Sea Level Lecture 6- Future Sea-Level Rise Flashcards

1
Q

What is sea level inherently linked to?

A

Temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Will sea level rise likely continue for many centuries beyond 2100?

A

Yes, virtually certain global mean sea level rise will continue for many centuries beyond 2100- will continue no matter what we do today due to decisions we have already made.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why will sea level continue to rise past 2100?

A

There are lags within the system – co2 stabilisation will take around 100 to 300 years, temperature stabilisation takes a few centuries, sea-level rise due to ice melting will take several millennia and sea-level rise due to thermal expansion will take centuries to millennia.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

In terms of sea-level, what dominates the 20th century?

A

Thermal expansion and glacier melting dominate 20th century- around 75% of the observed rise since 1971.
Since early 1990s contribution of Greenland and Antarctica has increased.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Has land-water storage made a huge difference to sea-level?

A

A small but measurable difference

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the IPCC emission scenarios?

A

Representative Concentration Pathways until 2100
Extension Concentration Pathways beyond 2100

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the 4 IPCC scenarios?

A

2.6- low forcing (CO2 peaks and declines by 2100)
4.5- lower stabilisation scenario (CO2 stabilises by 2100)
6.0 higher stabilisation scenario (no peak in CO2 by 2100)
8.5- high greenhouse gas emissions (no peak in CO2 by 2100)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happened to IPCC emission scenarios in AR6?

A

Added SSP (socioeconomic pathways)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the 5 SSPs?

A

1- sustainability
2- ‘middle of the road’ - world where trends follow broad historical patterns
3- Regional rivaly
4- Inequaity
5- fossil-fueled development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What year do IPCC scenarios start to look much more serious?

A

2050 outwards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are methods of future projections of sea-level?

A

Aggregated vs disaggregated
Point estimate vs fully probabilistic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are bottom-up scenarios?

A

Disaggregated and point estimate

Bring together all of the individual systems to feed into a sea-level prediction

Central range estimates: often the median, low and high quantiles

Have to incorporate processes we don’t understand well – issue within AR4

High end estimate: worst case scenarios- DeConto and Pollard (2016)

Probabilistic approaches: builds on the others.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are probabilistic approaches?

A

Disaggregated and fully probabilistic

Takes information and for each piece of information give it a confidence level and work out what sea-level may be.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are top-down scenarios?

A

Aggregated and point estimate

Focus on comprehensive metrics of change

Semi-empirical approaches

Expert judgement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are high end estimates and bottum-up central ranges?

A

Disaggregated but halfway between point estimate and fully probabilistic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Discuss how sea level projections have changes through time.

A

First estimates of sea level projections were semi-empirical

Move towards fully probabilistic models in the last decade- better understanding and greater computational power.

17
Q

What are semi-empirical models?

A

Aggregated and fully probabilistic

Look at relationships to predict aspect of model

Based on uncertainties and estimations

18
Q

What are ‘expert elicitations’?

A

Aggregated and halfway between point estimate and fully probabilistic

People believed IPCC predictions were low

Asked many experts who believed it would be higher

19
Q

How much was sea level projected to rise in AR4?

A

0.18-0.59 m

20
Q

How much was sea level projected to rise in AR5?

A

0.26-0.82 m by 2100 but some suggest this may be too low

21
Q

Why will sea level vary across the planet?

A

Many drivers of sea-level – will likely have some regional component. Will vary across the planet.

22
Q

Is the idea of a global signal for sea level change meaningless?

23
Q

What is UKCP18?

A

Fully disaggregated model, pull out different contributors.

24
Q

Do projections of GMSL need to be made local to be useful?

25
Q

A core sample from an elevation of -1.3 m relative to mean tide level (MTL) has a reference water level of 0.85 m MTL. Which is the correctly calculated relative sea level?

26
Q

During the last interglacial around 125,000 years ago, sea level was approximately how much higher than today?

27
Q

What is the major driver of storm surges?

28
Q

Fill in the blanks- Glacial isostatic adjustment can be explained by thinking of a cargo ship. In this example, the cargo is the BLANK1, the ship is the BLANK2, and the water is the BLANK3

A

BLANK1 = ICE
BLANK2 = LITHOSPHERE
BLANK3 = MANTLE

29
Q

Fill in the blanks- Due to the ongoing effects of glacial isostatic adjustment, relative sea level is BLANK1 by 9 mm/yr in Hudson Bay, Canada and BLANK2 by 4 mm/yr in Atlantic City, New Jersey.

A

BLANK1 = FALLING
BLANK2 = RISING