Impact of Climate Change on Carbon Accumulation Rates in Irish Blanket Bogs Over the Last Millennium

Peatlands store the most carbon per unit area than any other terrestrial ecosystem and play a crucial role in mitigating greenhouse gas emissions. Gaining a better understanding of how peatlands have responded to past climate changes could be key to predicting how these ecosystems will react to future climate change. While the sensitivity of boreal peatland carbon pools to climate change has been studied extensively, there is limited understanding of how the carbon accumulation rates of blanket bogs may change under future global warming. The fate of blanket bogs, particularly changes in their carbon sequestration capacity, is a concern for the entire peatland community, given their unique ecosystems, narrow ecological niches, and cultural significance.

Funded by Science Foundation Ireland, the PCARB project (Past CARbon accumulation by Irish Blanket bogs) aims to investigate the influence of past climate on the carbon accumulation rates of Irish blanket bogs, based on 30 blanket bog records developed under varying climate and geomorphological conditions. Here, we present the preliminary results of carbon accumulation rates (CAR) over the last millennium from four of these 30 blanket bogs in Ireland. Our preliminary findings indicate that the Medieval Warm Period was associated with relatively lower CAR compared to the Little Ice Age, during which CAR was higher, despite some centennial-scale variability. Although these results may change as new datasets are incorporated, our initial findings suggest that ongoing warming could slow the carbon accumulation capacity of Irish blanket bogs. It is important to note that, within the last millennium, in the absence of significant human disturbance, natural climate variability did not cause the blanket bogs to shift to a ‘carbon source’, despite their sensitive response to short-term climate fluctuations. Therefore, careful protection and management in the future will be crucial to maintaining blanket bogs as active ‘carbon sinks’.