Book Review – Breaking Boundaries

It probably doesn’t surprise you to learn that I’m a huge fan of Sir David Attenborough. I’ve watched every documentary I could find that he’s involved with. From groundbreaking work like Planet Earth and Blue Planet to more recent Netflix collaborations like David Attenborough a Life on Our Planet and Our Planet I feel like he has been a constant companion in my home, and one of the best teachers I’ve ever had.

So of course I was excited to watch Breaking Boundaries which debuted in 2021. I was fascinated by the message he had to give, and so I jumped at the chance to read the book that accompanied this film. Breaking Boundaries: The Science of our Planet was written by Johan Rockstrom and Own Gaffney, two scientists from the Stockholm Resilience Centre. It expands on a paper they originally published in 2009.

The central argument of the book is that our civilization is safe guarded by 9 planetary boundaries: climate, ozone, biosphere, novel entities (plastics and other trash), aerosols, ocean acidification, biochemical flows (nutrient pollution), freshwater, and land system change (habitat destruction). The authors use expensive research to support the idea that we have entered a new geological epoch, the Anthropocene. They argue that the Holocene Epoch, which started approximately 11,000 years ago, ended in the 1950s and our current epoch began. The evidence they present is damning and convincing. They use the 9 planetary boundaries to illustrate how humanity’s impact has exploded in the past 70 years and that we are now the primary force of change on the planet.

What’s essential to understand is that each of these systems has an outer boundary of what is desirable for human habitation. For some, such as novel entities, we ideally wouldn’t have any. But, for most of them, there is an acceptable amount of degradation we can commit while maintaining the planet’s livability for human civilization. Of the 9 categories, and two subcategories, we are into the danger zone for at least two of them, biochemical flows and biosphere integrity. For the moment, climate and land system change remain in the “caution” zone, though both are steadily approaching the danger zone.

Of the nine boundaries, only ozone depletion is moving in the right direction. That’s because it was the first of the problems that global policymakers took seriously when they passed the Montreal Protocol in 1987. In about 30 years, the ozone layer should be completely restored.

Once these systems are moving the wrong direction, it takes a long time to turn them around, and even longer to repair the damage. Breaking Boundaries puts a lot of emphasis on feedback loops and tipping points. To understand why this is critical, let’s do a quick dive into each of these concepts. (If you know what the are already, feel free to skip the next two paragraphs).

Feedback loop: This is a system that is self-reinforcing. Sometimes called a vicious or virtuous cycle, it is a key concept in systems thinking. We’ve all experienced this in some way or another and it’s pretty simple to understand. If you’re stressed out, it’s hard to sleep, and if you’re sleep deprived, it stresses you out even further. The longer the cycle continues, the more stressed and sleep deprived you become. One reinforces the other until something breaks the system (either you get help or have a nervous breakdown).

Tipping point: This is a point at which a process suddenly accelerates and becomes much more difficult or even impossible to reverse. Often there is a lot of time and energy put into a process with little results, until something tips and then things accelerate. Literally pushing a boulder up a hill until you reach the top and then letting it roll down the other side is an actual tipping point. Once it starts rolling, you have little chance of stopping it before it smashes into something.

Climate change is greatly affected by both tipping points and feedback loops. Here are just a few examples.

The Greenland Ice Sheet was formed over thousands of years, mostly during the last Ice Age, when global average temperatures were much lower. As the planet warms, the ice sheet melts. The ice sheet is about 2 miles thick, and the ice at the top thaws and refreezes each year. However, as the ice sheet thaws, it does not completely refreeze. Some of the ice is permanently lost. As the ice sheet gets shorter, it enters warmer air (since higher altitudes are colder). The shorter the ice sheet gets, the more it melts, and the more it melts, the shorter it gets. Eventually, we hit a point where the ice loss is irreversible and there’s nothing we can do to stop it, only to slow it down. If the ice sheet melted completely, it would raise global sea levels by about 6 feet. It’s possible that we have already passed this tipping point and the only question is how fast it melts.

Albedo is an effect in which light colors reflect sunlight and dark colors absorb it. We’ve all experienced this. When I was a kid we went to a public pool. Like many kids, I couldn’t be bothered with shoes at the pool, so I just went barefooted. In the parking lot there was blacktop and white lines marking the parking spaces. I would walk across the white lines and sprint across the blacktop, since it was scalding hot. I’m sure we’ve all done things like this. This process is hugely important for thermal regulation of our planet. In the northern latitudes, there is perpetual snow and ice. That snow is obviously light colored, and it reflects heat back into space. As the snow melts, it reveals darker colored ground beneath it. Rather than reflecting heat, these darker surfaces absorb the heat, causing the planet to heat more. This increased heating then accelerates the melting of ice, which accelerates the loss of albedo. As with the Greenland Ice Sheet, we may already have passed this tipping point, as more of the Arctic becomes ice free during the summer.

Frozen in the world’s permafrost is a massive amount of methane. Methane, while shorter lived in the atmosphere, is much more potent than CO2 at trapping heat. As this permafrost melts, it releases this methane, which then traps more heat, thus melting more permafrost. The melting of permafrost will continue long after our economy stops emitting greenhouse gases, the planet is simply too warm to hold onto it. Thus, we’ve likely passed the tipping point for permafrost melting.

Each of these examples illustrates that getting to a carbon neutral economy is really the second step of a long process (the first is capping our annual emissions and then reducing them year over year). We will then need to become carbon negative (which means drawing more carbon out of the atmosphere than we emit), and we will need to restore ecosystems around the world (some, like coral reefs, we may need to bring back from extinction), we’ll also need to adapt our civilization to a new reality, and prevent this from happening again. Ice sheets will continue to melt long after we hit carbon neutrality, and sea levels will keep rising for at least a few centuries.

Breaking Boundaries is not an uplifting book. You can feel the desperation of these scientists who have been screaming into the void for over a decade. However, it is succinct, easy to understand, and very clear about our situation. It presents the 9 life support systems in a way that anyone can understand, and it expertly shows how they are interrelated, and how action to address one can often help address the others. They are ambiguous about our need for systemic change as soon as possible, and they illustrate just exactly what our lives would be like if we blow past 2 degrees C warming.

In reality, these systems are actually quite fragile, and we humans have done our best to wreck them. Anyone who thinks we are too insignificant to change the entire climate should remember that 2.5 billion years ago, a tiny ocean life form called cyanobacteria (blue-green algae) managed to alter the Earth’s atmosphere and cause a catastrophic mass extinction. Humans are the first species since then to have this big of an impact. The Earth survived the Great Oxidation Event and it will survive us.