Medieval settlements in Iceland and Greenland were vulnerable to changes in spring (April-June) snow cover duration and depth. These would have adversely affected the viability of their pastoral farming systems, but the impact would have been spatially variable. We use a physical-based model of snow distribution and melt to model spring snow cover and depth at a scale relevant to human activities across four sites: southern and northern Iceland, and inner and middle fjord sites in South Greenland, using both present day and simulated climate data from the HadCM3 GCM-model. Our climate scenarios cover the period CE 1000–1500, encompassing a climate shift to cooler conditions. We find that under average present climate conditions the inner fjord site in Greenland has similar spring snow conditions to sites in Iceland, but that the middle fjord site has notably greater snow cover, and as climate cools spring snow cover at this site becomes extensive (>60 days). The largest increase in snow cover duration between current average climate conditions and the coolest climate scenarios (47 days increase) is experienced at our Iceland sites. Inner and middle fjord sites in Greenland diverge in terms of snow cover under all scenarios, a potential driver of the growing importance of marine wild resources and the end of the Norse Greenland settlement.

冰岛和格陵兰的中世纪定居点很容易受到春季（4 月至 6 月）积雪持续时间和深度变化的影响。这些将对他们的牧区农业系统的生存能力产生不利影响，但影响在空间上是可变的。我们使用基于物理的积雪分布和融化模型来模拟春季积雪和深度，其规模与四个地点的人类活动相关：冰岛南部和北部，以及南格陵兰的内峡和中部峡湾地点，同时使用现在和HadCM3 GCM 模型的模拟气候数据。我们的气候情景涵盖了 CE 1000-1500 时期，包括气候向凉爽条件的转变。我们发现，在目前的平均气候条件下，格陵兰的内峡湾地点与冰岛的地点具有相似的春季降雪条件，但是中间峡湾站点的积雪明显更大，并且随着气候变冷，该站点的春季积雪变得广泛（> 60天）。当前平均气候条件和最凉爽气候情景（增加 47 天）之间积雪持续时间的最大增加发生在我们的冰岛工厂。在所有情况下，格陵兰的内峡湾和中峡湾地点在积雪方面存在差异，这是海洋野生资源日益重要和北欧格陵兰定居点终结的潜在驱动因素。