Climate Change and Global Warming Questions and Answers

Answer: B

The answer is greenhouse gas emissions.

Seawater expands as it warms. Rising concentrations of carbon dioxide, methane and other greenhouse gases trap more heat, and the oceans absorb most of that extra heat, so their volume increases. Thermal expansion has been one of the two main contributors to sea-level rise, along with melting land ice.

Changes in solar radiation are far too small to explain the recent warming. Changes in salinity have only a minor effect on volume, and the ozone hole concerns ultraviolet radiation in the stratosphere, not ocean heat.

Answer: C

Carbon sequestration means removal of CO₂ from the atmosphere and storage in a reservoir.

Sequestration is the capture of carbon dioxide and its long-term storage, whether naturally in forests, soils and oceans, or artificially by injecting captured CO₂ into geological formations. Both parts, removal and storage, are needed.

Options A and B describe only half of the process each, and trading carbon credits between countries is a market mechanism, not sequestration.

Answer: D

The gas that does not contribute is oxygen.

A greenhouse gas must absorb infrared radiation, which requires a molecule whose vibrations change its dipole moment. O₂, like N₂, is a symmetrical two-atom molecule and absorbs almost no infrared.

Carbon dioxide, water vapour (the most abundant greenhouse gas) and ozone all absorb infrared radiation emitted by the Earth and contribute to the greenhouse effect.

Answer: D

The gas is methane.

Methane is highly flammable and explosive in air between about 5% and 15% concentration, the cause of mine and sewer explosions. It is a potent greenhouse gas, roughly 28 times as strong as CO₂ over 100 years. It is not toxic in the usual sense but can suffocate by displacing oxygen in confined spaces, which is the sense in which it is called poisonous here.

Compressed air, helium and argon are not flammable or explosive, and none of them is a greenhouse gas.

Answer: B

The key gives 2°C.

The Paris Agreement of 2015 does not aim to cool the planet; its central goal is to hold the rise in global average temperature to well below 2°C above pre-industrial levels. That 2°C limit is the agreement's headline commitment, which the paper's wording refers to.

The agreement also asks countries to pursue efforts to limit warming to 1.5°C, but that is framed as an aspiration rather than the main limit, which is why the key gives 2°C. Neither 1°C nor 0.5°C appears in the agreement.

Answer: B

NMSHE stands for National Mission for Sustaining the Himalayan Ecosystem.

It is one of the eight national missions of India's National Action Plan on Climate Change, released in 2008, and is run by the Department of Science and Technology to study and protect Himalayan glaciers, ecosystems and communities.

There is no national mission on 'solar hydro energy', 'sustainable hydrogen energy' or a 'survey' of the Himalayan ecosystem among the NAPCC missions; the solar mission is the Jawaharlal Nehru National Solar Mission.

Answer: C

The largest carbon sink on Earth is the oceans.

The oceans hold about 38,000 gigatonnes of carbon, mostly as dissolved inorganic carbon in deep water, many times more than the atmosphere, soils and vegetation combined. They also absorb roughly a quarter of the carbon dioxide emitted by human activity each year.

Soils are the largest terrestrial carbon store, holding more than plants and the atmosphere together, but they are far smaller than the oceans. Forests are important sinks on land, and animals hold a negligible share.

Answer: C

The Copenhagen Conference was a sequel to the Kyoto Protocol.

The Copenhagen climate conference, COP15 of the UN Framework Convention on Climate Change, held in December 2009, was meant to agree on a successor to the Kyoto Protocol, whose first commitment period ran from 2008 to 2012. It ended only with the non-binding Copenhagen Accord.

The Montreal Protocol (1987) deals with ozone-depleting substances, not climate change negotiations. The Basel Convention (1989) controls transboundary movement of hazardous wastes. The Ramsar Convention (1971) protects wetlands. None of them was the agreement Copenhagen tried to extend.

Answer: B

The correct match is a-3, b-1, c-4, d-2.

1. Kyoto Protocol: adopted in December 1997 at COP3 in Kyoto (3).
2. Copenhagen Summit: COP15, December 2009 (1).
3. Montreal Protocol on ozone-depleting substances: signed in 1987 (4).
4. Stockholm Conference on the Human Environment: June 1972, the conference that led to UNEP (2).

The option giving Kyoto 1972 and Stockholm 1997 swaps the two. The options giving Kyoto 2009 and Copenhagen 1997 swap those two, and the last of them also exchanges Montreal and Stockholm.

Answer: C

The compound that is not a greenhouse gas is NO₂, nitrogen dioxide.

NO₂ is an air pollutant and a precursor of ozone and nitric acid, but it is short-lived and absorbs little outgoing infrared radiation, so it is not counted among greenhouse gases. It affects climate only indirectly, through the ozone it helps to form.

The other three are greenhouse gases. Nitrous oxide (N₂O) and methane (CH₄) are among the gases covered by the Kyoto Protocol. Ozone (O₃) in the troposphere absorbs infrared radiation and is the third most important greenhouse gas after CO₂ and methane by radiative forcing. The similar names N₂O and NO₂ are the trap.