Scientists say that Earth has reached its maximum safe limit for humans

The research was published on Wednesday in Nature. It identified eight boundaries of the earth system, including climate, biodiversity, natural ecosystems, land use, and the effects of aerosols and fertilisers.

It said that human activities had moved seven of these boundaries past their “safe and justified limit” and into zones at risk, which indicate a threat to the health of humans and planets.

The Earth Commission study is an attempt to determine the limit beyond which humans will suffer serious harm.

This includes a lack access to clean drinking water, a lower level of food security and the displacement of people or the loss of their jobs due to temperature increases or flooding.

Johan Rockstrom of the Potsdam Institute for Climate Impact Research, and co-author, of the report said that it was “very concerning” that the boundaries have already been crossed.

“It is already starting to hurt.” . . He said that climate change was causing extreme events, and abrupt impacts, which went beyond heatwaves, floods and droughts. “Climate [change] is also affecting food security and water quality.

It’s not just climate that causes risks of displacement, immigration and conflict, but the whole of these breaches of safe and just borders.

The research shows that the global temperature increase limit is 1C above pre-industrial levels. This takes into consideration the impacts on the planet and the people.

According to the study, this rise is at least 1.1C or even as high as 1.2C. In the Paris Agreement, governments committed to limit global warming to 2C or, ideally, 1.5C. This is the level where irreversible changes to the planet are expected.

Earth Commission researchers stated that a rise in 1.5C would expose more than 200mn to temperatures unprecedented for the average annual temperature and over 500mn to sea level rises.

The study found that between 50 and 60% of the Earth’s surface needed to be covered with largely intact eco-systems. This level has already been reached, it said.

It was also concluded that the use of nitrogen in fertilisers needed to be halved to reduce excessive plant and algae blooms on water surface and to reduce ammonia and Nitrogen oxide emissions.

Earth’s so-called system is composed of interdependent processes which keep the planet stable but can alter its habitability if disturbed.

Rockstrom stated that all the boundaries of earth systems outlined in his research are “interconnected”, which means that exceeding the safe limit could have an impact on other boundaries.

“If you are going to solve the climate problem, it is important that the other boundaries remain intact. You want a healthy world when you are facing a climate emergency. . . But we have a weaker world than ever before,” said he.

Researchers used the same units to measure “justice” in scientific analysis for people as they did for safe limits on the planet.

Xuemei Bai is a professor at the Australian National University and co-author of the study. She said that by “putting a numerical value on human needs and impact”, the study “shows the way the protection of the environment is inseparable with the success of societies, communities and economies”.

The Intergovernmental Panel on Climate Change’s research this year showed that the richest 1% of the population of the planet was responsible for double the amount of carbon dioxide emissions as the poorest 50%.