9 limits of the planet and how we have already stepped over 4 of them

Scientists have found that there are 9 boundaries, the excess of which endangers the integrity of our existence. Unfortunately, humanity does not comply with them. This discovery is called the Planetary Boundary Theory.

In January 2015, in the Science publishing house, Johan Rockström stated that humanity had overcome 4 out of 9 boundaries that allowed us to keep the Planet at a comfortable level for modern life. “We, the people, are lucky - for many millennia we have had stable conditions on the Planet. But with the development of civilization, we began to transform landscapes by cutting down forests, growing crops. We created environmental pollution, which led to the extinction of plants and animals. However, the Planet still keeps our existence in balance.” Because of our actions, the climate is changing very quickly, species are dying out, additional nutrients like nitrogen are being added to ecosystems everywhere, forests are being cut down and other natural conditions are being disturbed. We are slowly approaching the crossing of the last 5 borders.

Johan Rockström ( TED Talk: Let the environment guide our development ) is Executive Director of the Stockholm Resilience Centre , an international research center at Stockholm University. He and his 17 fellow co-authors wrote an article saying: “The planet has been our friend, cushioning the consequences of our actions. But for the first time in history, we were able to turn a friend into an enemy.”

Rockström began his exploration of boundaries back in 2007, and in 2009 he published the first paper on the topic. The key assumption is that the exceptional climate stability of the Holocene Epoch, which began when the last Ice Age ended 11,000 years ago, was critical to human development. This period of planetary calm allowed our ancestors to emerge from the Paleolithic caves to cultivate wheat, domesticate animals, organize industrial and communication revolutions. As a result, there are now 7.2 billion people in the world, and almost all of them have cell phones.

Table with indicators of planetary boundaries

Index	Border	Where are we now
1. Climate change	The concentration of carbon dioxide in the atmosphere must not exceed 350 ppm (parts per million)	Carbon dioxide level is 400 ppm and continues to rise
2. Loss of biological diversity of species due to their extinction	Conservation of 90% of biological diversity	Biodiversity has dropped to 84% in places like Africa
3. Admixture of phosphorus, nitrogen and other elements to grown crops and other ecosystems	World use per year about 11 teragrams of phosphorus and 62 teragrams of nitrogen	Reached 22 teragrams of phosphorus and 150 teragrams of nitrogen
4. Deforestation and other landscape changes	Maintaining 75% of the world's forests	The indicator fell to 62%
5. Release of aerosols (microscopic particles) into the atmosphere that affect the climate and living organisms	The global boundary is unknown, but a local effect (like the South Asian Monsoon) occurs when the Aerosol Optical Density (AOD) exceeds 0.25	Exceeds up to 0.30 AOD throughout south Asia, but appears to be good (within or below the border) in the rest of the world
6. Stratospheric ozone depletion	Less than 5% below pre-industrial levels, which is 290 Dobson units (DU)	So far, it's safe inside the border, with the exception of the area around Antarctica in the spring, where the figure drops to 200 DU
7. Ocean acidification	When the oceans become acidic enough, marine minerals are forced to create shells, such as aragonite, which begin to dissolve.	_CO2 climate limit
8. Use of fresh water	Possible consumption up to 4000 m ³ per year	We consume approximately 2600 m3 ^of fresh water per year
9. Release of organic pollutants, radioactive materials, nanomaterials, microplastics and other human inventions into the global environment	border unknown	The indicator is unknown

Conclusions, questions, scientific disputes

In crossing two frontiers of climate change and the health of the world's ecosystems, what's particularly troubling is the fact that "it's possible to push the Earth into several very different states," says Will Steffen, executive director of the Australian National University's Climate Change Institute. It is enough to destroy the tropical forests and they will turn into savannahs - all the advantages of the forests will be lost. Or raise the temperature enough to cause glaciers to melt and reduce the amount of sunlight reflected back into space.

We are very close to the point of no return. “What scares me the most is that we have already crossed the tipping point in the loss of Antarctic glaciers,” says Johan Rockström. Is it time to give up our hands in despair? Not at all. “Our message is positive, not about the end of the world.” The beauty of the planetary boundaries teaching is that the diagrams will help keep the planet safe. For example, countries can reduce their carbon emissions slightly, thus returning to borders.

The idea of boundaries has also provoked new scientific questions. The history of geology shows that the planet can make a sharp jump towards extreme heat or cold if the climate point is crossed. But are there such inflection points in Rockström's system of analysis? For example, if we dump less nitrogen and phosphorus from fertilizers into rivers, lakes, oceans, will we just affect harmful algal blooms and increase nutrient dead zones? Or perhaps the entire water system will become inhospitable to human life?

Another question that remains unanswered is whether (and to what extent) the crossing of one of the boundaries affects the rest? Imagine if a combination of polluting nutrients and ocean acidification killed off most of the marine plankton, greatly reducing the ocean's ability to remove oxygen from the atmosphere. This will accelerate global warming, which accordingly requires lowering the carbon footprint. But all possible variations of such interactions are unknown. Rockström is trying to figure out these relationships and, together with his associates, is looking for funding for his research.

Rockström's theory has caused a lot of controversy. Some critics see it as an intellectual continuation of the now-discredited Limits to Growth (1970) and Population Bomb, which predicted a huge resource shortage on Earth. “Many countries do not like the idea of planetary boundaries, as for them it means the inability to follow the material prosperity of the West,” says Steffen.

But the existence of planetary boundaries does not mean the absence of growth. This means reducing carbon emissions to near zero, using solar and wind power instead, and increasing efficiency. Rockström argues that "The world economy can grow in a carbon-free space."

Columbia University sustainability professor and author of The Big Ratchet: How Humanity Thrives in the Face of Natural Crisis Ruth DeFries argues that the concept of boundaries ignores the fact that a person adapts to any changes, which is a hallmark of civilization. In response to this statement, Rockström asks: "Is it worth risking the edge of the Earth by creating advantages for this generation and assuming that the next generation will be more innovative?"

“There is no doubt we need to take urgent action to combat climate change,” says Joe Romm, editor-in-chief of Climate Progress and spokesman for the US Energy Department. “Obviously we explained it to people, but they didn’t understand.”

Will the world get a message about planetary boundaries? “It would be nice,” Rockström says. We may have entered the most challenging and exciting decade in the history of the Planet. We have a responsibility to leave it in a state as close to the Holocene as possible."

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