Scientists Warn We’ve Exceeded 4 of 9 Planetary Boundaries
The journal Science recently released a report that, in the past 100 years, human activity has altered the equilibrium of its planetary habitat so severely that several boundaries for sustaining life are being exceeded:
An international team of researchers says climate change, the loss of biosphere integrity, land-system change, and altered biogeochemical cycles like phosphorus and nitrogen runoff have all passed beyond levels that put humanity in a "safe operating space."
Civilization has crossed four of nine so-called planetary boundaries as the result of human activity, according to a report published today in Science by the 18-member research team. Among them is Steve Carpenter, director of the University of Wisconsin-Madison Center for Limnology and the only U.S.-based researcher on the study.
The report, an update to previous studies, is titled "Planetary Boundaries: Guiding human development on a changing planet," and will be discussed next week at the World Economic Forum in Davos, Switzerland.
It should be a wake-up call to policymakers that "we're running up to and beyond the biophysical boundaries that enable human civilization as we know it to exist," says Carpenter.
For the last 11,700 years until roughly 100 years ago, Earth had been in a "remarkably stable state," says Carpenter. During this time, known as the Holocene epoch, "everything important to civilization" has occurred. From the development of agriculture, to the rise and fall of the Roman Empire, to the Industrial Revolution, the Holocene has been a good time for human endeavors.
But over the last century, some of the parameters that made the Holocene so hospitable have changed.
While the study focuses on several of these, including climate change and a troubling loss of biodiversity, Carpenter led the examination of biogeochemical cycle changes. Specifically, Carpenter looked at two elements essential to life as we know it, phosphorus and nitrogen.
Both are widely used to fertilize crops, and the rise of large-scale, industrial agriculture has led to an immense increase in the amount of the chemicals entering our ecosystems.
"We've changed nitrogen and phosphorus cycles vastly more than any other element," Carpenter says. "(The increase) is on the order of 200 to 300 percent. In contrast, carbon has only been increased 10 to 20 percent and look at all the uproar that has caused in the climate."
The increase in phosphorus and nitrogen has been especially detrimental to water quality.
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The Science paper that this material is derived from is here. I doubt many have access to the full article so I will give a brief synopsis.
The big picture is that they have defined 9 categories of planetary boundary that characterize the last 11,700 years when all of recorded human history has occurred. Basically, since we adopted agriculture. The nine planetary boundaries are:
1. Climate change – one of two master boundaries that influences the others. Currently estimated to be in the 'zone of uncertainty' meaning increasing risk. (yellow)
2. Biosphere integrity – the other master boundary. Effectively this pertains to species extinctions. This metric is firmly 'beyond the zone of uncertainty' meaning high risk. (red)
3. Land-system change – Meaning changes in vegetation cover, primarily forests. Increasing risk (yellow)
4. Freshwater use – (green) though in their maps, several areas like the western US and the Middle East light up as red. Globally this pencils out as being safe overall but it doesn't actually account for possible destabilization caused by population migrations due to lack of water in some areas. Typically this is considered a major risk in other assessments.
5. Biogeochemical flows – primarily phosphorous and nitrogen. Linked to fertilization for agriculture, we've clearly whacked the global balances for these elements, doubling or even tripling previous flows of these elements for the entire planet. Listed as high risk (red).
6. Ocean acidification – currently listed as safe (green) since the arbitrary level for risk is set at 80% of the original aragonite in ocean surface waters (surrogate for acidity). Currently we are down to 84% so this will soon shift to yellow if this assessment continues.
7. Stratospheric ozone depletion – green/safe everywhere but Antarctica. Believed to actually be improving since the Montreal Protocol when we acted to limit CFCs! We are not universally screwing things up…
8. Atmospheric aerosol loading – effectively the pollution load we've pumped into the atmosphere. They do not try to set limits for this and leave it as a question mark '?' as to status.
9. Novel entities – a catch all category for things that might be important but that we didn't see coming. Ozone depletion would have started here before we knew that we were causing it, for example. Possibilities they list here are the 100,000-odd chemicals that we are pumping out across the planet without any knowledge of the long term effects and the ongoing rush to release genetically-modified organisms that may have untold effects on Earth's ecosystems. Ranked as another unknown with a '?' rating.
Things have been relatively calm here on the good ship Earth for over 11,000 years. Think of this study as describing the 9 load bearing beams holding up the roof. We've totally wrecked 2 including one major central post. We've severely compromised 2 more including the other main post holding up the roof. We've been whittling away at three more and two are getting close to being rather dodgy as load supporting beams you'd want to bet your life on while the third has some repairs ongoing, though it is still damaged. The last two are behind a closed door, so we don't know what has happened there, but we can hear the kids whacking away at them.
The roof hasn't fallen yet but chances are that the whole structure is getting shaky. In the metaphor I've laid out, high winds or a good snow could level the place.
We are clearly going outside of the realm in which all of human life has existed. Boldly (foolishly?) going were no one has gone before. This doesn't mean that suddenly human societies or life in general will collapse. It does mean though that neither human societies nor life in general can go on living the way we have until now.
Certainly an interesting list that they came up with and an extremely complicated problem to try to solve. An example would be the freshwater scenario. The algorithm would need to include food productivity by location, predicted population shifts by area because of human exodus after water depletion, etc. in order to actually predict the severity of the situation and potential outcomes. Each scenario is a very complicated math problem with variables not necessarily known. This is something that they for sure did not include in their study. I also don't believe those support beams are weighted equally. By presenting 9 problems in a list, the presumption is that they are all weighted equally, but the reality is that some have more structural support than the others.
I think one of the most interesting problems is the decline of % oxygen in the atmosphere as a result of carbon sources being exploited over the last 100 years as well as habitat loss and environmental changes that result in phytoplankton and other carbon sink declines.
Something that might interest some of you folks is a 175k reward for finding the best algorithm to predict plankton counts/types in the ocean offered on Kaggle.com http://www.kaggle.com/c/datasciencebowl . This is exciting because the software created out of this will offer an "accurate," but also importantly a "consistent" method to count plankton in our oceans.
I don't think there has ever been a 175k reward for a kaggle algorithm and there are some of the largest corporations in the world asking for the best predictive models on this website. I was very interested to see this.
You are right that evaluating something like freshwater use is a complex problem and can be handled to greater or lesser degrees of detail. They didn't try to look forward in time, they simply looked at current use of rivers, lakes and aquifers in a given region as compared to annual recharge rates. In terms of human societies, I think that they undersold the impacts of water resources (see the current situation in Brazil for example – link) but in terms of the effects on the total biosphere the impact isn't as great, so they are being consistent. We aren't the whole story.
They do (in this incarnation of the study) emphasize that both climate change and biosphere integrity (species loss) are master planetary boundaries that effect all of the others, so you are exactly right that some of these categories are carrying more of the load in the analogy.
The global atmospheric oxygen levels are being reduced in lock step with the amount of fossil fuels that we burn, but this is not such a big deal. Combustion is effectively photosynthesis run in reverse so it consumes an equal amount of oxygen and makes carbon dioxide and water. However, in the atmosphere, CO2 is a trace gas currently running at about 400 ppm (parts per million) while oxygen is present at 21% (parts per hundred). We’ve increased CO2 by 120 ppm and therefore potentially reduced oxygen by that amount. That would be the equivalent of changing global oxygen levels from 21% to 20.88%. Nothing to sneeze at but not noticeable for living organisms.
I did not know about the competition to calculate plankton counts! Thanks for the information. One of my eclectic list of prior activities was going to sea to collect pico-plankton count flow cytometer data in the Sargasso Sea for Penny Chisholm, my MIT advisor. It was interesting but instrumental in my deciding that I would much rather work with organisms that I could actually see!
This video is pretty shocking.
China has a really big problem.
Thanks for doing that math. So that means a decline of .6% oxygen. While not seeming like a big number, we both know organisms are going to have to work that much harder, expend that much more energy, in order to be a productive organism.
I'm sure there are many sensitive organisms to oxygen levels that have been impacted by that number. Our brain is very sensitive to oxygen levels. In theory, our brains lose that much in productivity because more energy needs to be transferred towards extracting oxygen. Haven't IQ scores been declining over the years? 😉
Anyways, I was lucky enough to work on some cyanbacteria research in college and did a tour of duty studying plankton myself. Daphnia are some the cutest organisms in the world. Now a new hobby/profession of mine is to study predictive modeling techniques, so I was happy to see the plankton competition. Very cool.
Perhaps a more accurate way of looking at the oxygen is to say that it could potentially be a serious issue for those organisms living on the margins where oxygen transfer rates are critical – say the dead zones in the oceans for example. Not too sure we can blame O2 changes for our poor thinking since our autonomic system should just make us breath a bit more. Our foundering IQ changes probably relate more to listening to main stream media ;^)
Now that I think about it, the place where the impacts would be evident is in organisms like insects which do not have lungs. Giant insects lived when oxygen levels on the planet were high, so perhaps our bugs have been getting smaller as the oxygen levels have dropped?
Great points. I still believe oxygen levels are something to pay attention to. Obviously not a trump card like many of the listed subjects, but I do believe breathing heavier/more has a direct impact on human health. Especially mental health. It's just logical.
I read your posts often Mark. You are one of those factual science types. I am an "intuition" science type. Both are founded on facts, but I tend to risk filling in the blanks (that's why I am a wildlife tracker 🙂 ). Both have their place though your science is certainly more reliable, and I'm happy you are here to share your thoughts to spark discussion and provide good content. Thanks.
I think that you are right that things like oxygen levels likely have greater impacts than we commonly would suppose, I'm just not quite sure where or how to prove it. I actually use a fair amount of intuition myself but I need to be able to back up what I say in anything I ever publish which kind of limits how far out on the branch I can go when representing something as fact.
Metabolic processes are a bit far afield for me but if I were hypothesizing I would still say the impacts are more likely to show up around the edges, so to speak. Causing problems for people at those times and under those conditions when they most need that little bit of extra oxygen. For example, when under extreme stress, exhaustion, or battling lung problems. I would also expect it to lead to a life time of subtly greater stress that would yield a bit more wear and tear on the heart. That said, we do know that the human body has a fair amount of plasticity for dealing with chronically lower oxygen levels by growing more red blood cells, which is why soccer teams in South America don't like to play the Bolivians in La Paz. There are probably a host of more indirect effects in the environment that would be hard to pin down.
We need a balance of thinking styles. There is no one path to knowledge. Happy to have discussions with you any time!
"Thoughts without intuitions are empty, intuitions without concepts are blind"
I. Kant, Critique of Pure Reason