‘Sick’ planet: Earth is past almost all of its safe limits for humans, scientists say

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Earth has pushed past seven out of eight scientifically established safe limits for life, according to a new study.

We are now heading into “the danger zone,” not just for an overheating planet that's losing its natural areas, but for the well-being of people living on it. 

A team of more than 40 international scientists looked at guardrails for the planetary ecosystem. For the first time, the study includes measures of “justice,” which includes preventing harm to countries, ethnicities and genders.

The research was published by the international scientist group Earth Commission in Wednesday’s journal Nature. 

Which planetary safe limits have been exceeded?

The eight limits the study looked at were climate, air pollution, phosphorus and nitrogen contamination of water from fertilizer overuse, groundwater supplies, fresh surface water, the unbuilt natural environment and the overall natural and human-built environment. 

Air pollution was the only planetary limit that wasn't quite at the global danger point but was instead dangerous at local and regional levels. 

Climate was beyond the harmful levels for humans in groups but not quite past the safety guideline for the planet as a system, the study from the Swedish group said.

Researchers found “hotspot” problem areas throughout Eastern Europe, South Asia, the Middle East, Southeast Asia, parts of Africa and much of Brazil, Mexico, China and some of the US West — much of it from climate change.

About two-thirds of Earth don’t meet the criteria for freshwater safety, scientists said as an example.

Earth is now in a 'danger zone' but it isn't terminal

“We are in a danger zone for most of the Earth system boundaries,” said study co-author Kristie Ebi, a professor of climate and public health at the University of Washington.

If planet Earth just got an annual checkup, “our doctor would say that the Earth is really quite sick right now,” Earth Commission co-chair Joyeeta Gupta, a professor of environment at the University of Amsterdam, said at a press conference.

"It is sick in terms of many different areas or systems and this sickness is also affecting the people living on Earth."

It’s not a terminal diagnosis. The planet can recover if it changes, including its use of coal, oil and natural gas and the way it treats the land and water, the scientists said.

But “we are moving in the wrong direction on basically all of these,” said study lead author Johan Rockstrom, director of the Potsdam Institute for Climate Impact Research in Germany.

“This is a compelling and provocative paper – scientifically sound in methodology and important for identifying the dimensions in which the planet is nearing the edge of boundaries that would launch us into irreversible states,” Indy Burke, dean of the Yale School of the Environment who wasn't part of the study said in an email. 

How did scientists create these safety limits?

The team of about 40 scientists created quantifiable boundaries for each environmental category, both what’s safe for the planet and the point at which it becomes harmful for groups of people, which the researchers termed a justice issue.

Rockstrom said he thinks of those points as setting up “a safety fence’’ outside of which the risks become higher, but not necessarily fatal.

In the past, he and other scientists have attempted this type of holistic measuring of Earth’s various interlocking ecosystems. The big difference in this attempt is that scientists also looked at local and regional levels and they added the element of justice.

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This justice element includes fairness between young and old generations, different nations and even different species. Frequently, it applies to conditions that harm people more than the planet. An example of that is climate change.

Damage is being done even at 1 degree of warming

The report uses the same boundary of 1.5 degree Celsius of warming since pre-industrial times that international leaders agreed upon in the 2015 Paris climate agreement. 

The world has so far warmed about 1.1 degrees Celsius, so it hasn’t crossed that safety fence, Rockstrom and Gupta said, but that doesn’t mean people aren’t being hurt.

“What we are trying to show through our paper is that even at 1 degree Centigrade there is a huge amount of damage taking place,” Gupta said, pointing to tens of millions of people who are exposed to extreme hot temperatures.

The planetary safety guardrail of 1.5 degrees hasn’t been breached, but the “just” boundary where people are hurt of 1 degree has been.

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“Sustainability and justice are inseparable,” said Stanford environmental studies chief Chris Field, who wasn’t part of the research. He said he would want even more stringent boundaries. 

“Unsafe conditions do not need to cover a large fraction of Earth’s area to be unacceptable, especially if the unsafe conditions are concentrated in and near poor and vulnerable communities.”

Another outside expert, Dr Lynn Goldman, an environmental health professor and dean of George Washington University’s public health school, said the study was “kind of bold,” but she wasn’t optimistic that it would result in much action.