Climate change - Climatology

Question 1

Ice ages have oscillations of what periods

Answer 1

Glacial (cold) and interglacial (warm) periods

Question 2

Forcing categories that control the average state of the climate system

Answer 2

External and internal

Question 3

External forcing involves

Answer 3

Solar variability and astronomical effects

Question 4

Internal forcing involves

Answer 4

Tectonic processes, volcanic eruptions, aerosols, radiative forcings

Question 5

How does the sun influence external forcing

Answer 5

Sun changes brightness and solar variability by changes in its mass

Question 6

Milankovitch cycles

Answer 6

Astronomical controls on solar output

Question 7

The three inter-related changes that cause long-term variations in solar output

Answer 7

1. Eccentricity - how elliptical the earth’s orbit is (aphelion and perihelion)
2. Obliquety - the tilt of the earth’s axis of rotation (more tilt in summer/winter)
3. Precession - the timing of the equinox (seasons) in relation to its revolution around the sun (caused by earth wobbling slightly on axis)

Question 8

Changes in eccentricity, obliquity and tilt occur in what timespan

Answer 8

23,000-100,000 years

Question 9

How does tectonic plate processes affect global processes in terms of internal forcing

Answer 9

1. They affect ocean circulation and atmospheric processes (continental drift)
2. Associated with chemical processes resulting in large carbon release
3. Presence of mountain ranges creates orogenesis

Question 10

How does volcanism affect global processes in terms of internal forcing

Answer 10

Large volcanic events launch dust into the atmosphere which leads to greater scattering and reflection of solar radiation - cooling effect

Question 11

How do atmospheric aerosols affect global processes in terms of internal forcing

Answer 11

Aerosols are tiny airbourne particles that come from forest fires, deserts, breaking ocean waves, pollution etc and leads to scattering and reflection of solar radiation - cooling affect

Question 12

How does changes on the surface of earth affect global processes in terms of internal forcing

Answer 12

Albedo is critical in controlling the global energy budget, and human modification like black asphalt roads and roofs results in less radiation being reflected back off the earth.

Question 13

How do we construct a climate record from the past

Answer 13

We use proxy data

Question 14

What are climate proxys

Answer 14

They are preserved physical characteristics of the past that allow us to reconstruct the climatic conditions that occurred before modern observations began

Question 15

Examples of proxies

Answer 15

Tree rings, ice cores, pollen, boreholes, corals, lake/ocean sediments

Question 16

What has proxy data shown us about climate change over the last 2000 years

Answer 16

Shows temperature reconstructions based on all available proxy data.
Variability over this temporal scale is controlled by both external and internal processes

Question 17

Difference between climate variability and climate change

Answer 17

Climate variability refers to variations in the mean state of the climate on all spatial/temporal scales beyond that of individual weather events
Climate change refers to a change in the state of the climate that can be identified by changes in the mean and the variability of its properties, and that persists for an extended period, typically decades or longer.

Question 18

Climate change indicators

Answer 18

Atmospheric/oceanic temperatures, glaciers, snow cover, sea ice, sea level, and atmospheric water vapor.

Question 19

Largest contributor to radiative forcing (climate change)

Answer 19

Increase in Co2 concentrations, primarily from fossil fuel emissions and secondarily from net land use change emissions.

Question 20

Ocean acidification

Answer 20

Ocean absorption of roughly 30% of the emitted anthropogenic carbon dioxide

Question 21

Greenhouse effect

Answer 21

The absorption of longwave radiation by the atmosphere, and re-emission in all directions results in a warming of the earths surface and lower atmosphere.

Question 22

How is radiation transmission varied in the atmosphere

Answer 22

Atmosphere has regions where longwave radiation is more likely to be absorbed (greenhouse gases).
Atmosphere also has regions that are fairly transparent, especially to short wavelengths

Question 23

Enhanced greenhouse effect

Answer 23

When extra ammounts of greenhouse gases are added from anthropogenic activities, they absorb more thermal radiation leading to extra warming

Question 24

Walker circulation

Answer 24

The starting point of ENSO that is driven by differences in ocean surface temperature between east and west tropical south pacific

Question 25

What controls the variability in air temperature and precipitation on large scales

Answer 25

El Nino-Southern Oscillation (ENSO)

Question 26

Southern Oscillation Index (SOI)

Answer 26

Characterizes the intensity of the walker circulation. When index is high (positive) the walker cell is normal and is called La Nina When index is low (negative) the walker cell weakens and is called El Nino

Question 27

Anthropogenic activities are said to have increased global warming by how much

Answer 27

1.0 degrees

Question 28

Dynamic models used to simulate earths atmospheric and oceanic circulation realistically

Answer 28

General circulation models (GCM)

Question 29

How do GCMs model climatology

Answer 29

Models are initiated with known climatology which then simulate atmospheric and oceanic processes over space and time using mathematics and physical laws.

Question 30

Global surface temperature change expected at the end of the 21st century

Answer 30

1.5 degress relative to 1850-1900

Question 31

The mean global temperature change from 1850-1900 to the end of the 21st century could be as large as _____ with a maximum temperature increase of ____

Answer 31

4.3 degrees, 5.4 degrees

Question 32

How is precipitation in high latitude and sub tropical land areas expected to change by the end of the 21st century

Answer 32

Precipitation increase in high latitudes and precipitation decrease in most subtropical land regions

Question 33

Mechanisms responsible for possible changes in precipitation on a global scale

Answer 33

1. More intense Hadley circulation - higher precipitation in equatorial regions 2. Decrease in subtropical regions - as the earth warms the extension of subtropical high pressure systems to higher latitudes will lead to further decreases 3. Higher temperatures in the high latitudes will promote more moisture (clausius-claperyron relationship) in the atmosphere leading to more precipitation (more snow on ice sheets).

Question 34

How much will sea level rise by 2100 relative to 1986-2005

Answer 34

Between 0.43 and 0.84m

Question 35

Dominant form of sea level rise contribution

Answer 35

Glacier and ice sheet contributions, now more than the contribution from thermal expansion of the oceans

Question 36

Glaciers and ice cap sea level rise capacity

Answer 36

41cm

Question 37

Greenland and Antarctica ice sheet sea level rise capacity

Answer 37

7 and 58 metres

Question 38

Precipitation likely to increase and decrease where in NZ

Answer 38

Increase in West and South, likely to decrease in North and East

Question 39

Wind speed likely to _______ in the future in NZ

Answer 39

Increase, especially in winter

Question 40

Warming is likely to increase greatly where in NZ

Answer 40

Up North and at high altitiudes

Question 41

As a result of warming, how does ice volume and glacier decline affect NZ

Answer 41

Increased westerly airflow, higher precipitation and sea level rise by 40-100 cm by 2100

Question 42

How does global warming increase westerly airflow

Answer 42

Evaporation intensifies as temperatures rise resulting in storms picking up more water vapor and heat making stronger winds and heavier rainfall