By Robin Kundis Craig, USC Gould School of Law
Most people know that nutrient pollution of water is a Bad Thing—it causes nuisance algae growth and harmful algal blooms, or HABs (see Figure 1). Fewer people realize, however, that nutrient pollution has gotten so bad that it puts the entire planet at risk.
Figure 1: A Harmful Algal Bloom Destroying Aquatic Life.
SOURCE: National Oceanic & Atmospheric Administration (NOAA), May 12, 2016: noaa.gov/content/Weather+Climate+Ocean-&-Coasts+Fisheries+Satellites+Research+Marine-&-Aviation+Charting+Across-NOAA+Sanctuaries/story?page=41
Nutrients cycle in global processes and hence constitute one of the nine planetary boundaries. Johan Rockström of the Stockholm Resilience Center and numerous colleagues introduced the concept of planetary boundaries in a 2009 article in Ecology & Society,[1] summarized (and commented on) in the journal Nature.[2] The nine planetary boundaries (see Figure 2) delineate a “safe operating space” for humanity—that is, the boundaries of the stresses that humanity can put on the rest of the planet to avoid creating a risk of changing the entire planet into a less hospitable place.
Figure 2: The Planetary Boundaries 2015
Note that under “Biogeochemical Flows,” both nitrogen (N) and phosphorus (P) are already beyond the safe operating space, meaning that humanity’s use of these nutrients is already putting the planet at risk.
Credit: J. Lokrantz/Azote based on Steffen et al. 2015.
Used in conformance with the license under CC BY-NC-ND 3.0.
SOURCE: https://www.stockholmresilience.org/research/planetary-boundaries.html.
Importantly, nutrient pollution—often labeled “biogeochemical flows”—has always been one of the planetary boundaries. More importantly, since the researchers first identified those planetary boundaries, anthropogenic nutrient pollution already puts the planet at risk—more risk than climate change, land use change, and freshwater depletion, and matched only by biodiversity loss (“biosphere integrity”). As the researchers noted in 2009, “Human activities now convert more N2 from the atmosphere into reactive forms than all of the Earth’s terrestrial processes combined, and much of that reactive nitrogen, often in the form of ammonia, “eventually ends up in the environment—polluting waterways and coastal zones, adding to the local and global pollution burden in the atmosphere, and accumulating in the biosphere.”[3] In the water, nitrogen pollution stimulates harmful algal blooms that can release toxic compounds, as in “red tides.” Moreover, when all that algae decomposes, it uses up the oxygen in the water column, creating hypoxic “dead zones” where no animal life can exist. Nitrogen pollution has already flipped freshwater and coastal ecosystems into new and less productive states.
In their latest 2023 version of the planetary boundaries, Rockström and colleagues have differentiated safe boundaries from just boundaries.[4] Just boundaries take account of interspecies justice and Earth system stability, intergenerational justice that accounts for future generations, and intragenerational justice between countries and among communities and individuals.[5] Notably, nitrogen pollution is one of the boundaries where the just boundary requires less nutrient use than the safe boundary, meaning that nitrogen use is unevenly distributed in ways that disadvantage certain people, communities, and countries. Specifically, the differing safe and just boundaries account for the facts that lack of access to fertilizers threatens food security in many places and that mining of phosphate “exposes poor and marginalized communities to mining waste, destroyed land and human rights abuses.”[6]
Most importantly, however, current global nutrient pollution again far exceeds both the safe and the just boundaries.[7] Nutrient pollution thus continues to put the entire planet at risk, suggesting that increased regulation is necessary.
ROBIN KUNDIS CRAIG is the Robert C. Packard Trustee Chair in Law at the USC Gould School of Law, where she teaches Environmental Law, Water Law, Ocean and Coastal Law, Toxic Torts, Civil Procedure, and Administrative Law. Craig specializes in all things water, including climate change adaptation in the water sector; the food-water-energy nexus; water quality and water allocation law; marine protected areas and marine spatial planning; and the intersection of freshwater and ocean and coastal law.
[1] Johan Rockström et al., Planetary Boundaries: Exploring the Safe Operating Space for Humanity, 14(2) Ecology & Society art. 32 (2009) [online journal], http://www.ecologyandsociety.org/vol14/iss2/art32/ [hereinafter Exploring the Safe Operating Space].
[2] Johan Rockström et al., A Safe Operating Space for Humanity, 461 Nature 472-75 (2009), https://doi.org/10.1038/461472a.
[3] Id. at 13.
[4] Johan Rockström et al., Safe and Just Earth System Boundaries, Nature (published online May 31, 2023), https://doi.org/10.1038/s41586-023-06083-8.
[5] Id. at 2.
[6] Id. at 7.
[7] Id. at 3 fig. 1.
