The correct option is (c).
Explanation
Global Warming refers to the gradual increase in the average temperature of the Earth's lower atmosphere. This phenomenon is primarily driven by the "Greenhouse Effect," where specific gases trap heat radiating from the Earth.
- Statement 1 is Incorrect: Global warming is caused by the increased concentration of greenhouse gases, particularly carbon dioxide ($CO_2$), in the atmosphere. These gases absorb infrared radiation and prevent heat from escaping into space. A decreased concentration of $CO_2$ would reduce the greenhouse effect, potentially leading to cooling rather than warming.
- Statement 2 is Correct: The rise in global temperatures leads to the thermal expansion of seawater and the melting of polar glaciers and ice sheets. These processes contribute directly to a rise in sea levels, which poses significant risks to coastal ecosystems and human settlements.
- Statement 3 is Correct: Most conventional fuels, such as coal, petroleum, and natural gas, are carbon-based. The process of combustion involves the reaction of these fuels with oxygen. This chemical reaction releases energy and produces carbon dioxide ($CO_2$) as a primary byproduct, thereby increasing the atmospheric load of greenhouse gases.
Key Takeaway: Global warming is the result of an enhanced greenhouse effect caused by the accumulation of gases like $CO_2$, which are released in large quantities through the combustion of carbon-based fuels.