Problem 10 - Biology: Concepts and Applications

Question

The Montreal Protocol banned use of ______ which contribute(s) to ozone depletion. a. DDT b. CFCs c. fossil fuels d. sulfur dioxides

Step-by-Step Solution

Answer

The Montreal Protocol banned the use of CFCs.

Step 1: Identify the Focus of the Montreal Protocol

The Montreal Protocol is an international treaty designed to protect the ozone layer. It specifically targets substances that are known to deplete the ozone layer.

Step 2: Consider the Options

Review the options provided: - a. DDT - b. CFCs - c. fossil fuels - d. sulfur dioxides Determine which of these are known for causing damage to the ozone layer.

Step 3: Determine the Correct Substance

CFCs, or chlorofluorocarbons, are well-known for their role in ozone depletion. They are the primary substances targeted by the Montreal Protocol due to their harmful impact on the ozone layer.

Step 4: Confirm the Correct Answer

By cross-referencing the options with the known focus of the Montreal Protocol, it's confirmed that CFCs are the substance that contribute to ozone depletion and were banned by this treaty.

Key Concepts

Ozone Depletion

Ozone depletion refers to the thinning and reduction of the ozone layer in the Earth's stratosphere. This layer acts as a protective shield, absorbing most of the Sun's harmful ultraviolet (UV) radiation. Without it, living organisms, including humans, would be at risk from increased UV exposure, leading to health issues such as skin cancer and cataracts.
The ozone layer's depletion was first noticed in the 1970s. This alarming trend was attributed to man-made chemicals such as chlorofluorocarbons (CFCs) that break down ozone molecules.
Protecting this vital layer has since become an international priority, underscoring the importance of efforts like the Montreal Protocol.

Chlorofluorocarbons (CFCs)

Chlorofluorocarbons, commonly known as CFCs, are organic compounds that contain carbon, chlorine, and fluorine. Though once widely used due to their low toxicity and chemical stability, they have been found to cause significant environmental harm when released into the atmosphere.
Here's how they impact the ozone layer:

• When released, CFCs rise into the upper atmosphere.
• They eventually reach the stratosphere, where they are broken down by UV radiation.
• This breakdown releases chlorine atoms, which interact with ozone molecules, leading to the destruction of ozone.

This destructive cycle prompted international measures to phase out CFCs and other ozone-depleting substances to preserve the ozone layer.

International Treaty

An international treaty is an agreement between nations to adhere to specific terms for a common cause, often complex issues like environmental protection. The Montreal Protocol is one such exemplary treaty, coming into force in 1989.
It was formulated specifically to address the global concern of ozone depletion and has been remarkably successful. Under this treaty:

• Signatory countries agreed to phase out production and consumption of ozone-depleting substances, like CFCs.
• It promoted international cooperation and was a significant step in global environmental policy.
• The protocol is periodically reviewed and updated, including stricter amendments to ensure ongoing protection of the ozone layer.

The Montreal Protocol remains a pivotal example of how international collaboration can lead to effective environmental action and positive outcomes.