Perched on a mountaintop in northern India, the Aryabhatta Research Institute of Observational Sciences has been monitoring the Earth and skies for about 15 years. The air here at the foothills of the Himalayas is especially pristine, thanks to the absence of human industry. Paradoxically, this makes the institute especially well-suited for research into air pollution.
Just below the mountains, pollutants aggregate from far and wide, brought in by strong winds and yearly monsoons. The mountain peaks act like chimneys, through which a small amount of air rises up from the plains, carrying the pollutants to higher altitudes, where scientists can easily detect them against an otherwise clean background.
“That is the beauty of this place,” said Manish Naja, an atmospheric scientist at Aryabhatta Research Institute of Observational Sciences. Inside his high-altitude laboratory sits a cacophony of buzzing instruments.
A tube from outdoors takes in for analysis mountain air that may contain particles emitted from the burning of fossil fuels, wood and cow dung. On this particular day, a printout from a machine that measures black carbon, called an aethalometer, is dotted with sooty spots – visual clues that scientists can use to help measure local pollution.
Stretching from Afghanistan to Myanmar, the Hindu Kush Himalayan region is a 2,000-mile-long mountain range, home to the world’s highest peaks. Because of the region’s unique climatic conditions, these peaks are warming faster than the rest of the planet.
Even if global temperatures rise on the lower end of climate projections, around 1.5 degrees Celcius, about one-third of the region’s glaciers will be gone by the end of the century. This, experts say, would be a disaster for the more than 100 crore people who depend upon the glaciers’ rivers for drinking, hydroelectric energy, grazing, and farming.
Data like Naja’s is key to building regional and global climate models that might inform policymakers and residents who must prepare for the inevitable changes ahead. Across the Himalayas, scientists capture information on local air pollution and weather, then share their findings with international teams.
These teams use computers to create three-dimensional maps of the planet, charting the interactions of mass and energy that drive the climate, shaping phenomena such as atmospheric and ocean currents or ice melt and formation. The locally-derived data serve as an important cross-check to ensure that the computerised models are accurate. But that local data is not always able to be shared.
The Himalayan region is divided not only by a patchwork of artificial national borders, but by deeply-entrenched political hostilities. In the past, diplomatic fallouts have disrupted scientific collaborations, making it exceedingly difficult for scientists to work on projects involving cross-border ecosystems.
This past May, for instance, a deadly border confrontation between Indian and Chinese troops raised concerns of further disruption among scientists who for decades have built shared platforms to manage the impacts of climate change in the region.
“Sometimes conflicts like that just make it harder for us to go and work,” said David Molden, former director-general of the International Center for Integrated Mountain Development, an intergovernmental institution based in Nepal that works with the eight countries of the Hindu Kush Himalayan region to protect its fragile ecosystem and tackle climate change.
Groups like the International Center for Integrated Mountain Development have managed to persevere by taking a long-term perspective, he said. Shorter projects, on the other hand, are more vulnerable to geopolitical disruption. If a new conflict leads to one and a half years of tensions during a two-year collaboration, for example, said Molden, “you are sunk”.
Reverse engineering emissions
Not far from Naja’s laboratory sits a squat building with nearly 600 antennas stretching from the rooftop. Each antenna stands about 6 feet tall and resembles a small utility pole. But rather than carrying electrical power, these antennas send radar signals into the atmosphere and measure wind direction and speed from the signals that bounce back. By tracking this information over time, scientists hope to better understand atmospheric turbulence, said Samaresh Bhattacharjee, an electrical engineer at Aryabhatta Research Institute of Observational Sciences who works with the radar.
Understanding how air moves throughout the plains and on the mountain peaks can help scientists create more accurate weather predictions and climate models. This particular radar has been conducting observations since 2017, so its current dataset is relatively limited. But Bhattacharjee hopes that within a decade the facility will have collected enough information to be useful to researchers across the region.
Naja’s laboratory, on the other hand, has been continuously collecting data since 2006. The team’s pollution measurements (referred to as “observations”) are used by both Naja and outside collaborators for a number of purposes, including identifying where pollutants originate.
For instance, Naja points to one study showing that the high peaks of the Himalayan region are touched by pollution coming from the Thar Desert on the border of India and Pakistan, from southern Europe and even from northern Africa.
The raw data from places like the Aryabhatta Research Institute of Observational Sciences can also be used to reverse engineer carbon emissions. By matching the raw data with the pollution models, scientists identify the relative contribution of each pollutant to the total amount of emissions. This sophisticated process, Naja explains, translates into a clear map of which sectors, including agriculture and transportation, contribute most to global warming.
International collaborators also use the data to perform inverse modelling. In this type of modelling, scientists compare locally-derived data on greenhouse gases with data obtained from satellites to see if the two match. This helps ensure the validity of climate models built from satellite data.
The Himalayas are home to a number of disputed international boundaries, including portions of the Pakistan-India border and the China-Bhutan border. Some of the dispute between China and India centres around the region of Ladakh, where the two countries and Pakistan butt up against one another. Today, the world’s two most populous nations regularly clash along a highly militarised dividing line known as the Line of Actual Control.
Scientists, however, insist that research and data sharing need to be decoupled from military disputes. That way, all the nations of the Himalayas can tackle a common threat: climate change.
While Aryabhatta Research Institute of Observational Sciences seeks to provide a steady stream of data gathered from its facility in the city of Nainital – less than 100 miles from Nepal – the Himalayas are a patchwork of unique microclimates.
To capture local variations, models need to be validated against a dense grid of datapoints providing information on pollution trends, temperature, wind speed, precipitation, snow cover, and more.
Elevation in the Himalayas can change dramatically from sea level to about 3,300 feet or more within a very short distance, explains Shichang Kang, a researcher at the State Key Laboratory of Cryospheric Sciences in Lanzhou, China.
Like Naja, Kang studies the movement of air pollution across the world’s highest peaks. His work tracks pollutants’ journeys using carbon-14, which is found in fossil fuels and biomass at varying concentrations depending on the altitude at which the particles travelled. Because the Himalayan terrain is so complex, said Kang, computer models require more data than would be necessary to understand relatively flat regions of India or China.
But synthesising that data is challenging when neighbouring nations are suspicious and even hostile.
Molden recalls how bad blood almost thwarted a key program involving the sharing of water data. In that instance, he said, an international team of scientists had gathered in Nepal, at International Center for Integrated Mountain Development headquarters, when one scientist claimed – without evidence – that data sharing would create a national security threat.
Molden said he worried that the scientist would press the issue with politicians, who might have called for an end to the collaborative project. “Luckily,” he said, “we had enough friends in enough places” that they were able to defuse the tension.
In 2017, Chinese and Indian troops faced off on a strategically important strip of land in the mountain nation of Bhutan. Shortly after, China suspended the continuous supply of rainfall, water level and discharge data that had helped downstream Indian communities predict and prepare for flooding events.
“A lot of people in this region say information is power, and they would like to retain that, control their power,” said Arun Shrestha, a climate change specialist who studies water systems and glaciers for International Center for Integrated Mountain Development. “They would think that having information gives you the upper hand in discussions and negotiations.”
The chronic border conflict between China and India flared up again last May, with troops clashing along the Line of Actual Control in the northeastern part of Ladakh. In June 2020, 20 Indian soldiers and at least four Chinese soldiers were killed in the fighting. In the subsequent months, India raised tariffs on many products it imports from China on which many of its industries – including renewable energy – depend.
That border confrontation continues to this day, posing a national security threat for both nations. In this particular instance, wildlife management programs may have suffered the biggest scientific blow, but the tension in the region threatens to disrupt climate science, too.
China and India have a lot to gain from climate cooperation, said climate policy researcher Robert Mizo of the University of Delhi in India. The two nations face similar challenges, including curbing pollution and safeguarding the glaciers, which feed the river systems that serve as vital sources of freshwater to both nations. And China and India often form a united front on climate diplomacy, with similar perspectives on issues such as emission caps.
Indian and Chinese leaders have so far missed some opportunities to work together to mitigate the impacts of climate change, Mizo said, noting that the lack of cooperation does not bode well for the environment. Either countries need to solve the problem of border security, he said, or they need to learn to separate border issues from climate change efforts. So far, he concedes, this hasn’t happened.
Even when data is shared freely, geopolitics can intrude on the science, said Ruth Gamble, a lecturer at La Trobe University in Melbourne, Australia. An expert in the history of Himalayan environmental changes, Gamble looked at efforts to study black carbon in the region.
According to Gamble, black carbon contributes significantly to the region’s warming. But when she looked at the available studies, she was surprised to discover that the bulk of the Chinese mapping efforts took place near the Indian border or in the middle of the Tibetan Plateau where nomad communities burn yak dung. Meanwhile, there was a dearth of data from the Chinese industrial areas where much coal is burned.
“I’m not actually sure that anyone set out to do this,” Gamble said. But, she added, “you get this kind of implicit nationalism in the way that these things are done. And then Indian sources will say ‘No, no, it is not us, it is China. They are the ones that produce a lot of carbon’”.
Today, the Ladakh standoff represents a major threat to Himalayan science, yet Molden said he feels that governments really do want to “leave a door open for science”. Last October, with political relations at one of the lowest points in recent history, government officials from India, China and the other Himalayan countries signed a joint declaration committing to increased cooperation in the fight against climate change and environmental degradation.
For now, the declaration remains aspirational. Molden acknowledges that after the violence at the border, there may be some areas in which both sides are more cautious about sharing information. “Luckily, on the science side, there’s typically been an open space for that kind of dialogue,” he said, “in spite of tension”.