15.04.25

Atmospheric River (AR) Event: In April 2025, the US experienced heavy rain, strong winds, and thunderstorms due to an AR, highlighting the increasing attention on this phenomenon due to climate change.

Definition: ARs are “rivers in the sky,” narrow bands transporting large amounts of water vapor from tropical oceans to continental regions. The “Pineapple Express” is a notable example.

Characteristics: ARs can be up to 1,600 km long and 400-600 km wide, carrying water vapor equivalent to the Mississippi River’s flow, or

Categorization: ARs are categorized from Category 1 (weak, beneficial) to Category 5 (exceptional, hazardous), based on their impact, with higher categories causing significant flooding and destruction.

Formation: ARs form from high evaporation over warm tropical oceans, guided by low-level jet streams toward mid-latitudes, condensing into rain or snow when forced upward by mountains or fronts.

Global Impact: ARs are most common in mid-latitudes and responsible for over 90% of poleward water vapor transport.

ARs and India: India experiences numerous AR events, mainly during the monsoon season, with ARs linked to major floods like those in Uttarakhand (2013) and Kerala (2018).

Climate Change Impact: Rising temperatures increase atmospheric moisture, intensifying ARs and leading to longer, wider, and more extreme events, doubling the frequency of intense ARs. Warmer air can hold about 7% more moisture for each 1°C increase

Hurricane-Like Conditions: ARs can cause hurricane-like conditions with intense rainfall, cyclone-force winds, and high waves.

Increased intensity: While frequency may not increase, the intensity of ARs is expected to rise, leading to more severe flooding worldwide.

Birth Anniversary: Celebrated on April 14th, marking the 135th birth anniversary of Dr. B.R. Ambedkar.

Key Figure: Principal architect of the Indian Constitution and a major advocate for social justice, known as the ‘Father of the Indian Constitution.’

Key Official Commemoration: A ceremony will be held at Prerna Sthal, Parliament House Lawns, on April 14th, 2025.

Dignitaries Involved: The President, Vice President, Prime Minister, and Lok Sabha Speaker are among those scheduled to pay floral tributes.

Public Access: The venue will be open to the public until noon.

Additional Services: Dr. Ambedkar Foundation will assist visitors and provide bus services to Dr. Ambedkar National Memorial (Mahaparinirvan Bhoomi).

First Law Minister: He served as the first Law and Justice Minister of independent India.

Dalit Rights

Educational and Political Contributions: Established organizations and movements like the Bahishkrit Hitakarini Sabha and Independent Labour Party.

Economic Impact: Influenced the establishment of the Reserve Bank of India. Advocated for labor reforms, including reducing factory hours and promoting minimum wages.

India’s Support: India, along with 62 other nations, voted in favor of the first global carbon tax on the shipping industry, as decided at the International Maritime Organisation (IMO).

Goal: Aims to cut greenhouse gas emissions from ships and promote cleaner technologies, taking effect in 2028.

Tax Framework: Ships over 5,000 gross tonnage must use cleaner fuels or pay a tax ($100-$380 per tonne of CO₂) based on emissions.

Revenue Generation: Expected to

Shipping’s Impact: The shipping industry contributes ~3% of global greenhouse gas emissions and wasn’t included in agreements like the Paris Agreement.

India’s Shipping Growth: India aims to be a top 5 shipbuilding nation by 2047 with its fleet growing to 1,530 ships by 2023, and is third in ship recycling. Major ports have increased cargo capacity.

Criticism: The deal has faced criticism for failing to address the climate finance needs of developing countries, revenue is allocated for only maritime sector decarbonization and also carbon pricing is expected to reduce shipping emissions by only 10% by 2030, far short of the IMO’s own target of at least 20%.

Opposition: Oil-rich nations like Saudi Arabia, the UAE, Russia, and Venezuela opposed the tax.

First Direct Observation: Scientists have directly observed Plastic Ice VII for the first time, a unique water phase previously only theorized.

Hybrid Properties: Plastic Ice VII exhibits both solid and liquid characteristics. Water molecules are fixed in

Plasticity: The “plastic” refers to its ability to deform under pressure like a malleable substance, not to synthetic materials.

Discovery Method: The discovery was made using neutron beam technology at the Institut Laue-Langevin, subjecting water to extreme pressures (up to 60,000 bars) and temperatures (326°C).

Conditions for Formation: Requires extreme pressure (above 30,000 bars) and high temperature (above 177°C)

Significance: Plastic Ice VII is believed to exist deep within icy planets and moons (e.g., Neptune, Europa, Titan).

Difference from other ices: Unlike common ice (Ice Ih) with a hexagonal structure, and Ice VII with a dense cubic structure, Plastic Ice VII has mobile water

Implications: Understanding Plastic Ice VII is crucial for planetary science, impacting theories about water distribution and potential habitability on icy celestial bodies.