Here Be Dragons, Part 2

2/24/22 – A Resource for understanding the Planetary Boundaries

from The Anthropocene Dashboard

Hello everyone:

Please remember to scroll past the end of the essay to read this week’s curated Anthropocene news.

Now on to this week’s essay:

This week is all about creating a resource to help you understand and make use of the Planetary Boundaries concept. I called their graphic a “map” last week, and that’s fine, but you can think of it as a mere illustration, or perhaps as a Rosetta Stone for the Anthropocene.

Heather reminded me that we all make different kinds of mental maps, and so we respond differently to different graphic representations. You’ll see above, then, another version of the boundaries concept. Take a look and compare to the versions from the top and the bottom of last week’s essay.

AN INTRODUCTION

What is this concept of planetary boundaries? Let’s start with the big picture: The Earth is an astronomical phenomenon, an object born of matter created in the early universe. It is a stony structure with a molten core, its heat derived initially from gravitational force but now sustained by internal radioactive heat that should last a few more billion years. Life on the surface depends on it.

For the next few billion years, then, the surface of the planet will be an evolving miracle of biological complexity, a rare or perhaps unique community of life in the cold vastness of space. Life on Earth is extraordinarily resilient and innovative; we have yet to find an environment here which does not host life. (As the paleontologist/Darwinist/writer Stephen Jay Gould said at my college graduation, we can nuke the planet back into a wasteland of microbial puddles but complex organisms will no doubt rise again.) The problem, though, is that the balance of life as we have known it is extraordinarily sensitive to biological, chemical, and physical changes in certain planetary-scale systems. Each of these systems, identified by Johan Rockström and his colleagues at the Stockholm Resiliency Centre (SRC), operates within a normal range. If one or more of these Earth systems becomes destabilized, then life on Earth becomes destabilized too.

The idea of a planetary boundary, then, is a threshold for human behavior that impacts one of these systems. According to the most recent science, humans have already pushed beyond several of these thresholds. Those are the yellow and orange zones in the image. The good news, however, is that it’s entirely possible for us to retreat from our civilizational transgressions and return each system back to the green center of the image, what the SRC calls our “safe operating space” for Earth.

What is the purpose of this image? How can it benefit society? The purpose of the Planetary Boundaries graphic is to depict the extent of our transgression of the nine planetary systems identified by the SRC as essential to maintain stability in the natural world. As I noted last week, the SRC is concerned not with maintaining a primeval Earth for nature’s sake, but in maintaining a biodiverse, healthy, and hospitable Earth for us.

The planetary boundaries concept, then, as inscrutable as it may seem, can provide society with a “map” of where we are and where we need to go in terms of resolving the most important impacts of the Anthropocene. As David Attenborough says in the Planetary Boundaries documentary on Netflix,

The planetary boundaries have given us a clear path ahead: simple things like choosing renewable energy, eating healthy food, planting trees, saying no to waste. Together these could transform our future on Earth. And the magic in this is that these transformations would also improve all our lives right now.

This is possible.

(Note that I have altered both structure and language here. I’ve put the two core boundaries at the top, grouped the boundaries most closely related to climate change and fossil fuels on the right, kept species paired up with habitat in the top left, and put atmospheric aerosols next to ozone depletion at the bottom.)

THE BOUNDARIES

Climate Change is the first of our two “core” boundaries. By definition, long-term disruption of any of the nine boundaries is calamitous, but the two “core” boundaries – Climate Change and Biodiversity – are particularly important.

Climate change is at the forefront of the civilizational discussion about human impact on the planet, but it should be clear from the graphic that it is only one of the consequences of excessive human activity. Our disruption of the climate is not an anomaly in terms of human impact: it's the norm. Continents and oceans are obviously altered; why not the atmosphere?

If it still seems extraordinary that we can alter the atmosphere so severely, remember two things: 1) for decades, we have emitted on average 100 times more CO2 (among other greenhouse gases) than the world’s volcanoes, and 2) the thickness of the atmosphere is equivalent only to a sheet of paper wrapped around the average tabletop globe. It’s a veneer.

That said, disruption of the climate is first in importance among the boundaries because of the terrifying scale of its impact. Bulldozing a forest or polluting an ocean shoreline is one thing; heating up the surface of the planet while changing the chemical composition of the atmosphere and oceans is quite another. Climate change reaches into every corner of the Earth, including those we still think of as pristine and untouched. In 2016, the South Pole reached 400 ppm of CO2 for the first time in 4 million years.

I won’t list every impact of climate change, but it’s important to state clearly that transgressing the safe operating limit for a stable climate disrupts everything. It’s not just the fires, droughts, sea level rise, turbulent weather, and disrupted ocean currents of a warmer world, it’s the way in which a warming climate interacts with the other boundaries. Ocean acidification is a direct result of CO2 emissions. Every ecosystem and its community of species already stressed by loss of habitat, man-made toxins, excess nutrients from agriculture, and decline in accessible freshwater will be pushed harder by a warming climate, sometimes catastrophically. Just look to Australia, where an estimated 3 billion animals were killed or displaced in the 2020 bush fires, while off the coast large swathes of the Great Barrier Reef have been lost to heat-related bleaching.

Worse, a 2018 study by researchers associated with the SRC raised the fear that tipping points which could shift the planet toward an irreversible “Hothouse Earth” state may be lurking even if we limit warming to 2°C, the aspirational goal set at the Paris agreement. One of the researchers stressed in a Guardian article that the fear was still speculative, but that the consequences were so dire that we’d better treat it as a real risk:

We note that the Earth has never in its history had a quasi-stable state that is around 2°C warmer than the preindustrial and suggest that there is substantial risk that the system, itself, will ‘want’ to continue warming because of all of these other processes – even if we stop emissions. This implies not only reducing emissions but much more.

If a mere 2°C could tip us into irreversible warming, then we’re in trouble. Climate stability may be even more fragile than we’d imagined. This is a stark reminder of Columbia climate scientist Wally Broecker’s darkly funny warning back in 1998: “The climate system is an angry beast, and we are poking it with sticks.”

That said, the solutions are known, and doable. They are a matter of policy and willpower. First, get rid of the sticks. We need to cut back immediately and permanently on fossil fuels and their greenhouse gas emissions, and we need to do so before irreversible tipping points in Earth systems are reached. We need to take every reasonable measure to draw down atmospheric CO2. Once again, I’ll recommend Regeneration as a comprehensive plan for you to study and participate in. For a deeper dive, read the 2018 report, Transformation is Feasible, from the Club of Rome on how to reach the U.N.’s Sustainable Development Goals with the planetary boundaries as a guide. To keep track of climate news, you can use Climate Central and Inside Climate News as reliable sources, as well as the excellent reporting from the New York Times, Yale e360, and many others.

Loss of Biodiversity (or Biosphere Integrity per the SRC) is the other core boundary. This is an assessment of the health status of all life on Earth – i.e. the biosphere – and the SRC has split its assessment into two metrics: extinction rate and the intactness of biodiversity (also defined as genetic diversity and functional diversity). Put more simply, 1) at what rate are species disappearing, and 2) how healthy are populations of the array of living species? This is a core boundary because it’s a measure of our impact on life itself. The biodiversity crisis is just as important as the climate crisis.

Species come and go, of course, but very slowly. Recent analysis suggests humans have already spiked the normal evolutionary extinction rate between a hundred-fold and a thousand-fold and that without full-scale intervention the increase will continue to intensify. There are a lot of species on the “critically-endangered,” “endangered,” and “threatened” lists, and a 2010 study found that about 52 species of birds, mammals and amphibians shift one step closer to extinction on the IUCN Red List every year. The SRC notes in their write-up on this boundary that

The Millennium Ecosystem Assessment of 2005 concluded that changes to ecosystems due to human activities were more rapid in the past 50 years than at any time in human history, increasing the risks of abrupt and irreversible changes.

There is nothing like the Anthropocene in Earth history, on such a quick timeline, other than the asteroid which wiped out about 75% of life 66 million years ago. Most mass extinctions take place over hundreds of thousands to millions of years. Our changes to the Earth have mostly taken place over decades, or a few centuries at most, all of it less than the blink of a geological eye. (For the ultimate resource on this topic read Peter Brannen’s excellent book, The Ends of the World.)

And ecologists are concerned, as they look at the thinning numbers of thousands of other species, that the community of life is less healthy than it appears. Remember, for example, that only 4% of mammal biomass is wildlife; 96% is us and our livestock. Agriculture in particular has pushed extinction rates and the loss in biodiversity, largely by being the main reason we destroy lush and complex habitats. Diverse plant communities, insect communities, birds, wetlands, rainforests, etc., have all fallen to the plow and cow.

The demise of pollinators – from a combination of farm chemicals and agriculture-driven habitat loss – has raised a lot of concern in recent years, and the Planetary Boundaries doc on Netflix points out the painful irony that “our global production of food is, in essence, wiping out the very thing our food production relies on.” 70% of the world's crop species rely on pollinators, but more importantly, as David Attenborough points out, “a planet without insects is not a functioning planet.”

A community of life relies on the integrity of its parts. Pulling threads from the tapestry unravels the cloth. As 85% of the world’s wetlands disappear, so too do the amphibians, the sedges, the damselflies, and more. Removing a keystone species like the beaver – reduced in North America from perhaps 200 million to 100,000 by the dawn of the 20th century (now back up to 10-15 million) – completely alters the complex balance of species in a landscape. As mile after mile of rainforests in Brazil and Indonesia fall to the machines making space for soybeans and palm oil trees, the number of lost species is tremendous but unknown because few have been studied or even discovered. In every ecosystem, evolution produces exquisitely entwined species – like the yucca and the yucca moth – which depend on the other to exist. Pull enough threads from the tapestry and innumerable relationships between species fall apart.

None of this conversation about loss of species even touches on what we might call the microbial Anthropocene. A pinch of healthy soil – where you can find it – contains more microbes than there are humans on Earth, so when you consider what’s happening to the soil communities in eradicated grasslands, forests, wetlands, etc., and in poisoned waterways and seas, it’s not hard to imagine radical increases in both the extinction rate and microbial biodiversity.

As befits a core boundary, the Life boundary is impacted by every other one. Populations of species are thinned and then lost as we destroy habitats, reduce access to clean fresh water, acidify the oceans, contaminate land and sea with man-made toxins and plastics and excess nutrients, reduce air quality with particulates, and increase UV radiation by depleting the ozone layer.

A collapse in biodiversity could reach a tipping point in the not-so-distant future, but it’s worth clarifying that we are not in the midst of a mass extinction. We are, if we don’t turn around, heading in that direction. A mass extinction is not the loss of bears and dolphins, platypuses and lynx; it’s the loss of whole branches of the tree of life. It’s only happened five times in Earth history. The consequences of a sixth – brought on by a long-term unresolved transgression of most of the planetary boundaries – are hard to imagine, and would be even harder to survive.

As with climate, the solutions here are straightforward but difficult: reduce the agricultural footprint, reduce the use of agricultural toxins and fertilizers, bring down global CO2, stop the destruction of key habitats, ban the leveling of rainforests for subsistence farming and palm oil plantations, reduce the production and use of chemicals and plastics and antibiotics and pharmaceuticals, engage and employ locals and indigenous peoples in the creation and protection of essential lands and waters. And much more. Read up on the U.N.’s Convention on Biological Diversity here and read a quick update/introduction to the goals here.

The good news here is that working to reduce any and all of the other transgressed boundaries will help with stabilizing the array of life on Earth that has sustained us. We still need that food, water, and shelter. Turning off the fossil fuel tap is extraordinarily important to preserve the biosphere.

Destruction of Habitat (Land-System Change per the SRC): This boundary is largely a mirror of the Eradication of Life, in that loss of habitat is the primary driver of loss of species. Any glance at a map, satellite image, or view out the window of a plane is enough to remind us that the majority of the planet has been physically edited to serve our purposes, heedless of the cost to biodiversity.

As mentioned above, agriculture (both farming and grazing) plays an outsized role in habitat loss, not least because there are nearly 8 billion of us and we’re increasing at the rate of 2.4 people per second, a million every five days. (You can read my essays on population here and here.) Some 38% of the global land surface has been co-opted by agriculture – that’s half of all habitable land – and much of that transformed land leaves little food, physical space, or chemical hospitality for other species. Monocultured crops laced with pesticides and herbicides are deeply unfriendly to insects, birds, even microbes, while pastures fenced for grazing livestock exclude much of the biodiversity that used that space for millions of years.

But food is not all about plows and cows. Feeding the human world has meant straining an increasingly unsustainable proportion of fish from the sea. Fishing around the extraordinary species-rich nurseries of coral reefs has taken a particularly serious toll. Fish- and shrimp-farming are increasingly important industries that often produce excess nutrients and other contamination in coastal waters.

There are many other significant drivers of habitat loss, from the flattening of ecosystems for urban and suburban development to the paving of millions of miles of roads that cut through environments like scars across skin, and from large-scale mining and drilling (with a waste footprint often exceeding the work area) to the innumerable industrial sites that contaminate waterways, groundwater, and the air of impoverished natural and human communities unable to fight back. (The U.S. has over 1300 Superfund sites which, as NPR reported, “disproportionately affects minorities: Among Black and Hispanic communities, 1 in 4 people live within 3 miles of a Superfund site.”) Large-scale deforestation is ecocide, dams drown valleys, and the invasive species we continue to shift around the world often displace so many native species that the habitat is essentially redefined.

Moreover, as the SRC notes, all of these local impacts have a synergistic effect: “While each incident of land cover change occurs on a local scale, the aggregated impacts can have consequences for Earth system processes on a global scale.” This has motivated the SRC to define the threshold for this boundary not only in terms of the quantity of repurposed land, but also in terms of the quality and fragmentation of the remaining habitat. For many species, a fragmented home isn’t home at all.

The path back to habitat restoration falls into two categories: protection and integration. We absolutely need to reduce our agricultural footprint, and protect vast swathes of habitat, especially entire complex ecosystems (wetlands, rainforests, etc.) to maintain their network of complex relationships and resilience in a changing world. But we also need to be mindful that these protected areas need to be large enough to be useful, and that often they need to be linked so that species can move through them, either because that’s their ancient path or because it’s a new path they need to follow to adapt to a warming world. We’ve seen some of this in efforts to protect habitat for charismatic keystone species – African elephants or Yellowstone wolves, for example – so that in effect we’re also protecting the myriad of plant and animal species that surround them. Through all of this effort to conserve nature, too, we have to maintain room for people, especially those who live in or near areas to be conserved.

The two main systemic ideas here are E.O. Wilson’s Half-Earth plan and the 30x30 plan for biodiversity (30% of Earth by 2030). There is increasing awareness and interest in dovetailing these plans with giving more ownership or governance of protected lands to indigenous groups, whose track record is unsurprisingly much, much better than mainstream civilization.

You can help by not only donating to groups (The Nature Conservancy, for example) working to protect large-scale wilderness areas and marine protection areas, but by starting at home and helping your local conservation groups and land trusts build small-scale bulwarks against loss of habitat and species.

One final point to chew on… We could reduce our agricultural footprint by 75% if we all ate a plant-based diet. That’s an unlikely scenario, but we can each significantly reduce our agricultural footprint by eating less meat. The less the better, given that two-thirds of all agricultural land is for grazing. It’s one of the best steps we can take to conserve habitat, protect species, and reduce greenhouse gas emissions. (The most effective step you could take is to have few or no children, but that’s a topic for another day.)

To be continued…

This week’s writing would be far too long if I included the write-up on all nine boundaries, plus a conclusion. I’ll be back next week with more resources for understanding the planetary boundaries.

Thanks for sticking with me.

In curated Anthropocene news:

Beavers to the rescue! Want to create more ecosystem resilience in an era of increased wildfires? Increase beaver populations.

Good news for gray wolves: From Sierra, a judge has reversed a Trump administration ruling that de-listed wolves from the Endangered Species Act, which had led to a killing spree across the West.

Measuring microplastics may be harder than we thought. A new study indicates that scientists may be contaminating their water samples with microplastics shed from their clothing and equipment. What this means for assessments of microplastics around the world is unclear, but it is clear that each of us lives in a cloud of microplastics.

A new 2022 report from the U.S. government on projected sea-level rise around the U.S. for the next 150 years. Scroll down on the landing page for an excellent summary of the main findings, which predict a foot or more of rise in the Northeast and Gulf Coast in the next 30 years.

A surprising feedback loop is increasing climate-related melting in Greenland’s glaciers. The vast amounts of meltwater sluicing from the glacial surface to bedrock is generating heat at the bottom from its gravitational energy, which causes more melting at the bottom of the ice, which in turn helps the glacier move more quickly toward the sea.