“Burning fossil fuels is a cause of global warming.” Justify this statement.
“Burning fossil fuels is a cause of global warming.” Justify this statement.
Burning fossil fuels (such as coal and petroleum) releases large amounts of carbon dioxide () and other greenhouse gases into the atmosphere. These gases act like a blanket, trapping the infrared radiation (heat) reflected from the Earth's surface and preventing it from escaping back into space. This greenhouse effect leads to a progressive rise in the average temperature of the Earth's atmosphere, causing global warming. Therefore, burning fossil fuels is a major human activity that directly drives global warming.
Marking Scheme
- 1Stating that burning fossil fuels releases greenhouse gases, primarily carbon dioxide (). [1 Mark]
- 2Explaining that these gases trap heat/infrared radiation reflected from the Earth, leading to an increase in global temperatures (greenhouse effect). [1 Mark]
Hint
Identify the main gas released during the combustion of carbon-based fossil fuels and explain how it interacts with heat reflected from the Earth's surface.
Quick Oral Answer
Burning fossil fuels releases carbon dioxide, which is a greenhouse gas. This gas traps heat in the Earth's atmosphere that would otherwise escape into space, leading to an increase in global temperatures known as global warming.
Analysis & Explanation
The statement is justified by examining the chemical and physical consequences of combustion. Fossil fuels are carbon-based compounds. When they are burned, they undergo combustion to release carbon dioxide (). is a greenhouse gas that is transparent to incoming solar radiation but absorbs outgoing thermal infrared radiation. This trapped heat increases the thermal energy of the atmosphere, leading to global warming. This is a prime example of how human activities change the environment around us, as discussed in the introductory sections of environmental impact.
Common Mistakes
- 1Confusing global warming with ozone layer depletion (e.g., stating that fossil fuels destroy the ozone layer, whereas ozone depletion is primarily caused by chlorofluorocarbons or CFCs).
- 2Failing to mention the specific mechanism of heat trapping by greenhouse gases.
Interesting Facts
Carbon dioxide levels in the atmosphere are currently higher than at any point in at least the past 800,000 years, primarily due to the burning of fossil fuels since the Industrial Revolution.
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Frequently Asked Questions
How many marks does this question carry in CBSE Class 10 Science 2012?
This question carries 2 marks in the CBSE Class 10 Science 2012 examination.
Which chapter does this question come from in Science?
This question is from the chapter "Our Environment" in the CBSE Class 10 Science syllabus.
What topic does this question cover in Science?
This question covers the topic "How do our Activities Affect the Environment?" from CBSE Class 10 Science.
What type of question is this in the CBSE Class 10 Science 2012 paper?
This is a Short Answer question from Section A in the CBSE Class 10 Science 2012 paper.