Climate Midterm Questions

What is the climatically relevant energy source for a rocky planet?

The Sun (solar radiation)

Does heat flux from the Earth’s interior modulate the Earth’s climate? If not, why?

No, it’s too small compared to solar input to significantly affect climate

What kind of heat transfer mechanisms exist? Which is relevant for heat gain from the sun and heat loss from the earth to space?

Conduction, convection, and radiation; Since Earth sits in the hard vacuum of the

outer space, Earth’s heat gain from the Sun

and heat loss from the Earth to the space occur

only via electromagnetic radiation.

What determines the amount and strength of radiative heat flux from a planetary body? (Stars, Planets)

Temperature, emissivity, and surface area (Stefan-Boltzmann Law)

What describes Stefan-Boltzmann and Wien’s Displacement laws?

Stefan-Boltzmann relates energy flux to temperature; Wien’s Law states the wavelength of the maximum intensity of blackbody radiation is inversely proportional to the temperature.

Does the incoming irradiance strongly interact with the atmospheric greenhouse gases?

The vibration wavelength (frequency) range of most greenhouse gasses in Earth’s atmosphere is ~ 4 to which is much larger than that of the Sun . In order a greenhouse gas to interact with radiation, both the latter and former need have a comparable wavelength ranges.

Why is atmospheric CO2 a strong greenhouse gas for a planet with a surface temperature around 280–310 K?

the deviation between the predicted and measured values of flux amount and spectral distribution of outgoing thermal radiation (at 284 K) is significantly large. This means that the outgoing thermal radiation interacts strongly with the atmospheric gases

Over a broad range of values, how is the relationship between atmospheric CO2 and outgoing longwave radiation?

Inversely related; higher CO2 decreases outgoing longwave radiation

What is the relationship between the mass, age, surface temperature, and luminosity of a star?

Larger and younger stars are hotter and more luminous

Is the Sun strong enough to facilitate liquid water on Earth?

No, not alone; greenhouse gases make conditions warm enough for liquid water

How does the evolution of atmospheric O2 influence greenhouse gas presence?

The absence of atmospheric O2 during the early part of Earth’s history, might have allowed a sustained presence of potent greenhouse gases such as NH3 and CO. The addition of these greenhouse gases would substantially increase Earth’s surface temperature, enabling the presence of liquid water. present atmospheric level

What makes the Cryogenian glaciation unique?

Global-scale (“Snowball Earth”) glaciation covering nearly all latitudes

What are the names, timing, and duration of the two Cryogenian glaciations?

Sturtian (~717–660 Ma) and Marinoan (~650–635 Ma)

What is the nature and sequence of Cryogenian glacial deposits?

Diamictites, deglacial (IRD), followed by cap dolostone (cd) layers

What caused and ended the Cryogenian glaciation?

cause: Warm and Wet climate, land masses centered around equator, presence of newly formed large igneous provinces (ILP)

end: Cold climate, wide-spread ice cover, reduced chemical weathering leading to increase of CO₂

What are climatic consequences of post-Pangaea tectonics?

an increase ocean ridge and hot spot activity, volcanism, led to unbalanced atmospheric CO₂ concentration, which were unbalanced by CO₂ removal from chemical weathering.

What happens with a strongly enhanced seafloor spreading rate?

Increased volcanic CO2, warmer climate, higher sea level, and lower deep-water oxygen

How does a weak pole-to-tropic temperature gradient affect deep water formation?

It weakens thermohaline circulation and reduces oxygenation

How does an extremely warm climate affect O2 in seawater?

Warm water holds less dissolved oxygen

Is there a link between sea level rise, warm climate, and black shale?

Yes; high sea level and anoxia promote black shale deposition

What was the driving force of the PETM?

Rapid release of greenhouse gases, likely methane

How does the PETM compare with Mid-Cretaceous warming?

PETM was shorter and faster; Mid-Cretaceous was longer and tectonically driven

Why is the carbon isotope ratio of carbonate indicative of PETM greenhouse gas?

The low carbon isotope ratio suggests the PETM was caused by marine methane hydrate destabilization.

What is methane hydrate?

Frozen Mix of water and methane

How and where is methane hydrate formed?

Under low temperature and high pressure in marine sediments and permafrost

Which parameters control methane hydrate stability?

Temperature, pressure, and methane concentration

What happened around 2.7 and 30–34 Ma ago?

2.7 Ma: Closure of central American seaway, cut off salinity water from pacific into the tropical Atlantic, which lead to warmer saltier Atlantic surface water, this induced Northern Hemisphere glaciation.

30-34 Ma: Drake passage opening lead to cooling in both northern and southern hemisphere and permanent glaciation of antarctica was established, beginning of the now current icehouse climate.

What are the factors that enhance chemical silicate weathering?

Mountain erosion driven by: Temperature, precipitation, and vegetation

despite the relative cold and dry climate, what enhanced chemical weathering and global cooling over last 10–15 Ma?

Uplift of mountain ranges increasing erosion and weathering rates; carbonate weathering affects short-term CO2 balance

Why is silicate weathering more effective at removing CO2 than carbonate?

It converts CO2 into stable carbonates permanently stored in rocks, carbonate weathering does not contribute to the removal of atmospheric CO₂

Did enhanced silicate weathering contribute to bipolar glaciation ~2.7 Ma?

Yes, by reducing atmospheric CO2 levels

What are the three main orbital parameter changes?

Eccentricity, obliquity, and precession

What causes cyclic variations in Earth-Sun configuration?

Gravitational interactions with other planets

Which Earth-Sun changes affect high vs. low latitudes more?

Obliquity affects high latitudes; precession affects low latitudes

Which physical law describes season length and intensity?

Kepler’s Second Law (equal areas in equal times)

What is the key statement of Kepler’s 2nd Law?

Planets sweep equal areas in equal times; orbital speed varies

How are season length and heat intensity related?

Shorter seasons are more intense when Earth moves faster in its orbit