Climate Change and Global Warming Questions and Answers

Answer: D

The wrong statement is that the second commitment period will end in 2030.

The Kyoto Protocol (printed 'Koyto') was adopted in December 1997 at COP3 in Kyoto and entered into force in 2005. Its first commitment period ran from 2008 to 2012. The Doha Amendment of 2012 set a second commitment period from 2013 to 2020, so it ended in 2020, not 2030.

The other three statements are correct: adoption in 1997, the end of the first period in 2012, and the Protocol's purpose, which is binding reductions of greenhouse gas emissions by developed countries. The year 2030 belongs to the targets countries set under the Paris Agreement.

Answer: B

Greenhouse gases trap energy from the earth and keep the earth warm.

Sunlight, mostly short-wave radiation, passes through the atmosphere largely unabsorbed and warms the surface. The warm surface then radiates long-wave (infrared) energy back upward. Gases such as carbon dioxide, water vapour and methane absorb this outgoing infrared radiation and re-emit part of it downward, so the surface stays warmer than it otherwise would, by about 33 °C.

They do not mainly act on incoming sunlight, and their effect is warming, not cooling, which rules out the other three options.

Answer: A

The gas that does not contribute significantly to global warming is NO, nitric oxide.

Nitric oxide is a short-lived air pollutant that takes part in forming smog and acid rain, but it is not itself a significant greenhouse gas. It should not be confused with nitrous oxide (\(\mathrm{N_{2}O}\)), which is a powerful, long-lived greenhouse gas.

The others are greenhouse gases: tropospheric ozone absorbs infrared radiation, sulphur hexafluoride (\(\mathrm{SF_{6}}\)) is the most potent greenhouse gas known and is covered by the Kyoto Protocol, and hydrofluorocarbons (HFCs) are also Kyoto gases with high warming potential.

Answer: B

The option that is not a Kyoto flexible mechanism is carbon trading.

The Kyoto Protocol set up three flexible (market-based) mechanisms by name: Joint Implementation (Article 6), the Clean Development Mechanism (Article 12) and International Emissions Trading (Article 17). They let developed countries meet their targets partly through reductions made elsewhere.

'Carbon trading' is a general, popular term for buying and selling emission allowances or credits in any scheme, voluntary or regulatory. It is not the name of one of the three Kyoto mechanisms, which is why the key singles it out while 'Emissions trading', the treaty's own term, is one of them.

Answer: A

UNFCCC stands for the United Nations Framework Convention on Climate Change.

The Convention was adopted in 1992 and opened for signature at the Rio Earth Summit, entering into force in 1994. It is a framework treaty: it sets the goal of stabilising greenhouse gas concentrations, while specific commitments come through later instruments such as the Kyoto Protocol and the Paris Agreement, negotiated at its Conferences of the Parties.

The options with 'Federation' or 'Center' misname the treaty.

Answer: A

The relation is \(\lambda_{m}T\) = Constant, Wien's displacement law.

For a black body, the wavelength of peak emission is inversely proportional to its absolute temperature:

\[ \lambda_{m} T = b \approx 2898\ \mu\text{m K} \]

The Sun, at about 5800 K, therefore peaks near 0.5 micrometres in visible light, while the Earth, at about 288 K, peaks near 10 micrometres in the infrared. The hotter the body, the shorter its peak wavelength.

Pressure does not appear in the law at all, which rules out both options with P. \(\lambda_{m}/T\) = Constant would make the peak wavelength grow with temperature, the opposite of what is observed.

Answer: D

At the equinoxes the sun shines equally on both Northern and Southern hemisphere.

Around 21 March and 23 September the Sun is directly overhead at the Equator. The circle of illumination then passes through both poles, so every latitude has about twelve hours of day and twelve of night, which is what 'equinox' (equal night) means.

The Sun is overhead at 23½°S, the Tropic of Capricorn, at the December solstice and at 23½°N, the Tropic of Cancer, at the June solstice. The Earth is nearest the Sun at perihelion in early January, which has nothing to do with the equinoxes.

Answer: D

The Earth's surface emits mostly Infrared radiation.

The surface has a mean temperature of about 288 K. By Wien's law its emission peaks at

\[ \lambda_{m} = \frac{2898}{288} \approx 10\ \mu\text{m} \]

which lies in the thermal infrared, roughly 4 to 100 micrometres. This outgoing long-wave radiation is what greenhouse gases absorb.

Ultraviolet needs a body as hot as the Sun. Microwave and radio waves are emitted by the Earth too, and are used in passive remote sensing, but they carry only a tiny fraction of the energy.

Answer: B

The Sun releases energy by Nuclear fusion.

In the Sun's core, at about 15 million K, hydrogen nuclei fuse through the proton-proton chain to form helium. The helium nucleus has slightly less mass than the four protons that made it, and that missing mass becomes energy by \(E = mc^{2}\), about 4 million tonnes of mass converted every second.

Nuclear fission, splitting heavy nuclei such as uranium, powers reactors on Earth, not stars. Combustion is a chemical reaction that would have exhausted a Sun-sized fuel store in a few thousand years. Hydrothermal processes involve hot water in the Earth's crust.

Answer: C

The answer is Methane and Carbon dioxide.

Both absorb outgoing infrared radiation from the Earth's surface and re-emit part of it downward, which warms the lower atmosphere. Carbon dioxide is the largest human-added contributor, and methane is about 80 times more powerful per molecule over 20 years.

Nitrogen and oxygen, the main gases of air, absorb almost no infrared, so the first two options fail even though ozone is a minor greenhouse gas. Ammonia is not a significant greenhouse gas. Carbon monoxide is an indirect contributor at most, through its effect on methane, and it is not one of the gases 'responsible' in the standard list.