Johansson Margareta, Christensen Torben R, Akerman H Jonas, Callaghan Terry V
GeoBiosphere Science Centre, Lund University, Sweden.
Ambio. 2006 Jun;35(4):190-7. doi: 10.1579/0044-7447(2006)35[190:wdtcpo]2.0.co;2.
In a warming climate, permafrost is likely to be significantly reduced and eventually disappear from the sub-Arctic region. This will affect people at a range of scales, from locally by slumping of buildings and roads, to globally as melting of permafrost will most likely increase the emissions of the powerful greenhouse gas methane, which will further enhance global warming. In order to predict future changes in permafrost, it is crucial to understand what determines the presence or absence of permafrost under current climate conditions, to assess where permafrost is particularly vulnerable to climate change, and to identify where changes are already occurring. The Torneträsk region of northern sub-Arctic Sweden is one area where changes in permafrost have been recorded and where permafrost could be particularly vulnerable to any future climate changes. This paper therefore reviews the various physical, biological, and anthropogenic parameters that determine the presence or absence of permafrost in the Torneträsk region under current climate conditions, so that we can gain an understanding of its current vulnerability and potential future responses to climate change. A patchy permafrost distribution as found in the Torneträsk region is not random, but a consequence of site-specific factors that control the microclimate and hence the surface and subsurface temperature. It is also a product of past as well as current processes. In sub-Arctic areas such as northern Sweden, it is mainly the physical parameters, e.g., topography, soil type, and climate (in particular snow depth), that determine permafrost distribution. Even though humans have been present in the study area for centuries, their impacts on permafrost distribution can more or less be neglected at the catchment level. Because ongoing climate warming is projected to continue and lead to an increased snow cover, the permafrost in the region will most likely disappear within decades, at least at lower elevations.
在气候变暖的情况下，多年冻土很可能会大幅减少，并最终从亚北极地区消失。这将在一系列尺度上影响人类，从局部的建筑物和道路坍塌，到全球范围，因为多年冻土融化很可能会增加强大的温室气体甲烷的排放，进而加剧全球变暖。为了预测多年冻土未来的变化，关键是要了解在当前气候条件下决定多年冻土存在与否的因素，评估哪些地区的多年冻土特别容易受到气候变化的影响，并确定哪些地区已经在发生变化。瑞典亚北极地区北部的托尔内特拉斯克地区就是一个记录了多年冻土变化的地区，而且该地区的多年冻土可能特别容易受到未来任何气候变化的影响。因此，本文回顾了在当前气候条件下决定托尔内特拉斯克地区多年冻土存在与否的各种物理、生物和人为参数，以便我们能够了解其当前的脆弱性以及未来对气候变化的潜在反应。在托尔内特拉斯克地区发现的斑块状多年冻土分布并非随机，而是由控制小气候以及地表和地下温度的特定地点因素造成的结果。它也是过去和当前过程的产物。在瑞典北部这样的亚北极地区，主要是物理参数，例如地形、土壤类型和气候（特别是积雪深度）决定了多年冻土分布。尽管人类在该研究区域已经存在了几个世纪，但在集水区层面，他们对多年冻土分布的影响或多或少可以忽略不计。由于预计持续的气候变暖将继续并导致积雪增加，该地区的多年冻土很可能在几十年内消失，至少在较低海拔地区会如此。
