Terrestrial archives

Question 1

What are terrestrial archives? Give examples

Answer 1

Archives found on land e.g. lake sediments, tree rings, peatlands etc.

Question 2

Why do terrestrial archives not go as far back as ocean archives?

Answer 2

They do not survive as long because they dry out.

Question 3

Why are terrestrial archives important?

Answer 3

They provide regional climate records, humans live on land (not oceans!) and they are of a high resolution.

Question 4

What proxies are associated with lake sediments?

Answer 4

18O Carbonate, pollen, algae etc.

Question 5

What proxies are associated with peatlands?

Answer 5

Pollen and other microfossils e.g. vegetation.

Question 6

What proxies are associated with tree rings?

Answer 6

18O and ring width.

Question 7

What is palynology?

Answer 7

The study of pollen and other microfossils e.g. fungal spores.

Question 8

What do changes in pollen show?

Answer 8

Changes in vegetation growing in that region which can be associated with changing climates.

Question 9

What causes pollen changes?

Answer 9

Climate, human activity e.g. chopping down trees.

Question 10

Name some advantages of pollen as a proxy.

Answer 10

They are easy to identify, have a high resolution and are very resistant to decay.

Question 11

Is pollen always representative of the climate where it was found?

Answer 11

No as wind can carry pollen for tens to hundreds of miles away from where it came from

Question 12

What can pollen tell us about past climates?

Answer 12

If there is more tree pollen it indicates wetter conditions, if there is more grass/shrub pollen it indicates drier conditions (Moore & Waddington, 2015).

Question 13

What does glacial refugia refer to?

Answer 13

Small populations of trees that survive the glacial periods. This depends on moisture availability and topographic variability (shelter)

Question 14

What is the Holocene and when did it begin?

Answer 14

The Holocene is the current interglacial period. It began around 11,700 years ago.

Question 15

Why do pollen proxies show slower climatic changes than e.g. lake sediments?

Answer 15

Because if a species hasn’t been in an area for a while they will not come back immediately – tree/plan species take time to spread back from their refugia.

Question 16

In what way are modern pollen-climate relationships modelled?

Answer 16

Numerically.

Question 17

Name some advantages of using tree rings as a proxy.

Answer 17

Most widely distributed and used proxy (lots of other data to compare with), high resolution, dating tree rings is effectively absolute (Li et al., 2016).

Question 18

Name some disadvantages of using tree rings as a proxy.

Answer 18

Limited ability of capturing slow climate change variability, sometimes trees ‘miss a year’ meaning there is a ring missing for that year which impacts interpretations (Li et al., 2016).

Question 19

What is dendrochronology?

Answer 19

Dendrochronology is the study of data from tree ring growth (Li et al., 2016).

Question 20

Name some advantages of measuring borehole temperatures:

Answer 20

Temperature-depth profiles of boreholes contains records of surface temperatures due to thermal diffusion (used to estimate past climates) - (Li et al., 2016).

Question 21

Name some disadvantages to borehole temperatures:

Answer 21

Only retains long-term trends, past climate temperatures become harder to recover the further back you go (Li et al., 2016).

Question 22

Why are multi-proxy climate apporches useful?

Answer 22

They reduce the number of uncertainties - if multiple proxies suggest the same climate then interpretations are likely correct (Li et al., 2016).