specifically for individual varieties, there are narrow climatic optimums that provide limited geographical zones of
suitability. The observed warming over the last 50 years appears to have been largely beneficial for viticulture in
many regions through longer and warmer growing seasons with less risk of frost. However, the trends have
been shown to more influential on the poleward fringes by providing more consistent ripening climates for
existing varieties, making warmer climate varieties more viable or opening up once forgotten regions again. On
the other extreme, already hot regions have experienced warmer and generally drier conditions that have
produced challenges in ripening balanced fruit. Concomitant with the warming trends have come better
technology, better plant material, and better vineyard management and these adaptations have allowed growers
to meet some of these challenges. However, the projections for future climate change will likely be more rapid
and to a greater magnitude than our ability to adapt without increased understanding of the impacts and
advances in plant breeding and genetics (Bisson et al., 2002; Vivier and Pretorious, 2002).
Overall climate change is one of the most studied and debated scientific issues of our day. While it is
clear from historical evidence that changing climates are a part of the Earth’s natural adjustments to both
internal and external forces, more and more evidence is pointing to increasing human impacts on our climate.
From processes such as desertification, deforestation, and urbanization where the global energy balance is
disrupted, to changes in atmospheric composition, which enhances the greenhouse effect beyond its natural
equilibrium, our role in climate change is increasing. From the latest Intergovernmental Panel on Climate
Change “Summary for Policymakers” (IPCC, 2007), the following statements express our current state of
knowledge: