How Climate Change and sea level rise will affect our coastal towns and cities.

A rise in sea levels and other changes fuelled by global warming global threatens coastal cities and towns in Ireland and worldwide. Housing, businesses, roads, rail lines, ports and other important infrastructure are all at risk and policy makers and planners should be acting now to avoid or mitigate their effects, according to a new report published by the Organization for Economic Co-operation and Development (OECD).

Sea levels and Earth climate changes are closely linked. Global warming is predicted to cause significant rises in sea levels this century, estimated by the IPCC (2007) as between 0.09 to c. 0.5m by the end of this century. As the climate warms sea level will continue to rise due to the reduction in volume of ice caps, ice fields, mountain glaciers, melting of the Antarctic and Greenland ice sheets in addition to the thermal expansion of ocean water. Research findings from Proudman Oceanographic Laboratories show, however, that sea levels globally may rise by up to 1.5m by 2100, values well above those quoted in the IPCC publications.

As Earth's climate continues to warm, then the volume of present-day ice sheets will continue to decrease. Some estimates show that a complete melting of the Greenland ice sheet could result in a sea-level rise globally of about 6.5 m; separately, melting of the West Antarctic ice sheet could result in a sea-level rise of about 8 m which would have a devastating impact on Ireland and other countries around the world. The West Antarctic ice sheet is especially vulnerable, because much of it is grounded below sea level. Small changes in global sea level or a rise in ocean temperatures could cause a break up of the two buttressing ice shelves, the resulting surge of the West Antarctic ice sheet would lead to a rapid rise in global sea level.

Sea-level rise increases the vulnerability of coastal areas to flooding during storms, increasing infrastructure losses, inundation of wetlands and other low-lying lands, Ireland loosing c.20% of its coastal wetlands by 2100, erode beaches, intensify flooding, and increase the salinity of rivers, bays, and groundwater tables.

Researchers and Governments around the world are currently examining the potential impact of sea level rise on coastal areas in order to start planning how to protect economic assets in cities, in the form of buildings, transport infrastructure, utility infrastructure and other long-lived assets from exposure to flooding as a consequence of climate change. No wonder, because if the Greenland ice sheet disappeared than what happened in New Orleans would be a gentle prelude to a chaotic and tragic future. Consider the global consequences for humanity with half of the worlds population needing to be evacuated to higher ground. It is unimaginable, where would they go, how would one feed humanity, provide shelter, sanitation, food and health care? We are the first generation to know with some certainty how our actions and behaviour today can change the world for future generations. We can plan for adaptation and survival or continue to ignore the global crisis humanity, and the planet, through our actions is in.

The OECD report examined 136 port cities around the world to estimate the exposure of the world’s large port cities (with a population of more than one million) to coastal flooding due to storm surge and damage due to high winds. This study also investigates how climate change is likely to impact each port city through exposure to coastal flooding by the 2070s, alongside subsidence and population growth and urbanization. The analysis focuses on the exposure of population and assets to a 1 in 100 year surge-induced flood event (assuming no defenses), rather than the risk of coastal flooding.

The study identified that the top 10 cities in terms of assets exposed are Miami, Greater New York, New Orleans, Osaka-Kobe, Tokyo, Amsterdam, Rotterdam, Nagoya, Tampa-St Petersburg and Virginia Beach. The total value of assets exposed in 2005 is estimated to be US$3,000 billion. By the 2070s, the asset exposure in the 136 cities studied could alone reach $35,000 billion; more than ten times current levels. Yes that’s 35 thousand billion dollars and that’s just for starters.

Given the financial losses on the international markets in the past year this figure taken in context of worldwide economic losses should compel all of us - world leaders, businesses and individuals - towards action rather than the paralysis of fear on climate change. The financial risks for inaction are enormous, more than anything they demand that we need both to reduce our emissions of greenhouse gases immediately and to prepare for the impacts of climate change.

The concentration of future exposure to sea level rise and storm surge in rapidly growing cities urgently underscores the need to integrate the consideration of climate change into both national coastal flood risk management and urban development strategies. Given the heavy concentration of people and assets in port city locations, such as Dublin, Cork Waterford, Limerick and the importance in global trade, failure to develop effective adaptation strategies would inevitably have not just local but also large national or even wider economic consequences.

Coastal cities will face great challenges in managing the significant growth in exposure that will come about from both human and environmental influences, including climate change. The size and concentration of population and economic development in many of the worlds largest port cities, combined with climate change, highlights the strong two-way linkage between development and climate change and the need for more effective governance for climate change adaptation at the city-scale.

The OECD report highlights that a strategic approach to adaptation will be necessary to minimize the likelihood of coastal disasters. The available policy options include a combination of:
• upgraded protection,
• land use planning,
• focusing new development away from the floodplain,
• selective relocation away from existing city areas, and
• flood warning and evacuation, particularly as an immediate response in poorer countries

All port cities require a combination of spatial planning and enhanced defences to manage the rising risk of sea level rise and storm surge with climate change. For cities with large areas at or below mean sea level, flooding can be catastrophic as they can be permanently flooded as illustrated in New Orleans in 2005. Such incidences are lively to increase in intensity in the coming years.

Port cities are a vital component of the global economy, and are also increasingly becoming important concentrations of population and asset value. Thirteen out of the twenty most populated cities in the world in 2005 were port cities. In addition, their economic importance in terms of international trade has grown markedly, as a consequence the concentration of these risks in a few of the world’s cities and nations underscores the urgent need for leadership and attention in these locations particularly as the risk of climate extremes to port cities risks will inevitably increase.

The OCED study examined the economic assets in cities in the form of buildings, transport infrastructure, utility infrastructure and other long-lived assets and their risk exposure to sea level rise, storm surges and population growth. What the reports highlights is that for Dublin by 2070 approximately €25 billion in economic assets in the form of buildings, transport infrastructure, utility infrastructure and other long-lived assets are exposed and that up to 45,000 people may be affected directly (for London the figure is €226 billion with 606,000 people affected).

Taken in a national context and that Ireland has over 7500km of coastline including the port towns of Cork City, Waterford, New Ross, Sligo, Dundalk, Wexford, Cobh, Galway, Wicklow, Limerick, Kinsale, Kenmare, Drogheda, Dundalk and Dun Laoghaire, the economic and environmental impacts are staggering, far in excess of the current financial crises. The cost to insurance markets and the national economy would be catastrophic. The report highlights more than ever the necessity for a national coastal management plan to include flood defense, land use planning and risk assessment. More importantly the report highlights the disturbing analysis from the EPA that greenhouse gas emissions for Ireland will rise in the years to come. So what should our national priorities be?

Putting into place effective disaster management strategies and protection investments will take time and money. According to the OECD the inertia of the socio-economic response suggests that action must begin today to protect port cities and to manage flood risk for impacts expected by the middle of this century. So what we are being told clearly is that we need to invest today to protect our towns, cities and infrastructure for the future, but paradoxically it also means the longer we wait to reduce our emissions the more we will have to pay and not just in fifty years time but tomorrow. Its time we woke up the real international emergency, to paraphrase President Clinton “its not the economy, it’s the environment stupid”