Climate Change and Global Warming Questions and Answers

Answer: B

The Global Warming Potential of carbon dioxide is 1 by definition, so it is the least among the gases listed. Methane has a GWP of about 25 over 100 years, nitrous oxide of about 300, and sulphur hexafluoride of more than 20,000. The answer is \(\mathrm{CO_{2}}\).

Answer: D

The region that is not an Atmospheric Brown Cloud hotspot is Australia.

The ABC hotspots identified in the UNEP assessment are East Asia, South Asia, South-East Asia, southern Africa and the Amazon basin, where biomass burning and fossil fuel use produce thick layers of aerosol. Australia has no comparable regional haze layer, so it is not listed. East Asia, southern Africa and the Amazon basin are listed hotspots.

Answer: A

Both statements are correct and the reason explains the assertion.

The 1991 eruption of Mount Pinatubo put large amounts of sulphur dioxide into the stratosphere, where it became sulphate aerosol. These sulphate particles reflect incoming sunlight away from the Earth, and global temperatures fell for the next two to three years. That is exactly the reason (R) given. The other codes call one statement incorrect or deny the link, and neither fits the event.

Answer: A

The gas that does not contribute to climate change is the option the key gives as NO.

Nitric oxide is short-lived and is not a greenhouse gas, although it takes part in the reactions that form ozone. Ozone, sulphur hexafluoride and the hydrofluorocarbons are all greenhouse gases: ozone absorbs infrared radiation in the troposphere, SF₆ has an extremely high global warming potential and the HFCs are potent synthetic gases. Of the four, only NO is left as the one outside the group.

Answer: C

REDD stands for Reducing Emissions from Deforestation and Forest Degradation.

It is a climate mitigation mechanism under the UNFCCC in which developing countries are paid for keeping forests standing and so cutting the carbon dioxide released by clearing and degradation. The other options change the words: it is not 'recurring' emissions, it does not reduce 'environmental degradation', and it does not concern degradable deposits of waste.

Answer: A

Permafrost is permanently frozen subsurface soil, rock or sediment that stays at or below 0 °C for at least two consecutive years, and it is found in polar and high mountain regions.

It has nothing to do with frozen leaves or needles, and 'temporarily frozen' contradicts the word permafrost, so those options are wrong.

Testing each of the remaining options against the same fact shows that every one of them fails on the point the question is asking about, which confirms the keyed answer.

Answer: D

The order of increasing carbon intensity is nuclear, then natural gas, then oil, then bituminous coal. Nuclear power releases almost no carbon dioxide in operation, natural gas has the lowest carbon content per unit of energy among fossil fuels, oil is higher, and coal is the highest.

The other options place coal, oil or nuclear in the wrong position, for instance putting nuclear last or coal before natural gas.

Testing each of the remaining options against the same fact shows that every one of them fails on the point the question is asking about, which confirms the keyed answer.

Answer: C

In REDD+ initiatives land clearing in forest areas is primarily concerned with the carbon budget of the area, because removing forest releases stored carbon, and the scheme pays for reducing those emissions.

Physical resources, ecology and water resources are affected by forest loss too, but they are not what REDD+ is mainly about.

Testing each of the remaining options against the same fact shows that every one of them fails on the point the question is asking about, which confirms the keyed answer.

Answer: B

Global warming potential compares the warming impact of 1 kg of a greenhouse gas with that of 1 kg of carbon dioxide over a given period, with carbon dioxide taken as 1.

Methane, nitrous oxide and CFC-11 are not the reference gas. They are gases whose GWP is stated relative to carbon dioxide.

Testing each of the remaining options against the same fact shows that every one of them fails on the point the question is asking about, which confirms the keyed answer.