As climate change driven by global warming advances, the severity of its impacts and the need for action are being raised around the world. Amid this, the El Niño phenomenon is said to be causing negative effects across various sectors.
Here, we have selected and are sharing two articles about the impacts of El Niño from TheCityFix, a media outlet produced by the World Resources Institute (WRI).
Polluted skies over Kuala Lumpur, Malaysia (Photo: ThisParticularGreg / Flickr [CC BY-SA 2.0])
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Southeast Asian cities have some of the most polluted air in the world. El Niño is making it worse
“TheCityFix translated article, by Fadhil Muhammad Firdaus, Beth Elliott and Daniel Ibanez (Note 1)”
On August 31, 2023, residents of Jakarta, Indonesia, woke up to a thick haze and the news that their city had again been ranked among the world’s most polluted. Singapore recently urged its citizens to prepare face masks in anticipation of smoke from wildfires and agricultural burning in neighboring Indonesia and Malaysia. In Thailand, where the dry season begins in November, air pollution is expected to disrupt flights and other transport through April 2024.
Such sharp deterioration in air quality is a regular occurrence in cities across Southeast Asia, including Jakarta and Bangkok. A lack of moisture in the air and other meteorological conditions combine with pollution from fossil fuels and other sources to worsen air quality. In 2023, El Niño weather patterns have prolonged and intensified these high-pollution events in the region.
Air pollution is already severe in Southeast Asian cities
Air pollution causes short-term acute side effects, including cardiovascular and respiratory illnesses, headaches, and eye irritation. Long-term, chronic effects are even more concerning. Exposure to air pollution is associated with oxidative stress and inflammation in human cells, and it can lead to chronic diseases such as cancer, cardiovascular and respiratory disease, diabetes, and obesity.
In Southeast Asia, nearly the entire population (99%) lives in areas where air pollution exceeds the World Health Organization’s (WHO) safe air standards. In fact, 37 of the 40 most polluted cities in the world are in Southeast Asia; the region’s average life expectancy is shortened by 1.5 years, and 352,000 people died prematurely in 2017.
The reasons for poor air quality in Southeast Asia are both natural and human-made. Here’s why the region experiences some of the world’s worst air pollution — and what cities can do to address it.
1) Weather conditions exacerbate pollution
Rising temperatures, insufficient rainfall, more hours of sunlight, and changes in wind speed and direction are all factors that worsen air quality in tropical monsoon climates. Southeast Asian cities are located near the equator, and air pollution intensifies during hot, dry periods. This is because particulate matter such as PM2.5, PM10 and black carbon — from vehicle exhaust, coal-fired power plants, industrial processes and open burning of waste — accumulates in the surrounding air.
An analysis of air quality monitoring data from 2019 to 2023 by WRI Indonesia confirmed a seasonal pattern in Jakarta’s monthly average PM2.5 concentrations: pollution peaks in June, July and August (the dry season) and then declines from September through April (the rainy season).
El Niño often prolongs the dry season into October or November, and that pattern was observed again in 2023.
While the timing of the dry season varies by city, worsening pollution during the dry season is a region-wide trend across Southeast Asia.
Sunlight and heat also contribute to the worsening of ground-level ozone (O3), a pollutant commonly experienced as haze that can affect lung and heart function. Haze forms when pollutants emitted by transport, industry and other sources undergo chemical reactions in sunlight.
2) El Niño amplifies weather’s impacts on air pollution
Research shows that El Niño affects climate across Asia, often creating drier conditions and altering PM2.5 concentrations, thereby impacting air quality in tropical and subtropical regions of the globe. Indonesia’s Meteorology, Climatology, and Geophysics Agency (BMKG) warned that the 2023 dry season would be the harshest since 2019, with the onset of the rainy season delayed until November in over 60% of the country, increasing the risks of poor harvests and fires.
Looking at the relationship between rainfall and PM2.5 levels measured at a central Jakarta monitoring station during the 2019 El Niño cycle, air pollutants peaked when precipitation hit its lowest level.
The rainfall deficit associated with El Niño contributed to Jakarta’s air pollution in 2019 and fueled an increase in forest fires that were a major source of pollution elsewhere in Indonesia. Since August 2023 alone, more than 300 forest and peatland fires have been reported on Sumatra island.
Field fire, Sumatra, Indonesia (Photo: World Resources Institute / Flickr [CC BY-NC-SA 2.0])
3) Transport, energy and industry are the main drivers of air pollution
Studies consistently identify the main sources of urban air pollution in Southeast Asia as motor vehicles, power plants and industrial emissions.
Take Jakarta as an example. The city sees a daily influx of 10 million commuters from satellite cities, doubling both its population and the number of vehicles on the roads. As of 2018, about 13 million motorcycles were among roughly 20 million motor vehicles in the city, and that number has continued to grow by nearly 5% per year. The most recent emissions inventory published in 2020 found that in 2019, transport accounted for 67% of PM2.5 emissions, 58% of PM10 emissions and 84% of black carbon emissions in Jakarta.
Similarly, in 2022, 72% of Bangkok’s air pollution was attributed to combustion engines.
In Jakarta and other cities, the manufacturing and energy sectors are the largest sources of sulfur dioxide (SO2) and nitrogen dioxide (NO2). These pollutants combine with other emissions and volatile organic compounds to form acid rain, PM2.5 and ground-level O3. Fossil fuel use in shipping and aviation, as well as in the commercial and residential sectors, are further sources of PM2.5 and other pollutants.
Urban air quality is also affected by sources beyond city limits. Polluters outside a city’s boundaries often degrade the air within it. Coal power plants and processing facilities are major contributors to air pollution from outside Jakarta. Agricultural burning in neighboring countries such as Myanmar and Laos can sometimes degrade Bangkok’s air. Haze from Indonesia’s forest fires affects Malaysia and Singapore, and both countries have called for coordinated efforts to tackle “transboundary haze.”
4) Many cities lack pollution forecasting tools to identify sources and issue public health warnings.
As in many cities in low- and middle-income countries, cities like Jakarta, Kuala Lumpur and Manila do not have enough air quality monitoring stations to measure pollution across the urban area. Nor do they, like Bogotá, Bangkok or Paris, use satellite imagery and air quality forecasting models to warn residents in advance about unhealthy air days.
Clean Air Catalyst (Clean Air Catalyst), a global initiative supported by USAID and WRI Indonesia, partnered with MAPAQ and used the Copernicus Atmosphere Monitoring Service (CAMS) global near-real-time forecasting system to study Jakarta’s pollution patterns during the first two weeks of August 2023. They found PM2.5 accumulating almost daily over the capital region and Surabaya in eastern Java, with pollution concentrations occasionally reaching unhealthy levels. Low wind speeds heading east and other dry season conditions likely trapped emissions near the surface. This indicates that most of the dirty air people breathed during this period was driven by emissions from traffic and power generation within the urban area.
Rush hour in Jakarta, Indonesia (Photo: UN Women / Flickr [CC BY-NC-ND 2.0])
If officials in Jakarta and other Southeast Asian cities could access such data regularly and consistently, they could identify sources, forecast pollution hotspots and plan more strategic, effective interventions — for example, limiting power generation, conducting vehicle emissions tests, reducing the number of private cars and heavy vehicles on the streets, or alerting residents to poor air quality days so they can plan their day and reduce exposure.
Southeast Asian cities can act on air pollution now
During periods of high pollution, local governments can take emergency measures.
Jakarta recently shut down a factory in East Jakarta considered a major source of pollution. In August 2023, the city ordered civil servants to work from home to improve air quality. Similarly, in September 2023, when air quality was particularly poor, multiple mayors in Metro Manila suspended classes and closed government offices. Air pollution in East Jakarta was initially attributed to a nearby volcano, but later traced to traffic emissions. It is also prudent to warn the public — especially people with respiratory or autoimmune conditions — to wear masks and remain indoors on high-pollution days. Health agencies in Bangkok and Jakarta have staffed clinics to treat pollution-related illnesses and provided education and preventive care.
In the medium term, authorities must prioritize measures in the most polluting sectors — transport, industry, energy and waste. In Indonesia, the government is stepping up efforts to cut vehicle emissions by mandating emissions testing and conducting random inspections. Since 2016, the government in Metro Manila has worked to reduce vehicle emissions by upgrading fossil fuel emissions standards from Euro II to Euro IV. The government has also established online permit issuance and a self-monitoring system to track operational status of industrial permits and compliance with emissions.
In the long term, cities need comprehensive strategies to accelerate a transition to clean, renewable energy and transport.
And city governments are not the only ones who can act. State, national and regional efforts are also needed at scale, particularly for transboundary air pollution — tightening and enforcing emissions standards on industries and power plants outside city limits, reforming agricultural burning practices, and developing rapid response plans for fire seasons. Finally, the public can use public transport, advocate for walking and cycling infrastructure, and switch to electric vehicles.
Healthy, clean cities can be built on effective policies, cooperation and community-led initiatives. Individual choices matter, but coalitions, collective actions and the voices of city residents have the potential to bring about larger change.
Coal mine in Indonesia (Photo: International Labour Organization / Flickr [CC BY-NC-ND 2.0])
The impacts of El Niño go far beyond water
“TheCityFix translated article, by Alex Simpkins, Marlena Chertock, Sara Walker, Héctor Miguel Donado, Katie Connolly and Iryna Payosova (Note 2)”
In recent months, the El Niño phenomenon has disrupted many regions and sectors across the world. Zimbabwe recently declared a state of disaster, primarily due to El Niño-driven drought. In Bogotá, Colombia, the city government announced water rationing for around 10 million people as reservoir levels fell to critical levels.
El Niño occurs every 2 to 7 years and usually lasts from 9 to 12 months. It weakens the Pacific trade winds, warms Pacific waters, and has a range of impacts on climate and weather in the Americas, southern Africa and Southeast Asia.
Attention around El Niño focuses on dryness and water scarcity, but the cascading impacts affect food and energy production, air quality, and human health. As climate change increases the frequency and severity of El Niño events and makes rainfall more erratic, these impacts are expected to worsen.
Below, we examine the ripple effects of El Niño-related drought in three countries where WRI works: Colombia, Indonesia and South Africa.
El Niño threatens Colombia’s energy production
Colombia’s energy sector is particularly vulnerable to drought: the country relies on hydropower for about 75% of its electricity generation.
In July 2023, the World Meteorological Organization declared the onset of an El Niño season. In August 2023, anticipating El Niño, energy prices rose and imports of liquefied natural gas (LNG) increased to prepare for potential dips in hydropower supply. By October 2023, based on past El Niño episodes in the region, experts warned of a prolonged dry season and further inflation risks. As of April 2024, Colombia’s reservoir capacity was below 30%, well under historical averages.
Dam in La Guajira, Colombia (Photo: Alejandrorestrepouribe / Wikimedia Commons [CC BY-SA 4.0])
Even so, Colombia managed to meet energy demand — but historically this has not always been the case.
During the 2015–2016 El Niño, rainfall in Colombia fell by 40%, straining the grid, driving up electricity prices and raising the risk of blackouts. In 1992, an unprecedented drought and El Niño triggered a severe energy crisis, and the government imposed electricity rationing for nearly a year — up to nine hours a day in Bogotá and up to 18 hours a day in San Andrés and Providencia. At midnight on May 2, 1992, President César Gaviria shifted Colombia’s time zone from UTC-5 to UTC-4 to extend daylight by one hour each day. Informally known as the “Gaviria Hour,” this measure lasted nine months.
El Niño linked to crop failures, fires and worsening air quality in Indonesia
Experts had warned that the current El Niño would increase the risks of fires and crop damage in Indonesia, with some regions becoming drought-stricken. Those predictions largely came true. Drought drove spikes in agricultural prices. The scale of fires in 2023 increased fivefold year over year. Coffee production fell by 20%, and rice prices rose 25% above the government’s recommended levels. Many farmers avoided a third rice planting between October and November 2023, or plantings failed due to lack of water.
El Niño’s warm, dry conditions also spiked air pollution in cities like Jakarta, far exceeding WHO guidelines for fine particulate matter (PM2.5). El Niño-fueled fires further degraded air quality, with smoke and haze observed domestically and abroad.
As in other countries, Indonesia experienced an intense El Niño in 2015–2016, with severe fires. Similar conditions caused crop failures and price spikes; the government resorted to food imports and cloud seeding to induce rain.
Since then, the government has taken proactive steps, enhancing firefighting capacity and importing 2 million tons of rice to bolster food supplies. It has also worked to reform agricultural practices by reducing the use of fire in peatland clearing for crops and shrubs and by restoring fire-damaged areas. Ultimately, however, more systemic interventions will be needed.
Rice terraces in Bali, Indonesia (Photo: Tomasz Baranowski / Flickr [CC BY 2.0])
El Niño hits South Africa’s economy
South Africa relies on rainfall and surface water for much of its water demand and is particularly vulnerable to temperature changes.
In the months leading up to the 2023–2024 El Niño, experts predicted severe drought. The current El Niño appears to have passed without dramatic impacts on the region’s water supply, but the 2018 El Niño showed just how disruptive weather patterns can be.
Six years ago, Cape Town faced “Day Zero,” a dangerous situation in which the city could run out of drinking water. The crisis was driven by a regional three-year rainfall deficit linked to El Niño’s influence on oceanic weather patterns. At the height of the crisis, residents faced daily limits of 50 liters of water. Water tariffs were raised, and heavy users faced fines and penalties imposed.
The impacts extended beyond water, disrupting the economy across the Western Cape and beyond. Over the years leading up to Day Zero, drought cost the Western Cape economy an estimated 15 billion rand (about US$780 million), roughly 3.4% of provincial GDP and 0.3% of national GDP. The agricultural sector alone suffered an estimated US$400 million in damages and tens of thousands of jobs were lost. Cape Town’s tourism sector was also affected, with April 2018 tourist arrivals down a record 12.6%, though declines were smaller over the full year.
The City of Cape Town and the Western Cape Province narrowly averted Day Zero by cutting water use 50% over three years through a combination of strict restrictions, public campaigns promoting efficient water use, technical solutions including groundwater and desalination, and a timely uptick in rainfall in 2018. Over the long term, however, more systemic measures will be needed to address the ongoing risk of drought.
Dam with drastically reduced water level, Western Cape, South Africa (Photo: Zaian / Wikimedia Commons [CC BY-SA 4.0])
Building resilience to El Niño and climate change
El Niño has historically been recurrent, and its impacts are expected to intensify due to climate change. At the same time, climate change itself is projected to make precipitation patterns increasingly erratic, with many countries facing greater risks of flooding, drought, or both.
Countries like Colombia, Indonesia and South Africa have managed to weather recent El Niño threats through crisis response measures, but stronger long-term planning and systemic interventions are essential to build resilience. National leaders and policymakers must strengthen both adaptation and mitigation measures to confront El Niño and climate change.
This means acting both within and beyond the water sector.
For example, South Africa can expand water-saving efforts and explore new water sources through desalination and water reuse. Around Cape Town, South Africa has already removed “thirsty” invasive tree species such as pines and eucalyptus. As of October 2023, 46,000 hectares of invasive trees had been removed, saving an estimated 15.2 billion liters of water annually.
Colombia can reduce its reliance on hydropower and cut emissions by integrating more renewable energy. Studies indicate significant potential to expand wind and solar generation capacity to 30 GW and 32 GW, respectively.
And in Indonesia, the government can go beyond reforms in agriculture and firefighting to scale up its efforts. Fully protecting the country’s wetlands and peatlands could further reduce fire risks, while protecting native food sources such as fish could lower pressure to convert more land to agriculture.
In addition, nature-based solutions can help build more resilient water systems capable of withstanding extreme weather linked to El Niño and climate change. For example, wetland restoration has the potential to recharge depleted groundwater. Healthy forests can filter pollutants from water sources. Ecosystem restoration can reduce fire risks.
The synergy between climate change and El Niño has global implications. To adapt effectively to changing and intensifying weather patterns, every country needs to act both domestically and cooperatively.
Note 1: This article is a translation of the piece “Southeast Asian Cities Have Some of the Most Polluted Air in the World. El Niño Is Making it Worse” on TheCityFix by Fadhil Muhammad Firdaus, Beth Elliott and Daniel Ibanez. We would like to thank TheCityFix and the authors Firdaus, Elliott and Ibanez for providing the article.
Note 2: This article is a translation of the piece “The Impacts of El Niño Go Far Beyond Water” on TheCityFix by Alex Simpkins, Marlena Chertock, Sara Walker, Héctor Miguel Donado, Katie Connolly and Iryna Payosova. We would like to thank TheCityFix and the authors for providing the article.
Writers: Fadhil Muhammad Firdaus, Beth Elliott, Daniel Ibanez, Alex Simpkins, Marlena Chertock, Sara Walker, Héctor Miguel Donado, Katie Connolly, Iryna Payosova
Translator: Akari Shutto
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