A Broad Overview of the Main Problems Derived from Climate
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A broad overview of the main problems derived from climate change that will affect agricultural production in the Mediterranean area Dimitrios Skuras and Demetrios Psaltopoulos Department of Economics, University of Patras, University Campus, Greece EXECUTIVE SUMMARY Climate change refers to present and future changes in climate conditions and is more frequently reflected by increasing average temperature, changes in precipitation and changes in the frequency, intensity, spatial extent, duration and timing of extreme weather and climate events. The Mediterranean region presents wide climate variability but the collective picture is one of substantial drying and warming. Especially in the warm season, precipitation decrease may exceed –25 to –30 percent and warming may exceed 4–5 °C. Extreme events in the Mediterranean region are related to droughts and floods that may give rise to deep erosion and landslides. For these reasons, the Mediterranean region is identified as one of the most prominent hotspots in future climate-change projections. Climate change is assumed to have significant effects on Mediterranean agriculture. Projected climate changes will have a direct impact on water resources and irrigation requirements, crop growth conditions, crop productivity and crop distribution, agricultural pests and diseases, and the conditions for livestock production. These impacts will generate changing land-use patterns and will trigger economy-wide effects. In the Mediterranean parts of Europe, the declining water balance has been documented over the past 32 years. In certain North African and eastern Mediterranean countries, climate change may result in surface water reductions of more than 35 percent. Rainfed agriculture, which, in certain areas of North Africa represents more than 90 percent of total agricultural land, will be particularly affected. Crop growth will be directly affected by climate change. In southern Europe, general decreases in yield (e.g. legumes –30 to +5 percent; sunflower –12 to +3 percent and tuber crops –14 to +7 percent by 2050) and increases in water demand (e.g. for maize +2 to +4 percent and potato +6 to +10 percent by 2050) are expected for spring-sown crops. However, in the warmer southern Mediterranean, increases in CO2 will help reduce the loss in yield arising from a warmer and drier climate, but will not be able to recover the losses completely. In the cooler northeastern Mediterranean, CO2 increases 217 BUILDING RESILIENCE FOR ADAPTATION TO CLIMATE CHANGE IN THE AGRICULTURE SECTOR associated with climate change will result in little net effect on most crops, provided that the increase in water demand, especially for irrigated crops, can be met. The change in land productivity brought by changing climate conditions may trigger economy-wide effects. In areas with significant productivity losses such as the Mediterranean south and with the agricultural sector still playing a significant role in the overall economy, gross domestic product (GDP) changes are expected to be negative and significant, especially under the A2 scenario. Climate change will apply an additional stress on rates of land degradation through changes in the length of days and/or seasons, recurrence of droughts, floods and other extreme climatic events, changes in temperature and precipitation, which in turn reduces vegetation cover, water resource availability, soil quality and changes in land-use practices, such as conversion of land use, pollution and depletion of soil nutrients. The impacts of climate change on storm runoff and erosion in Mediterranean watersheds are difficult to assess owing to the expected increase in storm frequency coupled with a decrease in total rainfall and soil moisture, added to positive or negative changes to different types of vegetation cover. However, the most serious effect of climate change and especially of increased temperatures and summer droughts on forest is expected to be the risk of forest fires. Depending on the scenario, it is expected that in southern Europe, climate change will increase forest fires by 10–20 percent. Resilience refers to actions aiming at building tolerance against the effects of global warming. At farm level, resilience actions include the adoption of drought-resistant crops, the adoption of water-saving cropping methods such as mulching, minimum tillage and maintenance of cover crops, a change in planting dates and cultivars, and even a shift to cropping zones by altitude and latitude. Resilience at farm level should be coordinated and planned to avoid possible internal incoherencies among resilience measures and inconsistencies of resilience with wider rural development objectives. Certain resilience measures are contradicting water conservation objectives while other resilience measures can be better coordinated in the framework of wider objectives such as the soil and water conservation strategies. Taking into account the specificity and diversity of the socio- economic conditions in the Mediterranean basin together with the fact that this region of the world is considered to be a climatic change hotspot, building a resilience strategy is a priority, “no regret” action. 1. INTRODUCTION The aim of this paper is to provide a broad overview of the main problems that will affect agricultural production in the Mediterranean area and are derived by climate change. In this section, the scientific ground of this work is set by presenting the basic definitions and the scientific evidence of the expected significant climate change in the Mediterranean area. In section 2, we provide an overview of potential climate change impacts on agricul- ture in the context of the Mediterranean area. Section 3 analyses the relationships between climate change, soil erosion and subsequent desertification problems. Section 4 considers the potential impact of climate change on Mediterranean forest with special reference to forest fires, not only on forests but also the important agro-forest systems characterizing 218 A BROAD OVERVIEW OF THE MAIN PROBLEMS DERIVED FROM CLIMATE CHANGE – MEDITERRANEAN AREA this region of the world. Finally, section 5 analyses the strategies that build resilience to climate change in agriculture in the Mediterranean region, while section 6 presents the basic conclusions of this critical review of the literature. 1.1 Definitions and the climate change framework Climate change is an issue of world importance not only because it affects the global physi- cal environment but also because its consequences will spread through planetary economic and social mechanisms to every nation irrespective of the local severity of impacts. A broad definition of climate change is adopted by the Intergovernmental Panel on Climate Change (IPCC), the leading international body for the assessment of climate change. Climate change in IPCC usage refers to a change in the state of the climate that can be identified (e.g. using statistical tests) by changes in the mean and/or the variability of its properties and that persists for an extended period, typically decades or longer. It refers to any change in climate over time, whether as a result of natural variability or as a result of human activity (IPCC, 2007a). A narrower definition is adopted by the United Nations Framework Convention on Climate Change (UNFCCC), where climate change refers to a change of climate that is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and that is in addition to natural climate variability observed over comparable time periods. In this work we adopt the IPCC definition of climate change and we accept the scientific evi- dence provided in IPCC’s Third Assessment Report (TAR) and Fourth Assessment Reports. Climate change refers to present and future changes in climate conditions. Present changes are based on observed scientific facts, while future changes are based on projected simulations under various scenarios. Ambiguity rises because of the frequently interchangeable use of these two terms. As concerns the present state, the IPCC is definite by stating that “Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice and rising global average sea level” (IPCC, 2007a). As a result, the observed climate changes have already produced a series of evident effects and a range of hypothesized effects. As the IPCC states “Observational evidence from all continents and most oceans shows that many natural systems are being affected by regional climate changes, particularly temperature increases” while “other effects of regional climate changes on natural and human environments are emerging, although many are difficult to discern due to adaptation and non-climatic drivers” (IPCC, 2007a). Taking into account the chain from greenhouse gas (GHG) emissions to atmospheric concentration, to radiative forcing and climate responses and effects, projections of the future are, primarily, based on scenarios about the likely evolution of GHG emission. The Special Report on Emissions Scenarios (SRES) has devised four families of likely future development pathways (A1, A2, B1 and B2) that include a wide range of demographic, economic and technological driving forces and their consequent GHG emissions but do not include climate policies above current ones. Each one of the four families of scenarios assumes a storyline concerning the likely evolution