After the discovery of the Antarctic ozone hole, scientists later detected a second major seasonal ozone hole over which region of the Earth?

Introduction / Context:
The ozone layer in the Earth's stratosphere plays a crucial role in absorbing harmful ultraviolet radiation from the Sun. In the late twentieth century, scientists discovered a dramatic thinning of this layer over Antarctica, popularly called the ozone hole. Continued monitoring later revealed significant ozone depletion episodes in another part of the world as well. This question asks about the region where a second major ozone hole or severe ozone thinning was detected, highlighting the global nature of atmospheric problems caused by ozone depleting substances.

Given Data / Assumptions:

• The first widely known ozone hole was discovered over Antarctica.
• We are now concerned with a second major ozone hole.
• Options include Tibet, Sweden, Northern hemisphere, and Antarctica.
• We interpret Northern hemisphere as referring to the broader Arctic and high latitude northern regions.

Concept / Approach:
Ozone depletion is driven by chemical reactions involving chlorofluorocarbons (CFCs) and other ozone depleting substances, which are activated under very cold stratospheric conditions and in the presence of polar stratospheric clouds. These conditions are strongest over Antarctica but can also occur in the Arctic and other high latitude areas in the Northern hemisphere. As monitoring improved, scientists reported severe seasonal ozone losses and an ozone hole like phenomenon over parts of the Arctic and the wider Northern hemisphere on some occasions. Therefore, when the question mentions a second ozone hole, it refers to this significant depletion over the Northern hemisphere rather than again pointing to Antarctica or a very local area like Tibet or Sweden.

Step-by-Step Solution:
Step 1: Recall that the famous first ozone hole was discovered over Antarctica in the Southern hemisphere. Step 2: Understand that similar ozone depletion chemistry can also occur in the Arctic and high latitude Northern hemisphere under suitable cold conditions. Step 3: Remember that scientists later reported severe thinning of the ozone layer over the Arctic and parts of the Northern hemisphere, describing it as a second ozone hole. Step 4: Evaluate the options: Tibet and Sweden are specific locations and do not represent the broader pattern of hemispheric ozone loss. Step 5: Conclude that the correct broad region referred to as the location of the second ozone hole is the Northern hemisphere.

Verification / Alternative check:
Environmental reports and atmospheric science summaries discuss how ozone depletion, once thought to be mostly an Antarctic problem, was later observed substantially in the Arctic and high latitude Northern hemisphere. These episodes led to headlines about a second ozone hole appearing above the Arctic region. Data from satellite and ground based measurements confirm significant seasonal ozone loss in the Northern hemisphere stratosphere during certain years. Meanwhile, Tibet and Sweden are just specific places within the Northern hemisphere and are not named as the main location of a second ozone hole in scientific literature.

Why Other Options Are Wrong:
Tibet is a high altitude region on the Tibetan Plateau, but it is not singled out in scientific literature as the main location of a second ozone hole; ozone depletion is discussed more broadly at the hemispheric and polar scale, so option A is incorrect. Sweden, although located in the Northern hemisphere and affected by ozone fluctuations, is only one country and not the primary label used for describing the second ozone hole, making option B wrong. Antarctica is associated with the first and most famous ozone hole, not the second one; repeating Antarctica would ignore the distinction the question is making, so option D is also incorrect. The phrase Northern hemisphere correctly captures the broad region where the second major ozone depletion episode was identified.

Common Pitfalls:
Some students may instinctively choose Antarctica again because they strongly associate ozone holes with that continent, missing the clue about a second hole. Others might mistakenly pick a specific place like Sweden or Tibet without considering that ozone depletion patterns are usually described in terms of hemispheres or polar regions. To avoid these errors, carefully read the wording and remember that the first ozone hole was over Antarctica, while later serious ozone depletion events were reported over the Arctic and the wider Northern hemisphere.

Final Answer:
The second major ozone hole or severe seasonal thinning of the ozone layer was detected over the Northern hemisphere, particularly in the Arctic region.