State of global Green House Gases emissions – 1
By Dr. Prem N. Sharma*
This article presents the state of global Green House Gases (GHG) emissions, especially from agriculture-related activities including land use change, forestry, pasture lands, livestock and crop production and recommends technical and policy options for their mitigation and adaptation globally.
The concentration of Green House Gases has been on the rise since the beginning of the industrial revolution circa 1750 (Table 1). This got further accentuated by the massive deforestation that followed the colonization of the world by European countries. GHG regulate the temperature of the earth at around 14-150C (circa the year 1800 level). But there has been an increase of average global temperatures by 0.6-1.10C since the year 1800 to 2022.
The concentrations of Green House Gases in the atmosphere were stable and in balance with nature until the pre-industrial times (the year 1800). This kept the earth cool and made it liveable. Even since 1990, it has increased by over 154% due to anthropogenic factors. This has already resulted in an about 1.10C rise over the normal average global temperature of 14-150C at which the earth was regulating itself.
The rise in temperature is expected to continue and is expected to go up to 2.80C by the year 2100 if present-day policies to control global warming are not amended. This is caused by an extranet anthropogenic global GHG emission of about 80 (+/- 6.6) GtCO2 equivalent (2019) over a normal of about 416 GtCO2eq/year. Up to 24% of the world’s anthropogenic GHG is contributed by about 50 million Km2 of agriculture sector lands (37% of land mass), 31% of which is from livestock-related activities on pasture/grasslands spread over 35 million Km2. These agricultural lands give livelihoods to 50-60% (out of which over a billion are on pasture/grasslands) world’s population most of who are poor.
Twenty to 50% of the land surface area is degrading often due to overgrazing caused by increased demand for meat and milk, among other factors. A right set of policies that incentivize sustainable management of agricultural lands and their use have the potential to reduce up to 30% of Green House Gases globally.
This can be achieved by mainly focusing on the reduction in deforestation for agriculture and pastures, sustainable land and water management practices, agro-silvo-pastoral improvements, reduction in enteric fermentation in animals, and appropriate manure and fertilizer management, especially on extensive pasture lands.
Reduction in Green House Gases emissions will also depend upon the level of resource use efficiencies achieved, added intensification to reduce pressure on agricultural, especially pasture lands, and success or failure of the appropriate market and regulatory policy interventions for making appropriate use of the agricultural land resources.
A predicted rise over 2oC in temperature is likely to have disastrous consequences for the earth and its environment. Even in a 2oC world, some 420 million additional people will be exposed to record heat stress, millions more will lose their livelihoods by higher seas and the frequency of ice-free Arctic will increase from 1 in 100 years to 1 in 10 years, according to a November 12, 2022 report published in The Economist.
Table 1: Concentration of important Green House Gases in parts per billion (ppb) and their Global Warming Potential (GWP) in the atmosphere (Source: IPCC, 2004; Blasing, 2014)
|GHG (≈0.05% of all atmospheric gases)*||Global share of GHG, %||Pre-Industrial (≈1750), Ppb||≈2013,
|Current (≈ 2022),
|Global Warming Potential (GWP)
Compared to CO2
|Carbon dioxide, CO2||76**||0.277||0.395||0.421||1 for 1,000 years|
|Methane, CH4||16||697||1,762||1,896||28 for 20 years|
|Nitrous oxide, N2O||6||271||324||334||296 for 100-1,000 years|
|Fluorinated (F) Gases (O3/HFC/CFC/PFC/NF, CO, SO6)||2||≈0||0.016
|1,000-23,500 for 100-1,000 years|
*Water vapour has been keeping the earth cool historically but every added 10C increases evaporation by 7% which can amplify warming by other Green House Gases and cooling by condensation in a thermodynamic heat pump cycle. More research is needed for better quantification.
**This 76% CO2 comes from fossil fuels, coal and petroleum products for electric generation (25%), transportation (12%), industry and its processes (12%), space and water heating (5%), cement manufacture (5%) and construction sector (5%) and deforestation (5-6%) and others.
The extent of anthropogenic global emissions and their mitigation/adaptation
The total Green House Gases constitute only about 0.05% of the atmosphere out of which about 55% is anthropogenic. But they were keeping the earth’s atmosphere cool for human evolution with the help of water vapour. Most GHG are contributed into the atmosphere by soil organic matter (SOM) oxidation and respiration by all living organisms. The same is taken out of the atmosphere mostly by plant photosynthesis followed by diffusion into the oceans.
i. Increase in anthropogenic GHG emissions
The remaining consists of an anthropogenic increase of Green House Gases which is an accumulated net of 80 (+/-6.6) Giga (billion) tons (Gt) of Carbon di Oxide (CO2) equivalent (GtCO2eq) by 2019 (Table 2). This is causing a rise in temperatures and increased global warming. Action is required to meet this imbalance so that global warming can be checked.
Table 2: Global cumulated anthropogenic GHG emissions increase(or gap) by gas compared to 1990, GtCO2eq
|Gases||1990||Increase from 1990 to 2019||% increase||2019 in Sector wise, %|
|CO2 – FFI
(from Fossil Fuels and Industry)
|38 +/- 3||15||167||65|
|CO2 : LULUCF (Net from land use, land use change and forestry)||6.6 +/- 4.6||1.6||133||10-15*|
|Total CO2||44.6 +/- 7.6||16.6||76-79|
|CH4||11 +/- 3.2||2.4||129||17-19|
|NO2||2.7 +/- 1.6||0.65||133||4-6|
|F-Gases||1.4 +/- 0.41||0.97||354||3-4|
|ALL TOTAL||59 +/- 6.6||21||154||100|
*All gases (all CO2-LULUCF,70% of CH4 and 50% of NO2) emissions in agriculture sectors globally = 14-24%.
Serious efforts to mitigate the emissions started in earnest only by 2010 onwards despite United Nations Framework Convention on Climate Change (UNFCC) having been agreed upon in 1995 after the Earth Summit in Rio de Janeiro, Brazil, in 1992. Since then, the Green House Gases emissions have increased by almost 154% to 80 (+/- 6.6) GtCO2eq by 2019 compared to 1990 (Table 2).
ii. Potential global gap in mitigation of GHG
UNFCCC has been holding the Conference of Parties (COP) (i.e. all 198 UN member countries) for the last 27 years after the Rio 1992 Earth Summit, to get global agreements to stop this increase in emissions through mitigation efforts, and adaptation to future scenarios as recommended by the Intergovernmental Panel on Climate Change (IPCC). Latest UNEP (2022) GHG emissions gap report projects anthropogenic emissions by the year 2030 and predicts the shortfall or gap in their sequestration if different Nationally Determined Contributions (NDCs) (UNFCCC, 2022) are fully implemented (Table 3). If no further NDCs to control emissions are made, at least 52 GtCO2eq will be added by 2030 to GHG under the best present-day scenario. This will leave a gap of an extra 20 GtCO2eq of emission in the atmosphere to keep the temperature within 1.50C by 2030 and it will further increase to 2.40C by 2100.
Table 3: Projected global anthropogenic Green House Gases emissions gap and resulting temperature increases at different global warming scenarios in years 2030 and 2100 over 100 year GWP
|Scenario||GHG in 2030, GtCO2eq||Emissions gap in 2030 (median range), GtCO2eq||Expected temperature outcome in 2100, 0C (90% chance)|
|Year 2010 policies||66||Up to 5.5|
|Global warming, 0C (with all NDCs)||2.2-2.4||1.9-2.2||1.6-1.9|
iii. Pledges and efforts to reduce the global gap in the mitigation of GHG
For mitigating the above situation by 2030; 100 countries have pledged to end deforestation completely, 150 to reduce methane emissions by 30%, 40 to phase out coal, and 45 to eliminate all emissions in the agriculture sector. India has not yet decided to be a party to any of these except methane reduction. Small Island Nations have pledged net zero emissions by 2030, 76 countries including USA and EU countries (29) by 2050, China by 2060 and India by 2070. This all requires about US$4-6 trillion/year (COP, 2022) investment till 2030 while only about US$ 800 billion (32%) are allocated by different countries for their pledges and NDCs today. A fund of only US$100 billion (out of which only US$82 contributed) for assisting the developing countries is pledged while US$ 600 billion/year is needed by 2030. Thus the resources allocated and pledged for conditional NDCs are way below the required. This will make global warming below 1.50C by 2030 or below 20C by 2100 out of reach. More aggressive NDCs and their implementation with sufficient resources are required if these temperatures are not to be exceeded.
iv. India’s Nationally Determined Contributions (NDC)
For reducing the above emissions gap, India’s present NDCs to be achieved by the year 2030 as declared at COP 26 in Glasgow, Scotland (2021), include: reaching 500 gigawatts (GW) of non-fossil fuel energy capacity (need 700 GW by 2050); producing 50 per cent of energy requirements via renewable energy sources; an annual reduction of 1 billion tonnes of CO2eq, reduction in the emissions intensity of the Indian GDP by 45 per cent, and most importantly achieving the target of net-zero emissions by the year 2070.
v. Outcome of COP 27 – recognition of loss and damage (L&D)
During the Conference of Parties in November 2022 (COP 27), held at Sharm-El-Sheikh, Egypt, there were no new NDCs declared by any country but it urged the parties that have not yet communicated new or updated NDCs (only 29 countries have updated so far including India) to do so as to limit the global temperature rise to no more than 1.50C by 2030 or below 20C by 2100 above pre-industrial levels. This will require rapid, deep and sustained reductions in global GHG emissions by 43% by 2030 relative to the 2019 level. Progress is noted in net emissions rate reduction from about 3% to 0.5 %/year by 2021 through the implementation of present-day NDCs despite their increase in urban areas. It was further agreed to establish a new fund for Loss and Damages (L&D) to help those most affected by rising temperatures. However, small-scale farmers’ agriculture (< 2 ha land holding) and their losses e.g. from drought, flood, heat waves, and crop and livestock productivity loss due to heat stress were largely left out of agricultural negotiations which predominantly focussed on big agriculture. This shows why such countries (e.g. India), representing over 84% of small farmers (over 500 million globally and poorest), have so far not signed the sustainable agriculture pledge. Additionally, it was recognized that about US$4 trillion/year needs to be invested in renewable energy till 2030 to reach net zero emissions by the year 2050 as part of climate finance in a socially just and inclusive manner minimizing negative social impacts. As in India’s mission “Life for Environment (LIFE)”, a sustainable lifestyle was also included in the cover decisions. Its impact can be seen clearly even by eating habits (Non-Vegetarian Vs Vegetarian Vs Vegan) (Table 4).
Table 4: Carbon footprint of different foods in KgCO2eq
Anthropogenic GHG emissions from the agriculture sector globally and in India
While agriculture is adversely impacted by the vicissitudes of climate change, the sector also is a net contributor to GHG emissions. Globally these vary from 18-24% of the total (Table 5). Of these, 31% is from the livestock and fisheries sector, 27% from crop production (e.g. on peat lands, agricultural expansion, poor pasture land management, rice cultivation etc.), 24% from land use change (e.g. deforestation for conversion to pasture and shifting cultivation, urban expansion etc), and 18% from associated supply chains (transportation, storage and processing). Deforestation of the Amazon forests mainly for pasture (1.3 million ha/year) and soybean and in the Republic of Congo for agriculture are of major concern. India and China have made great progress where deforestation rates are below annual reforestation rates.
Table 5: Share of anthropogenic Green House Gases emissions in the Agriculture sector (2016)
As per the Third Biennial Update Report submitted by the Government of India (GOI) in early 2021 to the UNFCCC, the agriculture sector contributed 14 per cent of the total GHG emissions in 2016. Within the sector (Table 5), the maximum is from livestock and related activities (Enteric fermentation 54.6%, Manure 6.7%, totalling 61.3%). Therefore, effective mitigation measures and appropriate adaptation technologies must be implemented to reduce GHG emissions from the agriculture sector, especially from the livestock sub-sector. While India’s deforestation rate in 2020 was 20,800 ha of primary forest and 137,700 ha of other tree cover loss, its plantation programs make up for it. Thus there has been an increase in net forest area by 0.4%/year over the last 30 years.
Forests, crops (except rice) and grasslands are all sinks of GHG. Hence they do not emit any GHG hence any global warming, rather they sequester Green House Gases. It is the unsustainable forestry (e.g. deforestation, poor management), agriculture (by loss of soil organic matter (SOM), about 50% of which is soil organic carbon (SOC), drying of peat lands and rice crops flooding and especially livestock production activities on poorly managed pasture lands that cause emissions into the atmosphere. Fossil fuels burned for agriculture also contribute to GHGs to an extent. Hence, Green House Gases mitigation and adaptation strategies need to focus on the mismanagement of the earth by these anthropogenic factors.
*Retired International Senior Natural Resources/Watershed Management and Operations Officer of the FAO-UN on global postings across continents.