Category:Climate Change
Contents
Introduction
From Ron Scarlett (1986:222): Sarah's Gully and Elsewhere. NZAA Newsletter v29(4)
One year there was a big earthquake in South America, followed by a tsunami which covered our beach and splashed up on part of the excavations. In intervals between digs I had been watching, from a little distance, a pair of banded dotterels which had a nest on the beach near cross creek midden. I knew their eggs were close to hatching before the tidal wave came, and was afraid the eggs would be ruined, and the parents, perhaps, drowned. It was a great relief when, shortly afterwards, I saw the birds, and two new chicks, running about the beach. The hatching was just in time.
The same tsunami left a nice warm pool where our creek entered the sea in front of the site of
Sarah's old whare. One afternoon, when the girls were all in camp, I stripped off and had a dip in the pool. Someone saw me, and called the girls who flocked to the top of the rise below our tents, but they were too far off to see much. It gave rise to more verse.
The strangest deep sea creature washed upon our beach. Twas only Ron with nothing on, and beyond the power of speech.
The last line is grossly inaccurate. The girls were a fine lot, but they were not above surrounding the men's tent, pulling up the pegs, simultaneously, and collapsing it on us.
To listen to a fragment of the quoted song "To Delve Into a Midden" here is an mp3 download
Information regarding the impacts of climate change on archaeological sites: A resource portal.
From Bickler and Clough (2007):
"Island nations face an uncertain future with the possibility of significant changes to their coastline as result of climate change. New Zealand is a similar size to the mainland United Kingdom, with an extensive and complex coastline, but unlike Britain, the archaeological record in the Land of the Long White Cloud is massively weighted towards that coastline. For both Maori arriving from Polynesia up in the order of 1000 years ago and European settlers in the 19th Century, the coast has been the focus. As a result, major changes in that coastline as the result of climate change will impact significantly on the archaeology record.
Walton (2007) has recently identified some of the many and varied dimensions relating the impact of climate change on archaeology in New Zealand."
However, climate change is not the only threat to archaeological sites, nor necessarily the biggest - in the short term. Today, coastal development is rampant, particularly in the North Island and some of the most attractive locations are close to, and occasionally on, the areas most vulnerable to changing sea levels and flooding. Tsunamis are high in people’s consciousness (see e.g., McFadgen 2007) while, weather patterns such as the cycle of El Niño and La Niña have also probably impacted on archaeological sites although the to what extent is not well documented (McFadgen 2001). These are the some of the more dramatic threats but normal farming, industrial and other modern human activities continue on in the background.
Indirect effects are likely to be material. Afforestation for carbon sequestration now has financial incentives and could affect large land areas. Changed frequencies and magnitudes of floods and droughts will require new and modified water engineering, such as new dams and flood detention basins. Renewable energy also has new incentives and new wind turbine farms and potentially wave and tidal power plants will be built. All of these have considerable potential to affect archaeological sites.
Tsunamis
Section on Tsunamis.
See McFadgen (2007) for a detailed discussion on this topic.
Sea Levels
Ancient Sea Levels
Monash University's Sahul Time
Climate Change Driven Sea Level Rise
Figure source IPCC 5th. Assessment Report. 2013 Summary for Policy Makers. http://www.climate2013.org/spm
The diagram shows forecast rise through to 2010 under different scenarios. Note there are smaller regional effects that need to be considered as well. In places there can as well be additional rises and falls from local or regional land level changes.
The major driver of sea level rise is heating of the oceans. Melting of land supported ice is only a contributor but in the long term poses a considerable risk. Greenland is the most at risk followed by the West Antarctic Ice Sheet. Loss of ice shelves can contribute indirectly as they buttress some glaciers flowing from the ice sheets and removal of this buttressing effect can increase ice sheet loss through increased glacier flows.
Even if the world's climate is stabilised in the present century that is not the end of sea level rise. Because of the thermal inertia of the oceans they will not have come into temperature balance with the atmosphere in that time. That process will take several centuries more, with accompanying thermal expansion of the ocean and sea level rise. Nor will the ice sheets necessarily be in equilibrium by then. Loss of archaeological sites to sea level rise is a very long term issue (Law 2007).
Sea level rise of itself is not singular threat. It is more the background against which other effects happen. It sets the base for high tides and for storm surge and for wave attack during those events. Coastal erosion is commonly worse in the combination of such events. Higher sea levels increase the potential for damage. Damage is often episodic rather than continuous.
Useful References
New Zealand
- Bickler, S. and R. Clough. 2013. The Impact of Climate Change on the Archaeology of New Zealand’s Coastline: A Case Study from Whangarei District.Link
- Envrionmental Defence Society, n.d. Resource Management Act for the Community, Coastal Management. Link
- Law, G. 2007. Letter to the Editor. Archaeology in New Zealand 50(4):277-278.
- McFadgen, B. 2001. Report on some implications of climate change to Department of Conservation activities. Science and Research Unit, Department of Conservation.
- McFadgen, B. 2007. Hostile Shores: Catastrophic Events in Prehistoric New Zealand and Their Impact on Maori Coastal Communities. Auckland University Press: Auckland.
- McGovern-Wilson, R. 2008. The Warm Up Heritage New Zealand 109:4-7.
- Walton, T. 2007. Potential Adverse Effects on Climate Change on Historic Heritage. Archaeology in New Zealand 50(3):186-194.
New Zealand Climate Change
Ministry for the Environment. 2004. Coastal Hazards and Climate Change: A guidance manual for local government in New Zealand. New Zealand Climate Change Office,
Ministry for the Environment. 2008. Coastal Hazards and Climate Change: A guidance manual for local government in New Zealand. New Zealand Climate Change Office,. 2nd Edition
Ministry for the Environment/Manatu Mo Te Taiao, Wellington. Available at http://www.mfe.govt.nz/publications/climate/coastal-hazards-may04/coastal-hazards-may04.pdf
External Links
Climate Change: Sites in Peril. Archaeology Volume 62 Number 2, March/April 2009, by Andrew Curry
IPCC 5th Assessment Report 2013/14
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