Earth is beyond six out of nine planetary boundaries

Question

I have just found out about the articles that scientist have recently published, talking about some planetary boundaries that we have crossed.

I wasn’t really able to get the full hang of it, but I’d really like to understand the concept of these boundaries and what they are, since there are only 3 left and 2 years ago we were crossing the fourth one and now we’re passed the 6th one, and according to news it could potentially cause societal collapse.

So, what are these boundaries and what happens if we cross all 9? How do they affect our society?

Edit:
The article I am on about is found [here](https://www.science.org/doi/10.1126/sciadv.adh2458)

In: 1826

Answer 1

Consider that a human body has a number of necessary systems, and we can treat them sensibly or we can abuse them and wonder why we get sick.

Our lungs need to take in oxygen and expel carbon dioxide. For fashion’s sake, we smoke tobacco which clogs the delicate lining with road tar and can cause cancer. Moral? Don’t smoke.

Earth scientists have identified nine similar symptoms on Earth:

1. CO2 levels
2. Ocean acidity
3. Ozone depletion
4. Fertiliser run-off into the oceans
5. Fresh water availability
6. Deforestation for agriculture
7. Extinction rates
8. Chemical pollution
9. Aerosol loading

These are the Earth’s equivalents of coughing up blood or obesity, and we have achieved six of these symptoms.

We need to work harder on:

2. Acidifying the ocean, killing marine life

3. Depleting the ozone so that we can fry in the Sun’s UV

9. Airborne particles, disrupting the effect of sunlight and making the climate even less predictable

So from 3 in 2009, it took us 6 years to get the fourth on 2015 but we got another two within eight years. At this rate, given the dismissive antipathy to hippy environmental issues we should have the full set within a decade.

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We don’t know what the outcome will be, any more than we can prove *exactly* what will happen to a bedridden obese stroke victim with a triple heart bypass. But it’s not likely to be good, and it’s silly to experiment on your only sample.