Current Affairs By Date

Context:

A new research, published in the journal Nature Climate Change has pointed at signs of slowing down overturning circulation of Antarctica and it’s happening decades earlier than predicted.

Probable Question:

Q. What is the Antarctic Overturning Circulation? Explain how it’s slowdown can accelerate global warming .

What is Overturning Circulation

Antarctica drives a global network of ocean currents called the “overturning circulation” that redistributes heat, carbon and nutrients around the globe.
In Antarctica, trillions of tonnes of cold, dense, oxygen rich water cascade off the continental shelf and sink to great depths.
This Antarctic “bottom water” then spreads north along the sea floor in deep ocean currents, before slowly rising, thousands of kilometres away.
The overturning is crucial to keeping Earth’s climate stable. It’s also the main way oxygen reaches the deep ocean.

Findings of the report:

Increased rate of slowdown: The overturning circulation has slowed by almost a third (30%) and deep ocean oxygen levels are declining. This is happening even earlier than climate models predicted.
Disruption in Antarctic cycle: Melting of Antarctic ice is disrupting the formation of Antarctic bottom water. The meltwater makes Antarctic surface waters fresher, less dense, and therefore less likely to sink. This puts the brakes on the overturning circulation.

Impacts of the slowdown

Oxygen reduction: As the flow of bottom water slows, the supply of oxygen to the deep ocean declines.
- The shrinking oxygen rich bottom water layer is then replaced by warmer waters that are lower in oxygen, further reducing oxygen levels.
Deep Ocean animals: Losses of oxygen may cause them to seek refuge in other regions or adapt their behaviour.
Intensification of global warming:
1. The overturning circulation carries carbon dioxide and heat to the deep ocean, where it is stored and hidden from the atmosphere.
2. As the ocean storage capacity is reduced, more carbon dioxide and heat are left in the atmosphere. This feedback accelerates global warming.

Sea level rise: Reductions in the amount of Antarctic bottom water reaching the ocean floor also increases sea levels because the warmer water that replaces it takes up more space (thermal expansion).
Pervasive consequences: The consequences of a slowdown will not be limited to Antarctica.
- The overturning circulation extends throughout the global ocean and influences the pace of climate change and sea level rise.
- It will also be disruptive and damaging for marine life.

ISRO’s new NavIC Satellite Launch

Context:

The Indian Space Research Organisation (ISRO) launched the first of the second-generation satellites for its navigation constellation successfully.

About the second-generation satellites:

Satellite Name	NVS-01, the first of ISRO’s NVS series of payloads.
Weight	2,232 kg
Launch Vehicle	Geosynchronous Satellite Launch Vehicle (GSLV) rocket
Onboard Technology	Rubidium atomic clock, developed by Space Application Centre-Ahmedabad.
Frequency Signals	It will send signals in a third frequency, L1, besides the L5 and S frequency signals that the existing satellites provide
Mission Life	More than 12 years for second-generation satellites, the existing satellites have a mission life of 10 years.

About Navigation with Indian Constellation (NavIC):

To meet the positioning, navigation and timing requirements of the nation, ISRO has established a regional navigation satellite system called Navigation with Indian Constellation (NavIC).
NavIC was erstwhile known as Indian Regional Navigation Satellite System (IRNSS).
NavIC is designed with a constellation of 7 satellites and a network of ground stations operating 24 x 7.
Three satellites of the constellation are placed in geostationary orbit, and four satellites are placed in inclined geosynchronous orbit.
The ground network consists of a control centre, precise timing facility, range and integrity monitoring stations, two-way ranging stations, etc.
Each of the seven satellites currently in the named NavIC, weighed much less — around 1,425 kg — at liftoff.
- They all rode the lighter Polar Satellite Launch Vehicle (PSLV), ISRO’s workhorse launch rocket.

Services Offered:

Types of services: Standard Position Service (SPS) for civilian users and Restricted Service (RS) for strategic users.
Frequency bands: These two services are provided in both L5 and S bands.
Coverage: The NavIC coverage area includes India and a region up to 1500 km beyond the Indian boundary.
Accuracy: NavIC signals are designed to provide user position accuracy better than 20m and timing accuracy better than 50ns.
Signals interoperability: NavIC SPS signals are interoperable with the other global navigation satellite system (GNSS) signals namely GPS,Glonass,Galileo, and BeiDou.
Constant speed: Unlike GPS, NavIC uses satellites in high geo-stationery orbit — the satellites move at a constant speed relative to Earth, so they are always looking over the same region on Earth.

News Source: Indian Express

Dengue Now a Nationwide Infection

Context:

The Indian Council of Medical Research (ICMR) confirmed that dengue’s infection geography, which was restricted to eight States in 2001, currently covers all the States and Union Territories in India.

Dengue has now breached the country’s last bastion, Ladakh.

About the news:

During the past two decades, there has been a significant geographical spread of dengue with an 11 fold increase and repeated outbreaks.
Rural areas contributed approximately 32% of the total cases in 2015-16 and have increased to 41%-45% now.
The ICMR said that the risk from dengue, which is now endemic in more than 100 countries, has been propelled by several factors, including climate change, increased urbanisation and increased travel.

About Dengue:

Dengue viruses are spread to people through the bite of an infected Aedes species (Ae. aegypti or Ae. albopictus) mosquito.
- These mosquitoes also spread chikungunya and Zika viruses.
Dengue is caused by one of any of four related viruses: Dengue virus 1, 2, 3, and 4. For this reason, people can be infected with dengue multiple times in their life.
The mosquitoes that spread dengue are found in most tropical and subtropical regions of the world, including many parts of the United States.
While many infections are asymptomatic or produce only mild illness, it can occasionally cause more severe cases, and even death.
Prevention and control of dengue depend on vector control. There is no specific treatment for dengue/severe dengue, and early detection and access to proper medical care greatly lower fatality rates of severe dengue.

Malnutrition Concerns of India

Context:

According to the Joint Malnutrition Estimates released by the UNICEF, the WHO and the World Bank, India continues to show a reduction in stunting and recorded 1.6 crore fewer stunted children under five years in 2022 than in 2012 commensurate with global and regional trends.

Findings of the report

Stunting:
1. Stunting among children under five years in India dropped from a prevalence rate of 41.6% in 2012 to 31.7% in 2022.
2. India’s share of the global burden of stunting declined from 30% to 25% in the past decade.

Wasting: The overall prevalence of wasting in 2022 was 18.7% in India, with a share of 49% in the global burden.
Obesity: The prevalence of obesity marginally increased in a decade from 2.2% in 2012 to 2.8% in 2022.

The decline in stunting in India is commensurate with National Family Health Survey (NFHS5) (2019-2021) data which estimated its prevalence at 35.5% as against 38% in NFHS4 (2016) and 48% in NFHS3 (2006).

What is malnutrition?

Malnutrition refers to deficiencies, excesses or imbalances in a person’s intake of energy and/or nutrients.
The term malnutrition covers 2 broad groups of conditions.
1. Undernutrition— It includes stunting (low height for age), wasting (low weight for height), underweight (low weight for age) and micronutrient deficiencies or insufficiencies (a lack of important vitamins and minerals).
2. The other is overweight, obesity and diet-related noncommunicable diseases (such as heart disease, stroke, diabetes, and cancer).

Critical Target of 1.5 Degree Celsius

Context:

The World Meteorological Organization (WMO) released two reports titled “Global Annual to Decadal Climate Update 2023-2027” and “State of Global Climate 2022.”

Findings of the Reports:

Annual Mean Global Surface Temperature: The annual mean global surface temperature between 2023 and 2027 will be 1.1 -1.8 degree Celsius higher than the baseline temperature of 1850-1900 or pre-industrial levels.
- In 2022, it was 1.15 degrees above the baseline, and by 2027, the average will exceed 1.5 degrees, a critical point beyond which there may be no return.

What is the 1.5 degree Celsius target?

The 1.5 degree Celsius target is the global climate target that aims to limit warming to said level by 2100, in order to prevent the planet from slipping into further climate crises.

Cancun COP16 (2010)	Countries agreed to limit the global average warming to below 2 degree Celsius.
Paris Agreement (2015)	Parties pledged to limit the average temperature rise to below 2 degree, while actively aiming for 1.5 degree above pre-industrial levels.
Intergovernmental Panel on Climate Change (IPCC), 2018	This was endorsed as a global target by the Intergovernmental Panel on Climate Change (IPCC) in 2018 and since then has been pursued in all climate dialogues.

Why is the 1.5 degree target critical?

IPCC Report on Anthropogenic Activities: In a special report of IPCC released in 2018, it was estimated that anthropogenic activities would have already caused 1 degree of warming, likely to reach 1.5 degree between 2030 and 2052 at the current rate.
Impacts of 2-Degree Warming: Frequent and intense heat waves, droughts, heavy precipitation, an additional 10 centimetre rise in sea level, destruction of ecosystems and mostly irreversible changes can be witnessed at the 2 degree level.
Need for Climate Action and Limiting Warming: The regional differences in warming across the planet and the vulnerability factors spell more urgency for climate action which must limit the average planetary warming to 1.5 degree.

Why are we missing the target?

Responsibility of Developed Countries: Historically, developed countries are responsible for a major chunk of Greenhouse Gas (GHG) emissions.
- Therefore, they are expected to assume more responsibility and implement climate action.
Climate Performance Index: The index over the years has shown that countries like Australia, the US, Japan, Russia and Canada have made little progress in meeting their pledges.
- Polluters like China, Iran and Saudi Arabia rank low in climate performance.
- There is little to no consideration for building back in a sustainable manner.
Ukraine conflict and Energy Crisis: The Ukraine conflict has further added to woes and sparked an energy crisis threatening climate goals.

Link between extreme weather events and the global rise in temperature

Precipitation Anomalies and Marine Heat Waves:
- WMO reports predict precipitation anomalies and increased marine heat waves.
- Comparatively fewer marine cold spells anticipated.

El Niño and Rising Temperatures:
- El Niño expected to strengthen, leading to higher temperatures.
- 98% likelihood of experiencing temperatures surpassing those of 2016 in the 2023-27 period.

Shrinking Cryosphere and Melting Greenland Ice Sheet
- Cryosphere, including glaciers in High-mountain Asia, Western North America, and South America, experiencing mass loss.
- Arctic Ocean warming accelerating melting of Greenland ice sheet, contributing to rising sea levels.

Impacts on Food Security and Agriculture:
- Climate change exacerbating food insecurity, displacement, and deaths.
- Negative effects on crop yields and increased risks of agricultural pests and diseases.

Additional Information:

About World Meteorological Organization (WMO):

It is an intergovernmental organization with a membership of 193 Member States and Territories.
It originated from the International Meteorological Organization (IMO), the roots of which were planted at the 1873 Vienna International Meteorological Congress.
Established by the ratification of the WMO Convention on 23 March 1950, WMO became the specialised agency of the United Nations for meteorology (weather and climate), operational hydrology and related geophysical sciences in 1951.
The Secretariat, headquartered in Geneva, is headed by the Secretary-General.
Its supreme body is the World Meteorological Congress.