La Niña and Its Impact on North India’s Winter Air Quality
This analysis of Gufran Beig’s article titled “The La Niña’s Shadow” in The Indian Express (October 1, 2024), explains how La Niña affects North India’s winter weather and air quality in complicated and unpredictable ways. These effects are made worse by climate change and activities like stubble burning. Because of this, we need to focus more on managing air quality in a way that protects people’s health across the whole region.
Introduction
La Niña is a natural climate phenomenon that affects weather patterns around the world. It happens when the surface temperatures of the Pacific Ocean near the equator become cooler than usual. This cooling has significant effects on weather patterns globally, including in India, especially during winter months. In North India, La Niña plays a key role in shaping the region’s winter climate and air quality. The complex interactions between La Niña, pollution, and human activities like stubble burning have become a major topic of concern for scientists and environmentalists.
In this essay, we will explore how La Niña affects air quality in North India, with a particular focus on how it influences pollution levels in Delhi and other northern cities. We will also consider the role of climate change and the importance of adopting better strategies to manage air quality.
What is La Niña?
La Niña is part of a larger climate pattern called the El Niño-Southern Oscillation (ENSO). ENSO has two phases: El Niño and La Niña. During La Niña, the waters in the central and eastern Pacific Ocean are cooler than normal. This cooling affects weather patterns across the globe, including India. Normally, La Niña is associated with stronger monsoons and colder winters in India. However, recent years have shown that the impact of La Niña can be unpredictable, especially when combined with factors like climate change.
How La Niña Affects North India’s Weather
In North India, La Niña typically brings colder and drier winters. The winds that blow from Siberia and South China towards India are stronger during La Niña, which leads to a significant drop in temperatures. During these periods, there is often less winter rainfall, and snowfall in the Himalayas is also reduced. This makes winter last longer, with the coldest temperatures occurring in the plains of North India.
However, recent studies have shown that La Niña’s effect on weather patterns is not always straightforward. For example, the winter of 2022-23 saw an unusual “triple-dip” La Niña event. This rare phenomenon resulted in unexpected weather patterns, such as improved air quality in cities like Delhi, which typically suffers from severe pollution during the winter months.
The Connection Between La Niña and Air Quality
Air quality in North India is affected by various factors, including local emissions, weather conditions, and climate phenomena like La Niña. When La Niña brings colder and drier conditions, it can cause pollutants to get trapped near the ground because the inversion layer—the part of the atmosphere that traps air pollution—becomes lower. This can make the air quality worse, especially during winter when the use of heaters and burning of stubble adds more pollutants to the air.
Interestingly, during the 2022-23 winter, La Niña brought an unexpected improvement in air quality in some cities like Delhi. This improvement was due to changes in wind patterns, which helped to clear out pollutants more effectively than usual. In cities like Ghaziabad, Rohtak, and Noida, air quality improved by as much as 28-33%, which surprised researchers.
However, this improvement in air quality was not seen across the whole country. While North India enjoyed cleaner air, cities in peninsular India, such as Mumbai, Bengaluru, and Chennai, experienced worse air pollution. This shows that La Niña’s effects on air quality are not uniform and can vary greatly depending on the region.
Climate Change and Extreme Pollution Events
There is growing evidence that climate change is making weather patterns more extreme and unpredictable. Scientists believe that climate change may be making La Niña events more intense, leading to more unusual weather patterns. These changes can have a direct impact on air quality. For example, the 2022-23 La Niña event caused unexpected improvements in air quality in North India, but it also raised concerns about how future La Niña events might behave in a warmer world.
Climate change also increases the risk of extreme pollution events. As the world gets warmer, we are seeing more stagnant weather conditions, where winds are too weak to disperse pollutants. This makes air pollution worse, especially in cities like Delhi that already struggle with high levels of pollution. Therefore, it is important for policymakers to consider the effects of climate change when developing strategies to improve air quality.
The Role of Stubble Burning in Air Pollution
One of the major sources of air pollution in North India is the burning of crop stubble in states like Punjab and Haryana. After the harvest, farmers often burn the leftover straw from their crops to clear their fields for the next planting season. This practice releases large amounts of pollutants into the air, which can be carried by winds to cities like Delhi, worsening the air quality.
La Niña can either help or hinder the dispersion of these pollutants. If La Niña strengthens during winter, it can bring stronger winds that help clear out the smoke from stubble burning. However, if La Niña is delayed, as predicted for the winter of 2024-25, the stagnant winds could trap these pollutants, leading to severe air pollution in northern cities.
Addressing the problem of stubble burning requires cooperation between states and better agricultural practices. Farmers need incentives to adopt alternatives to burning, such as using machines to clear their fields or turning the stubble into compost. Without these changes, stubble burning will continue to be a major contributor to North India’s winter pollution.
Rethinking Air Quality Management
In the past, air quality strategies have mainly focused on reducing local emissions, such as vehicle exhaust and industrial pollution. While this approach is important, it is no longer enough to address the complex challenges posed by climate change and large-scale climate phenomena like La Niña.
Scientists are now calling for a shift towards managing air quality on a larger scale. Instead of focusing only on individual cities, policymakers need to consider airsheds—areas where air pollution is influenced by the same sources. Airsheds often cross state or even national borders, so it is important for governments to work together to tackle air pollution as a regional problem.
In addition to this, there is a need for more health-focused air quality strategies. Previous policies have sometimes focused too much on larger particles like PM10, which comes mostly from dust. However, finer particles like PM2.5, which come from burning fossil fuels and stubble, pose a greater threat to human health because they can penetrate deeper into the lungs. Future air quality strategies need to prioritise reducing PM2.5 to protect public health.
Looking Forward: Predictions for the Winter of 2024-25
As we look ahead to the winter of 2024-25, there is uncertainty about how La Niña will impact air quality. The delayed onset of La Niña, expected between September and November 2024, could lead to severe pollution in the early winter months. If La Niña strengthens by December, it might bring stronger winds and clearer skies, which could improve air quality later in the winter.
However, La Niña could also lead to a longer and colder winter, which might make it harder for pollutants to disperse. This would keep air quality poor, especially in cities like Delhi. The slow retreat of the monsoon and the risk of stubble burning add further complications to the air quality outlook.
Conclusion
La Niña has a complex and often unpredictable impact on North India’s weather and air quality. While it can sometimes bring relief by clearing out pollutants, it can also contribute to worsening pollution if its onset is delayed or if it leads to stagnant weather conditions. The challenges posed by La Niña are made even more difficult by the effects of climate change, which is increasing the likelihood of extreme weather and pollution events.
To address these challenges, it is clear that a new approach to air quality management is needed. Policymakers must look beyond local emissions and consider larger meteorological factors like La Niña, as well as the impact of climate change. By adopting a more regional and health-focused approach to air quality, we can better protect the health of people living in North India and reduce the impact of pollution on the environment.
As we move forward, it is essential that we continue to improve our understanding of how climate phenomena like La Niña affect air quality. With better research and more coordinated policies, we can develop effective strategies to manage air pollution in an era of rapid climate change.
