, to setting up my own consulting company. I was concerned with healthy food and its link to climate protection. For eight years I was Managing Director of Bio Suisse, the parent organisation of Swiss organic farming. My wish was, and still is, that people appreciate nature and use it responsibly. We are not the owners of the land, the soil, the nature; we are only the custodians.

My interest in regenerative agriculture gained momentum a few years ago when I left Bio Suisse with the intention of expanding beyond “organic”. I was inspired in particular by the American author, farmer and philosopher Wendell Berry and visionary regenerative farmers such as Joel Salatin, Gabe Brown, Allan Savory, Charles Massy, David Montgomery, Tony Rinaudo and Allen Williams among others. Films have also been a source of inspiration, especially The Biggest Little Farm, Polyfaces, Kiss the Ground, and Sacred Cow.

In the course of my working life, I have become interested in conventional agriculture, which continues to go about its business with the pretence of controlling nature and influencing it to our advantage by means of all sorts of tools – with the one-sided goal of high yields. I will never forget the day when I first put on a protective suit and a mask, and walked through the potato field with a sprayer full of herbicide to combat weeds. The result of this operation was a field free of all vegetation – except for potatoes. The realisation that, after the harvest, a residue of this weed killer would linger in the soil and in the potatoes dampened the pleasure of the harvest six months later.

In my visits to farms in more than 50 countries, I learned about all possible – and impossible – forms of production, and often met hard-working people who cultivated their land with very simple tools. These farmers use the soil as a livelihood with heart and soul, but are heavily dependent on an extremely powerful agribusiness and misguided agricultural policies. In many places I have seen massive soil and environmental disturbance, degradation of animal life and exploitation of workers. In the Indian state of Uttar Pradesh, families with small farms went into debt to buy “modern” seeds, and fertilisers already coated with pesticides meant to increase their yields. When drought hit, the loans could no longer be repaid. Many farmers committed suicide as a result. How did they do that? With pesticides bought on credit!

Why have we let things go so far, despite science and technology? What are the underlying causes of the abuse of nature? Why are we unable to produce our food in harmony with nature? Why is there not enough food for everyone? I think we are all asking these questions in one form or another.

A different kind of agriculture is possible, indeed necessary, which will have a positive effect on our children and grandchildren. We need to start by understanding and respecting nature in depth and from there, find a form of production that is adapted to different environments. It is about reforming trade and consumption, strengthening local value-adding and adopting wise agricultural policies. All of this is aimed at enabling people to lead better lives through healthy food.

There is no magic formula that can be pulled out of a drawer to solve all the problems, nor is the solution a schematic application of standards and guidelines. Rather, it is a matter of implementing clear principles established by nature. We humans have the noble task of taking our role as competent stewards of planet Earth seriously, with the humility and respect due to this wonderful creation. This includes valuing the work of farmers. They are the source of our food, and they have the opportunity to change the face of the world through their work.

It is up to everyone – farmers, consumers, trade and processing companies, politicians, groups and organisations – to shape a future worth living for our children and grandchildren. This path is not new, radical or expensive; it is good for people, animals and the environment – it is good for everyone and everything!

The path leads – if we follow it to the end – to a more than sustainable agriculture, namely a regenerative agriculture. But not everything has to be invented, old knowledge can be combined with new scientific innovations, nature can be understood and used in a different way, uncharted paths can be bravely taken and the status of knower can be changed to that of learner – all in a lifetime and with joy.

Let’s embark together on a journey of regenerative agriculture! Let’s discover the simple and effective principles and effects of this ancient yet new form of more than “sustainable” agriculture.

THE FORGOTTEN ROLE OF WATER IN THE CLIMATE CRISIS

Ananda Fitzsimmons

Hydrate the Earth

The forgotten role of water in the climate crisis

Introduction

The narrative that climate change is caused by the accumulation of greenhouse gases released by human activities, has led to the predominant conclusion that the solution lies in reducing our emissions. While this is true, the deeper that scientists dig into analysing and modeling climate change, the more complex it becomes.

Now, new perspectives are emerging on climate change, focusing on water cycles. It is the main topic I will address in this book, illustrated with concrete and successful examples of water management projects from around the world. Whereas until now the focus has been mainly on carbon cycles, water cycles are now thought to contribute and mitigate climate change just as much.

It should meanwhile be remembered that climate balance cannot be reduced to a single equation. Because of the complexity of ecosystems, it is, in my view, useless to argue whether the true driver of climate change is the carbon cycle or the water cycle: it is both. But the more we understand about how the water cycle affects climate regulation, the more pathways we have to intervene.

Concerning complexity in ecosystems, it should be noted that all living creatures within them play a role, and that all are interconnected through cascades of dependencies. Take for example the wolves in Yellowstone National Park: when reintroduced, they controlled the populations of deer and elk which were overgrazing the vegetation; the vegetation grew back, bringing back small animals, then beavers, rabbits, and some birds. The beavers made dams which generated more wetland and so more aquatic

species: water birds, amphibians, then mink and moose. The point here is to show the reality of this interconnectedness, and the complexities how it works in rebalancing an entire ecosystem.

Taking a look back at some key events which have raised awareness of the importance of climate mitigation, I’d like to refer to the Special Report on Global Warming of 1.5°C, issued in 2018 by the IPPC (Intergovernmental Panel on Climate Change). This report was highly publicised in the international media and served as a wake-up call, giving us all a dire warning about how we are potentially destroying our planet. Two subsequent reports with further recommendations in 2019 focused respectively on the importance of land use and oceans in saving the planet. Yet we have already been hearing warnings about climate change for decades. The IPCC has been in existence since 1988; in the 2015 COP 21 climate talks in Paris, an idea was tabled by the 4 per 1000 Initiative that we must not only decrease emissions; we could also sequester huge amounts of atmospheric carbon in the Earth’s soil. The regenerative movement was born. Such official reports and meetings have built up the momentum, along with many extreme weather catastrophes around the world. They have enabled us to accept the realities of climate change, and realize that we all have a role to play in mitigation.

New words have since crept into everyday parlance, such as the Anthropocene, a geological era which is estimated to have started during the post war period and accelerated with the rapid industrialization and colonization of most the Earth’s surface.

Over the centuries, humans have radically altered the surface of the Earth by removing natural ecosystems and replacing them with human centric systems, which don’t deliver the same benefits. In the last panel on the right we see the proportion of natural ecosystems compared to human managed systems since industrial time.

Chapter One A new water paradigm

Let’s dive into these emerging stories about how hydrology is an important driver of our current crisis. One of the dominant voices which coined the term “New Water Paradigm” is that of Michal Kravcik, a Slovak hydrologist and water engineer. In a document by that name, which he published in 2007 along with his team of researchers, they describe two water cycles: the large water cycle and the small water cycle. The large water cycle refers to the movement of water over the wide landscape. It is also the one studied at school. Water falls from the sky and moves over the land, flowing from higher elevations to lower elevations, gathering in rivers and streams which ultimately flow back to the sea.

The small water cycle refers to the vertical movement of water. Water infiltrates into the earth, hydrating the land. It fills aquifers, which are groundwater storage places. Plants mediate the small water cycle because their roots make the soil permeable, letting water go in deep into the ground. They also transpire water vapour, which cools the earth and the air close to the ground then eventually rises up to become clouds.

Modern industrialized society has disrupted the small water cycle in important ways, and as a result, more and more of the water which falls as rain goes into the large water cycle and is carried back to the sea without cycling many times between the earth and the clouds. Kravcik and his team even posit that this, as much as the melting of glaciers, is contributing to sea level rise.

So how have we disrupted the small water cycle? First of all we have cleared vegetation from the land. Massive deforestation means there are vast areas where ground is not stabilized and protected by trees. Lawns, annual monocrops and

Water runs downwards in rivers to the sea, but it also seeps into the earth and is breathed out by vegetation.

shrubs don’t have such deep roots and don’t transpire as much as trees. Asphalt and concrete don’t transpire at all and don’t absorb rainfall. In cities and industrial areas sewage pipes and drainage ditches carry the rainfall away, straight back to rivers, often with a nice load of pollution and back to the large water cycle.

In agriculture, bare tilled soil loses not only its carbon but allows water to evaporate quickly as well. Heavy machinery has compacted agricultural soils, so that water runs off the surface rather than seeping in. Excess water is channelled into drainage ditches or drainage tiles and quickly evacuated. Agricultural drainage practices are concerned with preventing standing water and floods; they are less concerned with good water infiltration, so again, we are feeding the large water cycle but not the small one.

The planet is desertifying

There is such a thing as a natural desert, a dryland ecosystem where the vegetation is adapted to a dry climate, but desertification is another thing. Desertification is caused by the degradation of land, due to unsustainable land management. The same practices that are disrupting the small water cycle: deforestation, overgrazing, tillage, monocultures, urban sprawl, are creating larger areas of desertification around the planet.

There are vast deserts on the planet which were once fertile. The Fertile Crescent, an area in the Middle East spanning what is now Syria, Lebanon, Palestine, Israel, Jordan and Egypt, is called the cradle of civilization. Once a lush and fertile land, it was the birthplace of modern agriculture. There originated the practices of plowing, irrigation, raising domestic animals, and the culture of plants such as wheat, barley, chickpea and lentil. But today, no agriculture in that region is possible without extensive irrigation. The once fertile soils are contaminated by salinization, which is what happens when groundwater is used for irrigation over long periods of time. Minerals from the earth and synthetic agricultural amendments such as fertilizers concentrate in the ground water and accumulate in the soil, eventually contaminating the soil until it can’t sustain life.

Once fertile areas are becoming increasingly arid, due to poor land management and deforestation.

The same thing is happening in other places. In the southern USA, notably California and Arizona, where most of North America’s fresh produce is grown, little rain falls and agricultural fields are kept in production by irrigation, pulling the water from major rivers and underground reserves. But these reserves do not receive enough rainfall to refill them, so over time they are being depleted. When you travel, outside of the agricultural fields, you see dried up riverbeds and desert landscapes. And yet supermarkets over North America are selling lettuce produced in deserts with irrigation that is coming from diminishing aquifers.

Where I live in Eastern Canada, many people do not take seriously the possibility of a water crisis, mostly because we have plenty of water here. And it is true: often we have too much. When the snow melts in the spring, we frequently get flooding, and with climate change, that is happening more often. We have serious flooding events where people have to evacuate their homes, and cornfields can’t be planted. But in 2020, even after spring flooding, we had a six-week drought in the summer. Farmers who grow broad field crops are not equipped for irrigation because they never needed it here. That summer they became worried, and now wonder if, after all, they will need to install irrigation systems in the fields. Fruit and vegetable farmers are already doing it.

Too much rain and not enough are simply two sides of the same coin. Monsoon rains are a part of desertification. Even extremely dry places get torrential rains sometimes. When it rains, it rains more, but then it does not rain for a long time. There is no place on the planet which is not touched by the disruption of water cycles. When we think of deserts, we may think they are far away and don’t concern us. But we are doing the same things everywhere. We clear vegetation and mismanage water which eventually leads to soil degradation and desertification. It is only a matter of time unless we begin to do things differently.

How does the water cycle regulate climate?

Walter Jehne is an internationally acclaimed climate scientist and microbiologist, and is the founder of Healthy Soils Australia. He is another of the passionate voices saying that restoring the water cycles is our best chance to avoid catastrophic climate change. According to him, the rise in atmospheric carbon is a symptom of climate change, and not the biggest cause. Because water vapour is also a greenhouse gas, responsible for 95% of the heating and cooling mechanisms on planet Earth, it plays an even more significant role than CO2.

He goes on to describe those mechanisms and I will try to summarize what he says because it sheds light on how we need to change the way we manage both land and water.

Albedo effect

The sun radiates 340 watts of heat per square meter of earth surface every day. Some of it is absorbed while some of it is refracted off the surface. In order to keep the balance of warming and cooling of the Earth’s temperature, part of the heat that comes into the atmosphere each day has to escape back into space. This process is slowed down by the Earth’s atmosphere, which traps and slows the process of radiation going back into space. We call this the greenhouse effect and it is necessary to buffer this heating and cooling process so that we can keep a comfortable temperature on the Earth’s surface to sustain life as we know it. There is an input and an output rate, which need to be in balance.

Two things are happening with climate change which are altering this balance. One, well described and understood by most people now, is the accumulation of more greenhouse gases in the atmosphere. Greenhouse gases trap more heat close to Earth and slow its escape back to space.

The second factor is less understood. It has to do with how heat is absorbed or reflected as it strikes the Earth’s surface. If solar radiation hits a dark surface,

Patrick Love

Land and Climate

Insights from the IPCC Special Report

Note to readers

The aim of this book is to enable people without the necessary time or background to better understand an IPCC report published in 2019.

The title of this report is Climate Change and Land: An IPCC Special Report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems. 1 The report is also known as the Special Report on Climate Change and Land.

The Special Report “assesses the dynamics of the land-climate system, and the economic and social dimensions of addressing the challenges of land degradation, desertification and food security in a changing climate. It also assesses the options for governance and decision-making across multiple scales”. The Special Report was compiled by over 600 experts from varying fields of research. The majority of them (52%) are from developing countries.

The findings are based on over 7000 scientific and technical publications. Each finding is grounded in an evaluation of underlying evidence and agreement. A level of confidence is expressed using five qualifiers: very low, low, medium, high and very high.

In this short introduction, we only cite findings that are classed as “high confidence” or “very high confidence”. These are quoted word for word in our text, and are highlighted in italics.

The following text follows the structure of the IPCC report:

Chapter 1 introduces land-climate interactions at local, regional and global scales.

Chapter 2 examines the forces driving desertification and land degradation, and how these relate to human activity and climate change.

Chapter 3 describes the causes of desertification, and how these causes interact with climate change.

Chapter 4 focuses on food security, and the impacts of climate change on food systems, considering how mitigation and adaptation can contribute to both human and planetary health.

Chapter 5 analyses the interlinkages between options for climate mitigation and adaptation to address desertification and land degradation, and to enhance food security.

The concluding chapter assesses the opportunities, decision making and policy responses to risks in the climate-land-human system.

Since the examples and discussions in our text draw on sources other than the IPCC, the opinions expressed may not be those of the IPCC or its members.

Notes

1. IPCC, 2019: Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems [P.R. Shukla, J. Skea, E. Calvo Buendia, V. Masson-Delmotte, H.-O.Pörtner, D. C. Roberts, P. Zhai, R. Slade, S. Connors, R. van Diemen, M. Ferrat, E. Haughey, S. Luz, S. Neogi, M. Pathak, J. Petzold, J. Portugal Pereira, P. Vyas, E. Huntley, K. Kissick, M. Belkacemi, J. Malley, (eds.)]. In press. https://www.ipcc.ch/srccl/

Chapter One Land-climate interactions

The term ‘butterfly effect” comes from the work of meteorologist Edward Lorenz, who discovered in 1961 that a tiny change in data he typed into his numerical weather model (rounding up 0.506127 to 0.506) eventually led to a totally different forecast from the one using the original number.1 The idea that the flap of a butterfly’s wings in Brazil could lead to a tornado in Texas is far from Newton’s “For every action, there is an equal and opposite reaction”. In a Newtonian world, the flap of the wings would only cause a reaction in the air the wings pushed, allowing the butterfly to fly. But in talking about the climate, we have to move beyond action-reaction pairs to look at complex series of interactions involving the air, the land, the oceans, and human activity. We can view these interactions as an adaptive system, where each part is constantly influencing the others and being influenced by them.

In this chapter, we will look at one part of the dynamics of this system, landclimate interactions at local, regional and global scales. Land cover and land use are adapted to “climate envelopes”, combinations of ranges of temperature and/ or rainfall. Greenhouse gas (GHG) emissions caused by humans impact land through changes in the weather and climate and by modifying the composition of the atmosphere, especially by increasing the amount of CO2.

Anthropogenic warming has resulted in shifts of climate zones, primarily as an increase in dry climates and decrease of polar climates. Ongoing warming is projected to result in new, hot climates in tropical regions and to shift climate zones poleward in the mid- to high latitudes and upward in regions of higher elevation. (IPCC SRCCL, p. 44)

Energy moves from warmer regions to colder regions – from the tropics to the poles – and as the amount of heat in a region increases, the characteristics of that region change. The Sahara Desert for example grew by 10% during the 20th century,2 while Antarctic ice is now melting six times faster than in the 1990s.3

The shift of warmer climate envelopes into high latitude areas could help agriculture through extended growing seasons, warmer seasonal temperatures and increased atmospheric CO2 concentrations which boost photosynthesis. However, plants and animals have evolved to adapt to their climate niches. Even if they could change as much in the next few decades as they changed over the past thousands or millions of years, that still might not be fast enough to cope with changes projected to occur by the 2070s.4 Overall, loss of vegetation productivity in many parts of the world could overwhelm any benefits to land use and land cover from increased atmospheric CO2 concentrations.

Warming will also increase snowmelt and reduce albedo, the amount of solar radiation reflected rather than absorbed by a surface. When albedo is reduced, the land absorbs more heat. In polar regions, this is leading to a feedback loop where the increased heat absorption melts more ice, reducing albedo further. A similar phenomenon is happening in the tundra, where permafrost melting is releasing GHG trapped in the soil.

A counter-example from Spain shows how changes in land conditions from human use, literally from greenhouses, can affect climate. The semiarid Almeria province has both Europe’s biggest desert and the world’s biggest area of greenhouses, nearly 30,000 ha. The white plastic sheeting the greenhouses are made of has increased albedo so much that the average annual temperature of the region has actually cooled by almost one degree since the 1980s.5

The human species developed within a climate niche. For the past 6000 years, most of us have lived in areas where the average annual temperature is 13°C, but over the next 50 years, 1 to 3 billion people could be living in areas hotter than that.6 Moreover, some areas are already very close to experiencing

combinations of heat and humidity that make it impossible to survive for long outside, for example the southern Persian Gulf shoreline and northern South Asia, home to millions of people.7

The frequency and intensity of some extreme weather and climate events have increased as a consequence of global warming and will continue to increase under medium and high emission scenarios. [...] future climate variability expected to enhance the risk and severity of wildfires in many biomes such as tropical rainforests. (p. 45)

Flooding as an existential threat to life is mentioned in the Legend of Gilgamesh and later in the Bible, which also talks about destruction by fire. These archaic fears are coming to pass more and more frequently. The number of floods and other hydrological events has increased four-fold worldwide since 1980 and doubled since 2004. Extreme temperatures, droughts, and forest fires have more than doubled since 1980, as have storms.

As the summer of 2021 showed, all parts of the world are affected. In July alone, floods and the landslides they caused killed over 920 people, including 219 in Belgium and Germany; 192 in Mumbai and Maharashtra, India; 113 in Nuristan Province, Afghanistan; and 99 in Henan Province, China.8 Nine people were killed by wildfires in California, but deaths related to environmental disasters are not always immediate. Over 33,000 deaths a year can be attributed to air pollution from wildfires, including 7,000 in Japan; over 3,000 in Mexico; more than 1,200 in China; more than 5,200 in South Africa; nearly 5,300 in Thailand; and almost 3,200 in the US.9

In 2019, the worst natural disaster worldwide in terms of human lives lost was a heatwave in Europe, responsible for 2500 of the 11,755 deaths caused by natural disasters reported that year.10 Globally, heatwaves have become more frequent and longer since the 1950s, and the biggest increases are seen in areas that are expected to suffer most from the impacts of climate change.11 By the end of the century, heatwaves may become extremely long

(more than 60 consecutive days) and frequent (once every two years) in most areas of the world.

Droughts too are expected to get worse, with some studies predicting that by 2100, climate change could reduce terrestrial water storage (TWS) in many regions independently of other factors such as land use changes, especially in the Southern Hemisphere, the United States and southwestern Europe. The global land area and population in extreme-to-exceptional TWS drought could more than double, increasing from 3% to 7% for land area and 8% for population.12

There is an economic price to pay for natural disasters as well. In the US for example, the cost of 285 major weather and climate disasters since 1980 is estimated at over $1.875 trillion.13

The shift in climate zones means that wildfires are also shifting. In “traditional” wildfire regions, life has had time to adapt to the fires, through flame-resistance in tree bark for instance. Some species even rely on fires, like the giant California redwoods, that benefit from fires clearing undergrowth and enabling their seeds to germinate. But we are now seeing huge fires in new areas, or areas where they were very rare. The northern part of the planet is warming more quickly than the Earth as a whole, and boreal (northern) forests are now burning at a rate unseen for the past 10,000 years.14

Fire damage to tropical rainforests is getting worse too. Often, these fires are started deliberately to clear land for agriculture, but climate plays a role as well. Warming of the North Atlantic and tropical east Pacific oceans draws moisture away from the Amazon, making the dry season longer and increasing the risk that fires started deliberately will spread out of control.15

Changes in land conditions modulate the likelihood, intensity and duration of many extreme events. (p. 47) Regional climate change can be dampened or enhanced by changes in local land cover and land use but this depends on the location and the season. (p. 135)

Land conditions also affect “normal” climate and weather. Given the lack of historical data, there is no direct observation of how past land use changes affected atmospheric dynamics and physics globally or regionally, so models are used to estimate trends. However, climate modelling experiments only assess the impacts of land cover changes such as deforestation or urbanisation, and neglect the effects of changes in land management such as irrigation, use of fertilizers, or choice of crops. Because of this, we will use the term ‘land cover changes’.

Human-induced changes to land cover and land use are part of a cycle. Deforestation and afforestation, grazing, irrigation, urbanisation, and so on cause changes in atmospheric CO2. This provokes changes in global atmospheric variables (temperature, precipitation, atmospheric circulation, et cetera ) which alter local and regional variables such as temperature, precipitation, and wind. These in turn lead to changes in land functioning, land cover, and structure, including photosynthesis, drying, greening, distribution of natural ecosystems, and species composition. These changes then alter atmospheric CO2.

In boreal regions, where projected climate change will migrate the treeline northward, increase the growing season length, and thaw permafrost, regional winter warming will be enhanced by decreased surface albedo and snow. Warming will be dampened during the growing season due to larger evapotranspiration (evaporation of water from the land surface plus transpiration from plants). In the tropics, wherever climate change increases rainfall, vegetation growth and associated increase in evapotranspiration will dampen regional warming.

Agriculture, forestry and other land use (AFOLU) is a significant net source of GHG emissions. (p. 45)

Historical changes in anthropogenic land cover have resulted in a mean annual global warming of surface air from biogeochemical effects such as carbon emissions, despite being offset to some extent by biophysical cooling,

from increased surface albedo as seen in Almeria for instance. The key question is how much AFOLU contributes to global anthropogenic GHG emissions, starting the cycle described above.

Agriculture, forestry and other land use were responsible for around 23% of anthropogenic GHG emissions over 2007-2016, and were the main anthropogenic source of nitrous oxide (N2O) from fertilizer, the most important GHG after carbon dioxide and methane. Chemical fertilizers using nitrogen boost agricultural production, but plants can only use a certain amount of nitrogen. After this limit is reached in croplands, N2O emissions grow exponentially. Global N2O emissions have increased over the past two decades and the fastest growth has been since 2009, notably in China and Brazil due to increased use of nitrogen fertilizers and the expansion of nitrogen-fixing crops such as soybean.16

The impacts of changes to land cover are not restricted to the area where they occur. Changes in local land cover or available water from irrigation can affect climate in regions hundreds of kilometres away. This is one reason why torrential rain in Germany may be linked to urbanisation in Spain. Rainfall on the Spanish coast comes mainly from Mediterranean sea breezes that pick up extra moisture from marshes and wetlands. But as the marshes and wetlands are built on or drained for farming, the breezes cannot not pick up enough moisture for summer storms over the mountains. The water vapour they had picked up is returned to the Mediterranean, where it accumulates before drifting northward and falling as rain when it cools over central Europe.17

Climate change is already affecting the health and energy demand of large numbers of people living in urban areas. (p. 188)

Over half the world’s population live in towns and cities, generating around three-quarters of global total carbon emissions from energy use. The proportion of urban population is predicted to reach about 70% by the middle of this century, with most of the growth in the developing world. Of the world’s 33 megacities in 2018 (population of 10 million or more), 27 are located in the