Less technical summary:

As of 2021, according to SRI, we had already gone beyond the safe limit for five of these planetary boundaries:

• climate change;

• biogeochemical flows (i.e., excessive phosphorus and nitrogen pollution from fertilizer use);

• biosphere integrity (e.g., extinction rate and loss of insect pollination);

• land-system change (e.g., deforestation);

• and novel entities (e.g., pollution from plastics, heavy metals, and what are commonly referred to as “forever chemicals”).

In an April 2022 update, SRI found that a portion of a sixth planetary boundary – fresh water use – had also been crossed. In addition, in a June 2021 interview with the journal Globalizations, Dr. Will Stefan of SRI said that a seventh planetary boundary had also likely been crossed: ocean acidification (one that has been theorized as a key contributor to previous mass extinction events in geologic history). One other boundary has been too uncertain to judge: atmospheric aerosols from fine particle pollution caused by fossil fuel combustion. Yet, we are clearly pushing this boundary too, when considering that air pollution from burning fossil fuels has been blamed for 8.8 million deaths worldwide per year.

More technical version from 2023, please note that these scientific findings were OPTIMISTIC because scientists were told to not fear monger and that people would think they were crazy if they had less optimistic findings. As time has gone on, we are finding cascading events we didn’t anticipate significantly worsening everything.

https://www.science.org/doi/10.1126/sciadv.adh2458

Scientific insight into planetary boundaries does not limit, but stimulates, humankind to innovation toward a future in which Earth system stability is fundamentally preserved and safeguarded.

Many of the ecological factors not sufficiently represented in current biogeochemical models could lead to even less desirable consequences of leaving the safe operating space.

They furthermore support the placement of the planetary boundaries for climate and land system change at the lower end of the zone of increasing risk.

Note that these findings reflect optimistic modeling assumptions

Six planetary boundaries are found currently to be transgressed (Fig. 1 and Table 1). For all of the boundaries previously identified as transgressed [climate change, biosphere integrity (genetic diversity), land system change, and biogeochemical flows (N and P)], the degree of transgression has increased since 2015.

Note that these findings reflect optimistic modeling assumptions

The planetary boundary for atmospheric CO2 concentration is set at 350 ppm and for radiative forcing at 1 W m−2. Currently, the estimated total anthropogenic effective radiative forcing is 2.91 W m−2 [2022 estimate, relative to 1750 (17)], and atmospheric CO2 concentration is 417 ppm [annual mean marine surface value for 2022 (41)], i.e., further outside the safe operating space on both measures than in the last update (2).

Thus, anthropogenic ocean acidification currently lies at the margin of the safe operating space, and the trend is worsening as anthropogenic CO2 emission continues to rise.

Although the baseline rate of extinctions (and of new species’ evolution) is both highly variable and difficult to quantify with confidence through geological time, the current rate of species extinctions is estimated to be at least tens to hundreds of times higher than the average rate over the past 10 million years and is accelerating (24). We conservatively set the current value for the extinction rate at >100 E/MSY (24–26). Of an estimated 8 million plant and animal species, around 1 million are threatened with extinction (16), and over 10% of genetic diversity of plants and animals may have been lost over the past 150 years (23). Thus, the genetic component of the biosphere integrity boundary is markedly exceeded (Fig. 1 and Table 1).

Note that these findings reflect optimistic modeling assumptions

With such an enormous percentage of untested chemicals being released to the environment, a novel entities boundary defined in this manner is clearly breached. Persson et al. (43) did not identify or quantify a singular planetary boundary for novel entities but, nevertheless, also concluded that the safe operating space is currently overstepped.

while the climate warming problem became evident in the 1980s, problems arising in functional biosphere integrity due to human land use began a century earlier. Since the 1960s, growth in global population and consumption further accelerated land use, driving the system further into the zone of increasing risk. HANPP has always sustained humanity’s need for food, fiber, and fodder, and this will continue to be the case in the future, as well as for sustainable societies. The NPP required to support future societies must, however, increasingly be generated through additional production of NPP above the Holocene baseline, not including the NPP generated for biology-based carbon sinks. Feeding 10 billion people, for example, is theoretically possible within planetary boundaries but requires a number of far-reaching transformations to improve the impacts of production and regulate demand (36).