Department of Physical Oceanography and Instrumentation, Leibniz Institute for Baltic Sea Research Warnemünde, Seestraße 15, 181 19 Rostock, Germany.
Department of Physical Oceanography and Instrumentation, Leibniz Institute for Baltic Sea Research Warnemünde, Seestraße 15, 181 19 Rostock, Germany.
Sci Total Environ. 2024 Nov 15;951:175756. doi: 10.1016/j.scitotenv.2024.175756. Epub 2024 Aug 23.
This study explores the impact of global climate targets on sea surface temperatures and marine heatwaves (MHWs) in the Baltic Sea. We further evaluate potential adverse climate effects on the reproductive success of the western Baltic Sea (WBS) herring stock, which underwent a dramatic decline during the past two decades. For this, we use refined ensemble climate projections from the Coupled Model Intercomparison Project. For the WBS herring spawning ground, the number of MHW days nearly triples from 34 days/year in the historical period, to 102 days/year already under the optimistic 1.5 °C target of global climate warming (Paris, 2015) and further increases at a rate of 36 to 48 [days yr]/0.5 °C beyond the 1.5 °C target. The average MHW surface extent more than doubles in the 1.5 °C target from ~8 % to 21 % in this area. This study finds the phenological winter climate considerably altered in response to future global warming and more frequent MHW days in the WBS. The winter duration reduces by ~25 % already in the 2.0 °C target but by ~60 % in the 4.0 °C target compared to the historical climate. Winter inceptions/terminations occur successively later/earlier and the share of missed winters, i.e. winters unsuitable to support herring reproductive success, increases by up to ~70 %. Days with heat stress on the cardiac function of herring larvae will likewise increase and occur earlier in the year. Consequently, the early life cycle of herring will face more often winter conditions that were unprecedented during the historical past, and the risk for future reproductive failure will increase. However, our results reveal that abiotic disturbances for the marine ecosystem can be partly mitigated if global warming remains compliant with the 1.5 °C target.
本研究探讨了全球气候目标对波罗的海海表温度和海洋热浪（MHWs）的影响。我们进一步评估了潜在的不利气候对波罗的海西部（WBS）鲱鱼种群繁殖成功的影响，该种群在过去二十年中经历了急剧下降。为此，我们使用耦合模型比较计划的精细集合气候预测。对于 WBS 鲱鱼产卵场，MHW 天数几乎翻了三倍，从历史时期的 34 天/年增加到全球气候变暖 1.5°C 目标下的 102 天/年（巴黎，2015 年），并且在 1.5°C 目标之外，每升温 0.5°C，MHW 天数增加 36 至 48 天/年。在 1.5°C 目标下，MHW 表面范围在该地区的平均值增加了一倍以上，从~8%增加到 21%。本研究发现，未来全球变暖导致冬季气候发生相当大的变化，并且在 WBS 中冬季出现更频繁的 MHW 天数。冬季持续时间在 2.0°C 目标下已经减少了约 25%，但在 4.0°C 目标下减少了约 60%，与历史气候相比。冬季开始/结束时间相继推迟/提前，错过的冬季（即不适合支持鲱鱼繁殖成功的冬季）的比例增加了约 70%。对鲱鱼幼虫心脏功能产生热应激的天数也将增加，并在年初更早出现。因此，鲱鱼的早期生命周期将更频繁地面临历史上从未出现过的冬季条件，未来繁殖失败的风险将增加。然而，我们的研究结果表明，如果全球变暖仍符合 1.5°C 的目标，那么海洋生态系统的生物干扰可以部分得到缓解。
