4.3 Flashcards
What are greenhouse gases?
Gases that trap heat in the Earth’s atmosphere, including CO₂, methane (CH₄), nitrous oxide (N₂O), and water vapor.
What do greenhouse gases do in the atmosphere?
They absorb and re-radiate heat, warming the Earth’s surface.
What is the greenhouse effect?
A natural process where greenhouse gases trap heat in the atmosphere, keeping Earth’s temperature stable.
Why is the greenhouse effect important for life on Earth?
It keeps Earth warm enough to support life by maintaining a habitable temperature range.
How have humans affected the greenhouse effect?
By burning fossil fuels, deforestation, and industrial activities, humans have increased greenhouse gases, enhancing the greenhouse effect and leading to global warming.
What do ice cores reveal about past CO₂ levels?
Ice cores show CO₂ levels over time, providing a record of atmospheric changes and climate patterns up to 800,000 years ago.
How do ice cores indicate past temperature trends?
Ratios of isotopes in ice cores correlate with temperature changes, allowing scientists to infer past climates.
What is positive feedback in the context of climate change?
A process where a change amplifies further change, such as melting ice reducing reflection and causing more warming.
What is negative feedback in climate systems?
A process that counteracts change, helping to stabilize the system, such as cloud formation reflecting sunlight and cooling the surface.
How does increased CO₂ lead to a feedback cycle with water vapor?
More CO₂ warms the atmosphere, increasing evaporation and water vapor, which then traps more heat, creating a positive feedback loop.
What role does methane play in climate feedback cycles?
Methane is a potent greenhouse gas, and its release from melting permafrost can lead to further warming in a positive feedback cycle.
How do scientists use feedback loops to predict climate changes?
By analyzing positive and negative feedbacks, scientists can estimate future temperature and climate patterns.
What can historical CO₂ levels from ice cores suggest about future climate trends?
Past CO₂ increases are linked to temperature rises, suggesting current CO₂ trends may lead to further warming.
How does the melting of polar ice contribute to climate feedback?
Melting ice reduces the Earth’s albedo (reflectivity), causing more solar absorption and accelerating warming.
