A new study revealed that human activity has put almost half of Earth's ability to sustain life at risk.
An international team of 18 researchers provided evidence that four in nine systems, our planet's need to maintain resilience, have undergone alarming changes. One of the gravely affected processes is the nitrogen-phosphorus cycle. Nitrogen is essential for all life on Earth while phosphorus regulates the growth of our ecosystems. Without these two life materials: food and water supply will be non-existent.
"People depend on food, and food production depends on clean water," said Prof. Elena Bennett from McGill's School of the Environment who contributed the research on the nitrogen-phosphorus cycle to the study, in a press release. "This new data shows that our ability both to produce sufficient food in the future and to have clean water to drink and to swim in are at risk."
The researchers looked at the new planetary boundaries, or the changes in the systems that are considered irreversible, to determine which among the planet's systems are at risk. Their analysis showed that four systems have been significantly compromised by human activity.
The planetary boundaries directly affected by human activity include climate due to climate change; biodiversity integrity (extinction of plants and animals); land-system change (deforestation), and nitrogen-phosphorus cycle. The last one is the most critical as it will directly affect our food and water supply, so the researchers decided to focus their study on it.
Two issues related to the cycle were identified by the team. First was the concentration of phosphorus on three countries only, which limits the supply to Morocco, China, and Algeria. Another is the flow of the excess phosphorus-based fertilizers from the farms to the lakes resulting in water contamination.
"This kind of problem is likely to become much more common. We will see more lakes closed, will have to pay more to clean our water, and we will face temporary situations where our water is not cleanable or drinkable more and more frequently. That's what it means to have crossed this planetary boundary. It's not a good thing for any of us," said Prof. Bennett.
Other planetary boundaries listed by the researchers include stratospheric ozone depletion, ocean acidification, freshwater use, atmospheric aerosol landing, and the introduction of novel entities.
The study was published in the Jan. 15 issue of Science.
