The fifth assessment report by the Intergovernmental Panel on Climate Change (IPCC) in 2014 confirmed that warming of the atmosphere and ocean system is happening and that there is clear human influence on the climate. The concentration of greenhouse gases in the atmosphere has increased to unprecedented levels, and there is evidence that the extent of sea level rise since the mid-1800s has been greater than the mean sea level rise of the previous two millennia. Fossil fuel use is responsible for over half of all greenhouse gas (GHG) emissions globally, and the majority of these come from energy supply, transport, residential and commercial buildings, and industry.
The main greenhouse gases include carbon dioxide, methane, nitrous oxide, and fluorinated gases. It is predicted that further warming will continue if greenhouse gases continue to be emitted. At the end of the 21st century, the global surface sea temperature is likely to be 2 degrees warmer than that of the 1850 – 1900 periods. Climate change will impact globally on climate systems, air and ocean temperatures, and sea levels. Some parts of the world will become drier and others will have an increased risk of flooding, and these changes will impact on nature and human populations. Negative socio-economic impacts will arise.
The Environmental Protection Agency’s publication in 2012 titled ‘The Status of Ireland’s Climate, 2012’ provides some facts and trends that are cause for concern. Both mean annual surface air temperature and average annual national rainfall have been increasing. Sea level is rising at approx. 1.7cm per decade. Addressing the problem requires co-ordinated action at various levels, and also changes in behaviour. The city must aim to implement effective mitigation and adaptation measures.
The two terms are explained below:
‘Adaptation refers to the adjustment or preparation of natural or human systems to a new or changing environment, with the aim of moderating harm or exploiting beneficial opportunities. Climate change adaptation comprises all spontaneous responses and planned action taken to cope with the impacts of changing climate conditions.’ (DoECLG, 2012). Flood risk assessment and management is a key element of this.
‘Mitigation refers to actions to reduce emissions of the greenhouse gases that are driving climate change.’ (DoECLG, 2012).
Because a response to climate change requires an inter-disciplinary approach, this chapter necessarily cross-references other sections of this plan which include some detailed adaptation and mitigation measures. Of particular relevance are policies and objectives set out in Chapters 2, 8, 9, and 10 which address the core strategy, movement and transport, sustainable environment/infrastructure, and green infrastructure (see section 3.5.4).