4.1 Introduction
There is an increasing awareness that the Earth is changing, but it is still unknown whether these changes occur cyclically, stochastically, episodically, or are long-term trends. The contemporary global climate change is a reality and a result of human activities that annually release gigatonnes of carbon into the Earth's atmosphere (IPCC, 2007; Hansen et al., 2007). Direct consequences of cumulative post-industrial emissions include increasing global temperature, perturbed regional weather patterns, rising sea levels, acidifying oceans, decreasing oxygen concentration, changed nutrient loads, and altered ocean circulation (Brierley and Kingsford, 2009). All of these factors cause climate change to have different effects on marine ecosystems, their function, biodiversity, and on the goods and services that they can provide. These contribute to human welfare, both directly and indirectly, and represent part of the total economic value of the planet (Costanza et al., 1997); therefore, the loss of these goods and services has important social and economic implications. Also deepsea ecosystems, which have long been thought to be extremely stable in terms of physico-chemical conditions, may experience abrupt change and climate-driven temperature shifts as a direct consequence of the prevailing surface climate conditions (Smith et al., 2009; Masuda et al., 2010; Fahrbach et al., 2011). Contemporary climate change has the potential to perturb ocean circulation on a time-scale far shorter than that of continental drift. For example, a reduction in the North Atlantic Current could have major implications for northern Europe and beyond during this century (Cunningham et al., 2007). This emphasizes the importance of regional considerations versus global generalization of the ‘global warming’ paradigm (Brierley and Kingsford, 2009). Climate-induced changes strongly differ across the globe, especially along a latitudinal gradient. Warming appears more pronounced at the poles than at the equator, and the responses of climate change are expected to differ for different marine habitats (Hoegh-Guldberg and Bruno, 2010; McGinty et al. 2011). For example, whilst open oceans are more affected by the in fluence of wind on the timing and strength of stratification, coastal areas are expected to be more vulnerable to the effects of wind due to storms.