Energy Climate and Sustainability

4b: Nitrogen crisis #1

work@mishavelthuis.nl

Thu 6 March 2025

Today

Brief intro of N

Brief intro of N-crisis

Brief intro Dutch agriculture

How did we get here?

Where to go now?

A brief introduction of N

Abundant…

… yet scarce

Two planetary
nitrogen revolutions

Photosynthesizing cyanobacteria "discover" the ability to break the triple bond.

2.5 billion years ago.

Fritz Haber and Carl Bosch discover the ability to break the triple bond.

1910

"Breaking the bond" = turning dinitrogen into "reactive nitrogen".

Revolution #1

Before Great Oxidation Event (GOE) nitrogen limitation prevented photosynthesizing cyanobacteria from increasing in numbers.

Through the evolution of nitrogenases (enzymes that can break dinitrogen), the limitation becomes less pressing.

The boom in photosynthesizing cyanobacteria leads to the first major increase of oxygen in the earth's atmosphere.

Life, at that point, is not adjusted to an atmosphere with lots of oxygen.

See this blog post for a cute little background story about this.

Yesterday, Bart and I talked about this on Mastodon: link

Revolution #2

Throughout human history, nitogen availability has been a limiting factor in food production.

Som (relatively) marginal improvements in nutrient cycling helped.

In 19th century European powers "discovered" guano, and started importing.

In 1909-1910 two Germans find a way to capture nitrogen from the atmosphere: high temperature, high pressure, the right catalyst.

A brief introduction to
the N-crisis in the Netherlands

Equilibrium

Anthropogenic disturbance

input > output

Planetary boundary = 43 MT/yr. Agricultural surplus 119 MT/yr (Schulte-Uebing, 2022)

More info on denitrification:

Uncertainties around denitrification (Grosz et al. 2023)
Meta-analysis of research on denitrification (Martinez-Espinosa et al., 2021)

Grosz, B., Matson, A., Butterbach‐Bahl, K., Clough, T., Davidson, E. A., Dechow, R., DelGrosso, S., Diamantopoulos, E., Dörsch, P., Haas, E., He, H., Henri, C. V., Hui, D., Kleineidam, K., Kraus, D., Kuhnert, M., Léonard, J., Müller, C., Petersen, S. O., … Scheer, C. (2023). Modeling Denitrification: Can We Report What We Don’t Know? AGU Advances, 4(6). Portico. https://doi.org/10.1029/2023av000990

Martínez-Espinosa, C., Sauvage, S., Al Bitar, A., Green, P. A., Vörösmarty, C. J., & Sánchez-Pérez, J. M. (2021). Denitrification in wetlands: A review towards a quantification at global scale. Science of The Total Environment, 754, 142398. https://doi.org/10.1016/j.scitotenv.2020.142398

Schulte-Uebbing, L. F., Beusen, A. H. W., Bouwman, A. F., & de Vries, W. (2022). From planetary to regional boundaries for agricultural nitrogen pollution. Nature, 610(7932), 507–512. https://doi.org/10.1038/s41586-022-05158-2

So where does it accumulate?

input = output?

Source image: link

We "use" 13-14 gram Nr a day. So we eat (and excrete and sweat) 13-14 gram N a day.

If you're healthy these flows are in balance and nitrogen does not accumulate.

Quote Matassa et al.:

People dealing with sanitation know it: per person per day, some 13–14 g of ‘used nitrogen’ is excreted and needs, at present by the best available technology, to be removed - that means reconverted from the active form to the dinitrogen form. Hence, every person needs per day via their food uptake about 13–14 g of nitrogen, in the form of nutritious proteins, to main- tain good health and functionality (Courtney-Martin & Pencharz, 2016).

Matassa, S., Boeckx, P., Boere, J., Erisman, J. W., Guo, M., Manzo, R., Meerburg, F., Papirio, S., Pikaar, I., Rabaey, K., Rousseau, D., Schnoor, J., Smith, P., Smolders, E., Wuertz, S., & Verstraete, W. (2022). How can we possibly resolve the planet’s nitrogen dilemma? Microbial Biotechnology, 16(1), 15–27. Portico. https://doi.org/10.1111/1751-7915.14159

input = output?

Where does the N come from?

NH₃ (Ammonia)

Manure, and indirectly animal feed. Of the farm feed …
- … 10% is grown in the Netherlands
- … 67% in Europe
- … 23% outside Europe
- Veraart et al. (2023) link
Chemical fertilizers
- Why?
- Manure needs to be injected, not always possible.
- EU regulation of 170 kg/ha: some crops need more
- Manure has lower NUE
- Link to blog Wageningen University Research (WUR)

NOx (Nitrogen oxides)

Internal combustion engines.

Dutch translations:

Stikstof = Nitrogen
Nederland = the Netherlands
Ammoniak = ammonia NH₃
Stikstofociden = Nitrogen oxides (NOx)
jaar = year
Subscript says: "the balance of NH3 and NOx over the Netherlands, as calculated by the OPS model in kg/ha (Source data: RIVM).

Graph from Erisman, J. W., de Vries, W., van Donk, E., Reumer, J., van den Broek, J., Smit, A., … & van Schayck, P. (2021). Stikstof: de sluipende effecten op natuur en gezondheid. Uitgeverij Lias. (p. 29).

Veraart, M., Bikker, P., & van Laar, H. (2023). Monitor herkomst diervoedergrondstoffen: beschrijving van de opzet, uitkomsten en beperkingen van een monitor voor de herkomst van diervoedergrondstoffen gebruikt in mengvoer in Nederland in 2019 en 2020 (No. 1404). Wageningen Livestock Research.

Dutch chemical fertilizer

Where does the N come from?

NH₃ (Ammonia)

Manure, and indirectly animal feed. Of the farm feed …
- … 10% is grown in the Netherlands
- … 67% in Europe
- … 23% outside Europe
- Veraart et al. (2023) link
Chemical fertilizers
- Why?
- Manure needs to be injected, not always possible.
- EU regulation of 170 kg/ha: some crops need more
- Manure has lower NUE
- Link to blog Wageningen University Research (WUR)

NOx (Nitrogen oxides)

Internal combustion engines.

Dutch translations:

Stikstof = Nitrogen
Nederland = the Netherlands
Ammoniak = ammonia NH₃
Stikstofociden = Nitrogen oxides (NOx)
jaar = year
Subscript says: "the balance of NH3 and NOx over the Netherlands, as calculated by the OPS model in kg/ha (Source data: RIVM).

How much is emitted?

Where does it go?

Where does it go? NH₃:

11/25= 44% is deposited in the Netherlands

NOx:

2.5/19 = 13% is deposited in the Netherlands

Rest goes abroad.

There is also "import" of pollution, but much smaller than export:

7.5 kg.ha^-1.year^-1 N "import"
30.5 kg.ha^-1.year^-1 N "export"
"import" between quotation marks, because this is pollution, not trade.

Total deposited:

21 kg.ha^-1.year^-1 N

Erisman et al.: 10 kg.ha^-1.year^-1 is "the largest amount that nearly all natural systems can absorb without affecting the ecosystem and its services" (2015, p. 24)

Dutch translations:

Stikstof = Nitrogen
Nederland = the Netherlands
Ammoniak = ammonia NH₃
Stikstofociden = Nitrogen oxides (NOx)
jaar = year
Subscript says: "the balance of NH3 and NOx over the Netherlands, as calculated by the OPS model in kg/ha (Source data: RIVM).

See also the graph below, showing how a larger percentage of ammonia ("Ammoniak") is deposited at a shorter distance to the point source of emission ("afstand tot de bron"):

Graphs from Erisman, J. W., de Vries, W., van Donk, E., Reumer, J., van den Broek, J., Smit, A., … & van Schayck, P. (2021). Stikstof: de sluipende effecten op natuur en gezondheid. Uitgeverij Lias. (p. 29).

Decline is slowing down

Decline NOx: cleaner engines (further decreases?)

Decline NH3: injection of manure (further decreases?)

Translation from Dutch:

Graph left:

Landbouw = agriculture
Industrie, energie en raffinaderijen = industry, energy, refineries
Jaarlijkse emissie stikstofoxiden = annual emmission nitrogen oxides (NOx)
Handel, diensten, overheid = trade, services, government
Consumenten = consumers
Verkeer = traffic

Graph right:

Ammoniak emissies door de landbouw = Ammonia emissions by agriculture
Processen: bodem & gewas = processes, soil and crops.
Schapen & geiten = sheep & goats
Kunstmest = chemical fertilizers
Pluimvee = poultry
Varkens = pigs
Runderen = cattle/cows
Interimwet 'Ammoniak en Veehouderij' verplicht het emissiearm uitrijden van drijfmest = regulation requiring farmers to inject manure in soil.

The fact that the annual emissions go down does not mean that the accumulation of nitrogen stops. As long as input > output, the total stock of nitrogen increases.

Problems

Climate change

Total U.S. Emissions in 2022 = 6,343 Million Metric Tons of CO₂ equivalent (excludes land sector). link

IPCC (2021)

"Over the short-to medium turn, it is not clear what the net impact of N deposition on climate is. A review in the European Nitrogen Assessment (Butterbach-Bahl et al., 2011) suggested a slight cooling effect for Europe and a similar conclusion was drawn at global scale by Erisman et al (2011) but the uncertainty is too large for a definitive conclusion. Over the long term, however, it is likely that the Nr fertilisation effect on CO2 uptake by vascular plants will decline (De Vries et al., 2014), and the enhanced emission of the long-lived greenhouse gas N2O will ultimately dominate, with a net global warming effect" (Erisman, 2015).

N.B.: the production of artificial fertilizer is very carbon intensive!

Erisman, J. W., Galloway, J. N., Dise, N. B., Sutton, M. A., Bleeker, A., Grizzetti, B., … & De Vries, W. (2015). Nitrogen: too much of a vital resource: Science Brief. WWF Netherlands.

IPCC, 2021: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 2391 pp. https://doi.org/10.1017/9781009157896.

Multiple sectors involved …

But today: focus on agriculture

Brief introduction to
Dutch agriculture

Second biggest exporter of agricultural products

Nuance…

But large numbers…

And high density …

Scale increases

Higher productivity

Graph on the left: increasing productivity per person

Translation: Labour force in agriculture (split between family labour (light blue), and non-family labour (darker blue))
Source link (CBS, Centraal Bureau voor Statistiek)

Article on the right: increasing productivity per cow

Translation: "cows are producing more and more milk, and not everyone is happy with that"
In 2000, cows produced 24,000 liter milk
In 2010, 30,000 liter
In 2020, 34,000 liter

Made possible by …

… higher energy inputs (van der Ploeg, 2020)

In 1950: 81 GJ of energy input for 100 GJ of food.
In 2015: 225 GJ of energy input for 100 GJ of food.

… lower "grondgebondenheid" (van der Ploeg, 2020)

More feed imports
More manure disposal

van der Ploeg, J. D. (2020). Farmers’ upheaval, climate crisis and populism. The Journal of Peasant Studies, 47(3), 589–605. https://doi.org/10.1080/03066150.2020.1725490

How did we get here?

Post WWII Modernization

Geopolitics

Capitalism

Political opportunism

Input = output?

Latest chapter

Where to go now?

Scientists be like …

"The huge ammonia emissions of Dutch animal husbandry (that negatively aﬀect nature and biodiversity) are a strong reason for seriously discussing the magnitude and nature of the sector and arguing that reductions of the herds are unavoidable. Climate change does the same: it makes discussion about the magnitude of the national herd unavoidable" (van der Ploeg, 2020, p. 592).

Farmers be like …

But different sentiments

Sense of loss. Way of life is disappearing. Communities have disintegrated (see e.g. this document by the Wageningen University & Research (WUR)).

Pressure from banks, pressure from the market, pressure from the government (van der Ploeg, 2022).

Those who make it: sense of pride.

But does the underlying system of export-oriented modernization through scale and technological innovation enjoy wide support?

van der Ploeg (2022): differences between:

Peasant-like farmers
Large entrepreneurial farmers

"Only 16% of the farmers considered the emergence of mega-farms as a positive development … Eighty-two per cent of Dutch farmers indicated that they prefer ‘a farm of normal/average proportions that renders a good income’."

van der Ploeg, J. D. (2020). Farmers’ upheaval, climate crisis and populism. The Journal of Peasant Studies, 47(3), 589–605. https://doi.org/10.1080/03066150.2020.1725490

Regressive populism

Populism:

Anti elite
Emphasis "the people"
Appeal to simplicity

Regressive:

Opposite of progressive
Resisting change
Protection of status quo, including existing power balance

Term from van der Ploeg (2022)

"Above all it is regressively populist in as far as it used the many in order to obtain privilege for the few. It mobilized all farmers to protest against policies meant to redress the environmental eﬀects of contemporary farming, but the solutions it sought (and won) only served the interests of the few in the entrepreneurial pole, allowing them more opportunities for future expansion."

"It is regressively populist in as much as it does not provide a transparent analysis of the problems that need to be addressed. It just draws on, and further galvanizes, generalized feelings of grievance and neglect."

"There is this "… feeling of being subjected to unjustiﬁed views and actions of others made for an ‘underdog position’, the main thing that tied the angry farmers together. They typically presented themselves as ‘victims’ (even making shameful comparisons with Jews in WW2)."

No farmers no food…

Right-wing attack on science

Quotes from PVV election manifesto link to document:

We moeten af van alle bangmakerij dat onze natuur en onze leefomgeving op omvallen zouden staan. Onder het mom van een niet-bestaand stikstofprobleem worden hardwerkende boeren vakkundig de nek omgedraaid met verplichte uitkoop en uiteindelijk zelfs onteigening. Ook het Landbouwakkoord draaide feitelijk maar om één ding: krimp van de veestapel en krimp van de boerenstand.

Geen miljardenuitgaven meer aan links-liberaal ideologisch beleid als stikstof

We willen geen dictaten meer van ongekozen eurocommissarissen over klimaat of stikstof, over boerenhaat, of het binnenlaten van asielzoekers.

Er gaan miljarden naar een oorlog die niet de onze is, miljarden naar Afrika, miljarden naar Brussel, miljarden naar onzinnig klimaat- en stikstofbeleid, miljarden naar massa-immigratie

Daarom: schrap alle belemmerende regels, om te beginnen de stikstofregels.

Maar de laatste jaren horen we niets anders dan: stikstof hier, stikstof daar, boeren moeten stoppen, boeren moeten weg… Het is een totale hetze geworden. De PVV zegt heel duidelijk: nee, wij willen niet minder boeren, maar een einde aan de boerenhaat. We moeten weer terug naar die collectieve trots van weleer. De boeren moeten blijven.

One of my favourites:

Wij constateren in de scholen een toename van politieke indoctrinatie. Schoolkinderen worden geïndoctrineerd met klimaatactivisme, genderwaanzin en met een gevoel van schaamte over de geschiedenis van ons land.

Alternative? Eco-populism?

Post that was circulated on (old people's) social media: link

1️⃣ 𝗞𝗼𝗺 𝗼𝗽 𝘃𝗼𝗼𝗿 𝗱𝗲 𝘃𝗼𝗹𝗸𝘀𝘄𝗶𝗹

Populisten praten graag namens 'het volk'. Zo suggereren ze dat zij de enige ware spreekbuis zijn:

✅ “Wij zijn de stem van het volk, en het volk wil een eerlijke en leefbare toekomst voor onze kinderen.”

2️⃣ 𝗞𝗲𝗲𝗿 𝗷𝗲 𝘁𝗲𝗴𝗲𝗻 𝗱𝗲 𝗲𝗹𝗶𝘁𝗲

Populisten keren zich altijd tegen de elite. Schilder je tegenstanders af als een machtige en corrupte groep die de gewone mensen negeert en bedreigt.

✅ “De fossiele brandstofelite doet alsof we niets kunnen veranderen, maar dat is een leugen om hun winsten te beschermen.”

4️⃣ 𝗦𝗽𝗲𝗲𝗹 𝗶𝗻 𝗼𝗽 𝗵𝗲𝗶𝗺𝘄𝗲𝗲 𝗻𝗮𝗮𝗿 𝗵𝗲𝘁 𝘃𝗲𝗿𝗹𝗲𝗱𝗲𝗻

Populisten spelen graag in op een gevoel van nostalgie. Je verwijst naar een (geromantiseerde) tijd waarin het leven fijn en overzichtelijk was.

✅ “Kinderen moeten opgroeien zoals vroeger, met frisse lucht en een tuin vol bijen en vlinders.”