Saturday, 10 May 2008

Likely impacts of climate change on the Cornish coastline and management techniques available to combat it

"The problems of the world cannot possibly be solved by sceptics or cynics whose horizons are limited by the obvious realities. We need men who can dream of things that never were." (John. F Kennedy, 1963).

Climate change has emerged as the single greatest environmental challenge that the human race has ever had to face (Defra, 2008), its threat has been known for decades, however its consequences are only just beginning to develop, this report will discuss the physics behind climate change, its likely impacts on the Cornish coastline and appropriate management techniques that can be implemented to combat its risk.

The earth’s climate is a finely balanced system, which is governed by many factors such as temperature, wind and precipitation, it influences the weather, the way the ocean works and the way in which we live our lives. In the past the earth’s climate has changed radically in response to a number of natural causes, and unfortunately, it is doing so again. Since industrialisation occurred over a century ago, the earth has warmed by 0.74°C, with around 0.4°C of this increase occurring within the last 30 years (Defra, 2008). A report published by IPCC (intergovernmental panel on climate change) named the Fourth Assessment Report (AR4) stated that there was no doubt that the result of human activity is the main contributor to the changes in the earth’s climate (Defra, 2008). Global greenhouse emissions have increased by 70% since pre-industrial times (IPCC, 2007) and the accumulation of these gases (carbon dioxide, methane and nitrous oxide) in the atmosphere has created a greenhouse effect, which warms the planet and exaggerates its climatic conditions. Because of the excessive burning of fossil fuels and an increased amount of deforestation globally over the last century, the concentration of these greenhouse gases has now reached critical levels and increasingly irregular climatic conditions are beginning to become more apparent. The AR4 report predicts that if the levels of carbon emissions within the atmosphere continue to rise, average global temperatures over the next century are likely to rise between 1.1 and 6.4°C, this will result in a predicted rise in global sea level of between 20-60cm, increased melting of glaciers and ice caps and intensified weather conditions (IPCC, 2007). Unfortunately, these global scale problems, can often be overlooked at a local level and without the knowledge of how climate change will affect the locations habitats, ecosystems and economy, nothing can be done to preserve what needs to be protected.

Cornwall is a county surrounded by the ocean. More so than any other county in the United Kingdom, it is highly dependent on its physical characteristics and wildlife, its economy relies almost exclusively on the natural resources that exist within the local environment, these include, Agriculture, mineral extraction and tourism. The future of these resources depends on the natural environmental on which they stand, tourism for example, requires that the physical environment and coastal zones remain in good condition, however this environment is at risk of being changed or even destroyed as a result of climate change, this poses significant and life changing problems for Cornwall’s economy, ecosystems and communities, but also provides valuable opportunities.

Climate change and more specifically sea level rise over the next century pose a very real threat towards the Cornish coastline, predictions and scenarios made by the IPCC and UkCIP state that if sea level rise predictions develop, the south west will have to deal with an increased risk of flooding and sea incursion in coastal areas, Coastal erosion and increased storm damage which will inevitably lead to habitat and species loss (kerrier, 2008). Flooding has significantly increased in Cornwall over recent years and the environmental agency has estimated that up to 100,000 homes in the southwest are at risk from flooding, this number is only going to increase because of rapid and intensive development on flood plains. Rising sea levels, from both climate change and vertical land movements, threaten to intensify such flooding. Sea level measurements recorded in Newlyn since 1915 have shown rises in sea level of around 17cm per century and although subsidence of land is responsible for much of this increase, between 3 and 10cm are still unexplained leading experts to believe that it is linked to climate change. If this change continues there is no doubt that it will begin to affect more and more people throughout the county. Dr David Watkins from the Camborne School of Mines has illustrated predictions, which show the extent of flooding and sea level rise throughout Cornwall in the future

the future of Cornwall’s coastline is ever changing, Sea level rise will not only increase the probability of flooding but it will also greatly increase the effects of coastal erosion and saltwater inundation, thus destroying valuable habitats, ecosystems and creating a large change for tourism industry within the area to deal with and recover from. Coastal risk assessment results published by the National trust state that 279 kilometres of national trust land alone in the southwest will be at risk from erosion over the next 100 years (National trust, 2005) and it is not yet known what sort of effect this will have on the coastline and surrounding area. Cornwall is a host to a variety of diverse flora and fauna with a large proportion being found along the coastline, the effects of erosion and saltwater inundation due to sea level rise could destroy habitats and ecosystems that have been present along the coastline for hundreds of years, this may send species elsewhere and away from the Cornish coastline which will reduce the amount of visitors contributing to the Cornish economy. Many of the popular seaside towns that attract thousands of visitors each year are under great risk from the effects of sea level rise, be it from flooding or coastal erosion, because of this, Cornwall’s tourism and economy lie in the balance of successful and sustainable implementation of management techniques used to combat the problems linked to climate change and sea level rise.

The choice and implementation of successful management techniques used to combat sea level rise need to be carefully reviewed and researched before they can be considered for use, each location requires different methods of management and because of this it is important to look at the problems at a local level so that the type of management can be distinguished, all the management methods proposed should aim to meet the three objectives of coastal management, these are to avoid development in areas that are vulnerable to coastal inundation or erosion, ensure that coastal ecosystems and habitats continue to function and most importantly, to protect human lives, essential properties and the regions economy (IPCC, 1990). The techniques required to combat the effects of sea level rise and meet the objectives of coastal management in the southwest fall into three very different categories, retreat, accommodation and protection (IPCC, 1990). For each of these methods to function correctly it is important to keep in mind that one method alone may not be the answer to all the problems at any given location and that the implementation of each of the following management methods must be coupled with a large amount of public education, awareness and participation.

The retreat method of management may be the most extreme and uneconomical method for coastal communities to initiate, it involves little or no effort to protect the land under risk and requires the abandonment of valuable land and structures in areas of high risk, this will inevitably lead to a need for the resettlement of communities away from their original position and can force coastal ecosystems inland, possibly even destroying them (IPCC, 1990). Because of this, the retreat method can sometimes be seen as a last resort as it can change the coastline so much that the region economics, ecosystems and community morale suffer greatly as a result, because of this the retreat method may only be suitable under extreme circumstances of coastal erosion and inundation (IPCC, 1990). This method is currently being implemented by the National trust on the cliffs of Birling gap in Sussex, the cliffs are eroding at such a rate that the trust now believes that it is more sustainable and financially viable to abandon the coastguard cottages situated on the cliff, and allow the coastline to evolve naturally rather than try to create other forms of defence (National trust, 2005).

The protection method of coastal management requires defensive measures to protect the exposed proportion of coastline from saltwater inundation, flooding, wave impact and erosion (IPCC, 1990). It usually involves the construction of hard defensive structures such as breakwaters, floodwalls, groins and seawalls. These structures commonly have excessive build times and are often very expensive to build and maintain. Protection can also come in the form of soft defensive structures such as beach filling, dune building and wetland creation (IPCC, 1990). Unfortunately there is no guideline set for which defence to use in which situation and so each location must be carefully studied and evaluated to reach an educated conclusion. There is also no guarantee that hard defences will work over a long period of time. As sea levels rise and storms increase, it will become more difficult to maintain current defences and build new ones, the defences may even just direct the problem geographically elsewhere along the coast and cause environmental harm by moving the problem to a new, less prepared location, because of this organisations such as the National trust, believe that hard defences are no longer a sustainable and viable answer to the problems concern with coastal change (National trust, 2005).

The accommodation method of coastal management combines the positive attributes from both of the previous methods. It involves the continued use of the land at risk, but requires the evolution of buildings and farming techniques to accommodate for flooding and coastal erosion, this can include, elevating buildings on piles, switching from agriculture to aquaculture or growing salt tolerant crops (IPCC, 1990). This method is most economical and sustainable over a long period of time but can be hard to initiate. Accommodation provides opportunities for inundated land to be used for new purposes, which can improve the economy, an example of this is the use of different farming techniques (such as aquaculture), which would have previously been unavailable or economical before the inundation took place, thus expanding the regions choices for a more sustainable economy (IPCC, 1990). Unfortunately this can also have social implications because changes in farming techniques will no doubt result in major lifestyle changes and changing buildings to accommodate inundation may worsen living conditions which will have an adverse effect on public health (IPCC, 1990).

It seems ironic that the fossil fuels, which aided the growth and progression of the world around us today, are undoubtedly going to force us to change the way we live tomorrow. If climate change is not prevented there is the possibility that economies and communities will fall apart, however there is also the hope that it will bring communities together and allow them to have a greater knowledge about the environment around them hopefully helping them to live their lives in a more sustainable, natural and enjoyable way.

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