THE CONTEXT: Severe flooding across Europe has become a pressing issue, displacing tens of thousands as regions like Austria, the Czech Republic, Poland, and Romania face relentless rainfall. The role of climate change in exacerbating extreme rainfall events cannot be ignored, and such floods will intensify as global temperatures continue to rise.
RELATIONSHIP BETWEEN CLIMATE CHANGE, RISING TEMPERATURE AND INCREASING RAINFALL:
- Warmer Air Holds More Moisture: Air’s capacity to hold moisture increases by approximately 7% for every 1°C rise in temperature. As global temperatures rise due to climate change, the atmosphere can have significantly more water vapor. This means that when conditions lead to precipitation, more moisture is available to form rain, resulting in heavier downpours.
- Role of Greenhouse Gases and Global Warming: Burning fossil fuels releases greenhouse gases like carbon dioxide and methane, creating a “blanket” around the Earth. These blankets trap heat in the atmosphere, leading to global warming. Higher temperatures accelerate the evaporation of water from oceans, lakes, and soils, adding more water vapor to the atmosphere.
- Changes in Precipitation Patterns: With more moisture in the air, precipitation events become more intense. When weather systems trigger rainfall, the enhanced moisture content leads to heavier and more prolonged rain.
- Shift from Snow to Rain: In high-altitude and cold regions, warming temperatures cause more precipitation to fall as rain rather than snow. This can lead to rapid runoff and increased flood risk, as rainwater flows quickly into rivers and streams, unlike snow, which melts gradually.
- Storm Intensity and Frequency: Climate change affects atmospheric circulation patterns, potentially leading to more frequent and intense storms. These storms can carry large amounts of moisture and release it over short periods, causing flash floods.
- Delayed Weather Systems: Slower-moving weather systems can result in prolonged rainfall over the same area, increasing the likelihood of flooding.
- Increased Likelihood of Record Rainfall: Studies have shown that climate change has made extreme rainfall events more common. For example, what used to be a once-in-a-decade heavy rainfall event may now occur 1.5 times per decade at 1.5°C of global warming.
- Soil Saturation and Runoff: Increased heavy rainfall saturates the soil, reducing its ability to absorb water. Subsequent rains lead to more surface runoff, exacerbating flood conditions.
GLOBAL FLOOD RISKS:
- Increased Frequency of Extreme Events: At 1.5°C warming, heavy precipitation events that were once-in-a-decade occurrences are projected to happen 1.5 times per decade and be over 10% wetter.
- Higher Risk with Greater Warming: At 2°C warming, these events could occur 1.7 times per decade and be 14% wetter. With 4°C warming, the frequency could nearly triple, with 30% more rain.
- Economic Impact: Without adaptation measures, damages from flooding in Europe alone could reach €48 billion per year by 2100 under a 3°C warming scenario.
- Global Population at Risk: Approximately 1.8 billion people, nearly a quarter of the world’s population, are directly exposed to one-in-100-year floods.
- Increase Since 2000: The proportion of people exposed to floods has increased by 24%, driven by population growth and settlement patterns.
- Growth in High-Risk Areas: People living in very high flood-risk areas have risen by 122% since 1985. Rapid urbanization, especially in flood-prone regions, contributes to the growing number of people at risk.
REGIONS EXPOSED TO HIGH FLOODS:
ASIA:
- South and East Asia Dominance: About 89% of people exposed to high flood risk live in low- and middle-income countries.
- China: Approximately 395 million people are exposed to significant flood risk.
- India: Around 390 million people face high flood exposure.
- Bangladesh and Pakistan: They are highly vulnerable due to their geographical location and river systems.
AFRICA:
- Sub-Saharan Regions: Increasing flood incidents, affecting agriculture and displacing communities.
- Kenya: Recent floods have resulted in loss of life and property, highlighting the region’s vulnerability.
LATIN AMERICA:
- Brazil: Floods have damaged areas equivalent to the size of the UK, displacing over half a million people.
EUROPE:
- Germany: Highest number of people at risk, with recent floods causing significant damage.
- France and the Netherlands: Also, among the top countries with high flood exposure.
- Recent Flood Events: Austria, the Czech Republic, Poland, Romania, Italy, Norway, Sweden, and Slovenia have experienced severe floods due to heavy rainfall.
MIDDLE EAST:
- United Arab Emirates and Oman: Experienced the heaviest rainfall since records began, indicating changing precipitation patterns.
IPCC PREDICTIONS FOR RAINFALL EVENTS AT DIFFERENT WARMING SCENARIOS
- At 1.5°C Warming: According to the Intergovernmental Panel on Climate Change (IPCC), if global temperatures rise by 1.5°C above pre-industrial levels—a threshold the world is increasingly close to hitting—heavy precipitation events that were once expected to occur once every decade are projected to happen 1.5 times every ten years. These events are also expected to be over 10% wetter than historical averages.
- At 2°C Warming: With a temperature increase of 2°C, these once-in-a-decade heavy rainfall events are projected to occur 1.7 times per decade and be 14% wetter. This escalation indicates a significant increase in the frequency and intensity of extreme rainfall events.
- At 4°C Warming: When global warming reaches 4°C above pre-industrial levels, heavy rainfall events that historically occurred once every ten years could happen almost three times per decade. These events could also release 30% more rainfall, substantially increasing the risk of severe flooding.
POTENTIAL ECONOMIC IMPACTS IN EUROPE:
- Increased Flood Damage Costs: Without effective adaptation measures, Europe faces substantial economic risks due to increased flooding. The European Commission’s Joint Research Centre projects that if temperatures rise to 3°C by 2100, annual flood damages could escalate to €48 billion.
- Greater Population Exposure: Under the 3°C warming scenario, the number of Europeans exposed to flooding is expected to triple by 2100. This heightened exposure threatens lives and places additional strain on emergency services and disaster response mechanisms.
- Strain on Infrastructure: Frequent and severe flooding can damage critical infrastructure such as roads, bridges, and utilities. Repairing and reinforcing infrastructure to withstand these events will require significant investment.
- Agricultural and Environmental Losses: Flooding can lead to soil erosion, crop loss, and degradation of arable land, impacting food security and the agricultural sector’s profitability.
- Insurance and Economic Burden: Increased flooding can lead to higher insurance premiums and greater financial losses for businesses and homeowners. Governments may also face increased expenditure on disaster relief and recovery efforts.
- Disruption of River Networks: In 2023, one-third of Europe’s river network experienced flows exceeding high flood thresholds, with 16% exceeding severe levels. Such disruptions can affect trade, transport, and ecosystems dependent on these waterways.
THE WAY FORWARD:
- Transition to Renewable Energy Sources: As of 2021, renewable energy accounts for about 29% of global electricity generation. Increasing this share is crucial to reducing greenhouse gas emissions.
- Enhancing Energy Efficiency: Energy efficiency could contribute 40% of the emissions reductions needed to meet global climate goals by 2040.
- Implementing Carbon Pricing Mechanisms: As of 2022, 64 carbon pricing initiatives have been implemented or scheduled worldwide, covering about 21.5% of global greenhouse gas emissions.
- Adherence to International Climate Agreements: Nations must meet or exceed their Nationally Determined Contributions (NDCs) to limit global warming to below 2°C.
- Implementation of the Sendai Framework: Develop national and local strategies to reduce disaster risks, including those from floods. The framework aims to reduce global disaster mortality and economic losses by 2030 substantially.
- Resilient Infrastructure Design: Develop buildings and infrastructure that can withstand flooding. Investing $1 in resilient infrastructure can save $4 in reconstruction costs.
THE CONCLUSION:
The increasing frequency and intensity of extreme rainfall events underscore the urgent need to address climate change. As global temperatures rise, the risk of severe flooding is expected to grow, necessitating proactive measures to mitigate and adapt to these environmental challenges.
UPSC PAST YEAR QUESTIONS:
Q.1 The Intergovernmental Panel on Climate Change (IPCC) has predicted a global sea level rise of about one metre by AD 2100. What would be its impact in India and the other countries in the Indian Ocean region? 2023
Q.2 Describe the major outcomes of the 26th session of the Conference of the Parties (COP) to the United Nations Framework Convention on Climate Change (UNFCCC). What are the commitments made by India in this conference? 2021
Q.3 Climate Change’ is a global problem. How India will be affected by climate change? How Himalayan and coastal states of India will be affected by climate change? 2017
Q.4 Discuss the consequences of climate change on the food security in tropical countries. 2023
MAINS PRACTICE QUESTION:
Q.1 Discuss the role of climate change in influencing extreme rainfall and flooding events. How do rising global temperatures contribute to these phenomena?
SOURCE:
https://indianexpress.com/article/explained/explained-climate/climate-change-flooding-9572471/
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