Impact of Climate Change

Learning Outcomes:

1. Understand how climate change affects agriculture and food security globally and regionally.
2. Examine the impact of climate change on water stress, availability, and related security issues.
3. Learn about the rise in sea levels and its consequences on coastal areas.
4. Explore how climate change threatens ecosystems and biodiversity.
5. Assess the direct and indirect effects of climate change on human health.

Agriculture and Food Security

Climate change significantly influences crop yields and the types of crops that can be cultivated by altering factors such as water availability for irrigation, solar radiation, and pest prevalence. Changes in temperature and precipitation patterns are key determinants of agricultural productivity across regions.

1. Temperature Variations: Increased temperatures affect crops differently across regions. A 1-3°C rise benefits crops in temperate zones, while a 1-2°C increase negatively impacts crops in seasonally dry tropical areas. A rise above 3°C globally reduces agricultural production.
2. Decreased Water Availability: The Third Assessment Report (IPCC, 2001) emphasized that the poorest nations face severe reductions in agricultural productivity due to decreased water availability and changing insect/pest incidence.
3. Regional Crop Losses: South Asia may experience a loss of 10% in staples like rice, millet, and maize by 2030.
4. High Latitude and Coastal Land Changes: Melting snow increases arable land in high-latitude regions while sea-level rise reduces coastal agricultural lands.
5. Erosion and Salinity: Shoreline erosion, land submergence, and salinity due to sea-level rise impact agriculture by inundating low-lying areas.
6. Glacier Melt Impact: Studies indicate that the Himalayan glaciers, feeding Asia’s significant rivers (Ganges, Indus, etc.), are retreating faster and may disappear by 2035. This endangers rural livelihoods in Asia and Africa, increasing their food insecurity.

Important Note: A conifer typically exhibits a conical shape, with a primary stem tapering toward the top and lateral branches arranged in an upward succession.

Impacts on Indian Agriculture

India’s predominantly rain-fed agriculture depends heavily on monsoon patterns. Changes in rainfall timing and amount pose serious threats to both the economy and food security.

1. Monsoon Dependency: Summer monsoon provides about 70% of annual rainfall, crucial for Indian agriculture. Predictions indicate a decline in summer rainfall by the 2050s.
2. Regional Rainfall Shifts: Western India may see increased rainfall, while central India could experience a 10-20% winter rainfall decrease.
3. Arid Region Challenges: Arid areas, like northwest India, could face water resource challenges due to climate change.
4. Productivity Decline: Increased temperature and reduced water availability will lower crop productivity, especially in the Indo-Gangetic plains.
5. Increased Fertilizer Use: Rising temperatures may necessitate higher fertilizer usage, leading to increased GHG emissions and costs.
6. Increased Agricultural Variability: Higher frequencies of droughts, floods, and storms will amplify agricultural production variability.

Important Note: The sloth bear (labiated bear), native to the Indian subcontinent, is a nocturnal insectivore that consumes termites, honeybee colonies, and fruits.

Water Stress and Water Insecurity

Access to water is a growing concern, particularly in developing nations, with climate change expected to amplify existing stresses on water resources.

1. Projected Water Stress: By 2020, 75 to 250 million individuals could face heightened water stress due to climate change.
2. Food Security Impact: Increasing water scarcity intensifies food insecurity and escalates water competition within and among countries.
3. Global Temperature and Glaciers: Global warming has reduced mountain glaciers and snow cover, affecting water flow from significant mountain ranges (Himalayas, Andes).
4. Freshwater Availability: By the 2050s, freshwater availability in Asia’s large river basins is projected to decrease.
5. Hydrological Cycle Alteration: A warmer climate accelerates the hydrological cycle, changing rainfall patterns and river flows.
6. Flood Frequency: Research indicates an increase in severe floods in large river basins during the 20th century, challenging societies and infrastructure.
7. Rising Temperature Effects: Warmer conditions alter freshwater lakes and rivers, impacting water quality and aquatic life.

Important Note: The Indian Flying Fox, a fruit-eating bat, roosts in colonies of hundreds to thousands in large trees near fields, ponds, and roads.

Impacts on Water Situation in India

Water resources in India, especially those fed by the Himalayan glaciers, are increasingly pressured by climate change.

1. Himalayan Glacier Changes: Extensive land use in the Himalayas has caused frequent hydrological disasters and pollution. The Gangotri glacier retreats by 28 meters annually.
2. River Flow Alterations: Increased glacial melt may temporarily enhance summer flows before ultimately decreasing as glaciers diminish.
3. Rainfall Changes: Notable shifts in rainfall patterns have been observed in the 20th century, impacting water supplies.
4. Flooding Issues: Rivers in the Indo-Gangetic Plains periodically change course, creating flooding problems, as recently seen in Kosi.
5. Increased Food Production Needs: Food production must increase to 300 million tons by 2020 to support India’s population, emphasizing water resource challenges.
6. Groundwater Overexploitation: Increased groundwater abstraction, driven by agricultural, industrial, and domestic demands, threatens sustainability.

Comparative Table: Water Use and Future Demands

Important Note: Saponins, found in the Soap Nut tree, are water-soluble glucosides that create froth, form emulsions, and absorb gases like carbon dioxide.

Rise in Sea Levels

Sea levels are rising due to thermal expansion and ice sheet melt, accelerating since the 1990s. IPCC predicts rapid sea-level rises, threatening coastal areas.

1. Rapid Displacement: 3–4°C global temperature rise may displace 330 million people via flooding.
2. Storm Intensification: Warmer seas may generate more intense tropical storms.

Impacts on Coastal States in India

Indian coastal regions face severe threats from sea-level rise.

1. Land Loss and Flooding: Coastal states like Goa, Maharashtra, and Gujarat face potential land submersion and infrastructure damage.
2. Displacement: Flooding may displace many, stressing urban amenities.
3. Salinity Issues: Sea percolation into groundwater raises salinity, diminishing freshwater supplies.
4. Worsened Cyclones: Coastal states like Orissa may encounter more intense cyclones, threatening coastal biodiversity.

Important Note: The grizzled giant squirrel lives in riparian forests along the Kaveri River, classified as near threatened by the IUCN.

Ecosystems and Biodiversity

Climate change leads to biodiversity loss, impacting both individual species and the ecosystems sustaining economic growth.

1. Species Extinction: Human-induced climate impacts will drive species extinction from tropics to poles.
2. Marine Ecosystems: Ocean acidification harms coral reefs, shell-forming organisms, and related ecosystems.

Impacts on India’s Biodiversity

India’s rich ecosystems face significant climate change threats.

1. Mountain Ecosystems: Himalayan biodiversity faces fragmentation due to rising temperatures and human activities.
2. Desert Expansion: Indian deserts show signs of expansion, altering their natural attributes.
3. Coastal Ecosystems: Mangroves act as natural flood barriers, but rising sea levels threaten their existence.

Important Note: Narcotic substances for smoking are termed fumitories, while those for chewing are masticatories.

Climate Change and Health

Climate change introduces numerous health hazards globally, affecting air quality, water supply, and food security.

1. Disease Spread: Increased temperatures accelerate the spread of infectious diseases, such as malaria and dengue.
2. Heat Waves: More frequent and severe heat waves may result in increased mortality.
3. Waterborne Diseases: Droughts and floods compromise hygiene, increasing diarrhoeal disease incidences.
4. Malnutrition: Climate-related reductions in crop yields elevate the prevalence of malnutrition.

**

Important Note**: *Soap Nut Tree* produces saponins, which yield soap froth in water.

MCQ: Which factor contributes most to rising sea levels?

1. Increased solar radiation
2. Thermal expansion of seawater
3. Reduced freshwater lakes
4. Human activities in coastal areas
   Answer: 2. Thermal expansion of seawater.