Showing posts with label Climate. Show all posts
Showing posts with label Climate. Show all posts

Waste Management: An Overlooked Effective Tool to Cut Methane Emissions and Limit Global Warming. IPCC Report Review

August 17, 2021

Waste management, as a policy, brings the complementary emissions reductions required to reduce global warming, says the Intergovernmental Panel on Climate Change's new report (IPCC AR6 WGI) released on August 9. The statement is a huge step towards reducing emissions and a major departure from previous IPCC reports.


The waste sector emits methane (CH4), a potent greenhouse gas (GHG), through the decomposition of waste in dumps and landfills. While 82 times stronger than carbon dioxide (C02) after 20 years, for being a short-lived gas, methane was incorrectly thought to have a marginal role in global warming. Solutions reducing short-lived gases, such as effective waste management, have not been viewed as critical to mitigate climate change as solutions that reduce long-lived greenhouse gases. That all changed with the recent IPCC Report that places equal importance on limiting long- and short-lived GHGs, including methane.


GHGs effect on global warming - ten years sooner than expected

The new 4,000-page IPCC report breaks the news that human influence on the climate system is now an established fact and that a global temperature increase of 1.5ºC is likely to be reached in the early 2030s, ten years earlier than previously assessed. This reduced timetable factors in an increased concentration of emissions from human activities that more quickly accelerates global warming by creating a GHG effect that traps excess energy (see Figure 1).


According to the IPCC, global warming is responsible for changes in the climate system, such as "increases in the frequency and intensity of hot extremes, marine heatwaves and heavy precipitation, agricultural and ecological droughts in some regions, and proportion of intense tropical cyclones, as well as reductions in Arctic sea ice, snow cover and permafrost" (IPCC AR6 WGI, page 20. Fig. 2). 


Figure 1. The Earth's energy budget and energy loss / IPCC AR6 WGI, p. 1816 / Graphic by IPCC

Figure 2. Possible climate futures

The importance of near-term time scales & short-lived GHGs in limiting global warming

The IPCC has adamantly stated that reducing emissions is essential to limit global warming and stabilise climate systems. It has, however, focused its attention on reducing emissions with long-term effects on climate, such as CO2, as recommended by long-term time scales.


For scientists in creating their forecast models, metrics and time scales matter when it comes to understanding the effect of a GHG. There are several metrics and time scales. Global Air Temperature Change, for instance, measured over a 100-year period is largely affected by CO2, while in a period of 10 years methane plays a significant role in temperature change (fig. 3). Although 100-year time scales have been most prominently used in previous climate assessments, the new IPCC report leaves it to policymakers to decide which time scale - and emission metric - is most applicable to their needs.  


The IPCC report’s invitation to use near-term time scales closely relates to short-lived GHGs or Short-lived Climate Forcers (SLCFs), the GHG group that mostly affects climate over a 10- to 20-year period.


It has taken scientists a while to understand the effects of SCLFs on climate. Previous science thought that SLCFs’ reductions lead to disbenefits for near-term climate change, because aerosols, a SLCF gas, have cooling effects and were believed to drive the overall effect of SLCFs as a multigas. This is no longer the case and the new IPCC report confirms that changes in SLCFs will very likely cause further warming in the next two decades, and that the influence of SLCFs on global temperature is at least as large as that of CO2 (IPCC AR6 WGI, p. 110). 


This is an important statement. It means that a previously underrated GHG group has been pointed up as key to limiting warming to 1.5ºC in the near term. And this is where the IPCC report identifies waste management’s increased role in global warming mitigation, through its effectiveness in reducing methane, the main contributor to SLCFs.

SLCFs affect climate and are, in most cases, also air pollutants. They include aerosols, which are also called particulate matter (PM), and chemically reactive gases (methane, ozone, some halogenated compounds, nitrogen oxides, carbon monoxide, non-methane volatile organic compounds, sulphur dioxide and ammonia). Except for methane and some halogenated compounds whose lifetimes are about a decade or more, SLCFs only persist in the atmosphere from a few hours to a couple of months." (IPCC AR6 WGI, p. 1429) 

Until the 1950s, the majority of SLCFs emissions originated from North America and Europe. Since the 1990s more than 50% of anthropogenic SLCFs originate from Asia.


Figure 3. Global surface temperature change 10 and 100 years after a one year pulse of present day emissions / IPCC AR6 WGI, p. 178 / Graph by IPCC

Waste management is essential to cut methane emissions

Methane is a powerful short-lived gas that stays in the atmosphere for 12 years. Its global warming potential is highest when the gas enters the atmosphere and sharply declines with time. Methane is so powerful that after 20 years its warming potential is still 82 times greater than carbon dioxide’s (IPCC AR6 WGI, p. 1739).  


Methane emissions are growing since 2007 at a growth rate of 7 +/- 3 ppb per year. With an effective radiating forcing (ERF) of 0.54 Wm-2, methane has an attributed contribution to global mean surface air temperature (GSAT) of +0.3ºC (IPCC AR6 WGI, p. 1798).

The main sources of anthropogenic methane are agriculture (livestock production and rice cultivation), fossil fuel production and distribution, waste decomposition in landfills and dumps, and biomass burning (fig. 4).  

The waste sector generates 55-77 Tg of CH4 emissions per year, that is, 18% of global anthropogenic methane emissions, a large enough share to help limit global warming if they were to be avoided.

Although the agricultural and fossil fuel sectors offer the largest mitigation potential, they aren’t quite there with full-fledged, viable solutions to cut emissions. The agricultural sector hasn't got a large-scale alternative to the high-polluting meat industry, and the fossil fuel sector needs massive investments that aren't available due to divestment policies. The waste sector, on the contrary, has already proven practices and technologies in place to cut its methane emissions. Practices such as waste management in combination with energy recovery and recycling can end landfills and dumps the sector main emitters slash methane emissions, and positively impact climate stabilisation with the co-benefit of improved air quality.

In sum, by phasing out landfill and dumps, the world has a way to reduce methane emissions, which the IPCC report clearly says will lessen the newly-revised – negative – impact of SLCFs and help limit global warming to 1.5ºC.

Figure 4. Data by IPCC AR6 WGI, Table 5.2, p. 1189 / Graphic by PS
by Patricia Sendin, founding partner at Frontline Waste.

Joanie Lemercier: Art for Climate Action

July 15, 2021

At his solo exhibition at the Telefónica Foundation, Madrid, the French artist shows seven audiovisual installations that reflect on the relationship between nature and technology, and that pose a beautiful example of how art can serve climate action.  

Lemercier's earlier works at the exhibition explore the use of technology to represent nature with video mapping and projected light to capture the grandeur - the Sublime - in landscapes, while his more recent works shift to the grandeur in the technology itself and how it can act as a destructive force to nature. 


Joanie Lemercier, Fuji, 2014
  Bagger 293 / Slow Violence, The Hambach Project & the Technological Sublime, 2019-21

The Hambach Project and the Technological Sublime (2019-21) is one of Lemercier's recent works. It is structured in four audiovisual installations each showing a different aspect of Europe's largest coal mine: its exploitation; the destruction of the community; the activism supporting its closure; and the beauty of the remaining forest.

Slow Violence, the most striking of the Hambach installations, features the mine exploitation. It shows a giant bucket-wheel excavator scooping up earth from a plateau - pictured above. The machine is impressive and we read that it is a Bagger 293, the world's largest machine able to scoop 240,000 m3 of soil per day. The scene is at the Hambach open-pit coal mine close to Cologne, Germany, and the excavator is destroying the last remains of the 12,000-year-old Hambach forest to access the lignite deposits beneath. Operated by energy giant RWE, the 85 km2 mine extracts 40 million tonnes of lignite yearly for electricity generation in North Rhine-Westphalia, and emits 100 million tonnes of CO2 per year.


In addition to destroying a forest and polluting the environment, the Hambach mine has inflicted damage to the local communities and cultural heritage with the demolition of buildings and towns as the mine was expanding.  


Immerath's St. Lambertus church demolition / Slow Violence, The Hambach Project & the Technological Sublime, 2019-21

The installation Here Once Stood a Forest celebrates the ancient Hambach forest - its beauty and rich biodiversity - with a projection of the forest during daytime and a night view where a laser lights up the smallest details.  

Over the past 40 years, 90% of the forest has been destroyed for coal extraction. Since 2012 the forest has been a symbol of Germany's fight against climate change.


Laser lighting / Here Once Stood a Forest, The Hambach Project & the Technological Sublime, 2019-21


Hambach Forest / Here Once Stood a Forest, The Hambach Project & the Technological Sublime, 2019-21

With Action, Comes Hope is the last installation of The Hambach Project and the Technological Sublime. It shows impressive environmental activism opposing the mine and how climate action can look like. 

The artist tells how The Hambach Project has shifted his perspective on climate action and how he wants to do something and support activists through his work. This might come in addition to Lemercier's efforts to audit and minimize his carbon footprint as a digital artist. In March 2021 Lemercier notoriously teamed up with other digital artists to raise awareness on the huge CO2 footprint of CryptoArt.


Activists / With Action Comes Hope, The Hambach Project & the Technological Sublime, 2019-21

The show closes with Desirable Futures, a space packed with a mix of photography and projections with the artist's version of the future, a rather green and hopeful one. The space is possibly an invitation to visitors to think creatively about the future, while the previous installations provide encouragement to question our own use of technology and to take action.


Artist and Desirable Futures, 2020-21 / Photo courtesy of Fundación Telefónica


Joanie Lemercier. Lightscapes | Espacio Fundación Telefónica, Fuencarral 3, Madrid | 11 February - 25 July 2021

Featured Artist
Joanie Lemercier (Rennes, 1982)

Further Reading
The End of the World's Capital of Brown Coal | BBC Future Planet, 20 April 2021
Photos by PS
Cover picture, Desirable Futures (2020-21) by Joanie Lemercier


COP22 y el futuro de la Estrategia Española de Cambio Climático

September 16, 2017

Un año después del Acuerdo de París, la Conferencia de la Partes, el órgano supremo de la Convención Marco de las Naciones Unidas sobre el Cambio Climático (CMNUCC), se da cita en la COP22 en Marrakesh para revisar avances. Además de las Partes, o delegaciones autorizadas a negociar en nombre de su gobierno, acuden a la cita empresas e inversores, ONGs y gobiernos locales para ejercer presión política, hacer de observadores o promover sus intereses. Se organizan en estands, charlas y manifestaciones y se cercioran de que su mensaje sea claro y llegue al mayor número posible de personas.
Entrada COP22 Marrakesh | Activistas

No todos los países tienen un estand, pero el que lo tiene lo usa como escaparate para sus políticas y proyectos climáticos (Malasia, EAU); lo cede para debates a asociaciones y empresas del país (Brasil); o ambas cosas (India). Otros pabellones, como el de África, crean un espacio de apoyo en el que el público se puede reunir, cargar dispositivos electrónicos y usar internet. En cualquier caso, para la mayoría de los pabellones parece primordial tener un estand relativamente atractivo con funciones que atraigan al público. Para casi todos menos para uno: el español. 

El pabellón de España no presenta ningún proyecto, no organiza ningún evento público y permanece cerrado durante toda la COP; sin ningún cartel que explique cuál es el plan y sin redirigir a los visitantes a otro sitio, aunque sea virtual (foto abajo). La presentación resulta inexplicable entre otras cosas porque bastaba colgar un cartel, abrir la puerta y poner a una delegación dentro dispuesta a responder preguntas, como ha sido el caso del pabellón de la República Democrática del Congo. 

Aquí surge la curiosidad de saber qué está exactamente haciendo España con su política de cambio climático, para que no merezca la pena hablar de ella en foros internacionales. ¿Es realmente tan insignificante como el estand español parece indicar?

Pabellón India | Pabellón EAU

Pabellón Nórdico | Pabellón Malasia

Pabellón Brasil | Pabellón África
Pabellón España | Pabellón RDC
Para valorar la estrategia de cambio climático española parto de su hoja de ruta, la Estrategia Española de Cambio Climático y Energía Limpia del 2007 que describe las principales actuaciones en curso, y mido su progreso con los indicadores definidos por la oficina de cambio climático. Utilizo una plantilla diseñada por la iniciativa Sustainable Canada Dialogues para hacer lo mismo con la política climática canadiense. En ella comparo los últimos datos oficiales de cada indicador, que son del 2015, con los del año anterior: si son mejores, apunto un "avance" para el indicador y si son peores un "retroceso". El panorama emergente es claro: la Estrategia Española de Cambio Climático no está cumpliendo la mayoría de los objetivos que se marcó (tabla 1). 
Tabla 1. Progreso de las principales actuaciones de la Estrategia Española de Cambio Climático medido por los indicadores definidos por la oficina de cambio climático.
Para facilitar la lectura se omiten aquí las notas con las fuentes. 

¿Es España la única en Europa en no cumplir objetivos? ¿Cómo compara la actuación española con la de otros países europeos? 

España, como miembro de la UE, sigue las directrices europeas de reducción de emisiones de Gases de Efecto Invernadero (GEI). La UE se ha comprometido en el Acuerdo de París a una Contribución Prevista y Determinada a Nivel Nacional (INDC, por sus siglas en inglés) que supone una reducción del 20% de las emisiones para el 2020 con respecto a los niveles de 1990, y de un 40% para el 2030. Algunos países miembros consideran estas Contribuciones (INDCs) insuficientes y voluntariamente se han puesto metas más ambiciosas como es el caso del Reino Unido, Alemania y Suecia (tabla 2). 
Tabla 2. Comparación de estrategias y logros de las políticas de cambio climático de 4 países europeos

La comparativa en la tabla 2 muestra que:
1. España está lejos de alcanzar en el 2020 el objetivo de reducir sus emisiones GEI un 20% respecto al 1990, mientras que Reino Unido, Alemania y Suecia ya han cumplido - y superado - estos objetivos.
2. España no usa todas las posibilidades a su alcance para gravar las emisiones de carbono, ni invierte todo lo que recauda por esta vía en mitigar el cambio climático.
3. España es uno de los países europeos que menos invierte en I+D (1,2% del PIB) y en financiación climática.

Esta negligencia climática y aparente falta de compromiso sin duda pasará factura a España. Según la Agencia Europea de Medio Ambiente los impactos principales del cambio climático en la región mediterránea están siendo el aumento de temperaturas extremas, la reducción de precipitaciones y del caudal fluvial y un menor rendimiento de los cultivos. Revertir la situación española para empezar a alcanzar los hitos marcados, es posible desde un punto de vista técnico. Hay 3 acciones que ayudarían a España a encarrilar sus objetivos climáticos:


España necesita reducir sus emisiones a un ritmo del 13% anual en los próximos 3 años para alcanzar los objetivos del 2020 (gráfico 1). Una reducción similar ya se experimentó entre el 2008 y 2009, por lo que no es algo imposible.

Gráfico 1. Evolución de las emisiones GEI tomando como referencia el primer año de la serie (1990). Grafico: MAPAMA modificado para incluir la prevision hasta el 2020. Sin datos para el 2016.

El mayor emisor en España es el sector eléctrico, seguido del transporte en carretera.  El eléctrico es un sector regulado y sujeto al derecho y comercio de emisiones; aporta el 39% de las emisiones totales en España. El transporte es parte de los sectores difusos, que no están sujetos al comercio de emisiones y son libres de emitir gratuitamente. El transporte en carretera es responsable del 95% de las emisiones en el sector transporte. 

Las emisiones en el sector eléctrico derivan del consumo de carbón para la generación eléctrica. El consumo de carbón depende a su vez del precio del carbón. Un aumento del precio del carbón, disminuye su consumo y en consecuencia, las emisiones. Esto se vio en el 2008 cuando el precio del carbón internacional alcanzó un pico máximo de 120 $/t: la generación con carbón se redujo un 25,3% y las emisiones GEI del sector eléctrico un 21%. O cuando en 2015 pasó lo contrario: el bajo precio del carbón, 62 $/t, llevó a un aumento del 23,9% en la generación con carbón, y en consecuencia, de las emisiones GEI.  

El Reino Unido redujo en 2015 el consumo de carbón en un 33% y las emisiones GEI un 4%, después de introducir en 2013 el Carbon Price Floor o CPF, un mecanismo en el que los generadores de electricidad pagan un canon adicional por tonelada de CO2 emitida. 

Las emisiones del transporte en carretera también se ven afectadas por el precio del combustible. En 2009 se redujeron un 5,2% debido al aumento del coste del combustible y a la reducción de desplazamientos por efecto de la crisis. Otros países han reducido estas emisiones penalizando los combustibles fósiles (CO2 Tax Suecia); fomentando el uso del transporte por ferrocarril con incentivos económicos (1); aumentando la inversión en proyectos de transporte futuro (Alemania y RU); e impulsando el uso de vehículos eléctricos como Noruega (2).
La medida más eficiente para reducir el consumo de combustibles fósiles es el impuesto sobre el carbono Carbon Tax en inglés. Aunque no son muchos, sí son ya unos cuantos los países que han aplicado la medida variando mucho el precio por tonelada de CO2 emitida. Suecia es el país con el gravamen más alto, con 137€ /tCO2eq. En Reino Unido el canon adicional a los generadores de electricidad (Carbon Price Floor) es de 21€ /tCO2eq mientras que el precio medio del derecho de emisión (ETS, por sus siglas en inglés) en la UE es de 5€ /tCO2eq.
En 2016 el Reino Unido ingresó 2.025 millones de libras (2.275M ) con el Carbon Price Floor, cuatro veces más de lo que obtuvo ese mismo año por derechos de emisiónSuecia, cuyos ingresos por el impuesto de carbono han sido de €2.470 M en 2016, ha disminuido sus emisiones un 25% desde que en 1991 introdujo su impuesto sobre los combustibles fósiles.

Mapa de las iniciativas para gravar las emisiones de carbono: Régimen de Comercio de Derechos de Emisión (ETS) e Impuesto sobre el Carbono (Carbon Tax). Fuente: State and Trends of Carbon Pricing 2016, Banco Mundial
Lo más eficiente para combatir el cambio climático es reducir las emisiones y como se ha dicho antes, un impuesto sobre el carbono ayuda a reducirlas. El paso siguiente es compensar las emisiones que no pueden ser evitadas. El Acuerdo de París reconoce que algunos países o sectores, como la aviación, solo podrán o querrán cumplir con sus compromisos de reducción emisiones (INDCs) comerciando el exceso de las mismas, e introduce en su Artículo 6 un marco jurídico para un mercado de carbono entre países. En este Mercado de Carbono se comercian créditos o bonos de carbono. Un bono o crédito de carbono es un término genérico para cualquier certificado comerciable que represente el derecho a emitir una tonelada de dióxido de carbono u otro gas de efecto invernadero con masa equivalente. Hay varios sistemas de certificación así como varios tipos de créditos. 

Dentro del Mercado Voluntario de Carbono, es decir, el que facilita a entidades y personas que no estén dentro de los sectores regulados compensar voluntariamente sus emisiones, el sistema de certificación más reconocido es el Gold StandardLos VER, del inglés Verified/Voluntary Emission Reductions, en español Reducción de Emisiones Verificada/Voluntaria, son créditos generados por proyectos de pequeña o gran escala que capturan carbono y se utilizan para compensar -voluntariamente- las emisiones directas de dióxido de carbono como las generadas por la aviación o el transporte en carretera. La demanda de estos créditos es superior a la oferta y aunque esto debería conllevar un alto precio de los mismos, al ser, todavía, un mecanismo no regulado y voluntario de compensación, el precio de un crédito de carbono suele ser de 5 a 10€ t/CO2eq. 

La deforestación evitada y, en menor medida, la reforestación en estado avanzado son las principales fuentes de absorción carbono para los VERs. 
Los bosques naturales que se mantienen intactos son un sumidero de carbono, es decir, los árboles en crecimiento atrapan más carbono mediante la fotosíntesis del que liberan los árboles muertos. Los bosques almacenan continuamente carbono aumentando su biomasa y en el suelo. Los árboles grandes y de mayor edad eliminan de la atmósfera más carbono que los jóvenes. De los 10.400 millones de toneladas de carbono extraídos de la atmósfera cada año por bosques, 4.400 millones de toneladas son absorbidas por bosques maduros."  Extracto de Why Forests? Why Now? de Frances Seymour y Jonah Bush

Existencias de carbono en la biomasa forestal

España es con 27,7M de hectáreas el segundo país europeo detrás de Suecia con mayor superficie forestal total (datos 2010). También es el país europeo con mayor incremento de superficie arbolada con un ritmo anual del 2,19% desde 1990. Aunque su biomasa forestal es inferior a la media, sus existencias de CO2 fijado son de 3.753M de toneladas, con un incremento de 54M t/año (ver tabla 1).

España tiene margen para usar sus recursos de carbono fijado en bosques de una manera creativa que aporte ingresos adicionales y/o compense parte de las emisiones nacionales. El carbono contenido en los incrementos anuales de superficie de bosque y en la deforestación evitada, ¿no podría estructurarse para VERs? 

Generar ingresos adicionales es casi tan importante como saber invertirlos. Alemania ha creado un fondo especial, el Energy and Climate Fund (EKF, por sus siglas en alemán), para proveer financiación adicional a proyectos de electromovilidad, eficiencia energética y energías renovables entre otros (tabla 2). La casi totalidad de los ingresos del comercio de emisiones se transfieren a este fondo que se gestiona independientemente. 

Un fondo similar (SPV en el gráfico 2) que actuara en apoyo del plan climático, sería una herramienta crucial para avanzar los objetivos climáticos españoles. Inicialmente se pueden desviar a este fondo los ingresos del comercio de emisiones que más adelante pueden ser suplementados con otros ingresos climáticos (ver punto 2.). El fondo puede financiar desde acciones pequeñas, como la comunicación, a apoyar la I+D y la eficiencia energética. Este tipo de estructura, transparente, en directa relación con los proyectos y abiertamente comprometida con la acción climática, no solo avanzaría la agenda climática sino que posicionaría mejor a España en la lucha global contra el cambio climático. 

Permitiría también el acceso a iniciativas de inversión en el desarrollo tecnológico como Breakthrough Energy Ventures, el vehículo financiero liderado por Bill Gates para apoyar Mission Innovationuna iniciativa de 22 países y la UE. España, como miembro de la UE, es parte de Mission Innovation pero al no haberse comprometido a doblar su inversion en I+D de energías limpias, queda excluida de las inversiones del fondo

Las ventajas climáticas y sociales de un planteamiento similar, son obvias. 

Gráfico 2. 

COP22, Conferencia de Naciones Unidas sobre el Cambio Climático | 7-18 noviembre 2016 | Marrakesh, Marruecos

Este artículo es parte del documento "Evaluación de la Estrategia Española de Cambio Climático" de enero 2017. 
1. El precio de un billete “promo” en AVE Madrid - Barcelona (621km) es de €57,60. En Italia, un billete en Frecciarossa (el equivalente al AVE) Milán - Nápoles (657km) cuesta €39,99. La distancia recorrida es similar, el billete italiano cuesta un 30% menos, a pesar de que el kilometro construido de alta velocidad en Italia cuesta 61M€ y en España 10M€. 
2. Noruega ha conseguido que el 23% de su parque móvil sea  eléctricoproporcionando incentivos como exención de IVA y acceso al carril bus. 

Fotos gráficos por PS
Imagen cabecera: Ola de Calor 2014, NASA

#DiplomaciaClimatica #CambioClimaticoEspana #AccionClimaticaEspaña #ClimateChangePolicySpain #ClimateActionSpain 

Syntropic Agriculture: the Regenerative Food-Growing Method that Could Reverse Climate Change and End Hunger

August 12, 2016
12 August 2016

"There is no such thing as a poor soil," stretches Ernst Götsch, a farmer and researcher who for the past 30 years has turned degraded land in Brazil into highly productive agroforests (trees and crops) using no chemical inputs, heavy machinery or irrigation. 

Since Götsch hardly publishes papers, I have traveled to Brazil to learn first hand how he manages to create net positive ecosystems, that produce food, while restoring soils and trapping outstanding amounts of carbon. As it happens, his method is nature-inspired, intuitive and easy to understand; it carries almost no cost and works in all ecosystems. If we were to leave it to nature to fix climate change and food security, this is how she would do it. 

Why does the subject matter    
Feeding the world releases 17,000 megatonnes of carbon dioxide into the atmosphere annually (source) - 47% of the total global emissions - and still leaves 795 million people - 10% of the global population - chronically malnourished. The Sustainable Development Goals 2, End Hunger, and 13, Climate Action, are an inspiring call on how we can help, yet a complete rethink on how we produce food is desperately needed. 

Another important aspect relates to how and where we will live in future. Despite projections that foresee 70% of the world population living in urban areas by 2050 (source), most likely the opposite scenario - a migration to the countryside - will be true considering the factors below.

Factors contributing to a new urban-to-rural migration trend | by Send a City
But we may also be pushed towards rural living, if the commitment to limit the temperature increase by 2100 to 2ºC adopted at the COP21 gets implemented. According to the Committee on Climate Change to achieve this goal the global emissions should peak at 2020 and be halved (or more) by 2050, which means per capita CO2 emissions in 2050 averaging around 2 tonnes. This is a reduction of 72% relative to today 7.3 t CO2e/capita. Mission (or rather emission) impossible unless we radically change the way we live.

According to a study from the Federal University of Ceará in Brazil, bigger cities produce more carbon dioxide per capita than small ones. "This shouldn't be a surprise," says the research team, "there are many aspects of cities that scale with population size, such as the number of jobs, houses and water consumption." 

In light of this, if we were to plan the most carbon-efficient community, it ought to be on the smaller size. But how dense should it be? Here is where agroforests enter the picture. 

If a community were to integrate an agroforestry system, it could offset part of their CO2 emissions with the CO2 sequestered by its plants. According to Cooperafloresta Brazil (see picture below) agroforests sequester approximately 10 tonnes of CO2 per hectare per year: 6.6 tCO2/ha/yr from the air and 3.5 tCO2/ha/yr through pruning. If the per capita emission today is 7,3 t CO2 and the number is smaller in smaller towns, we could assume a possible per capita CO2 emission in a small town of 4 tonnes. Since our emissions allowance will be 2 t CO2e/capita, we'd need to offset the other 2 tonnes. The 10 tCO2/ha/yr sequestered by an agroforest is equivalent to the CO2 produced by 5 people/ha (or 500 people/km2) at 2 t CO2e/capita. To conclude: a small town with a density of 500 people/km2 will meet the 2050 climate action targets by means of incorporating agroforestry, without their inhabitants having to shift customs or behaviour.

Needless to say, however, that the behavioural change will in any case occur through the practice of agroforestry: people would consume organic, locally produced food which will further reduce their carbon footprint (agroforestry produces 40 tonnes of food per hectare per year!). Agroforestry practised in small, sparsely-populated communities would be a way to meet the climate targets and could lead to carbon neutral (or carbon positive) living. 

This surely sounds like heresy to urban planners, since it looks like a return to "urban sprawl", the phenomenon we've been fighting for the past 25 years. But it won't be comparable since 1) the conditions are very different: people will work locally and/or remotely, consume less, travel less etc, 2) compact cities will still exist, and 3) "urban density" is like "fiscal austerity", in theory a good idea but in practice not really taking us where we want to be.

Carbon sequestration in agroforests | Study by Cooperafloresta
Syntropic agriculture and the work of Ernst Götsch
Ernst Götsch at 4th Workshop on Syntropic Agriculture | Photo Chris Lima
The eyeopener for Ernst Götsch (Switzerland 1948) was a trip to the tropics in 1976 when he was stunned by the contrast between the poverty of cultivated lands and the wealth of the bordering tropical rainforest (1). He found similar wealth resulting from the way small farmers worldwide had been practising agriculture for over thousand years. They would combine trees with crops and/or pastures (agroforestry) to achieve an increase in biodiversity and an improvement of soil fertility, thus leading to a higher productivity. Exactly the opposite than conventional agriculture achieves with monocultures and the use of herbicides, pesticides and mineral fertilisers.
Taking agroforestry as a base line, Götsch developed by means of trial and error a system called regenerative analog agroforestry, known in Brazil for its acronym SAFRA. This method works with processes rather than inputs and supplements agroforestry with strategic interventions (see below) and the natural succession of species in a system. This, according to Götsch, is what ultimately brings a system to thrive and not the initial quality of the soil or the amount of light it receives (2). He observed that the natural succession of species is one of the driving forces of life.

Götsch's research and work keeps unfolding and he now refers to it as syntropic agriculture since it actually follows the law of syntropy (3), also known as negative entropy, or the principles that sustain life. He also defines his work as "a way to create a positive energy balance in the world by means of unconditional love and cooperation."

His numbers are as impressive as his methodology. He produces in his farm in Bahia cacao beans so superior in quality, that they sell for four times the market price to Italian Amedei, the best chocolate producer in the world according to the London Academy of Chocolate, says an article in O Globo Rural this month (4). "The quality arrives with the ecological balance of the system", Götsch tells in the article. Since his method requires no inputs, Götsch produces his cacao at zero cost. He also achieves higher than average yields and his crops are unaffected by pests. 

His best numbers though are in his comparison of the energy efficiency of nature and technology:

Energy efficiency comparison of nature and tech | Photo by Chris Lima, edited by PS
"Nature uses for its metabolic processes approx 3% of its capital in order to achieve a 10 to 15% surplus." This means, nature (green line above) will always increase its energy (syntropy) since it produces more than it consumes. Technology on the contrary will always tend towards energy depletion since to achieve the same surplus of 10%, a combustion engine, for instance, burns between 70-75% of its fuel energy, that is, it consumes more than it produces and will always need energy added to its system (entropy). Technology will never lead to abundance, nature will.

Götsch's syntropic agriculture mimics nature: it produces its own fertiliser, creates abundant black soil and nutrients, retains water and optimizes its circulation. Notwithstanding the complexity of the system that requires in-depth knowledge of the local flora, Götsch believes that everyone can be a practitioner and encourages to focus on understanding the processes rather than on the details. His advice: to experiment with the species and to keep an open heart for new knowledge to flow in.

Syntropic agriculture practices

#1 Permanent soil cover
In agroforestry the ground is covered throughout with organic matter obtained from weeding, pruning and removing plants. This material placed on the ground as mulch (chipped or unprocessed) both enriches and protects the soil. "Efforts are made to recycle and to increase the amount of organic material produced by the plantation itself" (2) thus making away with the need for external fertilisers.  

An agroforestry site has on average 4kg of dry organic matter per m2, constantly decomposing. This equals to an estimated production of 6-10 kg of mulch /m2/yr with more than 3 to 5 prunings (5). The mulch fixes carbon dioxide to the ground, protects the soil from erosion and preserves water (some vegetable beds hadn't been watered for a month and a half).

Wood chip mulch and small tree branches for the vegetable beds. Hay mulch between them | Photo Chris Lima
Wood chip mulch decomposes in 6 months

Lettuce seedling planted  in wood chip mulch

Banana tree trunks cut in half over loose soil to avoid erosion and canalise water in slopes | Photo Chris Lima
Broccoli and lettuce seedlings planted in soil between banana trunks
Sloping vegetable beds made with banana and acacia mangium tree trunks are protected from erosion
#2 Pruning
The drastic trimming of branches and trunks done on a regular basis is an important part of syntropic agriculture. Besides producing the dead material for the permanent soil cover, strategic pruning rejuvenates maturing plants and accelerates the rate of growth in the whole system by increasing the amount of light and nutrients available to the future generations of plants. It also speeds and directs the organic process of (plants) succession. 

Through pruning the carbon trapped in the trees goes back to the soil. A mature agroforest (10-15 years old) has a carbon stock of 48 t/ha (source).

Acacia mangium pruning | Photo Chris Lima

Acacia mangium trunks and branches cut to equal size for vegetable beds | Photo Chris Lima
Smaller acacia mangium branches for vegetable beds borders | Photo Chris Lima

Acacia mangium trimmings and foliage used for mulch or processed for wood chip | Photo Chris Lima
#3 Companion planting
"Living beings of each place and in each situation form consortia in which each member contributes with its particular capacity to improve and to optimize its conditions as well as those of the members of its consortium to grow, prosper and reproduce." (2)

"It appears that the critical factor in determining health and growth rate of the plants, as well as the productivity rate of the system, is not the initial quality of the soil, but rather the composition and density of individuals of the plant community." (2)

Götsch creates consortia of crop species with synergetic potentials that cooperate with each other. Maize, for instance, produces more when planted with beans or grass (brachiaria brizantha); bananas grow healthier with orange trees, pineapple with manioc.

Despite the complexity of syntropic agriculture consortia, for the purpose of this workshop, we experimented with simple ones. We planted 3 to 5 crops, known to thrive together, like tomato, maize and green beans; maize, pumpkin and rucola; passion fruit, tomato, cucumber and chayote (chuchú).

Tomatoes, maize, banana growing together.
 3 tomato seeds, 2 green beans and 2 maize, each in a separate hole, are planted in a handful of soil between tree marigold stem cuttings

Sowing layout #1. The grass between beds (called "green" fertiliser) adds organic matter and nitrogen to the soil; it protects against pests, preserves humidity and decompacts the soil | Sketch by Send a City
Sowing layout #2 | Photo by Thiago Rips

#4 Adoption of successional elements

"Each consortium creates the conditions for a new consortium with a different composition. Hence, each consortium is determined by the preceding one and will determine the following one. The different consortia succeed one another in a dynamic, ongoing process called natural species succession." (2)

"The order in which crops are planted is important, as most species only grow vigorously if they enter the flow of species succession in such a way that they come to dominate and to thrive in the system." (1)  Equally critical for the establishment and development of a plant is the timing of when it appears.

Natural species succession in agroforests | Snapshot of video by Cooperafloresta
The sowing layout #1 (pictured above) paves the way for trees, in this case açai and cacao, to enter the system at a later stage. Tree marigold, a bush and a pioneer specie, is the first to grow (quickly and abundantly). In 6 to 8 months it will be drastically cut, its organic matter left on the floor. Same will happen with the banana trees and the vegetable plants after their harvest in the same period of time. The açai and cacao seeds will then be planted in lieu of the ginger. This secondary system is expected to grow beautifully.

40cm long tree marigold stem cuttings, 35cm apart, buried to 2/3

Tree marigold (margaridão) grown from stem cuttings in 6 months
The correct way to cut back a banana tree | Photo by Jenner Jon Lopes

There are many other strategies included in the practice of syntropic agriculture and some bombshells. "Eucalyptus promotes food production", says Götsch challenging the belief that it depletes the soil. "It produces gibberellic acid, which makes eucalyptus leafs a top quality mulch, and its roots bring water to the system rather than sequestering it." 

Pests are nonexistent in syntropic agriculture. Apparently pests go to weak plants and are therefore to be seen as an indicator of the plant's health rather than a threat. The way out is to address the plant's health by strengthening it. Pests then disappear naturally. Nothing to do though against birds eating crops. "That's life," says Götsch.

Syntropic agriculture works in temperate climates too. This is the way our ancestors did things. Just take apples for açai and start the journey.

4th Workshop on Syntropic Agriculture | Casimiro de Abreu, Rio de Janeiro 25-28 July 2016
Organized by Agenda Gotsch, a non-profit founded by journalists Felipe Pasini and Dayana Andrade to document and spread Ernst Götsch's work, through documentaries, workshops and social media
4th Workshop on Syntropic Agriculture | Photo by Thiago Rips

(1) Götsch, Ernst (1992) | Natural Succession of Species in Agroforestry and in Soil Recovery, Pirai do Norte BA, August 1992
(2) Götsch, Ernst (1994) | Breakthrough in Agriculture, Pirai do Norte BA, August 1994  
(3) Di Corpo, Ulisse (year unknown) | The Conflict Between Entropy and Syntropy: the Vital Needs Model
(4) Taguchi, Viviane (2016) | Agricultura Sintrópica, SP, August 2016 | Globo Rural #370: Editora Globo 
(5) Cooperafloresta (2016) | Pesquisas ajudam a comprovar benefícios das agroflorestas | Divulgador de Noticias, 6 Aug 2016
Articles on agroforestry
"A revolução na floresta" | Super Interessante, July 2016
"Life in syntropy: breaking the paradign of modern agriculture?" | Natural capital, 24 Feb 2016
"Ernst Gotsch e a agrofloresta: como produzir com a logica da abundância" | Namu, 08 March 2016
Further reading 
Di Corpo, Ulisse & Vannini, Antonella (2009) | An Introduction to Syntropy 
Di Corpo, Ulisse (2013) | Life Energy, Syntropy, Complementarity and Ressonance 
Ministério do Desenvolvimento Agrário (2008) | Manual Agroflorestal para a Mata Atlântica, Brasilia, Oct 2008 
Steenbock, Walter & Machado Vezzani, Fabiane (2013) | Agrofloresta: aprendendo a produzir com a natureza, Curitiba 2013
Vaz, Patricia (2000) | Regenerative Agroforestry in Brazil, Piracicaba SP, September 2000 | Ileia Newsletter: Ileia Foundation

Pictures by PS unless otherwise stated. Cover photo by Natureza Fotos
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