Every breached planetary boundary hit its worst recorded value in PIK's 2026 check
The annual Planetary Health Check counts seven of nine boundaries transgressed, ocean acidification among them since 2025, and puts carbon dioxide at 426 parts per million against 280 before industrialisation. More than 60 scientists signed it.
The Scientist · Science desk
What happened
- Carbon dioxide reached a record 426 parts per million, which the report attributes to fossil fuel burning not falling at anything close to the needed pace.
- Only stratospheric ozone depletion and atmospheric aerosol loading have improved over the past decade, and the authors warn that the global aerosol picture may hide unsafe regional levels.
- Bleaching-level heat stress hit about 84.4% of the world's coral reef area between January 2023 and September 2025, the largest bleaching event observed so far.
Why it matters
- Who has to decide decision An assessment still citing six breached boundaries is describing the 2023 edition. The count has moved once in three years, so the baseline needs re-pulling each time the check publishes.
- What it limits constraint The framework scores distance from preindustrial conditions inside a zone of increasing risk, so it cannot supply the event probabilities an insurer or a capital works budget runs on.
- Who's exposed exposure By the authors' own caution, a global aerosol figure inside the boundary can sit above it locally. Anyone reading the two intact boundaries as locally safe can be misinformed about their own airshed.
- What it sets up precedent If heat, drought and fire keep cutting uptake by vegetation and soils, the climate boundary can worsen while emissions hold flat. Plans that assume cuts translate one-for-one into boundary improvement would need reworking.
Next story · Science · yesterday
Health alliance's scorecard faults EU, China, Brazil and UK climate plans on emissions targetsConfirmed2 publishers
An index like this measures distance from a reference state. Each of the nine measures is set against a preindustrial baseline, roughly the mid-19th century, and past each boundary lies what the authors call a "zone of increasing risk" [13]. Katherine Richardson, the Earth systems scientist at the University of Copenhagen, led the 2023 edition. She told Scientific American then that "it's like blood pressure": a high value is "not a guarantee that you're going to have a heart attack," but it raises the risk of one [12].
Carbon dioxide carries the fully specified numbers. The check records a record 426 parts per million [14]. Preindustrial concentration was 280 ppm, and 350 ppm is the level many scientists have treated as safe [15][16]. The gap to preindustrial air is 146 ppm, and the overshoot past 350 ppm is 76 ppm [27][28]. The 350 ppm line was crossed in 1987, 39 years before this edition [16][29].
The count itself has moved since the series began. The first check, in 2023, found six boundaries breached [11]. Ocean acidification went past its boundary in 2025, making seven [5], and all seven now sit at their highest recorded levels of transgression [4]. That is one additional boundary crossed across three annual editions [26]. Boris Sakschewski, the PIK scientist who led the report, said "Pressure is rising across every Planetary Boundary already outside the safe operating space" [6].
The two boundaries still inside the safe operating space are stratospheric ozone depletion and atmospheric aerosol loading, and both have improved over the past decade [30]. The aerosol result comes with a caution from the authors: global progress may mask unsafe aerosol levels persisting in some regions [30]. Scientific American's account is narrower, saying only ozone shows clear progress away from its boundary [8].
Vegetation and soils take up a substantial share of human carbon dioxide emissions. The report notes that repeated heat, drought, fire and ecosystem degradation can reduce that uptake and, in some regions, turn ecosystems from sinks into carbon sources [20]. Land-sink weakening moves the climate number without any change in emissions.
The 12 months covered include Pakistan's 2025 monsoon floods, which affected more than 6.9 million people [17], and a new record in global ocean heat content in 2025 [18]. Bleaching-level heat stress reached about 84.4% of the world's coral reef area between January 2023 and September 2025, the largest such event yet observed [19]. Western Europe had its hottest June-July on record in 2026, with drought in France, Spain, Germany and the United Kingdom [9].
Neither account puts a cost on a boundary. The one dollar figure on the record is a 2020 NOAA finding, cited by Scientific American, that ocean acidification would cost the US economy billions [22]. Johan Rockström, PIK's director and a co-author, said: "We do not have the luxury of time, but we do have the knowledge, capacity and solutions to change course" [7].
What to watch
- Whether the 2027 update shows any of the seven transgressed boundaries falling back from its record value.
- Whether PIK quantifies land and soil sink weakening inside the climate boundary number.
- Whether the aerosol boundary keeps its safe classification once the regional exceedances the authors flag are scored.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence62
- Adoption
- Not scored
- Hype gap+15
- Incentives65
- Confidence68
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
The annual Planetary Health Check was released on Monday by the Planetary Boundaries Science Lab at the Potsdam Institute for Climate Impact Research (PIK) in Germany.
- [2]
The Planetary Health Check 2026 is authored by more than 60 scientists and produced by the Planetary Boundaries Science Lab at the Potsdam Institute for Climate Impact Research (PIK).
- [3]
The report shows that seven of the nine chemical and physical boundaries needed to keep the planet habitable are at their worst recorded values since scientists first conceived of them in 2009.
- [4]
Seven of the nine Planetary Boundaries are now transgressed, and all seven are at their highest recorded levels of transgression.
- [5]
Ocean acidification was the latest boundary to breach its limit, in 2025.
- [6]
"The diagnosis is unambiguous. Pressure is rising across every Planetary Boundary already outside the safe operating space," said Boris Sakschewski, PIK scientist and lead author of the report.
- [7]
"We do not have the luxury of time, but we do have the knowledge, capacity and solutions to change course," said Johan Rockstrom, PIK director and co-author of the report.
- [8]
Just two of the nine limits remain intact, ozone depletion and aerosol pollution in the atmosphere, and only ozone shows clear progress away from the planetary boundary.
- [9]
In 2026 Western Europe experienced its hottest June-July period on record, with drought across France, Spain, Germany and the United Kingdom and major wildfires across Europe and Canada.
- [10]
The seven transgressed boundaries are climate change, change in biosphere integrity, land system change, freshwater change, modification of biogeochemical flows, introduction of novel entities and ocean acidification.
- [11]
The first Planetary Health Check, published in 2023, found that human actions had pushed Earth past six of the nine boundaries.
- [12]
Katherine Richardson, an Earth systems scientist at the University of Copenhagen and lead author of the 2023 report, told Scientific American at that report's release that "it's like blood pressure", and that a high value is "not a guarantee that you're going to have a heart attack," but raises the risks of one.
- [13]
Each measure is compared against a preindustrial baseline, roughly the mid-19th century, and beyond each boundary is a "zone of increasing risk" in which the odds of moving away from preindustrial conditions rise.
- [14]
Carbon dioxide concentrations reached a record 426 parts per million, because fossil fuel burning had not decreased at nearly the needed pace.
- [15]
Carbon dioxide concentration prior to the industrial revolution was 280 parts per million.
- [16]
Many scientists consider 350 parts per million a safe limit for carbon dioxide; that level was surpassed in 1987.
- [17]
Pakistan's 2025 monsoon floods affected more than 6.9 million people.
- [18]
Global ocean heat content reached a new record in 2025, with Hurricane Melissa rapidly ramping up to a Category 5 hurricane and striking Jamaica after passing over exceptionally warm seas.
- [19]
From January 2023 to September 2025, bleaching-level heat stress affected approximately 84.4% of the world's coral reef area, making it the largest global coral-bleaching event observed to date.
- [20]
Vegetation and soils absorb a substantial share of human carbon dioxide emissions, but repeated heat, drought, fire and ecosystem degradation can reduce carbon uptake and, in some regions, turn ecosystems from sinks into carbon sources.
- [21]
Earlier this month the United Nations acknowledged that global temperatures would blow past the Paris Agreement target of no more than 1.5 degrees Celsius of warming.
- [22]
A 2020 report by the U.S. National Oceanic and Atmospheric Administration found that ocean acidification would cost the country's economy billions of dollars.
- [23]
"These are not separate emergencies; the planet is telling us, in every region at once, that it is out of balance," said Hindou Oumarou Ibrahim, chair of the Planetary Guardians.
- [24]
"Seven of nine boundaries are broken, and no single nation can restore them alone; this is a peace process the entire world must commit to, together, starting now," said Juan Manuel Santos, former president of Colombia and co-vice chair of the Planetary Guardians.
- [25]
The ocean absorbs some of the excess carbon dioxide from the atmosphere, lowering the water's pH, and increasing acidity can make it hard for shell-building organisms to develop shells and could cause shells and corals to dissolve.
- [26]
One additional boundary has been crossed since the first check, taking the count from six breached in 2023 to seven with ocean acidification in 2025.
- [27]
Current carbon dioxide concentration is 146 parts per million above the preindustrial level.
- [28]
Current carbon dioxide concentration is 76 parts per million above the 350 ppm level many scientists treat as safe.
- [29]
The 350 ppm level was passed 39 years before the 2026 edition of the report.
- [30]
Only the stratospheric ozone depletion and atmospheric aerosol loading boundaries have shown improvement over the past decade, and the authors caution that global progress may mask unsafe aerosol levels persisting in some regions.
Sources
2 independent publishers whose own reporting we read for this story.
- phys.orgPlanetary Health Check 2026 finds mounting pressures across Earth's life support systems
1 article · September 21, 2026
- scientificamerican.com9 ‘boundaries’ keep Earth livable. We’ve breached 7 of them
1 article · September 21, 2026
Topics and entities
Topics
- Planetary boundaries
- Climate targets and treaties
- Extreme weather
- Ocean Acidification
Entities
- Hindou Oumarou Ibrahim
- Planetary Guardians
- Boris Sakschewski
- Paris Agreement
- Katherine Richardson
- NOAA
- Montreal Protocol
- Planetary Boundaries Science Lab
- Planetary Health Check
- Potsdam Institute for Climate Impact Research
- Juan Manuel Santos
- University of Copenhagen