Category Archives: Earth systems

Ecological realism in climate change investment

Awareness by podcast

My 7 December 2023 interview on The Why? Curve podcast aimed to raise awareness of the need for smarter investment in climate change mitigation to prevent major Earth systems breaking down in the 2050s or 2060s. Worse, there are reasons to think that the loss of Arctic summer sea ice from around 2030 could accelerate this process dramatically. These risks are so obvious and dire that they call for urgent precautionary action.

Cascades of chaos

Major Earth systems are becoming unstable under stress from global heating and other more direct pressures. These systems include the Arctic Ocean and its surrounding coasts and permafrosts, the Amazon and other rainforests, and major ocean currents and monsoons. They have been absorbing stresses for decades but are now approaching the limits of their tolerance. That limit is each system’s tipping point, when it becomes committed to chaotic transformation. Because Earth systems are connected they can pull each other over, so multiple systems could become committed to breaking down at about the same time. This would be a ‘biosphere-wide tipping point‘ (BTP), which is a key moment because we can influence outcomes until it is reached, but we will be powerless to do so afterwards.

Deadline awareness

Time for a re-think

The idea of a BTP challenges all our assumptions about the future. These were shaped during centuries of economic expansion into what was seen as an infinite global frontier. But our predicament now, at the end of that phase, leads us towards the idea of deadline-aware mitigation investment (DAMI) with a new purpose and a new approach.

The new purpose would be to postpone the BTP, thus buying ourselves time to strengthen our societies against climate chaos, decarbonise our economies, recapture GHGs from the air, and restore peace with nature.
The new approach would be to refocus investments on those that are proven to reduce net GHG emissions soonest and most cost-effectively, while remaining true to our other values.

Postponing the BTP

I have proposed and demonstrated a transparent and consistent way to calculate the cost-effectiveness of different mitigation investments in postponing the BTP. This relies on:

assuming a realistic date for the BTP;
calculating the amount and timing of net GHG emission savings from each mitigation investment up to that date (in tCO₂e);
valuing those savings exponentially more highly the sooner they are delivered relative to that date, to give us the ‘dated mitigation value’ of each investment (in tCO₂edmv); and
estimating true mitigation cost-effectiveness from the cost of the project over the same period (in tCO₂edmv/£).

DAMI useful

Armed with data on true mitigation cost-effectiveness, public servants can reliably choose the best public investments. This would improve governments’ ability to deliver on their ‘net zero’ or Paris Agreement goals. Taxes and other regulatory signals can also be adjusted to ensure that the most cost-effective mitigation projects attract the highest rates of financial return for private investors, while also valuing healthy ecosystems, biodiversity, human rights and other important co-benefits.

The Arctic threat

Summer sea ice decline

The progressive thinning and shrinking of Arctic Ocean sea ice since 1979 was first flagged by Peter Wadhams, former Director of the Scott Polar Research Institute, in his 2016 book A Farewell to Ice. The volume of Arctic summer sea ice continued to decline and is now expected to approach zero at its September minimum by around 2030.

Heating oceans

The context for the Arctic issue is the rising heat of the oceans. This has increased by hundreds of zettajoules (ZJ) since the mid-1980s (one ZJ ≈ double humanity’s current energy use). This is where most greenhouse heat has been going, with much of the rest going into melting ice.

Step-change in Arctic heating

Without summer sea ice to absorb excess heat, at least two mechanisms mean that the temperature of the Arctic Ocean and its seabed and coastal zone will begin to rise much faster than before. These are:

that it takes 80 times less heat to warm water than to melt ice (4 J/g/C for water [due to its ‘heat capacity’] vs 334 J/g/C for ice [due to its ‘latent heat of fusion’]); and
that without white and reflective ice, more solar heat enters the ocean.

Potential methane consequences

The likely rate at which Arctic Ocean temperature will rise under ice-free summer conditions is unknown, but could be high. Until we know what will actually happen, a precautionary attitude is called for since sudden Arctic heating could have the following consequences:

a potentially large share of many hundreds of billions of tonnes (Gt) of peat contained within permafrosts throughout the Arctic will decay and release methane (CH4); and
a potentially large share of the hundreds of Gt of CH4 contained within frozen clathrates (or hydrates) in the Arctic seabed will be released.

Potential climate consequences

Every tonne of methane is about 86 times more potent as a GHG over 20 years (the most relevant timescale) than a tonne of carbon dioxide (CO₂), so 1 Gt CH₄≈ 86 GtCO₂e, equivalent to about twice current global emissions of all GHGs put together. If there’s the slightest chance of this happening, urgent precautionary investment to mitigate harm would be justified. Since we cannot now prevent the loss of Arctic summer sea ice, this may have to involve open-air methane recapture. If we need to do this in the 2030s, we should start thinking about it now.

What is to be done?

As a contribution to safeguarding the process of urgent, fair and effective decarbonisation, my podcast aimed to raise awareness and encourage urgent, practical thought:

about the BTP deadline, to encourage greater cost-effectiveness in mitigation investment, so that everything we do contributes to postponing the BTP;
about the Arctic methane threat, to alert people to the need for precautionary action to make sure that we don’t sleep-walk into an early BTP; and
about both, to encourage anyone who can to spread the word, the sense of urgency, and the need for a new spirit of ecological realism in all our actions.

Julian Caldecott 2023

World Nature Conservation Day, 28 July 2023

Nature, Great Mother: “nothing compares to you.”

In her haunting song of grief and loneliness, the late Sinéad O’Connor summoned with precision and beauty the feelings of wrenching loss. Our hearts are likewise tormented by the ruin of life on Earth: mass extinction of our fellow beings, and destruction of their marvellous home ecosystems. For we now risk a devastating age of loneliness, a fate that we must prevent at all costs. On this day we celebrate our efforts to do so.

A day for the global grass-roots

Of mysterious origin but well-marked in India, World Nature Conservation Day has not yet been adopted into the UN calendar. Rather it is owned by the global grass-roots: those who cherish and wish to protect nature, without reference to officialdom. Their concern and leadership daily become more important, as the fruits of official neglect and unsupervised private opportunism fall into our laps as deadly heat-waves, wildfires, storms, and floods.

Business as usual, when the world is dying, is no help

Business as usual is ravaging our lives and futures. Millions are giving up hope in the face of what the UN Secretary-General now calls the era of global boiling. But we aren’t yet sure how this will turn out, and can still hope and strive for better outcomes than those we fear. Despair is relieved by knowing that we are on nature’s side, and that nature can help restore our world if she is allowed to. Knowing this, we can act with determination and confidence on her behalf.

Individuals and small groups have surprising power

Some things we can do by ourselves: pledging our loyalty to nature, restoring local ecosystems, talking with others, spreading the word, and keeping the faith. Other things we can only do together, with many hands making light work, and many minds amplifying each other’s influence. Every little helps, often in unexpected ways.

Big irresistible movements can change whole systems

But then there are the big system changes, the constitutional and institutional transformations, which every nature conservationist should be ready to promote. These are what will protect us all against those who would continue to torture and kill nature. We know what these changes need to be, including peace with nature constitutions, anti-ecocide laws, and judges and lawmakers trained in ecology. And we are starting to sense that they are within reach.

We’re all indigenous, and should start thinking like it

Big changes to save us and nature can only come from people feeling awe for nature and respect for the laws of ecology. This is part of what thinking like indigenous people means. But such changes are opposed by the lies of those protecting their own interests against society and nature. Those lies can be neutralised through knowledge, thought, and discussion about what is really going on, and how to undo it. Every lie destroyed in this way is a victory.

Everyone and everywhere is important

So conserving nature is not just something that happens far away, in tropical rainforests and coral reefs. These ecosystems are vital globally, but everywhere is equally important as a habitat for ourselves and other creatures. The system in which we live is where our own health, safety and joy come from. By saving local nature we become part of the great solution to the great danger of our time. It is this that we acknowledge and celebrate on this day each year.

World Ocean(s) Day, 8 June 2023

Celebrating oceans

The world ocean encompasses all the bights, gulfs, seas, straits, bays, inlets and deep waters of the Atlantic, Pacific, Indian, Arctic and Southern oceans. With 97% of Earth’s 1.4 billion cubic kilometres of water, it covers 71% of our planet’s surface to a mean depth of 3.7 km, but with trenches up to three times deeper. World Ocean Day and World Oceans Day both sprang from the 1992 Earth Summit in Rio de Janeiro, Brazil. On 8 June they focus our attention on the key role of the oceans in the biosphere of our blue planet.

Two days in one

Ocean Day is the more activist version, especially engaging young people and partnerships with aquariums, zoos and museums. In 2022 it involved over 10,000 organisations and businesses in more than 15,000 ocean-themed events in 140 countries. Oceans Day is more official, linked to international treaties on the law of the sea, biodiversity, climate change and desertification. So between them, the two days in one respond to our emotional and intellectual fascination with the world ocean as the dominant feature of the biosphere. And in doing so they focus public concern on the need for governments to cooperate in saving this rich and beautiful living world.

Life in the world ocean

Almost all ocean life is sustained ultimately by the largest photosynthetic mechanism on Earth, the phytoplankton of the top hundred metres or so of sunlit water. This is mixed by currents, the daily vertical migrations of planktonic organisms, and the churning of whales. Its abundance is harvested directly or indirectly by a great diversity of jellies, corals, sponges and sea-fans, amongst many others, and by swarms of finned, tentacled, iridescent and scaled creatures. Once dead, these fall into a seething community of scavengers in the muddy silt of the abyss: brittle-stars, sea spiders, crabs, polychaete worms, nematodes, giant isopods, slime eels and sleeper sharks. And the accumulated nutrients of the sea bed are sometimes lifted back to the shallows by up-wellings that support areas of enormous biological productivity.

Traces of deep history

The oceans cradled life on Earth, and many of its basic designs (phyla) are only found in the sea. From the distribution of these and other marine organisms we can trace the effects of continental drift going back scores of millions of years. Thus there was once a huge equatorial Tethys Ocean, named for the ancient water goddess and consort of Oceanus. It lay between the northern continent of Laurasia (now Eurasia and North America) and the southern continent of Gondwanaland (now South America, Africa, Madagascar, India and Australia). It remained tropical as the continents wandered and collided, but was gradually squeezed by the moving lands. So it ended up as the Coral Triangle, reaching from Malaysia to the Philippines, Papua New Guinea and Indonesia. That region preserves the whole evolutionary record of a long and continuous history, and therefore has more marine species than any other.

The over-fished ocean

People have been harvesting the abundance of sea life since the early days of our lineage. We may even have taken up walking on two legs for wading and foraging in coastal waters. Later we made more and more effective traps and boats, in recent years powering unbreakable fishing nets and steel trawls through delicate and complex marine ecosystems. For all our knowledge of wildlife ecology and sustainable yields on land, where we can see what’s going on, we never really understood how sea-life should be harvested properly. The result is that life in the ocean is now much depleted, and can only really recover where people agree to take the pressure off and let it breed and grow again. These precautionary and no-take agreements are very hard to reach, and meanwhile there are other threats that are even harder to manage.

The polluted ocean

Everything we make and do on land can be picked up and carried by water downstream and into the sea. Run-off includes phosphates and nitrates from farmlands, and sewage from livestock and people. Biologically active, these wastes drive algal blooms that sap the oxygen from sea water, suffocating other life and creating multiplying dead zones. Diverse poisons add to the harm: insecticides from farms, waste chemicals dumped or leaked from industrial plants, and toxins leached from garbage land-fills. We even allow about 11 million tonnes of plastic wastes into the ocean each year, all with their own physical and chemical impacts. And finally, carbon dioxide from almost everything we do is making sea-water steadily more acidic, dissolving the shells and skeletons of marine organisms. As UN Secretary-General António Guterres says, we’ve been using nature and the world ocean like a toilet.

The heating ocean

Far more than air and the land surface, water takes a lot of energy to heat up and it holds that energy for a long time. By absorbing most of the extra heat trapped on Earth by carbon dioxide, methane and other greenhouse gases, the world ocean has protected us against its effects. This let us ignore or deny the underlying problem of global heating for too long, but the days of wilful ignorance are over. Since about 1970 average deep ocean temperatures have been rising, and those of surface waters are now accelerating upwards. And this changes everything: sea level as the ocean expands, the volume and direction of ocean currents, the timing and quantity of rainfall on land, and the frequency and destructive potential of storms that hit the coasts.

Action stations: this is not a drill!

World Ocean(s) Day is now deadly serious. We need to get a grip on sewage, chemical and plastic waste, our destructive treatment of marine ecosystems, and greenhouse gas emissions if we are to navigate this century without global catastrophe. The world ocean is too big and far too powerful to harm with impunity. We know what we should be doing with ever-greater clarity, but taken together our governments and businesses are doing far too little of it. Some are leading, and we should be applauding and rewarding them. Many others are lagging, influenced by polluters and other short-term interests, and we should be pressing them to do better. What hope there is lies with the millions of young people and dynamic institutions who support World Ocean(s) Day, and in the human capacity to restore peace with nature.

International Day for Biological Diversity, 22 May 2023

A moment of global agreement

Biological diversity (or biodiversity) means the variety of living things. It is a term that passed from conservation science into international law through the Convention on Biological Diversity (CBD). This was agreed at a UN conference in Rio in 1992, along with the conventions on climate change and desertification, and entered into legal force on 29 December 1993. Those were the heady days when peoples, experts and governments could agree on the need for urgent action to save nature and the human future. But in the years that followed goals and targets were repeatedly missed, and our global problems kept on getting worse.

A subtle but important idea

Meanwhile the word ‘biodiversity’ never really caught on as a way to promote public understanding. To make it make sense it often had to be translated into stories and pictures about endangered animals, plants and nature reserves. This gave the impression that biodiversity just meant ‘wildlife’. But it is in fact a different, deeper and more subtle idea about the nature of all living systems, which are involved in crises of global heating and climate change, desertification and water stress, and poverty and insecurity. So it’s worth going back to the very beginning to see what ‘biodiversity’ really means.

Immortal life

All living things (or organisms) share a common and continuous ancestry from the start of life on Earth nearly four billion years ago. Life as a whole is thus effectively immortal, even though all individual organisms eventually die. But if they have been able to cope in their own particular environment, they will have reproduced before dying. If so, then their offspring will keep their lineage going for another generation. Uncountable lineages since the beginning have thus struggled to continue, all competing to seed every new instant and environment with their own kind of life.

Diverse life

Under this pressure, the lineages of life spawned a near-infinity of different forms. Each made a living in its own way, and bred almost true until opportunity or necessity changed the rules of its existence. Then new forms arose by natural selection, time after time, rising and falling into extinction as changing environments dictated. All this creativity and intergenerational memory was made possible by complex molecules that stored, copied and passed on the information needed to make each organism in each place and time. These molecules are what we call genes and genetic material, the stuff of heredity and design information in living systems.

The Tree of Life

Now consider the myriad trillions of individual organisms and tens of millions of distinct lineages (or species) at any moment of Earth’s history, all living in intricate relationships with one another. Then you see the complexity and diversity of life on Earth, which we call biodiversity. Add the perspective of billions of years, with each species only lasting a short while before being replaced, and you have the immortal Tree of Life itself. This is a metaphor for something well beyond ordinary human understanding. A Tree rooted in the unimaginably distant past, bearing a shimmering, ever-changing canopy of life forms on the twigs and branches of its many tangled lineages

The Living World

And now add the curved surface of the Earth, oceans and atmosphere within which the Tree grows: the great planetary ecosystem that we call the living world or Biosphere. This unites all the subsystems and environments inhabited by every organism and species that lives on the planet today. These two visions of the Tree of Life and the Biosphere are useful and important, and should be taught from birth in all societies (as they are in some). The idea of the Tree tells us how we as organisms came into being, and that of the Biosphere tells us where and how we live as organisms among many others. The idea of biodiversity is integral to both.

Our divided minds

These concepts help to place us in the Universe. They also give us a context and reason for our existence, both as organisms and as conscious, social beings able to make informed and debated choices. These two aspects of being human are equally true. We have an animal existence shaped by heredity and evolutionary change, as well as individual consciousness shaped by culture and life-experience. But tensions within this double truth yield dilemmas, as well as enormous potential for cooperation and selfishness, which we often call good and evil.

Careless economics

People have recently gained access to fossil energy in the form of coal and petroleum, and combined its use with powerful new technologies. Thus we have built an economic system that has been allowed to operate almost regardless of the rules of ecological sustainability. Dire and dangerous consequences are now rampant: global heating from pollution that traps the Sun’s heat in the Biosphere; ecosystem degradation from over-exploitation and the expansion of settlements, infrastructure, plantations and farmlands; and mass extinction of non-human life forms from direct harm to natural ecosystems and from climate change.

The shedding of leaves

By these means we have blighted the Tree of Life, which is now shedding ‘leaves’ (species), ‘twigs’ (genera) and ‘branches’ (larger and deeper lineages) faster than at any time since the meteor strike that killed the non-avian dinosaurs 65 million years ago. And it is doing so much faster than at any other time in Earth’s history. This loss of biodiversity is rapidly degrading the integrity of the living systems that we depend upon. The blight is also undermining the stability of the oceans, Amazon, Arctic and other major Earth systems. The consequences if they tip into chaos are scarcely imaginable, but on present trends it could happen in this very century. Thus the blight threatens to end our comfort and prosperity, and quite possibly our existence.

A day to remind us …

Which brings us to the International Day for Biological Diversity. This was declared by the United Nations in 1994 to mark the CBD’s coming into force on 29 December. But in 2001 the date was changed to 22 May to avoid the distractions of mid-winter and year-end festivals. Its purpose is to remind us of the need to respect the Tree of Life and the Biosphere, of what we have been doing to them with our careless economic system, and of how we must regulate our behaviour to stay within the bounds of sustainability. In short, of the need to restore harmony with nature before everything tips into chaos.

And a day for celebration and commitment

In 2023, the International Day for Biological Diversity is a reminder of acute danger. But it can also allow for celebration that we are starting to recognise the threat, and to act on it. Many now remember that nature is the most valuable thing we have. We are living more gently within nature, and voting for better and greener governments. Our great task now is to restore ecosystems and peace with nature, and on this day we should think realistically about how to do so. In practice it can mean donating to wildlife trusts and community rewilding initiatives, or participating in actions to protect nature, or helping to build a sense of ecological reality among young and old. All such efforts are welcome, and all are vital for the Tree of Life and Biosphere.

Earth Day, 22 April 2023

The power of seasonal transitions

There’s something about seasonal transitions which reminds us that we inhabit a living world, even if we often feel insulated from it by concrete, glass and traffic. The northern Spring of 1970 saw a peak of environmental awareness which left behind several permanent markers, like sea-weed on the beach after a storm. Prominent among them was Earth Day on 22 April.

The magnetic influence of 22 April

Earth Day has ever since been a way to drum up public awareness of growing threats to the global environment. Thus the UN chose 22 April 2009 to declare International Mother Earth Day, and 22 April 2016 to open the Paris Agreement on Climate Change for signature by the world’s governments. Since then, climate change has been a major theme as public concern has grown along with scientific understanding of its causes and consequences.

Where are we now?

And so we have reached Earth Day 2023. It would be good to be able to say that we are well on the way to solve our major environmental problems, but we cannot yet do so. Millions have taken to the streets, whether inspired by Greta Thunberg, the Extinction Rebellion, or Earth Day committees. But we are still emitting many billions of tonnes of greenhouse gases each year, a thousand times more than we save. As a result of these and past emissions, heat continues to build in the biosphere, and major Earth systems are wobbling towards their tipping points.

Tipping points in Earth and human systems

We don’t yet know how this will turn out, but just as tipping points in Earth systems can creep up on us unnoticed, so too can those in our societies. Countries can have anti-environmental governments for years, while their peoples become more and more frustrated and fearful, organising themselves in little groups and talking with one another. Then, out of what seems like a blue sky, change comes suddenly and positive energies are released.

In the transition, on the cusp, or just stuck?

But such breakthroughs are occasional events in a broad and diverse trajectory of change. Some places are in mid-transition, with stable majorities that expect their governments to ensure high environmental standards and reduced net carbon emissions. Others are on the cusp, with widepread public support for green policies that are still resisted by those with political power. And yet others are stuck, rejecting climate science as a plot, or lacking awareness of global conditions, or worrying about what seem to be more immediate issues.

The transition that matters

Where does your own place fit on this spectrum? In answering, remember that the transition that matters is not a one-day event. Rather it is a process that involves overlapping lifetimes and myriad conversations, elections, lawsuits and actions that add up to a direction of travel. Particularly in countries with indigenous populations, the respect with which indigenous insights on ecological sustainability are treated can shape the journey.

Changing the Zeitgeist

It is this gathering of energy from all sources within a society that eventually changes the Zeitgeist. If there is no direction of travel, it can be started. If it has started, it can be accelerated and made more inclusive. And if it is triumphant, it can be consolidated and joined up with others. It is to celebrate this whole process that Earth Day was set up in 1970, and it can still inspire today.

Fossil Fools Day, 2023

On this first day of April we celebrate foolishness. There is none greater than burning your own home because you like the pretty flames. It’s not even as clever as peeing in your pants to keep warm at the start of winter, as they say in the Nordic countries. So we throw more coal, peat, forests, petroleum and natural gas on the fire because it’s convenient right now. But the effects, as Al Gore and Greta Thunberg have pointed out, will be not just inconvenient but deadly.

Too many fires are making too much carbon dioxide too quickly. This traps the sun’s heat on Earth, warming the oceans and melting the ice of the poles. The Arctic is an ocean surrounded by land. In its bed are a trillion tonnes of frozen methane, which is already bubbling to the surface, and methane is much better at trapping heat than carbon dioxide. Moreover, in the frozen lands around about are another trillion tonnes of methane, held in frozen peat and organic soils. This is already leaking out as the ice lands melt and rot.

So what will happen when global heating pushes the Arctic beyond whatever tipping point keeps it in the deep freeze? Of course the answer is an immense pulse of methane. That’s the big show that could finish us off. Carbon dioxide is only the warm-up act. And when might that happen? All the signs suggest around the middle of this century. Are we ready for this, and do we even know what ‘being ready’ means? Are we even trying seriously to cut back on carbon dioxide emissions? We still churn out scores of billions of tonnes of the stuff every year, and save only a thousandth part of that. So the answers are: not yet!.

We seem inclined to keep putting things off. But with a mid-century deadline looming from the Arctic methane if nothing else, putting things off is really daft. Even if the sums are wrong and it’s really the 2080s rather than the 2050s when the Arctic methane hits the fan, that’s still not very long. We need to get a grip. And that means putting away the jester’s bladder and getting serious. So what to do instead of acting the Fossil Fool?

I could rattle off a list, but here are a couple. First, we should vote only for leaders who will tax carbon emissions radically and enable ferocious and fair investment in decarbonising our economies. And second, we should make sure that rewards from investment are highest when emissions are avoided soonest. With special merit points for those that also help protect and restore nature, and that promote human wellbeing and community solidarity. This would make working with local communities to prevent harm to all our remaining high carbon-density natural ecosystems the maximum top priority everywhere on Earth.

The simple fact in this emergency is that a tonne of emissions avoided now has much more survival value than a tonne of emissions avoided years from now. So that should be the starting point of all our policies, and it should shape all our efforts, incentives and disincentives. Any proposal to decarbonise anything should be met by the question: how much carbon saved how quickly? And be closely followed by another: and with what co-benefits?

These questions will lead not only to the best nature-based and community-based solutions, but to the best technological ones as well. The point is that every potential investment should be made to answer the same questions, so we can compare them. Talking up innovative and imaginative solutions is OK, but only if they are supported by evidence-based reasoning that lets us pick the most cost-effective ways to avoid global catastrophe. Survival value, precaution and co-benefits should be the watchwords. The time is over for Fossil Fool governments that fail to protect us, our children and the biosphere. No to more foolishness! Happy All-Fools Day.

International Day of Forests, 2023

How we treat our forests is a measure of our relationship with nature, with each other, and with common sense. With nature because natural forests are key components in the web of life: rich with biodiversity and evolutionary and biophysical processes that sustain the living world. With each other, because natural forests are lived in by many indigenous peoples and also support vast downstream and nearby populations who rely on them for water, environmental security and essential harvests. And with common sense, because natural forests make landscapes, countries and the world as a whole both habitable and beautiful, so wrecking them is our loss.

We know all this, but the harm still being done to forests shows that we find it hard to regulate our collective treatment of them. This is usually because the bounty that forests offer is most appreciated locally and globally, but less so at intermediate levels where businesses and national governments operate. Here there are incentives with their own logic, which make it profitable in the short term to over-harvest catchment forests for their timber, to replace wetland forests with aquaculture ponds, or inland forests with plantations, mines or planned settlements.

Local and indigenous people are often too weak politically to protect themselves against these forces, yet wherever they are empowered over their forests they prefer to keep them intact. Meanwhile, the global community looks on with rising alarm, conscious that with every hectare of forest lost, another few hundred tonnes of greenhouse gases are released into the air. The days are long gone when a forest could be destroyed in Borneo or the Amazon without anyone caring on the other side of the world. Now we know that we all have to live with the consequences of global heating: floods, droughts, crop failures and high food prices, a list lengthening inexorably towards worldwide suffering, war and total system breakdown.

The story of our efforts to slow and halt forest degradation and loss is dominated by the interplay of these three levels of human society. Local people have strived for recognition and control of their lands and ecosystems. Businesses and governments have strived for short-term wealth. And global actors have strived to moderate short-term demands on forests, while not interfering in national decisions but not able to pay enough to cancel out perverse incentives. Yet this dialogue has yielded victories when different interests aligned around workable solutions.

These usually result from governments and global actors agreeing that local people should take charge of local forests for everyone’s benefit, and should be supported in doing so. Examples include the successes of Danish and Swiss support for indigenous land titling in Bolivia and community forest user groups in Nepal, and Danish support for community forest protection in the Harapan area of Sumatra and the Mbeliling area of Flores in Indonesia. There are many others, and not just in forests. The combination of local empowerment and environmental education works just as well for mangroves, fisheries, grasslands, bush-savannahs and other ecosystems wherever one cares to look, from the equator to the poles.

As well as being good for human rights, traditional lifeways, local well-being, biodiversity and landscape-scale ecosystem services, community forest initiatives are also cheap. Just for carbon, test calculations from Danish investments show that protecting high carbon-density natural ecosystems with community help has far higher climate change mitigation effectiveness per unit cost than renewable energy generation projects ever can. And the co-benefits of these initiatives are abundant, diverse, and full of promise for fair and sustainable wealth creation.

So while we struggle to head off global catastrophe later this century, we should be concentrating on the most cost-effective ways to change outcomes. And that means massively accelerating our investments in nature-based and community-based solutions in natural forests, but learning from past successes and doing it right. Adequate funding for local partnership-based protection over millions of hectares can offer certainty that billions of tonnes of carbon will not be released quickly. As a precaution during a life-or-death gamble with the living world, the need for this assurance should be shaping the regulations and market preferences that control the flow of all climate-relevant investment. With local people as genuine partners, encouraged and enabled by wise governments and advised and financed globally, conserving the world’s remaining natural forests is key to solving the triple crisis of climate, nature and poverty that faces us all. This offers us hope and purpose for the International Day of Forests, 2023.

Buying time to avoid Earth system breakdown

In this talk at the Edinburgh Climate Change Institute, Julian Caldecott warns of tipping points driven by global heating in the Arctic and other complex Earth systems. These systems have been under stress for decades, due to the heat-trapping effects of excess greenhouse gases. Using the case of the Arctic sea ice ‘death spiral’ since 1979, Julian explains how complex systems under this kind of stress tend to resist change before suddenly tipping into new forms. He then uses his knowledge of government climate aid programmes to show how being aware of mid-century deadlines can help us make better choices in mitigating climate change. Having a dated reference point would make it easier to calculate the true mitigation value of investments, thus helping to buy us time to build a safer and fairer world, one with peace with nature at its heart. But peace with nature needs ecosystem thinking, and this must quickly become normal if system change is to occur. Julian asks challenging questions about ‘business as usual’ climate aid, and offers new solutions in this most vital area of public policy.

Watch the video, or read more …

Some of the thinking in the talk is new and unorthodox. It treats Earth systems as complex and assumes that, like other complex systems, they can tip suddenly from one state to another after they have been under stress for a long time. Julian argues that just such a stress is the trapping of heat in the biosphere by greenhouse gases at a concentration in the air above 300 ppm CO₂, which has been the case since about 1950. Its direct consequences include rising heat content of the world ocean and increasing global mean surface temperature (GMST). Its indirect consequences include declining polar sea ice volume, melting glaciers, marine and terrestrial heatwaves, weakening ocean currents and changing weather patterns that are often experienced as environmental chaos and usually described as climate change (CC).

The current 1.5 C goal, based on GMST, helps to focus public attention and mobilise action by governments. But it does not reflect the non-linear responses to be expected of a system as complex as the biosphere. The continuity of cause and effect over time, and the prospect of tipping points, challenge the realism of CC mitigation planning and investment assumptions. Improvements can be made by using an estimate of when Earth systems will, with current timing and heating trends, become irreversibly committed to transformational (‘tipping point’) change. This will pre-date the tipping point itself, so estimating when allows us to judge the effectiveness of CC mitigation investments in postponing it. Postponing tipping points is how we can buy ourselves time to make the changes needed for longer-term safety.

But such postponements may well become harder to do over time, as each system becomes steadily more inclined to transform itself. A relevant case is the ice-free Arctic Ocean, anticipated for September 2035 ± 5, which may already be unstoppable and could well drive a dangerous methane surge when it occurs. The mitigation value of delivering avoided net emissions would presumably decline in real terms as the commitment point is approached, either suddenly on its eve or more gradually in the preceding years. Uncertainties abound and call for precautionary thinking about the dates involved and the mitigation value of investments, including the unit value of mitigation returns on those investments. For these purposes, it is more realistic to reduce that value exponentially from now to the commitment point, rather than to assume a change from ‘valuable’ to ‘valueless’ the day before it.

Thus, a dated ‘deadline’ in mid century (2050 ± 10) might be chosen to represent the transformation commitment point of key Earth systems. This is based on the trajectory of change in sea ice minima in the Arctic Ocean, and on the rate and direction of change in other cryosphere (ice-world) and oceanic systems, and in major equatorial forest areas. Whatever the deadline chosen, precautionary investment plans would exponentially reduce the value of each expected mitigation unit as the deadline approaches. Such plans would therefore express all expected emission reductions not in tCO₂e but in tCO₂edmv, where ‘dmv’ stands for dated mitigation value. This would have the effect of valuing early net emission gains more highly than later ones. This is already in principle a common aim, but a standard metric would allow direct comparison of true cost-effectiveness between alternative investments in practice.

Julian tested the usefulness of this approach with data from projects funded by one EU member state in three developing countries, targeting: avoided deforestation; forest regrowth (also representing tree planting); wind farming (representing renewable energy, RE); and capacity building for economy-wide decarbonisation. Over 21 years with a constant 0.1 exponent used to depreciate mitigation value (such that 1 tCO₂edmv in year 1 = 0.41 tCO₂edmv in year 10 = 0.14 tCO₂edmv in year 21), returns were estimated at 0.90 tCO₂edmv/€ for capacity building, with least certainty; at 0.40 tCO₂edmv/€ for avoided deforestation, with moderate certainty; at 0.05 tCO₂edmv/€ for forest regeneration/planting, with moderate certainty; and at 0.01 tCO₂edmv/€ for wind farming, with most certainty.

Among the cases with moderate to most certainty, the much higher mitigation returns from avoided deforestation than from RE and tree planting investments offer a key lesson to mitigation planners. Variation in the certainty of returns is an important factor in choosing the right mix of investments for each location, but so too are the varied co-benefits (biodiversity, adaptation, human rights, sustainable development, etc.) available from different investment strategies. And the biggest risk of all is that transformation commitment points in Earth systems cannot be postponed (or will not, due weak precaution and/or weak leadership).

This all suggests that a key starting point for justifying the expenditure of public mitigation funds lies the calculation of tCO₂edmv/€. Once this is done, other factors such as expected co-benefits can be considered in detail. But the initial calculation would require an agreed deadline date (which could be moved by agreement later, if success is achieved), an agreed exponent for converting tCO₂e into tCO₂edmv, and attention to the comparative valuation of co-benefits for fine-tuning the justification of each investment.

Watch Julian’s talk and the Q&A afterwards here.