Question 1

Which are mineral deposits with caves and caverns?

Accepted Answer

Speleothems are mineral deposits that form in caves and caverns. These can include stalactites, stalagmites, flowstones, and other formations created from the slow deposition of minerals from groundwater.

Question 2

Which is the term for changes in the orientation of Earth's axis over a 26 000-year cycle?

Accepted Answer

Precession refers to the gradual changes in direction of Earth's axis of rotation over a 26,000-year cycle. This causes the direction of the North Star and the position of the equinoxes to change over time.

Question 3

Which of the following accurately describes 18O/16O ratios of the world's oceans?

Accepted Answer

During colder periods, more 16O is trapped in ice and snow, leading to a higher 18O/16O ratio in the oceans. During warmer periods, the ratio decreases as 16O returns to the ocean.

Question 4

Which of the following accurately describes 18O/16O ratios of ice sheets?

Accepted Answer

The answer of Which of the following accurately describes 18O/16O...

Question 5

As air temperatures increase,evaporation increases.Warmer temperatures also increase the capacity to absorb water vapour.More water vapour in the atmosphere accelerates the greenhouse effect.As temperatures increase further,more water vapour can enter the atmosphere,causing temperatures to increase even more.Which best describes this process?

Accepted Answer

This process is an example of a positive feedback loop, since the initial warming leads to further warming, in a self-reinforcing cycle.

Question 6

To what does the term 'Milankovitch cycles' refer?

Accepted Answer

Milankovitch cycles refer to changes in Earth-Sun relationships, namely Earth's orbit around the sun, Earth's axial rotation, and Earth's axial tilt. These cycles are named after Serbian scientist Milutin Milankovitch, who proposed the theory that these factors have a significant influence on Earth's climate over long periods of time.

Question 7

Radiocarbon dating of organic material may provide a climate record for up to how many years before present?

Accepted Answer

Radiocarbon dating can provide a climate record for up to 50,000 years before present. This technique is used to determine the age of organic material by measuring the amount of carbon-14 present in the sample. As carbon-14 decays over time, it can be used to date materials that were once alive and provide insight into past climate conditions. However, beyond 50,000 years, the amount of carbon-14 remaining in a sample is too small to accurately measure, making radiocarbon dating ineffective.

Question 8

Which is the term for changes in elliptical orbit of Earth around the Sun?

Accepted Answer

Eccentricity refers to the changes in the shape of Earth's elliptical orbit around the Sun, affecting the distance between Earth and the Sun over time.

Question 9

Increased cloud cover resulting from warming temperatures may lead to either cloud albedo forcing or cloud greenhouse forcing.Which correctly pairs the feedback loops for cloud albedo forcing and cloud greenhouse forcing?

Accepted Answer

Cloud albedo forcing refers to the cooling effect of clouds as they reflect the sun's energy back to space. An increase in cloud cover would result in a negative feedback loop as it would cause cooling and therefore result in less cloud formation. In contrast, cloud greenhouse forcing refers to the warming effect of clouds as they trap heat in the atmosphere. An increase in cloud cover would result in a positive feedback loop as it would cause warming and therefore result in more cloud formation. Therefore, the correct pairing is negative feedback loop for cloud albedo forcing and positive feedback loop for cloud greenhouse forcing.

Question 10

As air temperatures increase,evaporation increases,leading to more condensation and cloud formation.Low,thick cloud cover increases the albedo of the atmosphere,thereby having a cooling effect on Earth.Which best describes this process?

Accepted Answer

This process represents a negative feedback loop because as air temperatures increase, cloud formation increases, which in turn increases Earth's albedo and has a cooling effect, ultimately working to counteract the initial temperature increase. This loop helps to maintain a relatively stable climate.

Question 11

Which of the following accurately describes 13C/12C ratios of plant materials and their use in climate reconstructions?

Accepted Answer

Different plants use different types of photosynthesis, which results in varying ratios of carbon isotopes in their tissues. By analyzing the 13C/12C ratios in plant material, scientists can determine past temperature and rainfall conditions.

Question 12

What has happened since the Industrial Revolution?

Accepted Answer

Since the Industrial Revolution, there has been a significant increase in greenhouse gas emissions due to human activity, leading to a warming trend in global temperatures. This trend has continued and even accelerated in recent years, with 19 of the 20 warmest years on record occurring since 2001.

Question 13

Which of the following is not considered an important carbon sink?

Accepted Answer

Farmlands do not have the same capacity as forests or oceans to absorb and store carbon, and they can also contribute to carbon emissions through agricultural practices such as fertilizer use and tillage. While vegetation in agricultural systems can act as a carbon sink, it is not typically as significant as natural ecosystems such as forests and oceans. Therefore, farmlands are not considered an important carbon sink compared to the other options listed.

Question 14

Which of the following is an example of methods used for short-term climate reconstructions?

Accepted Answer

Carbon isotope analysis is a method used for short-term climate reconstructions, as it can provide information on past variations in atmospheric CO2 levels and can indicate changes in temperatures and precipitation patterns. Ice core and ocean sediment core analysis are typically used for longer-term climate reconstructions, while Precambrian rock tectonics is not related to climate reconstructions.

Question 15

Which of the following accurately describes the use of tree rings for studying past climates (dendroclimatology)?

Accepted Answer

Tree rings (dendroclimatology) can be used to study past climates by analyzing the width of annual tree rings. Wider rings suggest favorable conditions, such as warmer temperatures and higher precipitation, whereas narrower rings suggest harsher conditions, such as drought, cold temperatures, or low precipitation. This information can be used to reconstruct climate conditions over many years, as tree rings can provide information about climate conditions for the entire lifespan of a tree.

Question 16

Changes in Earth's orbital configuration may lead to warming temperatures.These warming temperatures,in turn,may lead to the release of both CO2 and CH4.Increases in these gases may further warm the planet.Which best describes this process?

Accepted Answer

This process describes a positive feedback loop where an initial change (warming temperatures due to orbital configuration) leads to further changes (release of CO2 and CH4, which further warm the planet), amplifying the original impact.

Question 17

Which is the most recent epoch of repeated glaciation on Earth?

Accepted Answer

The Pleistocene epoch is the most recent epoch of repeated glaciation on Earth. It began about 2.6 million years ago and ended about 11,700 years ago. During this time, there were several periods of glaciation, during which large ice sheets covered much of the Earth's surface.

Question 18

The Younger Dryas refers to which of the following?

Accepted Answer

The Younger Dryas refers to a brief return to near-glacial conditions during the transition from the last glacial period to the present interglacial period. It lasted from about 12,900 to 11,700 years ago, and was marked by a sharp drop in temperature, as well as a decline in precipitation levels in many regions. This period is named after the wildflower Dryas octopetala, which flourished during colder conditions in Europe.

Question 19

In which of the following ways is the study of tree rings,speleothems,and corals for understanding past climatic conditions similar?

Accepted Answer

The growth bands in tree rings, speleothems (stalagmites and stalactites), and corals can provide evidence of past climatic conditions. While radiocarbon dating may be used with some of these materials, it is not the main similarity between them. Additionally, tree rings can provide a longer chronology than 5000 years, and corals can provide a chronology up to ~50,000 years.

Question 20

The last glacial maximum (LGM)occurred approximately how many years ago?

Accepted Answer

The last glacial maximum (LGM) occurred approximately 20,000 years ago.

Quiz 11: Climate Change