Question

The dissolution of ozone layer causes ozone hole in the blanket surrounding the atmosphere. What e the ill effects of ozone hole? (a) Greenhouse effect (b) Global warming (c) Acid rain (d) UV rays reaching the earth.

Short answer

The correct answer is (d) UV rays reaching the earth, as the ozone hole allows for more UV radiation to penetrate the atmosphere and reach the surface, causing various health and environmental issues.

Step-by-step solution

Identify the Role of the Ozone Layer

Recognize that the ozone layer in the Earth's atmosphere serves to block a significant portion of the sun's harmful ultraviolet (UV) radiation from reaching the surface of the planet.

Understand the Formation of the Ozone Hole

Understand that the ozone hole refers to the thinning of the ozone layer, primarily caused by human-made chemicals like chlorofluorocarbons (CFCs), which leads to a decrease in ozone concentration.

Explain the Ill Effects of the Ozone Hole

Determine the detrimental effects of the ozone hole which include increased UV radiation reaching Earth, leading to potential health issues like skin cancer, cataracts, and immunosuppression, as well as environmental impacts on ecosystems.

Identify the Incorrect Effects

Recognize that while the greenhouse effect and global warming are related to atmospheric issues, they are not a direct result of the ozone hole. Acid rain is primarily caused by sulfur dioxide and nitrogen oxides, not ozone depletion.

Choose the Correct Answer

Select the answer that correctly identifies the ill effects of the ozone hole, which is (d) UV rays reaching the earth, because it directly relates to the function of the ozone layer in absorbing UV radiation.

Key concepts

Ozone Layer Depletion

The ozone layer, a protective shield in the Earth's stratosphere, absorbs most of the sun's harmful ultraviolet (UV) radiation. When we talk about ozone layer depletion, we're referring to the decrease in ozone concentration within this layer. This thinning is caused primarily by human-made chemicals, notably chlorofluorocarbons (CFCs), which were widely used in aerosols and refrigeration systems. When CFCs reach the stratosphere, they are broken down by UV light, releasing chlorine atoms that then deplete ozone molecules. This process significantly reduces the ozone layer's ability to filter out UV radiation.

Over time, this depletion has led to the formation of the so-called ozone hole, particularly over the Antarctic region, which poses serious consequences for both human health and the environment. Consequently, international agreements, such as the Montreal Protocol, have been implemented to phase out the production of ozone-depleting substances, which has helped in the recovery of the ozone layer, although it is a slow process.

Ultraviolet (UV) Radiation

Ultraviolet radiation is a type of energy emitted by the sun, which can be harmful to living organisms. It is categorized into three types based on wavelength: UVA, UVB, and UVC. The ozone layer effectively filters out most UVC and a significant portion of UVB, while UVA reaches the Earth's surface relatively unchanged.

With the ozone layer depletion, more UVB is able to reach the surface, leading to a myriad of health issues. UVB radiation can cause skin cancer, cataracts, and can even affect the immune system. Additionally, it can have detrimental effects on the DNA of plants and can be harmful to plankton populations in the ocean's photic zone, which is crucial for oceanic food webs and global carbon cycling. Understanding the impact of increased UV exposure is essential in recognizing the importance of the ozone layer in our planet's health.

Environmental Impact of Ozone Depletion

The environmental impacts of ozone depletion are broad and deeply concerning. Increased UV radiation as a result of the ozone hole can lead to reduced yields in crops and altered growing conditions, as plants are sensitive to changes in UV levels. This has implications not just for food supply, but also for the natural ecosystems where these plants play key roles.

In aquatic ecosystems, UV radiation can affect the developmental stages of fish, shrimp, crab, amphibians, and other animals, especially those near the surface. The breakdown of the ozone layer can also lead to an unbalanced ecosystem, as it disrupts the food chain starting with phytoplankton, the primary producers in oceanic food webs. On a wider scale, changes in the levels and patterns of UV radiation can affect various chemical and biological processes on Earth, disturbing biodiversity and altering biochemical cycles.