Study points at steady rise in carbon dioxide, methane over central Himalayas
For the first time Indian scientists have captured high-resolution continuous online data of key greenhouse gases in the Himalayas. The data reveals that greenhouse gas concentrations in the Central Himalayas are generally higher than those at other remote background sites.
Long-term trends pointed to a steady rise in both carbon dioxide and methane, underscoring the growing impact of anthropogenic emissions in the region, according to the study. In contrast, carbon monoxide showed a gradual decline, possibly reflecting improvements in combustion efficiency or changes in regional emission sources.
The data shows pronounced daily and seasonal cycles, with carbon dioxide reaching its lowest levels during daylight hours due to active photosynthesis, while methane and carbon monoxide tend to peak during the day as mountain winds transport pollutants upward from lower elevations.
Scientists at the Aryabhatta Research Institute of Observational Sciences (ARIES), Nanital, collected data over five years at a high-altitude research site, which highlighted how both environmental factors and human activities jointly impact greenhouse gas levels in this sensitive ecosystem.
Dr Priyanka Srivastava and Dr Manish Naja studied how natural processes and human activities together shape greenhouse gases – carbon dioxide, methane and carbon monoxide — in the Central Himalayan region.
The observations fill a critical gap in ground-based atmospheric data for South Asia’s mountain regions, which have long been underrepresented in global climate monitoring, according to the Ministry of Science and Technology. The study has been published by Germany-based Springer Nature.
Ground observations with diurnal variability over the Himalayas are crucial to validate climate mitigation efforts, build accurate emissions inventories and better forecasting. The unique vantage point of this Himalayan site in Nainital allowed researchers to disentangle the effects of biospheric uptake, regional emissions and complex meteorological patterns that shape the region’s air quality and climate.
Seasonal patterns, according to the study, were also evident. Carbon dioxide concentrations rose in spring, coinciding with increased biomass burning and limited vegetation cover, while methane levels were highest in autumn possibly due to agricultural activities such as rice cultivation. Carbon monoxide peaked in late spring, suggesting a strong influence from regional pollution transport during this period.
The study found that factors such as solar radiation, temperature and the atmospheric boundary layer — essentially the cap on how high pollutants can rise — are just as important as agricultural practices or urban emissions in shaping these gas patterns.
By disentangling these influences, the research gives policymakers and climate modellers a powerful tool – localised, high-resolution data that tells the real-time story of South Asia’s changing climate and offer valuable guidance for climate mitigation strategies and policy development in South Asia, the ministry said.
Technology