Risk assessments of future changes to ecosystem dynamics and risk of tipping points

Summary Risk Reports were produced for each iAtlantic Study Region, which overwhelmingly showed that we have the highest confidence in the risk that changing sea temperatures pose to the ecosystems we studied across the Atlantic. Moderate to high risk of changes due to T were identified in 9 out of 12 Study Regions. The combined risk scores across all three EOVs showed we have the highest confidence that the ecosystems we studied around Iceland (capelin, groundfish including monkfish, humpbacks) and in the Malvinas Current (cold-water coral mounds, billfish, tuna, and pelagic sharks) are most at risk of changing by 2070. We do not imply whether the risk of ecosystem change in a Study Region is a positive or negative outcome, just that the delivery of ecosystem services arising from those ecosystem compartments is likely to change, which should put managers and authorities on alert. For Study Regions and ecosystems where we were less confident about risks posed by future ocean conditions, our approach presents a simple integrated assessment framework to update risk scores in a Study Region once more ecosystem time series are added or new analyses of their drivers of change become available.

Our risk assessments provided the opportunity to reflect on what managers and authorities could integrate into their own decision-making powers at local, regional and international levels:

• Ramp up investments in monitoring and mitigating change in sentinel regions, especially at high latitudes where we are confident there is a high combined risk of ecosystem changes;
• Ensure adequate investment and resourcing to collect and share ocean observations across the Atlantic, particularly in sentinel regions and in the South Atlantic where warming surface to mid-depth ocean temperatures are likely to experience warming and where a marine “tropicalisation” has already been apparent the last two decades;
• Build and maintain public-private partnerships, industry collaborations, and data-sharing mechanisms across diverse knowledge systems to enable similar or repeat risk assessments;
• Deliver on commitments to slow the pace of global climate change, and use a portfolio of ABMTs to increase resilience.

Caveats and uncertainties in both inputs to the risk assessments were reported in Deliverables 1.2 and 3.2, but the present risk assessment still provides decision-makers with a better place-based understanding of whether future oceanographic conditions could alter living marine resources important to the Atlantic socioeconomy. Should human activities continue at current rates and blue growth be permitted in Study Regions scored as “High risk” without effective mitigation and monitoring, then these risk assessments indicate that impacts of additional human activities could further compound this risk and push or “tip” ecosystems into alternate states or regimes that may be less desirable.