The study revealed that while greenhouse gas concentrations in the Central Himalayas are generally lower than in urban areas, they are consistently higher than at other remote background sites. This highlights the combined influence of local emissions and pollutants transported from upwind sources
Indian scientists have unveiled a complex interplay of natural processes and human activities, including agricultural practices, that are significantly impacting greenhouse gas levels in the sensitive Central Himalayan ecosystem. This groundbreaking five-year study, conducted by the Aryabhatta Research Institute of Observational Sciences (ARIES), provides crucial insights into how agricultural methods and other factors are shaping the region’s climate.
The research, led by Dr. Priyanka Srivastava and Dr. Manish Naja, involved continuous, high-resolution measurements of key greenhouse gases – carbon dioxide (CO₂), methane (CH₄), and carbon monoxide (CO) – at a high-altitude research site in Nainital. Their findings fill a critical void in global climate monitoring, as South Asia’s mountain regions have historically been underrepresented in ground-based atmospheric data.
“Our observations are vital for validating climate mitigation efforts and building accurate emissions inventories, especially in a region as ecologically sensitive and agriculturally significant as the Himalayas,” stated Dr. Srivastava.
The study revealed that while greenhouse gas concentrations in the Central Himalayas are generally lower than in urban areas, they are consistently higher than at other remote background sites. This highlights the combined influence of local emissions and pollutants transported from upwind sources.
Agriculture’s Fingerprint on Methane Levels
One of the most significant findings with an agricultural focus is the pronounced seasonal pattern of methane (CH₄). The data shows that methane levels are highest in autumn, a period directly linked to agricultural activities such as rice cultivation. This suggests that common farming practices in the region are contributing significantly to methane emissions, a potent greenhouse gas.
Beyond seasonal variations, the research also found that carbon dioxide levels reach their lowest during daylight hours due to active photosynthesis, demonstrating the natural carbon uptake by vegetation. However, CO₂ concentrations rise in spring, coinciding with increased biomass burning, which can include agricultural waste burning, and limited vegetation cover.
Long-Term Trends and Policy Implications
The long-term data indicates a steady and concerning rise in both carbon dioxide (2.66 ppm per year) and methane (9.53 ppb per year) in the Central Himalayas. These increases are even higher than those observed at Mauna Loa, a globally recognized background site, underscoring the growing impact of human activities in the Himalayan region. While carbon monoxide shows a gradual decline, possibly due to improvements in combustion efficiency, the overall trend for major greenhouse gases points to an intensifying challenge.
The study emphasizes that factors like solar radiation, temperature, and the atmospheric boundary layer are as crucial as agricultural practices or urban emissions in shaping these gas patterns.
“These comprehensive, high-resolution observations provide an essential baseline for validating satellite data, refining emissions inventories, and improving atmospheric models,” Dr. Naja explained. “By disentangling these influences, we’re giving policymakers and climate modelers a powerful tool to understand the real-time story of South Asia’s changing climate and offer valuable guidance for climate mitigation strategies and policy development, particularly concerning agricultural emissions.”
This research serves as a critical call to action for the agricultural sector in the Central Himalayas, highlighting the need for sustainable farming practices that can help mitigate greenhouse gas emissions while ensuring food security for the region.