1. CLIMATE CHANGE In Norfolk Jökulsarlon, Iceland
Please refer to the Microsoft Word and Adobe PDF documents available on the website for the further information required to present this PowerPoint presentation. The information in this presentation refers to the text in the document called “Climate Change”.
Jökulsarlon, Iceland
© NERC 2005, AM Jarrow

2. Introduction Norfolk’s location and low lying coast
vulnerable to climatic changes
Natural glacial-interglacial cycles for last 2.6 million years (Quaternary)
Not a recent trend caused by us
But humans are having an affect too

3. North Norfolk Quaternary (2.6 million years ago to present)
interglacial stages (warmer)
warmer than present - Costa del Cromer
glacial stages (colder)
like present day Antarctica
These climatic changes have affected Norfolk’s coastline and appearance

4. Norfolk during glacial stages
During a glacial stage
glaciers grow around the world
take water from the seas
lower global sea levels
coastline moves outwards
Norfolk increases in size
If glaciers grow and reach Norfolk
glaciers cover Norfolk and change the land’s appearance

5. During interglacial stages
Opposite during interglacials
global sea levels rise
No solid high cliffs to keep sea out
coastline migrates inland
To simplify the Quaternary we will split it into two…

6. 2.6 million years ago to 900,000 years ago
Coastline further inland (sea levels)
S England joined to France
creating a land bridge
Warmer climate
Small oscillations
Small sea-level changes
Ever-changing coastline
© NERC 2006, JR Lee

7. 2.6 million years ago to 900,000 years ago
Landscape similar to today
saltmarshes, tidal creeks, estuaries, beeches
sands, gravels and muds laid down during this time are called ‘crags’ by geologists
An ancient beach deposit at Norton Subcourse in southern Norfolk. These sands and gravels are called the Wroxham Crag.
© NERC 2005, JR Lee

8. 900,000 years ago to present A large climatic shift occurred
Climate dominated by extremes
Global, not just felt in Norfolk
About 10 shifts from glacial to interglacial
Several identified in geology of Norfolk

9. 900,000 years ago to present
Several occasions – Norfolk covered by ice or near ice margin
At maximum extent – British Ice Sheet reached London.
about450,000 years ago
known as the Anglian Glaciation

10. How Norfolk changed
Each of the glaciations had a dramatic affect on Norfolk
glaciers smear sediment on land surface
Sediment laid down by glacier in this way
geologists call this deposit Till
usually clayey, also some sand and gravel
depends on what glacier is ‘carrying’
depends on which rocks ice has travelled over
Reason many fields in Norfolk are clayey

11. How Norfolk changed
When the glaciers retreat northwards due to global warming
water released from the ice
lots of sand and gravel carried by water
this is deposited as water slows down
Reason there are many sandy fields and quarries/pits in Norfolk

12. Layer cake Geologists think of Norfolk as a cake with many layers till
sands and Gravels
etc…
The cliffs at Happisburgh, showing deposits laid down during a glaciation. Two tills are separated and overlain by sands that were deposited within a glacial lake.
© NERC 2005, JR Lee

13. Coastline variations
These large-scale climate changes = large-scale changes in sea level
change of several 10s of metres
© NERC 2006, JR Lee

14. Rivers River pathways affected by glaciations
glaciations erode and bury earlier landscapes
change direction of river drainage
can destroy whole river systems
glaciers melt and drainage of the meltwater uses old river pathways
modern day drainage network is based on ancient drainage pattern

15. Drivers of climate change
Fjallsjokull, Iceland
© NERC 2005, AM Jarrow

16. Drivers of climate change 1
Distribution of land and water on the Earth
thermohaline circulation

17. Drivers of climate change 2
Solar radiation
orbital shape or eccentricity
axial tilt or obliquity
axial orientation or precession
© NERC 2006, JR Lee

18. Climate change record Present 2.6 million years ago
© NERC 2006, JR Lee