Global Climate Change
Short Questions
1. What is the average global surface temperature of Earth?
Answer: The average global surface temperature of Earth is approximately 14°C.
2. Which year showed the least temperature difference from the 20th-century average (1985–2015)?
Answer: The year 1985 showed the least temperature difference from the 20th-century average.
3. What is the primary human-related cause of global warming?
Answer: Fossil fuel combustion is the primary human-related cause of global warming.
4. Which greenhouse gas has the highest contribution to global emissions?
Answer: Water vapour has the highest contribution to global greenhouse gas emissions.
5. What is the rate of global sea level rise per year?
Answer: Global sea level rises at a rate of about 3 mm per year.
6. Name one glacier that has significantly retreated due to global warming.
Answer: The Gangotri Glacier has significantly retreated due to global warming.
7. What is coral bleaching caused by?
Answer: Coral bleaching is caused by rising ocean temperatures expelling symbiotic algae.
8. What does paleoclimatology study?
Answer: Paleoclimatology studies the weather and climate of Earth’s past using proxy data.
9. Which international treaty aims to limit global warming to 1.5°C?
Answer: The Paris Agreement aims to limit global warming to 1.5°C.
10. What is the National Action Plan on Climate Change (NAPCC) year of initiation?
Answer: The NAPCC was initiated in 2008.
11. Which natural factor can cool Earth by reflecting sunlight?
Answer: Volcanic eruptions can cool Earth by reflecting sunlight with aerosols.
12. What is the term for the habitable zone where Earth lies?
Answer: The Goldilocks Zone is the habitable zone where Earth lies.
13. What is the primary source of methane emissions?
Answer: Agriculture and livestock are the primary sources of methane emissions.
14. Name one tool used to study past climates.
Answer: Ice cores are used to study past climates.
15. What is the approximate CO2 concentration considered harmful by WHO?
Answer: CO2 concentrations above 350 ppm are considered harmful by WHO.
Long Questions
1. Why is the 0.8°C rise in global temperature considered significant?
Answer: The 0.8°C rise in global temperature, though small, has profound impacts due to its rapid rate and global scale. It triggers extreme weather events like heat waves, floods, and cyclones, and causes sea level rise, threatening coastal regions. These changes disrupt ecosystems, agriculture, and human livelihoods, making it a major concern.
2. How do scientists measure global temperature anomalies?
Answer: Scientists measure global temperature anomalies by comparing daily temperatures at land and ocean stations to a 30-year average for each location. These differences, called anomalies, are averaged monthly and seasonally to track long-term trends. Data from ships, buoys, and satellites ensure a comprehensive global picture.
3. What role do greenhouse gases play in global warming?
Answer: Greenhouse gases like CO2, methane, and nitrous oxide trap heat in the atmosphere, increasing Earth’s temperature through the greenhouse effect. Human activities, such as fossil fuel burning and deforestation, significantly raise their concentrations, enhancing heat retention. This leads to global warming and associated climate changes.
4. Why is sea level rise a major concern for India?
Answer: Sea level rise threatens India’s extensive coastline, with projections of 9–90 cm by 2100, endangering cities like Mumbai and regions like Kutch and Kerala. It risks flooding deltas of major rivers like Ganga and Krishna, disrupting agriculture and habitats. Coastal communities face increased flooding and saline groundwater intrusion.
5. How does global warming contribute to the retreat of glaciers?
Answer: Global warming raises temperatures, causing glaciers to melt faster than they accumulate snow, leading to retreat, as seen in the Gangotri Glacier’s 850-meter recession over 25 years. This reduces freshwater availability and contributes to sea level rise. Retreating glaciers are a key indicator of climate change.
6. What are the natural causes of climate change mentioned in the chapter?
Answer: Natural causes include variations in solar output, which affect insolation, and Milankovitch oscillations, altering Earth’s orbit and tilt. Volcanic eruptions release aerosols that temporarily cool the planet, and shifts in the Goldilocks Zone influence long-term climate. These factors have driven climate changes historically.
7. How does deforestation impact climate change?
Answer: Deforestation reduces the number of trees that absorb CO2, increasing atmospheric greenhouse gas levels and contributing to global warming. Burning forests releases stored carbon, further elevating CO2 concentrations. It also alters rainfall patterns and increases regional temperatures, exacerbating climate change.
8. What are the tools used in paleoclimatology to study past climates?
Answer: Paleoclimatology uses proxy data like ice cores, tree rings, coral reefs, and ocean sediments to study past climates. Ice cores reveal annual climate variations, tree rings show environmental conditions, and coral reefs indicate ocean temperatures. These tools help reconstruct climate patterns over millennia.
9. What measures has India taken to combat climate change?
Answer: India has implemented the National Action Plan on Climate Change (NAPCC, 2008) with eight sub-missions for mitigation and adaptation. The National Adaptation Fund for Climate Change (NAFCC) supports vulnerable states, and the National Clean Energy Fund (NCEF) funds renewable energy R&D. These initiatives promote sustainability and resilience.
10. Why is the current warming trend more concerning than past climate changes?
Answer: The current warming trend is driven by human activities, particularly since the mid-20th century, and occurs at a rate ten times faster than natural post-glacial warming. It is caused by rapid increases in greenhouse gases from fossil fuels and deforestation. This unprecedented speed and scale threaten ecosystems and human societies globally.
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