Climate change, deforestation worsened impact of SE Asia cyclones, Pg18

Key Highlights:

• A study published on December 11 found that rising global temperatures, rapid urbanization, and deforestation worsened the impact of cyclones in Sri Lanka, Malaysia, Indonesia, and Thailand.
• Cyclone Ditwah struck Sri Lanka on November 27, while Cyclone Senyar made landfall in Indonesia on November 26 and Malaysia on November 27.
• Extreme rainfall events have become more intense, with Sri Lanka experiencing a 28% to 160% increase in heavy five-day precipitation and the Malacca Strait region seeing a 9% to 50% increase.
• The floods caused widespread damage and resulted in at least 1,600 deaths across the four countries, with economic losses in Sri Lanka estimated between $6 billion and $7 billion.

Detailed Insights:

• The study by the World Weather Attribution (WWA) group highlighted that while the affected countries experience annual monsoon floods, the proportions of the floods this year reached unprecedented levels due to climate change.
• Rising global temperatures, about 1.3 degrees Celsius warmer since the mid-1800s, lead to increased evaporation and moisture in the atmosphere, intensifying precipitation during storms and causing severe flooding.
• Sea surface temperatures (SSTs) in the North Indian Ocean were 0.2 degrees Celsius higher than the 1991-2020 average during the cyclones, adding energy for storm development and evaporation, contributing to heavy rainfall.
• Deforestation, driven by plantation crops, infrastructure projects, and illicit timber felling, exacerbated the impact of extreme rainfall by accelerating runoff and reducing slope stability, particularly in Sri Lanka and Indonesia.
• Rapid urbanization has increased the number of people living in high-intensity flood-risk zones, leading to greater economic losses and damage to critical infrastructure, such as roads, railways, and cropland.

Key Concepts Involved:

• Deforestation: The clearing of forests for other land uses, such as agriculture, urbanization, or logging.
• Global Warming: The long-term heating of Earth's climate system observed since the pre-industrial period due to human activities.
• Runoff: The flow of water that occurs when excess stormwater, meltwater, or other sources flows over the earth's surface.