The European Union has adopted a long-term climate protection target to limit global mean temperatures to not more than 2°C above pre-industrial levels. This is in response to the United Nations Framework Convention on Climate Change (UNFCCC) Article 2 objective which is to stabilise “greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system”. Scientific analysis suggests that atmospheric greenhousegas concentrations would need to be stabilised at levels close to 450 ppm CO₂ equivalent to ensure that the 2°C target is not breached. However, there is still considerable uncertainty surrounding this stabilisation level. Defining what is “dangerous” requires an analysis of the various impacts of climate change and the temperaturechange at which they occur. For Ireland, the 2°C target represents an appropriate ‘guard rail’ for avoiding dangerous climate change in relation to major climate impacts. Exceeding this target, the melting of the West Antarctic Ice Sheet and the Greenland Ice Sheet and subsequent sea level rise, as well as a reduction of theThermohaline Circulation, are among the most important‘high-impact, low-probability’ events which would have substantial impacts for Ireland. Ireland will also experience significant climate changeimpacts below 2°C, many of which are now unavoidable. Adaptation actions will be required to reduce adverse impacts of these changes. Vulnerable sectors which will be impacted upon as a result of increasing global mean temperatures include:

• water resources – reduced soil moisture, increased frequency and magnitude of flooding, changes in water quality
• ecosystems and biodiversity – change in distribution of plants and animals, for example a possible decline and extinction of Arctic species
• agriculture and food production – increased demand for irrigation, potential for new crops
• sea level rise – loss of coastal habitats, increased erosion, increased incidence of coastal flooding
• the marine environment – impacts upon fish stockssensitive to small changes in temperature such asphytoplankton, northward movement of cold waterspecies.

The EU climate protection target can only be reached through international co-operation in combating climate change. Further, effective mitigation and adaptation strategies are needed to prevent dangerous anthropogenic interference with the climate system. Ireland should therefore promote this target at the EU and wider international levels. Further research is required to reduce uncertainty in relation to the impacts of increasing greenhouse gas concentrations in the atmosphere.