The question asks for the contemporary meaning of "climate change." This term has a specific scientific definition, particularly in the context of current global environmental discussions. We need to identify the option that accurately reflects this widely accepted definition.
Correct Option: C) Change in long-term weather patterns mainly due to human activity
This option accurately captures the essence of climate change as understood today. It distinguishes climate from weather, emphasizes the long-term nature of the change, and correctly identifies human activities (like burning fossil fuels, deforestation) as the primary cause of the current accelerated climate change.
The question asks why increasing carbon dioxide (CO2) in the atmosphere leads to a rise in temperature. This phenomenon is known as the greenhouse effect. We need to identify which type of radiation CO2 primarily absorbs to cause this warming.
D) the infrared part of the solar radiation
This option correctly identifies that carbon dioxide absorbs the infrared radiation. While the sun emits some infrared radiation, the crucial part for the greenhouse effect is the infrared radiation re-emitted by the Earth's surface after being warmed by solar radiation. CO2 absorbs this terrestrial infrared radiation, trapping heat and causing the atmosphere to warm.
The question asks to identify the year recorded as the hottest globally. This requires knowledge of recent climate data and trends, which are often reported by meteorological organizations.
Correct Option: B) 2016
Which gas is the largest overall contributor to the greenhouse effect?
Carbon dioxide
Methane
Water vapour
Nitrous oxide
The question asks to identify the gas that is the largest overall contributor to the greenhouse effect. This requires understanding the relative contributions of various greenhouse gases present in the Earth's atmosphere.
Correct Option: C) Water vapour is the largest overall contributor to the greenhouse effect. It accounts for about 36% to 70% of the greenhouse effect, depending on how cloud feedback is accounted for. Its abundance and strong absorption of infrared radiation make it the most impactful natural greenhouse gas.
The question asks about the potential impacts of a global temperature increase exceeding 3Β°C above pre-industrial levels. We need to evaluate each statement based on scientific understanding of climate change impacts.
Statement 1: Terrestrial biosphere tends toward a net carbon source. As global temperatures rise, increased respiration by plants and microbes, coupled with more frequent droughts and wildfires, can lead to ecosystems releasing more carbon dioxide than they absorb. This turns the terrestrial biosphere from a carbon sink into a net carbon source. This is a well-documented potential impact of significant warming.
Statement 2: Widespread coral mortality will occur. Coral reefs are highly sensitive to temperature changes. Even a 1-2Β°C increase can cause significant coral bleaching and mortality. A 3Β°C increase would undoubtedly lead to widespread, if not near-total, coral mortality globally. This statement is accurate.
Statement 3: All the global wetlands will permanently disappear. While climate change, sea-level rise, and altered precipitation patterns will severely impact wetlands, it is an overstatement to say that all global wetlands will permanently disappear even with a 3Β°C rise. Some wetlands might adapt, shift, or persist in altered forms, though many will be lost. The word "all" makes this statement too extreme.
Statement 4: Cultivation of cereals will not be possible anywhere in the world. Climate change will significantly impact agricultural productivity, especially for cereals, leading to reduced yields and shifts in suitable growing areas. However, it is highly unlikely that cultivation of cereals will become impossible anywhere in the world. Some regions might even see temporary benefits, or new areas might become suitable, while others suffer. Adaptation measures and technological advancements also play a role. This statement is an extreme overgeneralization.
Based on this analysis, statements 1 and 2 are likely impacts of a 3Β°C global temperature increase, while statements 3 and 4 are too extreme.
Correct Option: B) 1 and 2 only
The question asks to identify the correct statements about 'Earth Hour'. We need to evaluate each statement based on factual knowledge about Earth Hour.
C) 2 and 3 only
Statements 2 and 3 are correct descriptions of Earth Hour's activities and objectives.