Problem 51 - A Complete Resource Book in Chemistry for JEE Main

Question

There is a possibility of melting of polar ice caps and increase in the level of sea water due to (a) greenhouse effect (b) acid rain (c) depletion of ozone layer (d) any one of these

Step-by-Step Solution

Answer

(a) greenhouse effect

Step 1: Understand the Problem

The problem is asking for the cause of melting polar ice caps and rising sea levels. We need to identify which environmental phenomenon listed contributes to these effects.

Step 2: Evaluate Each Option

Let's consider each option: (a) The greenhouse effect refers to the phenomenon where gases in Earth's atmosphere trap heat, leading to global warming and thus potentially causing the melting of polar ice caps and an increase in sea water levels. (b) Acid rain results from sulfur dioxide and nitrogen oxides in the atmosphere, causing acidity in rainwater, but does not directly impact sea level rise. (c) The depletion of the ozone layer relates to the reduction of ozone in the stratosphere, increasing UV radiation in other forms but indirect effects on ice caps melting. (d) This suggests one of the above options could be correct.

Step 3: Identify the Correct Answer

From the evaluation, the most direct cause of polar ice melting and rising sea levels is the greenhouse effect. Global warming due to the greenhouse effect directly contributes to the melting of ice caps.

Key Concepts

Greenhouse Effect

The greenhouse effect is a natural process vital for life on Earth. It involves gases in the atmosphere, such as carbon dioxide, methane, and water vapor, trapping heat from the sun. This trapped heat warms the planet, maintaining the temperatures necessary for survival. However, human activities have intensified this effect by increasing the concentration of these greenhouse gases.

• Burning fossil fuels for energy production and transportation has significantly increased carbon dioxide levels.
• Deforestation reduces the number of trees that can absorb carbon dioxide, exacerbating the issue.
• Industrial activities release other potent gases like methane, enhancing the greenhouse effect further.

This heightened greenhouse effect leads to global warming, a central factor contributing to the melting of polar ice caps and rising sea levels. The extra heat trapped in our atmosphere causes ice at the poles to melt faster than it would naturally, resulting in more water flowing into the oceans.

Polar Ice Caps Melting

Polar ice caps are vast sheets of ice covering the North and South Poles. They are crucial for regulating Earth's climate because they reflect sunlight, helping to keep our planet cool. Due to global warming, these ice caps are melting at an alarming rate.

• As ice melts, it loses its ability to reflect sunlight efficiently, causing further warming and more melting in a vicious cycle.
• Melting ice caps contribute fresh water to the ocean, increasing sea levels and altering marine ecosystems.

The loss of ice also impacts global weather patterns, potentially leading to more severe storms and unpredictable weather. Preserving these vital ice masses is essential to mitigate these detrimental changes.

Sea Level Rise

The rise in sea levels is a direct consequence of global warming and the associated melting of ice caps. Another contributing factor is the thermal expansion of sea water as it warms. Here’s how it unfolds:

• Warmer temperatures cause ocean water to expand, while melting ice adds more water volume, both leading to rising sea levels.
• Coastal areas around the world are at risk, with increased flooding and erosion affecting millions of people.
• Habitat loss for species dependent on coastal environments is also a significant concern.

This rise threatens to displace populations and disrupt ecosystems. Strategies to manage these impacts include improving coastal defenses and reducing greenhouse gas emissions to slow down global warming.