Abstract
Two climate metrics, Global surface Temperature Change Potential (GTP) and the Absolute GTP (AGTP) are used for studying the global surface temperature impact of CH4 emission from livestock in India. The impact on global surface temperature is estimated for 20 and 100 year time frames due to CH4 emission. The results show that the CH4 emission from livestock, worked out to 15.3 Tg in 2012. In terms of climate metrics GTP of livestock-related CH4 emission in India in 2012 were 1030 Tg CO2e (GTP20) and 62 Tg CO2e (GTP100) at the 20 and 100 year time horizon, respectively. The study also illustrates that livestock-related CH4 emissions in India can cause a surface temperature increase of up to 0.7 mK and 0.036 mK over the 20 and 100 year time periods, respectively. The surface temperature response to a year of Indian livestock emission peaks at 0.9 mK in the year 2021 (9 years after the time of emission). The AGTP gives important information in terms of temperature change due to annual CH4 emissions, which is useful when comparing policies that address multiple gases.
Generated Summary
This research investigates the climate change impact of livestock-related methane (CH4) emissions in India, focusing on the Global Temperature Change Potential (GTP) and Absolute GTP (AGTP) metrics. The study estimates the impact of CH4 emissions on global surface temperature over 20 and 100-year time horizons. The methodology involves using district-level livestock population data to estimate CH4 emissions, which are then converted into GTP equivalents. Furthermore, it assesses the surface temperature response to CH4 emissions and generates spatial maps of livestock CH4 emissions using Geographical Information System (GIS). The study aims to predict climate change responses and potential rises in global surface temperature due to anthropogenic emissions, providing insights for climate mitigation policies and sustainable livestock farming practices. The study utilizes the IPCC Tier 1 approach to estimate livestock CH4 emissions across different categories, with data sourced from the Department of Animal Husbandry and Statistics, Government of India.
Key Findings & Statistics
- In 2012, livestock-related CH4 emissions in India totaled 15.3 Tg.
- The GTP of livestock-related CH4 emissions in India in 2012 were 1030 Tg CO2e (GTP20) and 62 Tg CO2e (GTP100).
- Livestock-related CH4 emissions in India can cause a surface temperature increase of up to 0.7 mK and 0.036 mK over the 20 and 100-year time periods, respectively.
- The surface temperature response to a year of Indian livestock emission peaks at 0.9 mK in 2021 (9 years after the emission).
- The livestock CH4 emission in India in 2012 is 15.3 Tg yr-1.
- Cattle and buffalo are the major sources of CH4 emissions, with 7.83 Tg yr-1 and 6.41 Tg yr-1, respectively.
- Enteric fermentation is the major contributor to CH4 emission (92.8%).
- Uttar Pradesh, Rajasthan, and Madhya Pradesh contribute 36% of national CH4 emission.
- The top 100 emitting districts account for 179 million livestock and 37% of national livestock CH4 emission.
- In 2012, CH4 emissions from enteric fermentation were 14.20 Tg yr-1, and from manure management, 1.18 Tg yr-1.
- At a national level, GTP due to livestock CH4 emission are 1030 Tg CO2e (GTP20) and 62 Tg CO2e (GTP100).
- The livestock CH4 emission can cause the surface temperature rise up to 0.69 m K and 0.036 m K over 20 and 100 year time period, respectively.
- At a state level, the emission can cause the surface temperature response (AT) to vary from 8.49 × 10-5 to 1.25 × 10-1 m K in 20 year time horizon and from 4.23 × 10-5 to 6.25 × 10-2 m K in 100 year time horizon.
- At district level, the AT varies from 1.53 × 10-7 to 0.005 m K in 20 years and from 7.66 × 10-9 to 0.0002 m K in 100 years’ time frame.
- AGTP is estimated at 4.6 × 10-14 K kg-1 and 2.3 × 10-15 K kg-1 for 20 and 100 year timeframe, respectively.
Other Important Findings
- The study highlights that livestock-related CH4 emissions in India can lead to a noticeable increase in surface temperature, with the potential to rise by 0.7 mK over 20 years and 0.036 mK over 100 years.
- The surface temperature response to a year of Indian livestock emissions peaks approximately 9 years after the emission, in the year 2021, reaching 0.9 mK.
- Enteric fermentation is identified as the primary source of CH4 emissions from livestock, accounting for the majority of the total emissions.
- The research underscores the significance of cattle and buffalo as major contributors to CH4 emissions within the livestock sector in India.
- The GTP is a more policy-relevant tool than GWP, as it provides climate impact in terms of temperature change, particularly for short-lived GHGs like CH4.
- The AGTP is useful for assessing climate impact in terms of potential surface temperature rise, offering insights for comparing policies targeting multiple gases.
- The study found wide variations in district and state-level livestock populations, and hence, CH4 emissions are observed in India.
- At a national level in the baseline year 2012, livestock CH4 emission in India is 15.3 Tg yr-1.
- The study presents a comparison of the findings with previous studies, noting that while the CH4 emission estimates vary due to different methodologies, the results are generally consistent.
- The GTP20 is 17 times higher than that of GTP100, while GWP20 is only 3 times higher than that of GWP100.
- The contribution of methane emission from the country to the AT for 20 and 100 year time frame are 0.69 m K and 0.036 m K, respectively.
Limitations Noted in the Document
- The study acknowledges the potential for uncertainty in the livestock population data and emission factors used, as well as the methodology used.
- The IPCC Tier 1 methodology, while suitable for broad application, may overestimate CH4 emissions compared to more detailed Tier 2 or 3 methods.
- The study’s focus is limited to livestock emissions, without accounting for other GHGs.
- The analysis is based on the assumption of a constant rate of CH4 emission, which may not fully capture the complexities of real-world scenarios.
Conclusion
In conclusion, this study underscores the significant impact of livestock-related CH4 emissions on India’s climate. The application of GTP and AGTP metrics provides a nuanced understanding of the temperature change potential associated with these emissions. The findings reveal that livestock emissions have the potential to cause substantial surface temperature increases, highlighting the urgent need for effective mitigation strategies. The study emphasizes the role of enteric fermentation and specific livestock categories, like cattle and buffalo, as key contributors to these emissions. The research also highlights the importance of considering the time horizon when assessing the climate impact of GHGs, as the GTP values decrease with longer time frames. The study’s comparison of GTP with GWP underscores the former’s advantage in providing a more direct measure of temperature change, making it a valuable tool for policy-making. The research emphasizes that the continuous AGTP calculation is useful for policy makers when comparing multiple greenhouse gases. The study’s findings can serve as a foundation for future research and the development of targeted policies to reduce methane emissions and mitigate climate change. Furthermore, the study suggests that regional variations in livestock populations and management practices necessitate tailored interventions. The results further suggest that policy makers should consider both short-term and long-term climate impacts when developing mitigation strategies. The study highlights the potential for livestock-related emissions to cause climate damage, and its findings support the need for climate mitigation strategies.
DOI
10.1016/j.ecoenv.2017.09