World’s Physical Geography

Model Answer

Air masses are large volumes of air that have a uniform temperature and moisture content, extending from the Earth’s surface to the lower stratosphere. They typically cover vast areas, sometimes thousands of kilometers, and can influence weather patterns over large regions. The characteristics of an air mass are determined by the temperature and humidity, which are shaped by the region where the air mass originates.

Types of Air Masses

1. Maritime Tropical (mT): Warm and humid, originating over tropical oceans.
2. Maritime Polar (mP): Cold and humid, forming over the oceans in polar latitudes.
3. Continental Polar (CP): Cold and dry, originating from land in the polar regions.
4. Tropical (CT): Hot and dry, originating over land in tropical regions.
5. Continental Arctic (CA): Extremely cold and dry, originating from the North Pole.
6. Continental Antarctic (CAA): Extremely cold and dry, originating from the South Pole.

Significance of Air Masses

Air masses influence local weather by carrying the temperature and moisture characteristics from their source regions to new areas. Fronts are formed when air masses meet, leading to significant changes in weather patterns. Air masses also modify their weather based on the surface they move over. For example, a continental polar air mass can pick up moisture from warmer waters.

Air masses contribute to precipitation, drought, and variations in weather. For instance, hot and dry air masses may lead to drought conditions, while moist air masses can cause rain and thunderstorms. Thus, air masses play a crucial role in determining the climate and weather of different regions.

Model Answer

Heatwaves, defined as prolonged periods of abnormally hot weather, are increasing globally due to several interconnected causes:

1. Climate Change: The primary cause of rising heatwaves is climate change. Human activities such as burning fossil fuels and deforestation have significantly increased greenhouse gases in the atmosphere, raising global temperatures. This warming has created a higher baseline for heat events, making extreme temperatures more frequent and intense. For instance, the 2019-2020 Australian fire season, known as ‘Black Summer,’ was exacerbated by these climate shifts.
2. Urbanization and Heat Island Effect: Rapid urbanization, with more concrete and asphalt, leads to urban heat islands, where cities experience higher temperatures than surrounding rural areas. This localized heating effect amplifies the severity of heatwaves in urban regions.
3. Land Use Changes: Deforestation, desertification, and changes in land cover affect the Earth’s surface, altering heat absorption and reflection, and contributing to more intense heatwaves.

Consequences of Increased Heatwaves

Heatwaves have significant impacts on both human and environmental systems:

1. Health: Heatwaves increase the risk of dehydration, heat cramps, heat exhaustion, and heatstroke, especially among vulnerable populations like the elderly and children.
2. Agriculture and Food Security: Prolonged heat stress damages crops, reduces yields, and disrupts livestock production. This, combined with water scarcity, further threatens food security.
3. Infrastructure and Energy: The demand for cooling increases electricity consumption, which can overload power grids, leading to blackouts. Additionally, infrastructure is stressed, and there may be disruptions to daily life, particularly in industries like agriculture, construction, and tourism.
4. Biodiversity: Heatwaves can destroy ecosystems. For example, heat stress leads to coral bleaching, causing the loss of marine biodiversity.

Adaptation and Mitigation Strategies

1. Adaptation:
   • Early Warning Systems: Implement systems to predict and prepare for extreme heat events.
   • Public Health Measures: Raise awareness about heatwave risks and provide cooling shelters for vulnerable populations.
   • Community Support: Establish support systems for those most at risk during heatwaves.
2. Mitigation:
   • Reduce Greenhouse Gas Emissions: Transition to renewable energy sources and reduce carbon footprints to slow climate change.
   • Sustainable Agriculture and Water Management: Promote water conservation and efficient farming practices.
   • Urban Heat Island Reduction: Increase green spaces, cool roof programs, and enhance urban vegetation to lower urban temperatures.

In conclusion, addressing the rise in heatwaves requires global cooperation, efficient adaptation and mitigation measures, and a concerted effort to reduce greenhouse gas emissions.