Recurrence of the term ‘Carbon footprint’ (CF) is quite usual during debates and discussions on climate change and global warming. This article clarifies its meaning and also gives a glimpse of its definition’s evolution. Standard measurement units of CF have been mentioned. CF has crucial importance in indicating the GHG emissions and recognizing the areas of improvement which can be worked on by adopting eco-friendly measures to reduce GHG release by different sectors.
The agriculture sector has been zoomed in as it is one of the most significant contributors to global anthropogenic CF. Studies lighted on carbon offsetting through intelligent cultivation practices like organic content enrichment and diversification of cropping patterns. Reducing or reusing GHG emissions is an imperative need!
Keywords- Carbon Footprint (CF), Greenhouse Gases (GHG), direct and indirect emissions, Agriculture sector’s CF, carbon offsetting, carbon sequestration
What is Ecological Footprint and Carbon Footprint?
Sustainability requires that anthropogenic usage of natural resources should not exceed Earth’s regenerative capacity and also, that the natural assimilative capacity should be able to tolerate current rates of waste production by humans. [1] Ecological footprint and Carbon footprint are indicators of anthropogenic impact on the environment-
Ecological Footprint
Analysing the ecological footprint of a defined human population or economy in terms of a productive land area enables the estimation of resource consumption and waste assimilation requirements of that population. [2]
Carbon Footprint
Wackernagel and Rees defined Carbon footprint (CF) as a subset of the above-mentioned ecological footprint. As the issue of global warming dominated, more and more utterance of carbon footprint ensued. [3]
Despite its ubiquitous appearance, there’s huge ambiguity in the meaning of the word ‘Carbon Footprint’. According to the ecological footprint methodology, Carbon Footprint, a component of the total ecological footprint, is the amount of bio-productive land required to sequester human-emitted carbon dioxide, at the world average sequestration rate.[1] Thomas Wiedmann and Jan Minx argued that 'Carbon footprint' is a measure of all the direct as well as indirect CO2 emissions. Inclusion of other greenhouse gas (GHG) emissions in the calculation would rename this indicator as 'Climate Footprint'. [4] Terms like embodied carbon, carbon content, embedded carbon, carbon flows, virtual carbon, and GHG footprint can be used synonymously with Carbon Footprint. [5]
Measuring Unit of Carbon Footprint
As mentioned by Carbon Trust (2007), [6] all the greenhouse gas discharges are measured by mass and are converted into C02 equivalent emissions using 100-year global warming potential (GWP) coefficients (from the Intergovernmental Panel on Climate Change (IPCC). For example, 1 kg of methane has the global warming potential of 23kg of CO2 and alternatively, we can say that CH4 has a GWP coefficient of 23.
Significance of Carbon Footprint
Carbon footprint represents the absolute GHG emissions quantitatively, and thus, helps in the identification of possible sources and areas of GHGs. [2] Analyses of the same help the environment with the creation and implementation of measures targeted towards the decrease in GHG production and advancement in sustainability efficient technologies.
Lately, CF has established profound relevance both in the public and private sectors because it identifies all the areas of emission reduction and suggests necessary changes to improve the eco-profile of market products considering the socio-environmental responsibility of people and organizations.[7] The L.E.K. Consulting Carbon Footprint Report 2007 shows that 44% of consumers switch to products possessing relatively lower carbon footprints, even if they have a different prior preference. People are willing to recalibrate their buying behaviour if products carry carbon footprint information, and are ready to pay more for products or services that would assist them in reducing their carbon footprint. [8]
Hence, even the corporate sector is considering this GHG indicator important with the amplification of environmental issues involving climate change day by day.
Different Sectors’ CF Contributions
An amount of 5.8 Gt CO2-eq methane per year, which is about two-thirds of absolute human-derived CH4 emissions, is a production of mere agriculture and fossil fuel consumption. Other activities like waste treatment and biomass burning donate comparatively less. [9]
The Wine sector contributes approximately 0.3% to the global annual anthropogenic CF. [7]
If we consider services, the highest GHG emission is a donation by aviation. Therefore, analysis of the Carbon footprint of airlines has been common lately and European Union has initiated the formulation of some measures aiming at reducing the emissions embodied in the aviation sector. [5]
Focus on agriculture
Agriculture covers about 35% of the global land area. Total direct and indirect (indirect including electricity consumption, fertilizer production, transportation, disposal, etc.) GHG discharge from agriculture is 30% of the global GHG emission, and on ramifying the major GHGs, we observe that carbon dioxide contributes 25%, nitrous oxide -70%, and methane-50%. On the other side, just direct sources (use of fossil fuels, animal breeding, storage of livestock, manure, fertilization with mineral and/or organic fertilizers, decomposition of crop residues, etc.) contribute to 10-12% only.[10]
Principal GHG release occurs as methane (from rice cultivating systems and domestication of cattle) and nitrous oxide (from fertilizers involved procedures). [5]
A heavy contributor to carbon footprint in agriculture is the sugar industry, run by the cultivation of sugarcane. An examination of LCA (Life Cycle Assessment) in the sugar industry followed that- for a sugar mill producing 1 ton of sugar, energy usage was 761.667 MJ and GHG emissions were 46.536 kg-CO2eq. [11]
Carbon Offsetting
Carbon offsetting means reducing carbon dioxide or GHG emissions to compensate for their release by industries or any random anthropogenic activity. And currently, this is the need of the hour considering this rapid climate change due to GHGs.
This can be done by increasing the organic content in soil and by minimizing soil disturbance as it results in effective carbon sequestration (i.e., transfer of atmospheric CO2 into the soil). Latter can be attained by planting cover crops, using organic manure, adopting no-tillage, reducing the fallow period, intercropping with legumes, etc. A recent study has shown that preferred utilization of organic manure over mineral fertilizers increases the carbon sequestration capacity of soil in the range of 70–551 kg C/ ha. Along with carbon offsetting, carbon sequestration recovers the soil from carbon deficiency due to erosion. [5]
Studies have also found that adapting to certain permutations of crop rotations can also be highly effective.[5][12]
Analysis of five types of cropping systems in North China Plain was done from 2003 to 2010. These were- (a) winter wheat- summer maize (WS, 1-year cycle), (b) peanut-winter wheat- summer maize (PWS, 2-year cycle), (c) ryegrass- cotton - peanut - winter wheat- summer maize (RCPWS, 3-year cycle), (d) sweet potato - cotton- sweet potato - winter wheat- summer maize (SpCSpWS, 4-year cycle), and (e) continuous cotton cropping (Cont C).
They were arranged in sequence of increasing annual Carbon footprint_ SpCSpWS < Cont C < RCPWS < PWS < WS. Hence, we can conclude that Carbon Footprint can also be lowered by diversifying crop rotation systems. [12]
Conclusion
Carbon Footprint has been widely accepted as a GHG and climate change indicator. More and more volunteering has taken place in the calculation of carbon footprints of different sectors. Lower Carbon footprint possessing products and services are preferred by humans as well as the environment. Carbon footprinting analysis in the agricultural sector is prominently existent, as well as is further required to cut down the possible GHG emissions according to the assimilative capacity of nature. More and more invention of scientific cultivation practices and technologies is essential to further compensate for GHG discharge in nature.
References
Mancini MS, Galli A, Niccolucci V, Lin D, Bastianoni S, Wackernagel M and Marchettini N (2015). Ecological Footprint: Refining the carbon Footprint calculation, Ecological Indicators; 1-4
Wackernagel M and Rees WE (1996). Our Ecological footprint: reducing human impact on the earth; 9-10
Pandey D, Agrawal M and Pandey JS (2010). Carbon footprint: current methods of estimation; 136-160
Wiedmann T and Minx J (2007). A Definition of 'Carbon Footprint'; 7
Pandey D and Agrawal M (2014). Carbon Footprint Estimation in the Agriculture Sector
Carbon Footprint Measurement Methodology, Version 1.3, 15 March 2007
Rugani B, Vázquez-Rowe I, Benedetto G and Benetto E (2013). A comprehensive review of carbon footprint analysis as an extended environmental indicator in the wine sector; 61-77
The L.E.K. Consulting Carbon Footprint Report 2007, Carbon Footprints and the Evolution of brand-consumer relationships
Montzka S, Dlugokencky E and Butler J (2011). Non- CO2 greenhouse gases and climate change. Nature 476: 43-50
Al-Mansour F and Jejcic V (2016). A model calculation of the carbon footprint of agricultural products: The case of Slovenia, Energy; 1-9
Varun and Chauhan MK (2014). Carbon Footprint and Energy Estimation of the Sugar Industry: An Indian Case Study
Yang X, Gao W, Zhang M, Chen Y and Sui P (2014). Reducing agricultural carbon footprint through diversified crop rotation systems in the North China Plain, Journal of Cleaner Production; 1-9
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