Land use and carbon mitigation in Europe: A survey of the potentials of different alternatives

Abstract

This paper surveys studies applied to Europe that analyse carbon emission mitigation alternatives involving the use of land. We analyse a variety of alternatives that include land-use changes, forest management and bioenergy production. Our aim is to approximate the aggregate amount of carbon offsets that can be achieved through these alternatives and to show to what extent the results of the different studies are compatible and take into account the fact that land is a finite resource. Finally, based on the surveyed studies, we estimate the potential contribution of these alternatives to the goals of emission reduction proposed by the European Union for the years 2020 and 2050. Taking into account the results of the different studies analysed in this survey, land-based alternatives can contribute from 13% to 52% of the European proposed target by 2020. The implementation of these alternatives would concurrently require from 8% to 30% of EU-25 agricultural land to be afforested or diverted to bioenergy crops in this period.

Introduction

Land-use changes have significant impacts on the dynamics of terrestrial ecosystems and are the main factors influencing biodiversity on a global scale (Turner et al., 1995; Sala et al., 2000). Land-use change (especially deforestation) has been historically responsible for a large part of the cumulative human-induced greenhouse gas (GHG) emissions (IPCC, 2007; Watson et al., 2000). Likewise, forest and agricultural lands may play a key role in the overall strategy for slowing the atmospheric accumulation of GHG.

The basic ways in which forest and agricultural lands can directly or indirectly contribute to GHG mitigation efforts are the conversion of non-forestland to forest, preserving and increasing carbon in existing forest and agricultural soils, growing biomass to substitute fossil fuel-based products and altering agricultural and forestry fossil fuel usage patterns (Richards et al., 2006).

Land use, land-use change and forestry (LULUCF) alternatives are a fundamental part of the Kyoto Protocol (KP) and the Marrakesh Accords (UNFCCC, 1998, UNFCCC, 2001). Forest, cropland or grazing land management as well as afforestation, reforestation or revegetation are all alternatives that can be used to achieve the target that each developed country has under the KP. In addition, growing biomass and recovering forestry or agriculture residuals have emerged as promising alternatives for the production of renewable energy (Sims et al., 2006; Vries et al., 2007) and can also be used to reach the KP and post-KP targets. Thus, there are a number of available options for carbon mitigation that imply the use of land. However, since the agriculture and forestry sectors are linked through a single land supply, the potential of one land-use practice is not independent of the level of other land-based GHG mitigation alternatives (Antle and McCarl, 2002; Schneider et al., 2007). Bioenergy, biomaterials, afforestation and food production should ideally be studied jointly because they compete for scarce land resources (Gielen et al., 2003). Unfortunately, as we will show in the survey below, most studies analyse certain land-based carbon mitigation options without allowing for a combination of competing alternatives. Taking this limitation into account, the main objective of this study is to provide an overview, based on the results offered in recent literature, of the carbon sequestration and mitigation that could be achieved through the different alternatives involving land use in Europe.

The rest of the survey is organized as follows. Section two provides an overview of general approaches used for estimating carbon sequestration or biomass energy potentials. This is followed, in section three, with the survey of studies focused on carbon sequestration practices and then moves on to studies focused on bioenergy production. Implications of these practices on the overall land budget available are analysed in the third part of section three. The fourth part of section three examines the likely contribution of land-based GHG mitigation strategies to the goals agreed by the Council of the European Union for 2020 and 2050. Section four concludes.