Ireland's State of the Environment Report 2024

85 Chapter 4: Climate Change Climate tipping points and Ireland The ICCA report 3 addresses climate tipping points as ‘low-likelihood high-impact’ outcomes. It indicates that climate tipping points that shift the global climate or alter the regional climate in the North Atlantic and in north-western Europe would have implications for Ireland. For Ireland, the stability of the North Atlantic Ocean determines our climate and agricultural productivity. The stability of the AMOC is the most immediate potential tipping point. It is thought that the AMOC will almost certainly weaken over the 21st century, and a full collapse cannot be ruled out. This would have profound implications for Ireland’s climate and society as a result of considerably colder winters and warmer summers and a likely increase in storminess, with potential implications for sea levels. Projections of global sea level rise past 2100 have large uncertainties and will be determined by the effectiveness of current global climate policy. Much of the uncertainty is related to the stability of major ice sheets in Greenland and Antarctica. Their loss may become inevitable at certain levels of global warming. The loss of the West Antarctic Ice Sheet could result in a sea level rise of several metres over time. Currently, thawing permafrost 4 is losing carbon to the atmosphere. Model projections and paleoclimate evidence indicates that, as the global climate warms, permafrost extent and volume will shrink, releasing further greenhouse gases into the atmosphere. The complete thawing of permafrost cannot be ruled out, and this would emit more carbon into the atmosphere than humans have emitted to date, leading to substantial additional warming. Recent developments The apparent acceleration of global warming and the increase in ocean temperatures have resulted in considerable focus on climate change impacts. Recent high-profile research publications have suggested that the AMOC may collapse abruptly during this century, see, for example, Van Westen et al. , 2024. These and other developments, as well as the high level of scientific uncertainty around climate tipping points, highlight the need for targeted and managed research. 3 www.epa.ie/our-services/monitoring--assessment/climate-change/irelands-climate-change-assessment-icca/ (accessed 17 July 2024). 4 Permafrost is defined as ground that remains below 0°C for 2 years or more (ACGR, 1988). The ICCA report (Thorne et al. , 2024) highlights that climate change impacts will directly and indirectly affect health and wellbeing, while vulnerability is likely to increase as Ireland’s population increases and ages over the coming decades. We may see reducing excess cold mortality rates as a result of fewer cold extremes in winter, but conversely we may see increased impacts of heat stress, particularly as our population ages in the coming decades. Longer growing seasons may lead to an increase in respiratory diseases, such as asthma, as a result of the increased circulation of pollen and spores and public health issues may also arise from poor water quality as a result of extreme rainfall and flooding. The consequences for psychological health and wellbeing that can result from the loss of valued places, flooding and other extreme conditions cannot be underestimated. Projected increases in the frequency of extreme precipitation events may result in more waterborne disease (e.g. due to Escherichia coli ) arising from contaminated drinking water because of overland flows of pollutants. Projected increases in annual average temperature, combined with wetter conditions, may result in enhanced environmental conditions for bacterial growth and viral survival, with a potential increase in food-borne disease. Increases in the frequency of heatwaves and drought are projected to result in the increased frequency of wildfires damaging forests stands. Significant impacts on biodiversity are also anticipated, including an increase in the presence of invasive species, some of which may have negative impacts on the economy (e.g. via impacts on farming and fisheries). Local and transboundary risks related to impacts on local and imported food supplies may lead to increases in productivity for some crops and decreases for others.