Silk and CO2 and greenhouse gas reduction

Silk would not exist without the Mulberry tree, the Mulberry would not be cultivated without the production of silk. This close connection is the basis of a study that highlights how the production of silk allows significant reductions in greenhouse gases and CO2 .

Textiles: a highly polluting system

The silk sector is part of the large textile sector which represents one of the most polluting sectors on the planet:

• 2 to 10 percent of LCA impact in Europe
• responsible for 20% of water pollution and the largest contributor to the presence of plastic microfibers
• responsible for 10% of greenhouse gas emissions – in Europe alone, purchases of textile products generated emissions, per person, of 270 kg of CO2 in 2020, equal to 121 million tonnes overall
• responsible for accumulation of clothes/waste (about 11 kg per capita)

How Silk Can Reduce CO2

The silk system

The silk system represents a unique feature in the textile panorama, equipped with a series of elements of absolute ecological and environmental respect, in perfect compliance with the targets of productive, economic and social sustainability of the United Nations Agenda 2030.
Among these characteristics, the ability to implement and guarantee a significant reduction in the presence of CO2 and greenhouse gases in the atmosphere

The Silk System Supply Chain

The silk production system is a particularly complex supply chain that involves a series of sectors, with characteristics and peculiarities that are very different from each other:

• Agricultural sector - Cultivation of the mulberry tree, as a fundamental sustenance tree, (through its leaves), for the cultivation of silkworms
• Agricultural/livestock sector - Breeding of lepidoptera (mainly the Bombyx Mori species), which, through a series of transformations and mutations, will lead to the creation of a silk cocoon, as the final stage in its mutation into a butterfly.
• Agro/Biotech Sector – Selective crosses between species and selection of eggs laid by butterflies destined for the reproductive phase, in order to make the species more resistant to diseases
• Artisanal/industrial sector – Production, starting from the cocoon, of silk products for both the textile sector (continuous silk thread and fibre derived from waste, with related products or by-products from subsequent processing) and the non-textile sector (silk products for protein extraction to be used in various fields: biomedical, medical, high tech, cosmetics, composite materials, food, etc.).

Mulberry, Silk, Carbon dioxide and greenhouse gases

The production system and the silk supply chain have a low environmental impact, which in many cases is protective, especially in relation to carbon dioxide emissions ( CO2 ), through some fundamental aspects:

1. Mulberry Cultivation : Silk production does not require cutting down mulberry trees as only the leaves are used as the exclusive food for the silkworms. The trees are maintained from season to season. This approach prevents deforestation, helping to keep CO2 levels low.
2. Land Use : Mulberry cultivation maintains the land use unchanged, avoiding changes in crop or destination, (1/3 of CO2 emissions come from deforestation and change of use). Mulberry is considered a cover crop and allows, between one tree and another, rotational or compensatory agriculture crops.
3. Economic Sustainability : The conservation of mulberry plantations, linked to the breeding of cocoons, offers farmers higher standards of remuneration than other intensive crops (such as corn, rice and cereals), which emit high quantities of CO2 and consume many natural resources, especially water.
4. Limited Use of Fertilizers : No high-impact chemical fertilizers are used in silk production, as their use could compromise the productivity of silkworms. This approach reduces CO2 emissions.
5. Pollution Filtering : Mulberry has the ability to capture, in addition to CO2, dust in the atmosphere and absorb pollutants, including volatile organic compounds (VOCs) such as hydrocarbons and aldehydes, thus contributing to a cleaner environment.
6. Impact of Livestock Farming : Silkworm farming does not produce significant CO2 and greenhouse gases, unlike many farms which create methane gases which are responsible for approximately 2/3 of the greenhouse effect.

Silk Vs CO2 – Numbers and Data

No. of Mulberry trees per hectare

In 10,000 square meters of land, equal to 1 hectare, approximately 13,200 adult mulberry plants can be grown

Silk Fiber Production per Mulberry Plant and per Hectare of Land

1 hectare of land allows the production of approximately 111 kg of silk fibre, in the form of silk thread and/or silk waste.

Reduction of CO2 and greenhouse gases of a mulberry tree

Through photosynthesis, a mulberry tree captures approximately 6.18 kg/year of CO2 equivalent and greenhouse gases, synthesizing them in its structure and/or in the soil.

Oxygen production of a mulberry tree

Through photosynthesis, a mulberry tree produces approximately 110 kg/year of oxygen.

CO2 reduction and oxygen production of 1 hectare of mulberry plantation

One hectare of land cultivated with mulberry trees allows to reduce 81,650 kg/year of CO2
One hectare of land cultivated with mulberry trees allows the production of 1,452,000 kg/year of Oxygen

1 kg of silk produced allows for the maintenance of an ecosystem capable of removing 735 kg of CO2 from the atmosphere
1 kg of silk produced allows to maintain an ecosystem capable of releasing 13,081 kg of oxygen into the atmosphere

Other excellences related to the mulberry tree

1. Phytoremediation – Phytoremediation : Mulberry intercepts and accumulates, in the first root zones, polluting minerals such as mercury, lead, cobalt, cadmium, nickel, manganese, zinc and copper. It is highly recommended in land remediation projects and environmental remediation.
2. Land recovery – Mulberry has the characteristic of growing in a very wide temperature range -30°C / +40°C, in every situation and type of soil. It is successfully used to restore, in a natural way, desertified areas or to recreate life in salty areas from marine or marshy floods.
3. Subsoil optimization – thanks to a well-developed, deep and high-density root system, the mulberry tree keeps the subsoil vital, ensuring life for decomposing microorganisms, small insects and a diverse number of organisms, optimizing and draining groundwater and balancing the water retention of different subsoils
4. Hydrogeological seal – Thanks to its structure and root branching, it reduces water flow during particularly serious natural phenomena, up to 10/20%

Silk Vs CO2 - The Benefits of Silk for the Environment: Studies - Bibliography - Publications

Carbon Footprint

The carbon footprint, ( carbon footprint ), is a modern environmental indicator that quantifies, in a single numerical value, the total emissions of greenhouse gases , (GHG, Greenhouse Gases), of a product, an activity, an organization. These emissions are converted into an equivalent of carbon dioxide, (CO2), expressed in kilograms or tons. The carbon footprint is an objective indicator:

• Based on ISO 14067, with parameters defined by the UN body IPCC (Intergovernmental Panel on Climate Change)
• Developed on the basis of life cycle assessment (LCA), which, thanks to the work of the Society of Environmental Toxicology and Chemistry (SETAC), has become an international standard based on the ISO 14040:2006 and ISO 14044:2006 standards.

Silk and carbon footprint mitigation

During the 17th World Textile Conference Autex in 2017 – “ Shaping the future ”, one of the most important scientific and comparison events in the textile field, a large comparative study was presented, aimed at giving an objective evaluation of the environmental impact of the silk system.
The analysis “ Silk industry and carbon footprint mitigation ” - Giacomin, Garcia, Zonatti, Silva-Santos, Laktim, Baruque, Ramos - analyses:

• Mulberry cultivation in India, through an extensive supporting literature, laboratory tests and field analysis on mulberry trees, with data collected over a period of 5 years at the Central Sericulture research and Training Institute, Mysore (INDIA), (Dr. Srikantaswamy and Bindroo)
• Cultivation, yield and production data from sericulture activities in Brazil on a sample of 4338 hectares of mulberry cultivation, 2080 rural families, 2836 tons of fresh cocoons
• collection and processing of data, over a period of one year, in the English market, on the carbon footprint associated with different types of garments produced and disposed of in different fibres. Execution by the English non-profit association WRAP (Waste & Resources Action Programme). Wrap is specialized in the study and analysis of the sustainable use of resources, in the fight against waste, in the study of pollution factors and their reuse both in terms of products and resources. It collaborates and is funded by DEFRA, the Northern Irish government, the Scottish Zero Waste department, the Welsh government and the European Community.

The study allowed to determine, in an analytical way, the importance of the agricultural element on the silk production system, quantifying, on the basis of the collected data, a CO2 mitigation factor equal to 735 times the weight of the silk fibre produced.

For every kg of silk fibre produced, carbon dioxide is removed from the atmosphere.

732.96 Kg. of CO2

For every kg of silk present in a product, 1000 grams of silk is removed from the atmosphere.

709.57 Kg. of CO2

Silk Vs CO2 - The Benefits of Silk for Economy and Society

In addition to the countless positive aspects, relating to the social, cultural and economic benefits of the silk system, a collateral but not secondary element, linked to the agricultural mitigation factor, concerns the social and economic costs deriving, directly or indirectly, from the reduction of CO2.
The estimates and data, in this area, are very different from each other but start from the common and now accepted consideration that the presence of greenhouse gases , pollutants and CO2 in the atmosphere is the main cause of the current climate change and therefore of:

• significant direct and indirect social costs
• lack of economic and social growth

A study by Stanford University “ Temperature impacts on economic growth warrant stringent mitigation policy ” Frances C. Moore, Delavane B. Diaz, concluded that these direct and indirect costs can be quantified at USD 220.00/ton.
The study and analysis in this field is in full evolution with equally authoritative studies that speak of USD 800.00/ton. (source EEIE European Institute on Economics and the Environment )

For every kg of silk present in a product, a social economic return equal to approximately is guaranteed.

156.11 USD

(calculated based on Stanford University studies)

Silk production not only contributes to global environmental protection, through the absorption of CO2 , but also generates significant economic and social benefits, supporting local communities and promoting sustainable practices.