When the high-speed rail line between Barcelona and Madrid opened in 2008, hundreds of thousands of people ditched the plane in favor of the train, helping significantly lower carbon dioxide emissions in the country. Progress elsewhere in Europe has been slow. But with the European Commission’s new plan to accelerate the development of high-speed rail in Europe, the continent’s travel emissions could plummet.

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It is a well-known fact that short-haul and domestic flights are the most polluting forms of travel. Despite this, European governments have long subsidised and invested in air travel over rail travel, resulting in today’s norms of continental travel being very plane-centric. 

In 2016, the European Union announced the Fourth Railway Package, a set of legislation aimed at “revitalising the rail sector and making it more competitive vis-à-vis other modes of transport.” While this package did not directly fund any infrastructure or route developments, nor subsidies for the rail industry, it removed a lot of the red tape that had historically held back rail development, creating a legislative environment more conducive to a competitive rail industry and paving the way for more concrete initiatives and investment.

Last month, the European Commission announced a comprehensive plan to accelerate the development of high-speed rail in Europe through greater coordination and streamlining of ticketing, timetabling, funding, operations and legislation. The plan aims to deliver a continent-wide high-speed rail network by 2040. This will be achieved through a series of actions, including improving funding sources and private investment coordination as well as cross-border rail ticketing and booking systems; simplifying train driver certification, and removing redundant national rules.

The project is also expected to significantly reduce the EU’s transport-related emissions, supporting its goal of achieving carbon neutrality by 2050. Spain’s high-speed rail impacts on CO2 emissions are a good example to illustrate the potentially huge impact that an Europe-wide initiative could have.

Case Study: Spain

In 2008, a new high-speed rail line opened between Barcelona and Madrid, cutting the journey time between the two cities by train from around nine to two-and-a-half hours. Almost instantly, air passenger numbers declined. 

Data from Eurostat shows a reduction of roughly one million passengers per quarter –  or 40% – immediately after the high-speed line was opened in February 2008, rising to around 60% by 2024. The Comisión Nacional de los Mercados y la Competencia (CNMC) – Spain’s independent competition regulator – has been only collecting data on passenger numbers since 2016.

A 2005 study at Oxford University calculated that around 153 grams of CO2 is emitted per passenger kilometer on short-haul flights. This means that every passenger that flies the 481-kilometer stretch between Barcelona and Madrid airports emits roughly 74,000 grams of CO2.

As for high-speed rail, the UK Department for Energy Security and Net Zero (DESNZ) and the French public train company SNCF estimate four and three-and-a-half grams of CO2 per passenger kilometer, respectively. The high-speed line between Barcelona and Madrid is 681 kilometers long, meaning every passenger emits around 2,550 grams of CO2.

The Results

Using the passenger figures from Eurostat and CNMC, we can draw a graph that shows the number of passengers by mode of transport over time. As we can see, the total number of passengers between Barcelona and Madrid wasn’t hugely affected, as the new train route took on the passengers that were no longer choosing to fly. This shows that peoples’ ability to travel between these cities was not affected – only they now had an alternative, which quickly became the preferred mode of transport.

But what is really striking about these figures can be seen when we apply our estimates for the amount of CO2 emissions per passenger. These estimates allow us to compare the CO2 emissions over time of air travel and train travel between Barcelona and Madrid.

Here we can plainly see just how much greener high-speed rail is than air travel. Even though the number of train passengers was higher than plane passengers from around 2012 onwards, rail emissions pale in comparison to the emissions from air travel. Had the high-speed line never been built, CO2  emissions from this route would be three times as great in 2024.

As more people opt to take the train instead of a flight, as has been the case since the pandemic, CO2 savings grow. In the second quarter of 2024, the actual total emissions were 275 million kilograms lower than if all passengers had flown, which is roughly equivalent to the emissions of over 183,000 British households over the same time period.

Learnings for Europe

The European Commission’s newly announced plan targets a number of routes. Some of the biggest improvements include reducing the Copenhagen–Berlin route from seven to four hours; Berlin–Vienna from over eight hours to four and a half; and Sofia–Athens from nearly 14 hours to just six. Additionally, the plan would create new routes, between Paris, Madrid and Lisbon, and between the Baltic states and Warsaw.

No doubt, the improvement, or opening, of high-speed rail routes across Europe will present an alternative to flying as a means to travel between two cities, and as a result will take passengers off planes and put them onto trains instead, lowering the overall emissions. As the Barcelona–Madrid route shows, this can have a stunning impact – across 2024, around one million fewer tonnes of CO2 were emitted than if the high-speed line had never been built, which is more than the total annual CO2 emissions produced by the Faroe Islands, Gambia or French Polynesia.

It is difficult to estimate exactly how large the impact could be on any given route. The corridor examined here was very successful, and a 60% reduction in air passengers is not to be taken for granted. Nevertheless, it is clear that investment in railways as an alternative to air travel has the potential to have a hugely positive environmental impact, and the EC’s plan must prioritize maximizing passengers in order to make this impact as big as possible. The key to this will be  through affordable tickets, fast and reliable journeys and reduced red-tape, and it’s vital that the EC recognises this. It’s high time that countries begin to offer the same, if not greater, legislative benefits that the aviation industry has enjoyed for decades.

Featured image: Wikimedia Commons.

Kazakhstan has lost 21% of its per capita water availability since 1999. But what are the main forces behind the country’s rapidly worsening water crisis? 

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Only 42% of Kazakhstan’s water is available for consumption due to outdated infrastructure and poor management. Over 45% of available water is transboundary, meaning it comes from sources such as the Irtysh and Ili rivers from China and the Syr Darya from neighboring Kyrgyzstan and Uzbekistan, making Kazakhstan vulnerable to politics and foreign water mismanagement.

The poor irrigation productivity, at less than US$0.5 US per cubic meter, means that for every cubic meter of water (1000 liters) used for irrigation, the resulting agricultural output generates less than half a dollar in value. Combined with unmaintained infrastructure and low returns from water-intensive crops this also plays a role, translating into huge missed economic opportunities. The inadequate sanitation alone costs the government some US$750 million per year, compared to $500 million in investments needed to close this gap.

Glacial Threat

Kazakhstan’s water sources are heavily dependent on glacier-fed rivers from the Tien Shan mountains. Glaciers in this region have already lost about 30% of their mass and may retreat by another half by 2050.

The initial deluge in meltwater is temporary; soon enough, these rivers will dry out in the summer months, when water is most needed for cooling and irrigation, eventually leading to seasonal shortages and ecological collapse.

Agriculture: Thirsty and Wasteful

In 2021, 63% of annual water withdrawal in Kazakhstan was spent on agriculture, making it the largest sector of water waste, compared to 19% for domestic use. It is reported that only half of the water determined for agricultural use is utilized effectively or reaches the crops.

Additionally, only 16% of all irrigated land uses modern irrigation techniques, such as drip or sprinkler systems. The government introduced a policy on Water Resources Management (2023–2029), which acknowledges these challenges and aims to reduce agricultural water loss through main canals from 20% to 15% by 2029.

The agricultural inefficiencies not only stress the country’s water resources but also put additional pressure on food security and economic stability.

Unequal Access to Water

Despite Kazakhstan’s efforts to improve water infrastructure, differences between urban and rural areas still exist. While urban centers enjoy access to centralized water and sanitation, rural residents face challenges that affect their health and quality of life.

As of 2024, around 99.5% of urban residents had access to clean water, with 97.8% of rural settlements having similar access. Access to piped water shows a more pronounced discrepancy. While 94% of urban households are connected to piped water systems, the number is closer to 60% for rural households – forcing people to rely on other sources of water like public standpipes or wells.

The differences in water access between urban and rural areas are not only an infrastructural issue; they also have serious implications for public health, economic development, and social equity. Addressing these challenges requires investments in rural water infrastructure, community engagement, and policy reforms targeted at ensuring equal access to water sources across Kazakhstan.

Geopolitics

Kazakhstan’s water resources, as was mentioned earlier, are dependent on transboundary rivers – particularly the Ili and Irtysh rivers, which originate in China and are vital for Kazakhstan’s agriculture, industry, and ecosystem in general.

Negotiations between Kazakhstan and China to reach an agreement on water equitability have been ongoing. But despite some progress, such as the joint construction of hydraulic facilities on shared rivers like the Khorgo, a broad agreement on water allocation remains ambiguous.

The situation is complicated by Kazakhstan’s dependence on other transboundary rivers such as the Syr Darya, which flows through Kyrgyzstan and Uzbekistan before reaching Kazakhstan. Effective use of these water resources requires regional cooperation, which is challenging due to differing national interests and priorities.

Kazakhstan has taken steps to reduce tensions with its neighbours. For example, Kazakhstan and Uzbekistan installed transboundary water meters to monitor water consumption and share data, improving cooperation and transparency.

However, the challenge remains because of the lack of binding international agreements and the ever-increasing demand for water in the region, depicting risks to Kazakhstan’s water security. Addressing the geopolitical challenges is essential for sustainable water management and preventing conflicts over this vital resource.

What the Future Holds

The predictive model Earth.Org has built depicts an uneasy reality. Renewable internal freshwater resources have been in decline since the 1990s, and forecasts show this trend will continue, potentially dropping to 2,750 cubic meters by 2031.

The widening uncertainty interval emphasizes the importance of action – policy changes, investments in water-saving technologies, and improved regional cooperation.

Water scarcity has further effects on public health, economic resilience, and national security. The best time to act is now.

You might also like: The Aral Sea Catastrophe: Understanding One of the Worst Ecological Calamities of the Last Century

Energy demand is growing in India, but current renewable additions are not enough to meet this rising demand, let alone replace existing coal. 

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In Gujarat’s white desert, the Khavda renewable power plant is set to become the world’s largest clean energy installation, generating a staggering 30 GW of solar and wind power by 2030. Yet, across the country, a 3 GW coal-fired plant in Chandrapur, Maharashtra, continues to spew smoke, one among hundreds that still power over 60% of India’s grid.

This juxtaposition captures the central tension in India’s energy transition: How can a developing nation reconcile its growing hunger for energy with its increasingly ambitious climate goals?

Development vs. Decarbonization

Unlike developed economies, India is still growing. Its people still consume far less energy than the global average. Electricity provision – a given in the developed world – is still a development imperative here. 

Over the past two decades, India has made remarkable progress in electrification. Thanks to targeted government programs, electricity access rose from just 60% in 2000 to near-universal coverage today, and electricity shortfalls have fallen below 1%. However, this electrification has been driven primarily by coal. 

Coal capacity surged in the previous decades, and continues to rise, albeit more slowly. Today, the electricity sector accounts for over half of India’s emissions. While its per capita emissions remain low, India is now the world’s third-largest emitter of greenhouse gases.

Even so, India has emerged as a climate leader. Its 2015 Nationally Determined Contribution (NDC) pledged that 40% of its electricity capacity would come from non-fossil sources by 2030. In 2022, it raised that target to 50% and set a net-zero goal for 2070. Since 2015, India’s renewable capacity has grown nearly 20% annually, crossing 200 GW in 2024.

Still, as the world’s “well below 2C” window closes fast, attention is turning to India. While global emissions are expected to peak soon, India’s are still climbing. The country is projected to drive over a quarter of global energy demand growth through 2040. As the world is trying to phase out coal, why isn’t India able to move away from it? 

Renewables Are Cheaper, But that Is Not Enough

Over the past decade, the costs of solar and wind have plummeted. On a levelized cost of energy (LCOE) basis – the average unit cost of electricity over a plant’s lifespan – renewables are now cheaper than coal. Even by variable cost comparisons, solar now beats coal. Then why are new coal plants still being built and planned? 

The answer lies in what cost metrics do not capture.

A Kilowatt Isn’t Always a Kilowatt

Solar and wind – classified as variable renewable energy (VRE) – generate power only when the sun shines or the wind blows. A solar plant generates only 15-25% of its maximum output over a year – known as the Capacity Utilization Factor (CUF) – while wind averages 25-35%. A coal plant, in contrast, can run 24/7, with CUFs as between 70-90%. This means that much more VRE capacity must be built to meet the same demand, requiring greater upfront investments, especially challenging in a country where capital is expensive.

But the challenge isn’t just how much power is generated. It’s also about when and where.

Integration Challenges: Time and Space

A key challenge is timing. India’s power demand peaks twice daily: once at noon and again after sunset. Solar power helps with the former, but not the latter. And with solar making up the bulk of new renewable additions in India, there is little clean energy available after sunset, just when people return home and air conditioner use spikes. 

This temporal mismatch between demand and supply could be solved through battery storage. Solar output during the day could be stored and used for nighttime demand. But utility-scale battery storage remains far from commercially viable. Another option is to use flexible fuels like natural gas: its generation can be ramped up or down quickly to complement renewable generation. Countries in the Global North rely on it to complement VRE. India, however, lacks the infrastructure for gas at scale. Instead, it relies on coal.

Coal is less nimble, and costly to turn on and off. As a result, coal plants are often kept running all day, even when renewable generation is high. This lowers their CUFs, and drives up their per-unit costs, since fixed costs are spread over fewer units of output. Paradoxically, it was the overcapacity of coal built in the previous decade that provided much needed flexibility to integrate VRE at scale. But it also drove coal CUFs to record lows.

Geography is another challenge. 

While coal thermal plants can be built close to demand centres, India’s solar and wind resources lie far away. The Khavda facility, for instance, lies far from Gujarat’s industrial and urban hubs. Connecting these new energy sources requires massive new transmission infrastructure.

Moreover, India’s renewable potential and current installed capacity are geographically concentrated in six southern and western states. Meanwhile, coal-rich states in central and eastern India account for much less. And although India has a nationally integrated grid, actual dispatch and balancing are often done at the state level. So excess solar in Rajasthan cannot easily serve daytime peaks in neighboring states. 

While transmission infrastructure is being expanded, it is struggling to keep pace with renewable deployment. This mismatch has led to curtailment – clean power that goes unused because the grid cannot absorb it – which has increased in multiple states in recent years.

These integration challenges – temporal, geographic and institutional – add hidden costs. They lower CUFs and increase curtailment, neither of which are captured in LCOE calculations. They also limit the share of VRE that can be integrated to the grid, regardless of how cheap it becomes. The remaining demand must be met by other sources, which in India’s case, is predominantly coal. 

When Might Coal Peak?

Rahul Tongia, Senior Fellow at think tank Centre for Social and Economic Progress (CSEP), offers a useful framework: the Ladder of Competitiveness. 

• Stage 1: VRE is costlier than new coal → Coal dominates new capacity.
  
• Stage 2: VRE becomes cheaper than new coal → Renewables meet some new demand, but coal persists. India is here today.
  
• Stage 3: VRE + storage becomes cheaper than new coal → Renewables meet nearly all new demand, coal additions stop.
  
• Stage 4: VRE + storage is cheaper than existing coal → Renewables start to meet demand earlier met by coal. Coal starts to decline.

A number of studies project India’s annual electricity demand growth at 6-6.4% until 2030. According to CSEP, meeting this demand without accounting for storage would require adding 46 GW of solar and wind each year, consistent with India’s 500 GW target. But factoring in storage pushes the number higher.

CEEW finds that once transmission constraints are included, the 500 GW target may fall short, but diversifying VRE capacity across states could help reduce the shortfall. Ember and TERI find battery costs keep falling by roughly 7%, India may remain in Stage 2 at least until 2032, when storage at scale becomes viable. Until then, VRE could meet over 75% of solar-hour demand, but only a third in non-solar hours, the rest met by coal.

Yet, actual deployment is lagging. Annual additions may be lower–20-30 GW for solar and 4-8 GW for wind. If that gap persists, coal dependency may grow further. 

The Way Forward 

Until storage scales, increasing the flexibility of India’s power system is key. Demand response measures such as Time-of-day (ToD) pricing could incentivize customers to shift demand to times when the supply is more plentiful, reducing the need for battery storage. 

Grid operators need better real-time monitoring and control systems to manage intermittency, such as a sudden cloud cover over solar fields. Coal plant flexibility increases, such as ramping down during solar peaks and ramping up during time hours, could enhance supply flexibility, but doing so could be costly, making operators reluctant. Finally, transmission reforms, such as improving inter-state coordination could drastically reduce curtailment, cut emissions and minimise unnecessary coal additions.

Final Thoughts 

We began with a striking image: the gleaming Khavda solar park and the aging Chandrapur coal plant. But perhaps framing India’s energy story as a battle is misleading. 

India’s energy demand is still growing. Current renewable additions aren’t enough to meet this rising demand, let alone replace existing coal. So for now, it is coexistence – with coal filling gaps that renewables can’t yet close.

The stakes are global. How India balances its growth and decarbonization over the next decade will play a major role in determining whether the world can limit warming below 2C. But for now, the world may have to accept the fact that coal isn’t going anywhere anytime soon.

Earth.Org’s Data Analyst and Visualization Expert Madina Tussupova uncovers the patterns, causes, and real consequences of global temperature rise.

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Instead of exploring average temperature data, this article looks at temperature anomalies; in other words, deviations from average temperatures. Why is it more useful? Because the “normal” temperature range for each location is widely different – by looking at anomalies, we can effectively measure the temperature trend while avoiding climate bias.

References to global warming in this article include both land and ocean warming. The decision to not overlook ocean warming makes sense, as 90% of global warming occurs in the ocean.

Historical Temperature Trends

Historical records from the mid-20th century indicate a steady rise in average temperatures. While natural climate variability has caused certain fluctuations, the general trend has been a consistent warming.

Our analysis show the following observations:

• The global average surface temperature has risen by approximately 1.5C since 1924.
• The global warming rate of this century (1924-2024) is approximately four times higher than the rate observed in earlier years (1850-1923), emphasizing a significant acceleration in climate change during the last century [linear regression was used to calculate the slopes]
• The 21st century has seen some of the warmest years on record, with 2024, 2023, and 2016 topping the ranking. 

Regional Differences in Temperature Rise

The rise and impact of global warming are not the same across the world. Some regions face more accelerated warming due to specific climate and weather conditions. 

The highlighted observations are as follows:

• The Arctic has warmed at a rate nearly four times the global average, leading to significant ice melt and ecosystem disruptions.
• Continental regions such as North America, Europe, and Asia have experienced significant increases in extreme weather events, such as compound droughts and heatwaves.
• Oceans have absorbed much of the excess heat, contributing to rising sea levels and more frequent and intense hurricanes.

Global Warming and Greenhouse Gases

Greenhouse gas emissions, particularly methane, nitrous oxide, and carbon dioxide (CO2), are the main driver of global warming. Human activities are the dominant force behind rising CO2 concentrations, accounting for 55.4% of total emissions. Industrialization and urbanization have also contributed significantly to localized warming, known as the urban heat island effect.

Natural emissions play a role, too, ranging from 18.13 to 39.30 gigatonnes of CO2 equivalent (Gt CO2-eq) annually, with a likely value around 29.07 Gt CO2-eq. Key natural sources of emissions include forest fires, oceans, wetlands, permafrost, volcanoes, and earthquakes.

CO2 levels reached approximately 420 parts per million (ppm) in 2023 – the highest value since records began. That year was also the warmest year within the last century, until 2024 – currently the hottest on record.

Deforestation and land-use changes have further reduced the planet’s ability to absorb CO2, intensifying the temperature rise. Forests, like oceans, are invaluable carbon sinks, absorbing and storing large quantities of CO2 from the atmosphere. 

Soil holds carbon in forms like permafrost or peat, but temperature rise makes it hotter and drier, making it more difficult to store more carbon.

In the oceans, one of the main players in carbon absorption is phytoplankton, microscopic bacteria that consume CO2 and release oxygen. However, high concentrations of microplastics in the water disrupt the structure of algal communities, which negatively affects the entire marine ecosystem. Plants absorb CO2 thanks to a process called photosynthesis. With the help of light, trees generate glucose – which they later use to produce cellulose and other things they need to grow – and oxygen, which they release into the atmosphere.

Predictions and Future Outlook

A polynomial regression model was used to make predictions for the next 25 years. While it fits the overall trend well, we can see slight underfitting around the years 2022 and 2023. This can be explained by a spike in anomaly that could not be captured by the model.

This means our predictions might be underestimated – in reality, the values could be much higher than forecasted. Nevertheless, we can still capture some valuable insights from the model’s predictions:

• If current patterns persist, we could see anomalies surpassing +2C by 2045, which crosses several critical climate thresholds.
• The model also predicts that we could breach the 1.5C anomaly as early as the 2030s – a major climate milestone referenced in the Paris Agreement.

Conclusion

Historical temperature time series affirm that, in the last century, global warming has accelerated, with much of this intensification attributed to anthropogenic activities. While the impact varies from place to place, what makes it truly alarming is the global nature of temperature rise.

The time left to halt greenhouse gas emissions, transition to carbon-free energy, and push for sustainable environmental policies is very limited.

Featured image: Arian Zwegers/Flickr.

The average wildfire season in Western US is now 105 days longer, burns six times as many acres, and sees three times as many large fires, according to Climate Central. Earth.Org looks at the data to establish whether there is a link between increased wildfire activity and drought severity.

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Drought is one of the most devastating natural disasters, affecting millions of people worldwide. Unlike hurricanes or earthquakes, droughts develop slowly and can persist for months, years, and even decades, leading to lasting effects on agriculture, water supply, and ecosystems. 

In 2024, 48 of 50 US states faced drought conditions, the highest proportion ever recorded in the country, while wildfires scorched over 8.9 million acres nationwide. As climate change accelerates, droughts are becoming more frequent and widespread, and their relationship with wildfires is no longer speculation.

Drought Trends

Drought occurs when a region experiences prolonged periods of lower-than-average precipitation, leading to water shortages and drier lands. Both natural and human factors can influence it, including varying climatic conditions, rising global temperatures, deforestation, and unsustainable water use. 

The US Drought Monitor provides historical drought data, classifying drought severity into categories ranging from D0 (Abnormally Dry) to D4 (Exceptional Drought).

A time series plot from 2000 to January 2025 illustrates trends across different drought categories (D0 to D4), revealing a periodic pattern. Severe droughts (D2-D4) peak every 3-5 years, likely influenced by climate oscillations such as El Niño and La Niña. Autocorrelation tests confirm this periodicity, showing strong correlations at 2-3 year lags, particularly for D3–D4 droughts. 

Additionally, drought severity has intensified, with “exceptional drought” coverage increasing by 12% since 2000. While mild droughts (D0–D1) follow annual wet/dry cycles, severe droughts (D2–D4) persist for multiple years. 

Given this cyclical behavior, an important question arises: do wildfires follow a similar pattern? 

Wildfire Trends

Using historical wildfire data from the National Interagency Fire Center, we analyzed the total acres burned over the years. The data reveals that wildfires also exhibit a periodic pattern. This raises a critical question: is there a direct relationship between drought and wildfires?

To investigate this, we utilized a Normalized Weighted Drought Index, which quantifies drought severity on a scale from 0 (least severe) to 10 (most severe) by weighting different drought categories. Similarly, wildfire data including total acres burned and the number of fires was normalized to enable a direct comparison with drought severity. 

Normalization is a method that scales different types of data to a common range, allowing us to compare them more fairly. For instance, drought severity may range from 0 to 10, while acres burned could be in the thousands or millions. Without normalization, one might appear more significant just because it uses larger numbers. By bringing everything to the same scale, we avoid misleading comparisons and can better evaluate how closely drought conditions and wildfire activity are connected. This approach provides a dimensionless framework to explore their correlation more accurately.

The plot reveals a strong relationship between drought severity and wildfire activity, with extreme drought years, such as 2020, coinciding with an increase by 2.5 times in burned area compared to non-drought years. However, an anomaly appears between 2011 and 2015, where overall drought levels were lower, yet wildfire activity remained high. 

A more focused analysis considering only severe drought conditions (D3-D4) provides further clarity, highlighting that localized extreme droughts can significantly impact fire activity, even when total drought levels appear moderate. This suggests that while broader drought classifications may not always capture fire risk accurately, high-intensity droughts in fire-prone regions play a crucial role.

The data also shows that fire frequency increased by 40% in the western US during severe droughts. A case study from 2020, when D4 drought covered 23% of the western US, aligns with a record 10.1 million acres burned. Time series plots indicate overlapping spikes in drought severity (D3-D4) and wildfire acreage during key periods, such as 2011–2015 and 2017–2021. This trend is particularly evident in California, where persistent drought conditions from 2011 to 2017 closely align with intensified wildfire activity, as well as the record-breaking fires of 2020 and beyond.

From the data, it is evident that there is a strong correlation between drought severity and wildfire activity. As climate change accelerates, addressing this relationship through proactive policies and climate adaptation strategies becomes increasingly urgent. Policy urgency is evident, as regions with frequent D3–D4 droughts, particularly in California and the Southwest, require enhanced fire mitigation strategies and water-resilient infrastructure.

Featured image: CAL FIRE_Official/Flickr.

You might also like: 3 Facts About California’s Climate That Explain the LA Fires

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References:

– U.S. Drought Monitor
– National Interagency Fire Center
– Williams, A. Park, et al. “Large contribution from anthropogenic warming to an emerging North American megadrought.” Science 368.6488 (2020): 314-318.
– https://en.wikipedia.org/wiki/2011%E2%80%932017_California_drought

For years, media headlines have depicted a dire situation regarding global bee populations. While it is true that honey bee numbers in certain areas, especially in North America and Europe, have plummeted due to habitat loss, pesticide use, and climate change, recent data reveals a more nuanced picture. In fact, bee populations in some Asian countries have been steadily increasing. This contrasting trend prompts important questions: why are bees flourishing in some regions while facing challenges in others?

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When we examine global trends, we can observe a promising rise in the number of bee stocks. But is it as straightforward as it appears?

A Tale of Two Trends: The Rise and Fall of Bee Populations

By diving deeper and categorizing the data, we can identify conflicting trends. A comparison between North America and Asia highlights these differences.

North America: A Decline in Numbers

In the United States, bee populations have encountered significant obstacles in recent decades. Data shows that honeybee colonies have been on the decline since the 1960s. The primary causes include habitat destruction, pesticide exposure, climate change, diseases, and parasites.

Asia’s Growing Bee Populations: A Different Story

In contrast to the declines observed in the West, some Asian countries have experienced stable or even growing bee populations. Several factors contribute to this positive trend: a diverse natural landscape, a mild climate, a long-standing tradition of beekeeping, and the rise of commercial beekeeping. For instance, China, the world’s largest honey producer, has significantly boosted its managed honeybee populations to satisfy global demand, compensating for the declines in wild bee populations.

Predicting the Future of Bee Populations

The future of global bee populations is uncertain, but there is hope. The following projection outlines potential trends for bee populations over the next decade across various continents.

Our analysis indicates that while managed bee populations in Asia and Africa are likely to grow, North America may face further declines unless significant conservation efforts are implemented.

Key factors influencing these projections include:

• Using probiotics to boost bees’ immunity in the face of rising threats from pests and diseases due to climate change.
• Encouraging a variety of floral environments and protecting natural habitats to provide bees with a steady and plentiful food source.
• Minimizing the use of synthetic pesticides and fertilizers: biopesticides, which come from plants, bacteria, or fungi, can reduce the dangers linked to pesticide application. However, it’s important to assess the safety of biopesticides for bees, as not all are beneficial.
• Promoting sustainable farming methods: Techniques like polyculture, where multiple crops are grown together, and crop rotation, which involves changing crops on the same land over time, can improve biodiversity and strengthen ecosystem resilience.

A Call for a Balanced Perspective

The idea of a global bee population collapse is not entirely accurate. While some regions are experiencing alarming losses, others are seeing increases, demonstrating that proactive measures can lead to positive outcomes. To truly understand these trends, we need a data-driven and region-specific approach rather than relying on generalized predictions of doom and gloom.

If regions facing declines adopt stronger conservation policies and sustainable farming practices, they could stabilize and even boost their bee populations in the years ahead. At the same time, countries with growing bee populations must stay alert to emerging threats to protect their achievements.

Bees play a crucial role in global food security and biodiversity, and their future hinges on our capacity to adapt, innovate, and safeguard their habitats. Instead of concentrating solely on declines, we should also examine and replicate the success stories of thriving bee populations around the globe.

Data for the graphs in this article was retrieved from FAOstat.

This article explores trends in past hurricane data to understand the significance of these warnings and track the evolving nature of hurricanes over the years. As the intensity of hurricanes grows due to the climate crisis, so too does their damage potential and, along with it, the financial costs we deal with in the wake of destruction.

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Last month, Hurricane Beryl crashed into Texas, taking out power for more than 2 million people. Its sustained high speed winds brought excessive rainfall and flooding inland while creating a deadly storm surge reaching 4-7ft in places along the coast. 36 people have died Texas and Louisiana after 33 deaths across the Caribbean. An initial estimate put the total economic loss from Hurricane Beryl in the United States alone between $28 to 32 billion. This not only includes storm damage but also wage loss, interruptions of supply chains, and flight delays and cancellations.

Hurricane Beryl reached Category 5 status with winds of 165 mph, marking an early start to the hurricane season and becoming the earliest Category 5 hurricane ever recorded. However, it is not necessarily an anomaly. In May, the National Oceanic and Atmospheric Administration (NOAA) issued a warning for an “above average” hurricane season in the North Atlantic, which, according to the World Meteorological Organization, would make 2024 the ninth consecutive year of “above average” hurricane seasons.

This article explores trends in past hurricane data to understand the significance of these warnings and track the evolving nature of hurricanes over the years. As the intensity of hurricanes grows due to the climate crisis, so too does their damage potential and, along with it, the financial costs we deal with in the wake of destruction.

Data & Categorization

The analysis in this article utilizes data from NOAA’s International Best Track Archive for Climate Stewardship (IBTrACS) Project and the Costliest US Tropical Cyclones Listing. The IBTrACS Project compiles comprehensive tropical cyclone data gathered from agencies worldwide, while the listing concentrates on the damage costs incurred in the US due to these cyclones.

This study focuses specifically on hurricanes occurring between 1980 and 2024. Instead of relying on standard classifications, our analysis adopts a modified version of the Saffir-Simpson scale, which includes a newly introduced Category 6, as proposed by recent research. This addition aims to more accurately capture the exponential increases in tropical storm wind speeds, which has been observed more frequently in recent years.

The table below contains a detailed description of the scale that was used.

International Trends

Upon initial observation, the data indicates that the total number of hurricanes is not rising over time. In fact, there appears to be a slight decline in the number of hurricanes, with fewer storms on average each year. The following graph illustrates this trend, showing that the frequency of hurricanes has remained fairly consistent across decades.

Looking at the data across different regions, we can see a similar trend. Most ocean basins, with the exception of the South Atlantic and North Indian, experience around 10 hurricanes per decade. As of May 2024, most basins have recorded approximately 5 hurricanes, seemingly on course to reach the expected 10 hurricanes by the end of the decade.

So this raises the question, what is an above average hurricane season if hurricanes aren’t becoming more frequent?

There has never been a Category 6 hurricane before the year 2013.

When zooming out to observe 15 year intervals, the same pattern unfolds across our international data; there is a nearly identical number of Category 1-4 hurricanes occurring over each time period. However, there is one alarming shift in recent years: the emergence of Category 6 hurricanes. Before 2013, no recorded hurricanes ever met the threshold for Category 6. These hurricanes are characterized by higher wind speeds capable of much more catastrophic damage, especially near coastal areas.

With a focus on the recent emergence of Category 6 hurricanes, our investigation then turned to examining the average wind speeds of hurricanes over time. As depicted in the graph below, there appears to be an ongoing upward trend in average wind speeds by year.

To validate this trend, we conducted further analysis to assess the correlation between average wind speed and year. The calculated correlation coefficient (~0.57) indicates a moderately strong relationship, suggesting that hurricanes have indeed been getting stronger on average in recent years.

According to our linear model, average wind speeds increase by approximately 0.217 knots per year on average. Our statistical tests confirm that this increase is statistically significant (with a p-value of 0), and the narrow confidence interval (0.121-0.314) around the coefficient of 0.217 reinforces the precision of our linear estimate.

These findings underscore the concerning trend of escalating hurricane intensity over the years, potentially leading to more catastrophic damage from these severe storms.

Case Study: U.S.A

Financial impact is one of the metrics used to quantify the resulting damage of tropical cyclones and conceptualize their impact on existing infrastructure. As such, we used the United States as a case study to evaluate the economic impact of hurricanes and identify comparable trends. Our focus was on storms that caused 1 billion dollars of damage or more when they occurred–these costs were adjusted based on the 2024 Consumer Price Index. In total, our analysis encompassed 52 storms occurring between 1980 and May 2024 that had a direct impact on the United States.

The chart below illustrates how the cost of damage caused by hurricanes in the United States has skyrocketed over time. Every 15 years, this amount grew by over 300 billion dollars. In the most recent period alone, costs totaled to around 800 billion dollars. This staggering figure is more than seven times the total costs incurred from 1980 to 1994.

Analyzing the data by decade revealed even more striking disparities. The damage costs incurred in the 2000s exceeded those of the 1980s by more than tenfold, while the 2010s’ costs were nearly thirteen times that amount. In the early 2020s, we have not only surpassed the individual damage costs of the 1980s and 1990s but also their combined total.

Alongside growing costs, the frequency of hurricanes causing over 1 billion dollars of damage has continued to rise as time goes on. When looking at the chart below, we can see that each decade since 2000 has exceeded its 1980s and 1990s counterparts. While we are only halfway through this current decade, the United States has already experienced 15 hurricanes that caused over 1 billion dollars of damage—more than any previous decade. This number is only expected to rise.

Conclusion

Hurricane Beryl marks a violent start as the first major hurricane of 2024. With wind speeds surpassing the Category 6 threshold, it underscores the alarming trends outlined in this study. These trends are a stark reminder that none of our weather phenomena is isolated from the escalating impacts of the climate crisis. Long-term greenhouse gas emissions caused by actions such as burning fossil fuels have significantly warmed the ocean. The higher wind speeds and intensity of hurricanes are largely fueled by rising ocean temperatures, which allows them to gain more speed and power.

As storms like Beryl continue to exhibit increased intensities and destructive potential, reducing greenhouse gas emissions and addressing the root causes of the climate crisis remain imperative to protecting the world from future disasters.

More on the topic: What Are Tropical Cyclones? Hurricanes and Typhoons, And Their Link to Climate Change

The CBAM legislation addresses the European Union’s (EU) concerns about domestic firm competitiveness and carbon leakage. By incentivising EU trade partner firms to reduce emissions and EU trade partner states to adopt carbon-forward policies, the legislation may be instrumental in reducing carbon emissions across the globe to meet the 1.5C target. However, risks of retaliation from the developing world may do more harm than good.

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What Is the EU’s Carbon Border Adjustment Mechanism?

The European Union’s Emissions Trading Scheme (EU ETS), rolled out in 2005 and gradually expanded since then, sets a cap on greenhouse gases (GHGs) emitted by firms based in the EU by providing them a quantity of Emission Allowances. Firms producing relatively lower emissions can sell their excess allowances to firms producing relatively higher levels of emissions, creating a secondary market for trading these emission allowances.

Announcements geared towards expanding the scope of the EU ETS, along with the phaseout of free allowances, raised concerns that the subsequent increased costs to domestic producers would place them at a competitive disadvantage compared to foreign firms producing goods without a corresponding carbon price. 

Competitive disadvantages for domestic firms could result in carbon leakage, a process in which domestic enforcement of a price on carbon increases emissions elsewhere, either by domestic firms moving production offshore or external firms increasing production to meet the growing demand. In response, the European Commission legislated the Carbon Border Adjustment Mechanism (CBAM) to enforce a carbon price on imported goods in certain industries.

The rationale for the CBAM is that a carbon “tax” on imports of goods covered under the ETS would maintain the domestic competitiveness of European Union (EU) firms and prevent carbon leakage towards EU Trade Partner Countries – countries exporting CBAM related goods to the EU – thereby not undermining the EU’s ambitious emissions reduction goals. 

Initially, the six industries most susceptible to carbon leakage – i.e., emissions-intensive and trade-exposed (EITE) industries – have been included in the mechanism. During the transition phase between October 2023 and late 2025, importing firms will have to report the quantity and emissions intensities of CBAM goods imported. The definitive phase, which is set to commence in January 2026, will require importing firms to pay a price on the carbon emissions on imported goods, linked to the price of EU ETS Emission Allowances.

More on the topic: The Implications of the EU Carbon Border Adjustment Mechanism on the Environment and Global Trade

Firm-Level Incentives and Emissions Reductions

The CBAM Implementing Regulations (2023) require trade partner firms to report their direct as well as indirect emissions, such as those from the generation of electricity consumed for production and from certain production precursors. There are concerns that to minimize their carbon tariffs, firms may engage in “reshuffling”, i.e., exporting to the EU from plants with “cleaner” production (relatively lower direct and indirect emissions) and sending goods from “dirty” plants (relatively higher direct and indirect emissions) to other parts of the world. This could create a two-tier system where relatively “clean” goods are exported to CBAM regimes while “dirty” goods are shipped to non-CBAM regimes with lax climate policies, potentially resulting in relatively lower emissions reductions than anticipated. 

Firm-level emissions reduction incentives also depend on their levels of export dependence on the EU and the carbon emissions intensities of their exports relative to EU goods. The figure below, produced using data from the World Bank CBAM exposure index, provides some useful insights.

Countries with higher levels of export dependence on CBAM products to the EU (measured on the horizontal axis as the share of a country’s total exports of CBAM products that go to the EU) may find it difficult to find alternative export markets. Some African countries (Cameron, Zimbabwe and Mozambique) and Non-EU European countries (Albania, Belarus and the UK) have more than 50% of their CBAM related goods going to the EU. The vertical axis represents CBAM product related emissions intensities relative to EU manufacturers (measured as the excess carbon price to be paid per dollar of CBAM product exports to the EU relative to EU manufacturers). Higher relative emissions intensities signal a competitive disadvantage for a country’s producers and vice-versa. Trinidad and Tobago and Colombia face disproportionately higher (26%) and lower (-11%) relative CBAM tariffs, respectively.

More generally, firms in countries positioned higher up and towards the right would be more susceptible to CBAM tariffs. Countries including India, Georgia, and Ukraine, although not as export dependent, face a cost increase greater than 10% relative to EU manufacturers. Zimbabwe and Belarus face both significant export dependence and higher CBAM tariffs.

Policymaker Responses

Trade partner governments highly dependent on CBAM product exports to the EU may be incentivised to implement their own carbon pricing schemes. In Figure 2, the size of the bubbles indicates the share of a country’s GDP dependent on CBAM product exports to the EU, serving as a proxy for CBAM’s potential spillover effects on a country’s economy. Governments in relatively highly exposed economies may face less domestic resistance towards carbon pricing initiatives, increasing the chances of adoption. Moreover, implementing their own carbon pricing schemes would not only help firms offset CBAM tariffs, but also provide governments with an additional revenue stream. Some countries, including Argentina, China, Chile and South Africa, already have some form of carbon pricing, with many more following suit, including India, Indonesia, Turkey, Brazil, Mozambique and Zimbabwe.

On the other hand, the negative impacts of the CBAM on developing economies, the largest exporters of EITE goods to the EU, may lead to opposition, and potentially retaliatory measures against the policy. Simulations have shown that, in addition to the regulatory burden of CBAM, such countries could face significant welfare losses, exacerbated by lower safety nets. This shift of the burden of fighting climate change towards developing economies disregards their “historical responsibility” for causing the most amount of climate damage. In addition, indirect “sanctions” on (mostly developing) countries violate the principle of “common but differentiated responsibilities and respective capabilities” by coercing them to take action, which most certainly may be beyond their current means. Unsurprisingly, the CBAM has seen negative reactions from many developing economies, particularly from the BASIC group comprising China, India, Brazil and South Africa.

Looking Ahead

The CBAM is just the beginning of a series of climate-related legislations. Similar carbon border tariffs have been proposed by other countries such as the US, Canada, UK, and Australia. As these carbon border legislations increase in scope and geographical coverage, the road will only get tougher for developing countries and for the future of international climate diplomacy. It is too early to say if CBAM is the right way forward. While such policies may be necessary to reach the Paris Agreement goals, the risks of global disorder and the potential unraveling of the global climate agenda may do more harm than good.

Land access rights in England and Wales severely restrict the public from freely accessing local outdoor green spaces for leisure and exercise. Improving these rights is crucial to moving towards a more sustainable outdoors that is fairer to people of different backgrounds, less polluted, and more natural. Recent campaigns which have gained popularity during the pandemic have called for more public and government action on this issue. In this article, we analyse various sources of public data to show that, while public appreciation of the outdoors and local nature has increased since the pandemic, there is a need to give the public wider access to paths and areas of land to sustain this trend. It is hoped that this article will promote awareness of the importance of land access rights in striving towards a more sustainable and fair outdoors for the population of England and Wales and inspire others to follow suit. 

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The Benefits of Outdoor Spaces

Access to the outdoors, nature, and green spaces is vital to humans for exercise, mental well-being, creativity, and many other benefits. In the UK, not long ago, coronavirus-induced lockdowns removed the public’s freedom to explore the outdoors, forcing us to make the most of whatever local green space we had on our doorstep. However, two years of these restrictions have changed the UK’s attitudes and we can now expect more interest in exploring these local outdoor spaces for recreation and exercise. As well as the restrictions of the pandemic, increased awareness of sustainability and environmental issues amongst the population has also contributed to this shift. From a sustainability point of view, better access to local natural spaces is desirable, paving the way for a wide variety of social and environmental benefits:

• Lower emissions, pollution and congestion as well as better quality of life associated with travel to natural spaces for exercise and recreation.
• Better public awareness of issues facing nature and the environment, as well as a more responsible approach to the outdoors. Reclaiming land for public use also contributes to the discussion of the importance of land ownership and use issues in tackling the climate and nature crises.
• More sustainable tourism, to conserve beauty and support rural communities, for example in mitigating tourist hotspots in National Parks. 
• Increased fairness of access to the outdoors; access to local nature is unequal across, for example, ethnicity or income, and this issue has been exacerbated by lockdowns.

It is unsurprising that access to and within local outdoor spaces highly depends on land access rights. However, in England, (figures are similar in Wales, but rights differ in Scotland and Northern Ireland), current rights dictate that the public have the right to freely access only 8% of land around the country and are excluded from the remaining enclosed private land under the fear of trespass. Such places include high-walled aristocratic country estates (G. Shrubsole, Who owns England?, 2019), golf courses or gardens hidden behind a National Trust membership. Campaigns, such as those of the Ramblers, Wildlife and Countryside Link and Right to Roam, are advocating for the reclamation of land to support nature and for public access, arguing for its environmental and health-related benefits as well as its historical and legal importance.

Photo: Andrew Wang.

In this article, we argue that a data-backed approach can support these campaigns to reclaim local outdoor spaces. We present recent data reflecting how the public interact with the outdoors and nature around the country and discuss why this necessitates an improvement in land access rights in the UK.

Importance of Local Natural Spaces

During the multiple UK coronavirus lockdowns, UK restrictions prohibited travelling “outside your local area” to exercise and walk, and permitted local “public outdoor places” to stay open, including parks, “countryside accessible to the public”, gardens, and “the grounds of a heritage site”. This automatically highlighted the importance of having access to local outdoor spaces, which for most of the public meant nearby public urban parks and paths crossing local countryside, but for a select few, also the grounds of their own estates. 

Data collected during this time showed that the number of people around the country walking for leisure and exercise rose higher than before the pandemic, especially those getting out several times a week, with walking one of the few things one could do out of the house (Figure 1). Local green spaces were crucial in giving the public the opportunity to get outside and improve their mental health. Furthermore, another survey’s data showed that an increasing proportion of the public said that they were spending more time outside than before the pandemic. To encourage people to continue exploring and exercising outdoors and having an interest in nature after the pandemic, we must ensure that more natural spaces are accessible to the public in England and Wales (as explained here).

Figure 1: Proportion of adults who walk for leisure averaged across all of England from 2016 to 2021, according to the Active Lives Survey by Sport England. This graph incorporates the recently released 2021 survey data not included on past reports; 2022 survey data is scheduled for release in summer 2023.

To support the idea that these outdoor spaces remain important even after the pandemic has ended, recent data presented in Figure 2 showed that both interest in exercising locally and leisure visits to green spaces has stayed at an elevated level compared to before the pandemic – in particular, local exercise interest remains at a statistically significant higher level than before. This suggests the prolonged importance of local outdoor spaces, supporting the focus on sustainable access to the outdoors long after the pandemic.

Figure 2. Left: Google search interest in “walks near me” and “local walks”, according to Google Trends data from 2018 to present, inspired by this article. Each series is normalised according to its own data within the timeframe, so the units are arbitrary and comparison cannot be made between series. An unpaired t-test between pre- and post- pandemic search results suggests a highly statistically significant difference (p≈10-11) for both series (assuming stationarity). Right: proportion of adults who visited green and natural spaces for leisure in the past fortnight from April 2020 to March 2022 in England, according to the People and Nature Survey. This incorporates recently released monthly indicator data not presented on government reports. Data before this period is not available since the data was collected in a different format, and data after this period is unreleased. 

Towards A Public-Informed Approach to Land Access Rights

The data above has shown that green and natural spaces in the local area are important to people seeking to go outdoors for leisure and have an interest in nature. However, the public is legally barred from setting foot on the vast majority of the outdoors around the country – 92% – because of poor land access rights dictating the few places granted access to the public and defining the rest as trespass. In this section, we consider a direction for a possible solution.

In line with the data-backed approach of this article, we compare where there is land granted public access by law with where the public are actually walking and moving. The hypothesis is that there may be private paths or areas of land which show public activity, whether out of convenience, unawareness, or simple desire to explore local green spaces. Surely land access rights should evolve to reflect and protect by law the places where people want to walk? Suggestions from these findings could then strengthen existing campaigns to reclaim private areas for the public, such as that of the Ramblers.

For our approach, we take the English and Welsh network of publicly accessible paths, called public rights of way (PRoW), as a proxy for land access. As a simple illustrative analysis using openly available data, we compare the rights of way network with a large dataset of public GPS traces recorded around the country by members of the public. Example results for Bedfordshire are shown in Figure 3.

It must be mentioned that there are many other interesting data-oriented avenues of highlighting regional need for access to outdoors spaces. For example, in hyper-urban settings such as Greater London, a tool was built to suggest areas for green space creation based on current green space access and demand, pollution and land availability.

Figure 3. Interactive map showing GPS activity recorded by the public (such as walking, running and cycling) in Bedford and Central Bedfordshire up to 2013, taken from a dump of GPX file data from OpenStreetMap in 2013. Black represents activity data that coincides with public rights of way, that is, where the activity was legal. Red/magenta represents activity data that does not, that is, where the activity counted as trespass. Deeper red indicates higher activity levels. Read more and get started with analysing other areas by following the instructions in the code: github.com/Andrewwango/prow-ml

We see that, while most activity coincides with where it is legal (and often signposted), there are paths of interest that are not public, which therefore can be fenced or blocked without notice. For such a path, this information could be used to support a campaign to change their status, especially if the path has already been identified as, for example, a former historic right of way (cf. the Ramblers). Of course, our identified paths will inevitably be a subset of all possibilities since trespass that is recorded is a subset of the total desire to trespass.

Conclusion

Nature should be accessible for all, and survey data presented in this article has shown us that the public’s interest in nature and accessing the outdoors for exercise and recreation locally is now higher than before the pandemic. This is important in moving towards a more sustainable approach towards the outdoors. 

The limited public land access rights in England and Wales mean that for the majority population, access to much of the outdoors and countryside is illegal, behind closed doors or subject to a fee. By looking at data showing public activity on footpaths, we can identify possible paths to protect with the status of being free for the public to access. 

There is much more work to be done in providing fairer access to the outdoors in England and Wales. For readers from other countries, I would love to hear about attitudes towards how land access rights shape the sustainability of the outdoors – please get in touch!

Featured image by Andrew Wang

Note: all statements about availability of released data is true as of date of publication.

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Air pollution is a global crisis that has severe implications for the environment and human health. This article provides a comprehensive analysis of the most polluted cities around the world. We look at the main sources of pollution, analyse the efficiency of the measures that are being taken by governments to tackle the issue, and provide insights into the future of air quality.

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“Clean air is a human right. Unfortunately, it is not a reality for a large proportion of the world’s population.” – Dr. Maria Neira, Director of the Public Health, Environment and Social Determinants of Health Department of the World Health Organization.

Why Should We Care About Air Pollution?

Air pollution is the greatest environmental threat to public health globally. Improving our air quality will bring health, development, and environmental benefits. With every breath we take, we suck in tiny particles that can damage our lungs, hearts, and brains and cause a host of other health problems. The most dangerous of these particles, which can include anything from soot, soil dust, to sulphates, are fine particles 2.5 microns or less in diameter – shortened as PM2.5.

According to Dr Maria Neira, Director of Environment, Climate Change and Health at the World Health Organization (WHO), about 9 out of 10 people are exposed to air pollution at levels above the WHO air quality guidelines. Researchers found that daily air pollution levels globally exceed 15 μg/m3 – the safe threshold value recommended by the WHO – for more than 70% of days in 2019. As a result, about 7 million people die every year due to ambient or household air pollution. This number is only the tip of the iceberg, as there is also a huge burden of sickness, hospitalisation, reduced life expectancy, and the associated social and economic impacts of lost productivity and healthcare costs. 

Mapping the Cities With the Most Dangerous Levels of Pollution

Mapping the most polluted cities and countries in the world helps identifying the primary sources of pollution and their causes, as well as understanding the consequences of high levels of pollution on human health and the environment.

According to IQAir’s 2022 World Air Quality Report, most of the world’s 50 most polluted cities are in Asia, particularly India and Pakistan. 

The following are the 10 most polluted cities in the world: 

1. Lahore, Pakistan

2. Hotan, China

3. Bhiwadi, India

4. Delhi (NCT), India

5. Peshawar, Pakistan

6. Darbhanga, India

7. Asopur, India

8. N’Djamena, Chad

9. New Delhi, India

10. Patna, India

While Indian cities top the world’s most polluted cities’ list, India does not place among the five most polluted countries globally. The latter are topped by nations much smaller in geographical area, which brings up the annual average PM2.5 concentration (μg/m³).

The following are the 5 most polluted countries in the world, according to IQAir: 

1. Chad

2. Iraq

3. Pakistan

4. Bahrain

5. Bangladesh

What Is Air Pollution?

Ambient air pollution is caused by a number of air pollutants, including NOx, ozone, carbon monoxide, and sulphur dioxides.  PM2.5 is the air pollutant that has been most closely studied and is most commonly used as a proxy indicator of exposure to air pollution more generally. Particulate matter consists of a complex mixture of solid and liquid particles of organic and inorganic substances suspended in the air. 

The major components of PM are sulphates, nitrates, ammonia, sodium chloride, black carbon, mineral dust, and water. The most health-damaging particles are those with a diameter of 10 μm or less, which can penetrate and lodge deep inside the lungs. Both short- and long-term exposure to air pollutants have been associated with health impacts such as lung cancer, heart disease and stroke, according to the World Health Organization.

More on the topic here: What is Indoor Air Pollution?

What Are the Main Sources of Air Pollution?

The primary sources of pollution in each of the most polluted cities are residential pollution, mostly from cooking and heating using biomass, generating electricity from fossil fuels for our homes, and transport. Windblown dust is also a major source in portions of Africa and West Asia that are close to deserts. Windblown dust, emitted from the surface of the earth to the atmosphere, has significant impacts on atmospheric phenomena, air quality, and human health. 

Respiratory and cardiovascular disorders, meningococcal meningitis, conjunctivitis, and skin irritations are among the health problems that have been associated with exposure to dust. Specifically, airborne dust particles (in particular those finer than 10 microns in diameter, called PM10) can penetrate deep into the lungs and impair respiratory processes. Dust that contains heavy metals or other toxic compounds can also cause a wide range of acute and chronic health effects. 

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Where Are People Dying of Pollution?

Explore the map below to understand the impact of air pollution on human life in each country.

The most common health problems associated with air pollution include stroke, heart disease, lung disease, lower respiratory diseases, and cancer. Explore the map below to find out what percent of death in any given country can be attributed to outdoor fine particles.

Despite the grave health risks associated with air pollution, many countries still face challenges in meeting their clean air targets. However, some countries are making progress, such as the Philippines, Indonesia, and Brazil, among others. The global community needs to take action to reduce air pollution by making lifestyle changes, reducing energy consumption, and adopting environmentally conscious alternatives to wood-burning stoves, among others.

How Does Air Pollution Affect the Environment? 

Air pollution has significant negative impacts on the environment. Acid rain, caused by air pollutants such as sulphur dioxide and nitrogen dioxide, is harmful to natural ecosystems, interfering with the root’s cell division and ability to elongate, reducing essential nutrients for plants, and threatening wildlife, particularly aquatic animals. Eutrophication, the enrichment of a waterbody with minerals and nutrients that lead to excessive algae growth, blocks sunlight from underwater plants and consumes large amounts of oxygen in the water, resulting in the death of aquatic plants and animals. Human activities, such as energy production and fertiliser use, contribute significantly to eutrophication.

While air pollutants are distinguished from greenhouse gases, some air pollutants, such as ground-level ozone, possess warming power and can trap heat in the atmosphere. However, some air pollutants, like aerosol, have a positive effect on resisting climate change, as they possess cooling power by changing the amount of solar energy entering and leaving the atmosphere and forming clouds. Scientists are exploring the possibility of manipulating aerosols to slow down climate change, but controlling the number of airborne particles within a safe range remains a challenge. 

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What Can We Do?

There are many ways individuals can reduce their personal air pollution footprint, including using public transportation, reducing energy consumption, moderating waste, and using air filtration and purification systems to improve indoor air quality. Additionally, people can limit outdoor activities when air quality is at unhealthy levels and stay informed about real-time air quality conditions using apps.

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However, the problem of air pollution requires the collective efforts of individuals, communities, and governments worldwide. Governments can invest in energy-efficient power generation, improve waste management, and promote greener and more compact cities with energy-efficient buildings. Additionally, providing universal access to clean, affordable fuels and technologies and building safe and affordable public transport systems can help reduce air pollution. 

As we continue to map the most polluted cities in the world, let’s also work towards a future where clean air is a fundamental human right, and every individual has the opportunity to live a healthy and fulfilling life.