Transcript Find some land, build a house?

Date: 21-Jul-15
Unit 1 Global Challenges
Sea level and global
warming
Maldives
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Unit 1 Global Challenges
Aim
Should we save low-lying areas?
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Unit 1 Global Challenges
An Unfair World?
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Unit 1 Global Challenges
An Unfair World
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Unit 1 Global Challenges
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• Read p56-59 Philip Allan
Unit 1 Global Challenges
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Unit 1 Global Challenges
Pacific Islands
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Unit 1 Global Challenges
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Unit 1 Global Challenges
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Unit 1 Global Challenges
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Unit 1 Global Challenges
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100 metres rise!
Unit 1 Global Challenges
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Unit 1 Global Challenges
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Unit 1 Global Challenges
Thermal
Expansion
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Unit 1 Global Challenges
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Isostatic Readjustment
Unit 1 Global Challenges
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Unit 1 Global Challenges
Sea levels are rising
Sea level change can be difficult to measure. Sea level changes over the last century have been
derived mainly from tide-gauge data, where the sea level is measured relative to a land-based
tide-gauge benchmark.
Local and regional sea level is subject to natural variation due to tides, waves, storm surges, and
seasonal temperature effects.
Such influences can generally be readily characterised and accounted for to reveal over-riding
trends in long-term records.
Observed trends, however, can be complicated by the fact that the land can experience vertical
movements (e.g. from ISOSTATIC effects related to post-glacial rebound, tectonic activity causing
subsidence or uplift, and sedimentation or erosion) the sea level to rise.
Recent improved methods of filtering out these
effects, as well as a greater reliance on the
longest tide-gauge records for estimating
trends, have provided greater confidence that
the volume of ocean water has indeed been
increasing, causing
Date: 21-Jul-15
Unit 1 Global Challenges
The two main components contributing to sea level rise are:
•Ocean warming and the resultant thermal expansion of seawater.
•Ice mass loss from glaciers, ice caps, and the Greenland and Antarctic ice sheets.
Reliable tide-gauge records indicate that sea level rose at a rate of about
1.7 millimetres per year during the 20th century. Recent satellite altimetry data, in
agreement with recent tide gauge measurements, show that this rate is increasing,
and sea level has risen at about 3 millimetres per year since 1993.
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Unit 1 Global Challenges
Much of the observed rise in sea level is directly related to the concurrent rise in global
temperature over the last 100 years.
Water expands as it gets warmer. Thermal expansion of the oceans to account for about 25 per
cent of the observed sea level rise from 1961 to 2003 then 50 per cent from 1993 to 2003.
Melt water related to the retreat of glaciers and ice sheet melting is the other major contributor.
The ice sheets remain a major source of uncertainty in accounting for past changes in sea level
because of insufficient data over the last 100 years.
There is also significant uncertainty about the possible contribution of ANTHROPOGENIC changes in
land water storage to changes in sea level, including groundwater extraction (and eventual
discharge to the ocean), destruction of wetlands and other land-use changes (again adding to
ocean storage), increased evaporation from surface water diversions for irrigation and industry, and
storage in dams (reducing the amount of water flowing to the ocean).
Estimates of contributions to sea level rise in recent decades
Source
Sea level rise (mm per year)
1961–2003
1993–2003
Thermal expansion
0.42
1.6
Glaciers and ice caps (including polar)
0.50
0.77
Greenland ice sheet
0.05
0.21
Antarctic ice sheet
0.14
0.21
Sum
1.1
2.8
Observed
1.8
3.1
http://www.aph.gov.au/library/Pubs/ClimateChange/theClimate/seaLevels.htm - Australian Government
Date: 21-Jul-15
http://news.bbc.co.uk/1/hi/sci/tech/8266500.stm
Unit 1 Global Challenges
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Unit 1 Global Challenges
Research on sea level rise?
a)Where are the Maldives and what are they like?
•You need to know the location and basic information about the Maldives.
•You need to know what the main elements of the Maldives' economy are.
b)What threats will there be to the people and the environment with rising sea
levels?
c)How should the Maldives government and people react to the problem of
global warming?
http://www1.american.edu/ted/ice/maldives.htm
http://news.bbc.co.uk/2/hi/south_asia/7945877.stm
http://papers.risingsea.net/Maldives/Small_Island_States_3.html
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Unit 1 Global Challenges
The UN Human Rights Council has adopted a resolution proposed by the Maldives to hold a panel
discussion on the relationship between human rights and climate change.
The resolution states that “Global warming violates human rights of millions of people, especially in countries vulnerable to
climate change such as the low-lying island state of the Maldives.”
“Climate change is one of the most serious challenges mankind has ever faced and has serious implications for the realization
of human rights,” says High Commissioner for Human Rights Navi Pillay in her contribution to the Climate Thinkers Blog, an
online discussion forum hosted by the Copenhagen Conference.
It is a response to a UN study in January which offered evidence that global warming undermines a number of basic rights such
as food, water, shelter, health, life and self-determination.
The panel debate is to be held in Geneva in July this year, and the aim is to pressure governments to reach an agreement at
the climate change negotiations in Copenhagen in December.
http://www.npr.org/templates/story/story.php?storyId=18425626