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Blog > Ecology > What You Need to Know About Monsoon Season

What You Need to Know About Monsoon Season

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In this article, we’ll dive into what makes the monsoon season so important, the challenges it brings, and how climate change is making it harder to predict.
Ecology
2024-11-04T00:00:00.000Z
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For millions across the world, the monsoon season is more than just a seasonal weather pattern - it’s actually a lifeline. It brings rain to dry lands, sustains agriculture, and fills vital water reservoirs that communities rely on. But climate change is changing monsoon seasons across the globe. 

As climate change intensifies, these once predictable seasonal weather patterns are becoming increasingly erratic, transforming the monsoon into an unpredictable force. As global temperatures rise, monsoon patterns are shifting, causing shorter bursts of heavy rain in some areas and long stretches of drought in others. These changes don’t just disrupt daily life, they also lead to more extreme weather events like floods and landslides, impacting both ecosystems and local economies. 


👉 In this article, we’ll dive into what makes the monsoon season so important, the challenges it brings, and how climate change is making it harder to predict.

What is Monsoon Season?

Monsoon season is a period of intense rainfall that sweeps across many regions of the world, particularly in parts of Asia, Africa, and the Americas. Contrary to popular belief, a monsoon isn’t just a period of heavy rain - it's actually a shift in wind patterns that brings moist air from the oceans onto land. This shift is driven by seasonal changes in temperature between the land and sea, which create a pressure difference that pulls moist air inland. As this moisture encounters warmer landmasses, it condenses into rain, often bringing heavy downpours and thunderstorms.

Monsoon seasons vary greatly by region. In South Asia, for example, the monsoon rains typically start in June and last until September, bringing over 70% of the region’s annual rainfall. Meanwhile, East Africa’s “long rains” occur from March to May, followed by shorter rains in October and November. Each region’s monsoon season has its own timing and intensity, influenced by geography, elevation, and proximity to the ocean.

However, while on one hand monsoons are essential for replenishing water supplies and supporting agriculture, they can also be unpredictable and, at times, dangerous. This is especially true as climate change alters the stability of these wind and rainfall patterns. As we’ll explore, rising global temperatures are making monsoons less predictable, increasing the risk of both extreme rain events and dry spells that can severely impact the communities that rely on these rains.

Key monsoon seasons across the world: 

Region Monsoon Season Characteristics Benefits Risks
South Asia June to September Characterised by heavy, sustained rainfall; brings 70-80% of annual rainfall to countries like India and Bangladesh. Vital for agriculture, particularly rice and tea crops; replenishes water reserves. Flooding, landslides, and infrastructure damage due to intense rain; affects urban areas.
East Africa Long rains: March to May
Short rains: October to December
Long rains bring steady, moderate rain; short rains are intense but shorter-lasting. Supports agriculture (especially in Ethiopia, Kenya, and Uganda) and helps fill reservoirs. Flooding and crop damage during intense rains; potential for drought if rains are delayed.
West Africa April to October Marked by thunderstorms and heavy rains, especially along the Guinea Coast and Sahel region. Essential for crops like millet, maize, and sorghum; refills lakes and rivers. Increased risk of malaria and waterborne diseases; risk of crop loss during heavy storms.
Australia and Oceania November to March Northern Australia sees intense tropical storms and cyclones; high humidity and warm temperatures. Provides water for arid regions; crucial for the Northern Territory and Queensland crops. Cyclones and flooding; damage to coastal infrastructure and risks to wildlife habitats.
North America (Southwest) July to September Short, intense storms with lightning; primarily in Arizona, New Mexico, and Northern Mexico. Important for desert ecosystems and helps control wildfire risk; refills groundwater. Flash floods in canyons and arid areas; risk of lightning-induced fires during dry storms.
East Asia June to August Heavy rains in South China, Korea, and Japan; impacts coastal and mountainous areas. Supports rice farming and water reservoirs; cools temperatures in summer. Risk of landslides, especially in mountainous areas; flash floods in urbanised regions.
South America (Amazon Basin) December to March Period of intense rainfall in the Amazon rainforest; high humidity and tropical storms. Supports the Amazon ecosystem; vital for biodiversity and indigenous communities. Increased river levels causing floods; impact on transportation within the rainforest.

The Science Behind Monsoon Season

Monsoons are complex climate phenomena that result from the interactions between land, ocean, and atmospheric systems. While many people associate monsoon season with heavy rain, monsoons are primarily defined by seasonal shifts in wind patterns. This shift, driven by temperature differences between land and ocean, brings moist air from the sea to land, resulting in significant rainfall.

How Do Monsoons Form?

The formation of a monsoon begins with the sun's warming of the Earth’s surface. During summer in the Northern Hemisphere, large landmasses like South Asia and Africa heat up more quickly than nearby oceans. This creates a temperature difference between the hot land and the relatively cooler ocean. As the air over land heats up, it rises, creating a low-pressure area. In contrast, the air over the cooler ocean is denser and sinks, forming a high-pressure area.

The pressure difference causes winds to move from the high-pressure zone over the ocean to the low-pressure zone over land. These winds, which carry significant moisture from the ocean, are known as monsoon winds. When this moist air reaches land and rises due to heat or encountering mountainous terrain, it cools and condenses, forming clouds and, eventually, heavy rainfall. This cycle of rising hot air and moisture-laden winds drives the monsoon season’s intense and sustained rains.

Regional Differences in Monsoon Systems

Monsoons vary widely across the globe, adapting to the unique geography of each region. The South Asian monsoon, for example, is the world’s largest, bringing between 70 and 80% of annual rainfall to countries like India, Nepal, and Bangladesh. In contrast, the North American monsoon affects a smaller area, bringing rain primarily to parts of the southwestern United States and northern Mexico, where it helps alleviate the dry summer heat. Similarly, the East Asian monsoon influences countries like China, Japan, and Korea, with rain occurring from June to August and impacting agricultural cycles and water resources.

In each of these regions, local geography, such as mountain ranges and coastal features, affects how monsoon winds behave. For example, the Western Ghats and the Himalayas in India cause moist monsoon air to rise, cooling it rapidly and leading to intense rainfall on the windward side of these ranges.

The Role of Monsoons in the Global Climate System

Monsoons play an important role in the global climate system, acting as a natural balancing force. By transporting moisture from the oceans to land, they help regulate temperatures and precipitation patterns. Monsoons also redistribute heat energy, moving warm, moist air from the tropics to higher latitudes. This movement helps moderate global temperatures and maintain biodiversity by supporting ecosystems that rely on seasonal rainfall.

Additionally, monsoons are essential for the global carbon cycle. The dense vegetation that flourishes in monsoon regions, like rainforests and wetlands, absorbs carbon dioxide from the atmosphere, acting as a natural carbon sink. This helps offset emissions and mitigate the effects of climate change. However, as climate change disrupts monsoon patterns, this natural balance faces increased stress, leading to feedback loops where irregular monsoons can further affect global climate patterns.

The Science of Monsoon Variability

Scientific studies have shown that monsoon strength and timing are highly sensitive to atmospheric and oceanic conditions, particularly in relation to phenomena like El Niño and La Niña. These oceanic events, part of the El Niño-Southern Oscillation (ENSO) cycle, cause fluctuations in sea surface temperatures in the Pacific Ocean, which in turn influence global weather patterns, including monsoons. An El Niño event, for example, often leads to drier-than-average monsoons in South Asia, while La Niña is associated with wetter monsoon seasons.

Understanding the science behind monsoons is essential for predicting how they may continue to change under the influence of global warming. As climate change alters sea surface temperatures and atmospheric circulation, scientists are closely studying these interactions to anticipate how future monsoons might behave. By deepening our knowledge of monsoon dynamics, we can better prepare for the risks and opportunities that monsoon seasons bring, especially in a changing climate.

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What’s the Difference Between Monsoons and Tropical Storms?

Monsoons, hurricanes, typhoons, cyclones, and tropical storms are all weather phenomena, but they aren’t the same thing. Monsoons are seasonal wind patterns that bring heavy rain to certain regions as a result of atmospheric shifts. Unlike storms, a monsoon isn’t a single weather event but rather a period of rainy weather driven by changing wind directions.

Hurricanes, typhoons, and cyclones are all types of tropical storms that vary mainly by region and intensity. These storms form over warm ocean waters and are characterised by strong winds and heavy rain, but they’re named differently depending on their location: in the Atlantic and Northeast Pacific, they’re called hurricanes; in the Northwest Pacific, they’re typhoons; and in the South Pacific and Indian Ocean, they’re cyclones. Tropical storms are similar to these but are generally less intense, with maximum sustained wind speeds below 73 miles per hour (118 km/h). Once a tropical storm surpasses this wind speed, it’s classified as a hurricane, typhoon, or cyclone depending on the region.

In short, monsoons are distinct seasonal patterns, while hurricanes, typhoons, and cyclones are powerful storm systems with regional naming variations.

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Why the Monsoon Season Matters

Monsoon season plays an important role, especially in regions that rely on its rainfall for drinking water, agriculture, and economic stability. For millions, the monsoon brings much-needed water to reservoirs, rivers, and soil, creating better conditions for growing staple crops like rice, tea, and millet. In fact, around 20% of the world's population relies on the monsoon rains, especially those who are residing in South Asian countries. 

Beyond agriculture, monsoon rains also help maintain local ecosystems by supporting diverse plant and animal species. In places like the Amazon Basin and East Africa, these seasonal rains nurture forests, grasslands, and wetlands, which in turn provide habitats for countless species and support biodiversity. The rains also help keep temperatures down, cooling the air and providing some relief from the intense heat typical in many monsoon regions.

However, the monsoon season is a double-edged sword. While it brings life and renewal, it can also bring destruction. Intense rainfall can quickly lead to flooding, which can displace communities, damage infrastructure, and disrupt local economies. In areas with mountainous terrain, landslides triggered by heavy rains can wipe out entire villages and roads. The risks posed by these events make it essential for communities to prepare for both the benefits and the potential hazards of monsoon season, particularly as climate change amplifies these effects.

The benefits of monsoon season: 

Benefit Description
Water Supply Replenishment Monsoon rains help refill rivers, lakes, and reservoirs, providing essential drinking water and supporting local communities and agriculture.
Agricultural Support Heavy rains create ideal conditions for growing water-intensive crops like rice, tea, and sugarcane, essential for the food supply and local economies.
Temperature Regulation The cooling effect of rainfall helps lower temperatures, providing relief from extreme heat in many monsoon regions.
Soil Fertility Enhancement Monsoon rains help restore soil moisture and nutrients, making land more fertile and suitable for farming.
Support for Ecosystems and Biodiversity The rains sustain diverse ecosystems, including forests, wetlands, and grasslands, which are home to many plant and animal species.
Groundwater Recharge Monsoon rains help recharge groundwater levels, a critical source of water for many arid and semi-arid regions.
Hydroelectric Power Generation In regions with dams and hydroelectric facilities, monsoon rains increase water levels, boosting electricity production.

The risks of monsoon season: 

Risk Description
Flooding Intense rainfall can lead to severe flooding, especially in low-lying and urban areas, displacing communities and causing widespread damage to infrastructure.
Landslides Heavy rains on mountainous or deforested terrain can trigger landslides, endangering lives and obstructing roads and access to remote areas.
Waterborne Diseases Flooded areas can become breeding grounds for diseases such as cholera, dengue, and malaria, posing significant health risks to affected populations.
Crop Damage Excessive rainfall can damage crops, leading to reduced yields and financial losses for farmers, especially if fields become waterlogged.
Infrastructure Damage Intense rain and flooding can damage roads, bridges, and buildings, disrupting transport and essential services.
Disruption of Local Economies Monsoon-related disasters can halt business operations, tourism, and local markets, affecting income and economic stability in impacted regions.
Power Outages Flooding and high winds can damage power lines and infrastructure, leading to prolonged power outages in affected areas.

Climate Change and the Changing Monsoon

Climate change is altering the monsoon season in ways that are becoming increasingly visible and challenging. Rising global temperatures are disrupting established weather patterns, causing shifts in the timing, duration, and intensity of monsoon rains. In some regions, these changes are leading to shorter, more intense downpours, while other areas experience prolonged dry spells or even drought conditions when the rains fail to arrive as expected.

How is Climate Change Impacting Monsoon Patterns?

Rising temperatures influence the way moisture is absorbed and released into the atmosphere. With a warmer climate, the air holds more moisture, resulting in heavier and more sudden rainfall when monsoon winds pull moist air from oceans over land. This increased moisture content has a dual effect: in some areas, it leads to intense rainfall and flooding, while in others, the shifting atmospheric conditions cause dry spells and delayed rains. Both situations bring their own set of risks, from floods and landslides to droughts and crop failures.

These changes are particularly pronounced in regions where monsoons are already variable. In South Asia, for example, rain patterns are shifting in such a way that the traditional early June onset is becoming less predictable, affecting farmers who plan their planting around the start of the monsoon. A similar shift is happening in East Africa, where the once-reliable long and short rain seasons are no longer as steady, impacting agricultural cycles and water availability.

Increased Frequency of Extreme Weather Events

One of the starkest consequences of climate change on the monsoon season is the rise in extreme weather events. As warmer temperatures drive more intense rainfall events, the likelihood of severe floods, landslides, and cyclones increases. These events often hit urbanised and densely populated areas the hardest, leading to human displacement, loss of life, and damage to infrastructure. For example, in the Himalayas and other mountainous regions, sudden downpours has destabilised slopes, leading to landslides that wipe out villages, roads, and essential infrastructure.

And the extreme events aren’t limited to rain and floods. Warmer global temperatures also contribute to heatwaves, especially before monsoon rains arrive. These intense heat periods not only increase evaporation rates but also make the soil more vulnerable to erosion once the rains do arrive. This means that areas that experience both heatwaves and heavy rains face an elevated risk of environmental degradation and infrastructure damage.

Economic and Agricultural Impacts

The economic implications of climate-altered monsoon seasons are also significant. For regions that are heavily reliant on agriculture, the shifting and unpredictable rain patterns make it difficult to grow staple crops. In India, for example, rice and wheat yields can vary dramatically with changes in rainfall timing and intensity. Smallholder farmers, who often lack access to adaptive resources or technology, are particularly vulnerable. Crop failures lead to food shortages, increased prices, and even economic strain at the national level.

Water availability is another area deeply impacted by monsoon shifts. In countries where monsoon rains are essential for replenishing rivers, lakes, and reservoirs, delayed or insufficient rainfall leads to water shortages that impact drinking water supplies, agriculture, and industry. The need to manage these changes is pressing, as populations grow and demand for water rises.

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Monsoon Season and Climate Resilience

Addressing the impacts of climate change on monsoon seasons requires a dual approach of adaptation and mitigation. Mitigating further climate change involves reducing emissions, transitioning to renewable energy sources, and promoting carbon management practices. Lowering carbon emissions can help stabilise global temperatures, potentially slowing or reversing some of the changes to monsoon patterns.

At the same time, communities must adapt to the current and projected shifts in monsoon behavior. This includes investing in resilient infrastructure, such as improved drainage systems, flood defenses, and water management technologies. 

Sustainable agriculture practices, such as crop diversification and soil conservation, can also help reduce vulnerability to erratic weather. Additionally, developing early-warning systems for floods, landslides, and extreme weather events can give communities more time to prepare and reduce the loss of life and property.

👉 Building resilience to the changing monsoon season is essential for protecting ecosystems, economies, and communities. Governments, businesses, and communities must work together to adopt practices that both mitigate climate change and strengthen resilience to its effects. By prioritising sustainable development, investing in adaptive infrastructure, and promoting carbon management strategies, societies can better prepare for the evolving challenges posed by monsoon season in a warming world.

How Greenly Can Help Your Company

As climate change continues to alter monsoon patterns and increase the frequency of extreme weather events, businesses must adapt to new environmental realities. Greenly is here to support companies on their journey toward more sustainable and resilient operations. By providing a suite of carbon management solutions, Greenly helps organisations understand and reduce their environmental footprint, preparing them to respond effectively to climate risks and regulatory pressures.

Carbon Management

Greenly’s platform enables companies to track their carbon emissions across all scopes - direct (Scope 1), indirect (Scope 2), and those throughout their supply chain (Scope 3). Lowering emissions not only supports global climate goals but also builds resilience by ensuring that your company is prepared for the changing environmental landscape.

Actionable Insights and Tailored Emissions Reduction Plans

Greenly goes beyond measurement, offering recommendations to help companies make practical, science-based changes. Greenly can help you create customised action plans aimed at reducing emissions across energy, transportation, waste, and more. These steps can significantly impact your company’s ability to handle the disruptions associated with climate change, such as energy supply challenges and operational risks.

Building a Sustainable Supply Chain

Greenly offers tools to assess and mitigate the carbon footprint of suppliers and partners. Greenly’s solutions support sustainable procurement, helping companies to work with suppliers who are aligned with their climate goals. This approach helps reduce Scope 3 emissions while building resilience across the entire supply chain.

👉 Greenly empowers companies to take control of their environmental impact. By adopting carbon management practices, building sustainable supply chains, and ensuring regulatory compliance, your company can work towards sustainability. Get in touch with us today to learn more. 

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