Climate Change and Its Impact on Terrestrial Ecosystems

Introduction

This chapter provides a general overview of the effects of climate change on terrestrial ecosystem and is meant to set the stage for the specific papers. The discussion in this chapter focuses initially on individual factors as affected by climate change or, for instance, choice of adaptation strategy, followed by some discussion of how these factors might interact with each other. The northernmost terrestrial regions of Norway and Sweden are experiencing an increasingly warmer and wetter climate and the rate of warming is projected to increase in the future (IPCC 2013). Climate change in concert with land-use change and other anthropogenic drivers like air pollution, of change are already rapidly affecting northern ecosystems with consequences for living beings, infrastructure and economic condition (Arctic Council 2013). The 1992 Framework Convention on Climate Change (FCCC) includes climate changes connected directly or indirectly to increasing anthropogenic activities on the globe. The impact that climate change has on natural terrestrial and other ecosystems, on human society and economies could be disastrous. The potential effects range from sea level rise and melting ice at higher latitudes and altitudes, to changing regional weather patterns. The increase in the atmospheric abundance of greenhouse gases alters the energy balance of the climate system of terrestrial ecosystems, and causes a variety of natural disturbances such as increased desertification, extreme droughts, floods, tropical cyclones, more frequent wildfires, rising sea levels and melting glaciers (IPCC, 2007).

While there is a range of factors contributing to long- and short-term climate variability, it is now clear that changes during recent decades are at least partly related to the accumulation of anthropogenic greenhouse gases (GHGs) accumulating in the atmosphere (Crowley 2000; Karoly et al. 2003; Kerr 2001; Mann and Jones 2003; Stott et al. 2000), and while terrestrial and marine systems may act as natural sinks, helping to buffer the total GHG accumulation (Field and Fung 1999; Fung 2000), there will be a net increase in atmospheric GHGs over time (Falkowski et al. 2000). The Intergovernmental Panel on Climate Change (IPCC) has recently projected a global temperature increase of 1.4–5.8 °C by 2100 (IPCC 2001a). The global average surface temperature increased during the twentieth century, with the 1990s the warmest on record. Snow and ice cover have decreased, global average sea level has risen, and the heat content of the oceans has increased (IPCC 1997). Other aspects of climate phenomenon have during the recent century, such as: changes in precipitation and cloud cover, low and high temperature periods, more frequent, persistent and intense episodes of the El Nino and related adverse effects on weather in many areas and an increase in drought and severe wet periods (IPCC 1997). Some climate and weather related phenomenon, including tornadoes or tropical storms, do not shown any change in their patterns (IPCC 1997).