Introduction

Global environmental problems such as climate change, tropical deforestation, loss of biodiversity and desertification are receiving serious attention of all stakeholders including scientists, citizens and policymakers. Interestingly, all these environmental issues are linked to land-use systems. Climate change and its manifestations, particularly rising temperatures, changing precipitation patterns and sea level rise (IPCC 2007a), are of global environmental concern and have the potential to impact most natural ecosystems (such as forests, grasslands and wetlands) and socioeconomic systems (such as food production, fisheries and coastal settlements) in all countries. Under extreme conditions, the impacts are likely to be catastrophic to human survival and may lead to irreversible loss of natural ecosystems. Climate change in the long term is projected to adversely affect supply of fresh water, production of food and forest products and ultimately economic development of both industrialized and developing countries (IPCC 2007b).

Concentrations of greenhouse gases (GHGs) in the atmosphere and their positive radiative forcing have increased since the Industrial Revolution, and particularly faster in the last 30-50 years. Among the GHGs, carbon dioxide (CO2) is the most dominant, accounting for nearly 77% of the global total CO2 equivalent greenhouse gas emissions (IPCC 2007c). In terms of radiative forcing by GHGs emitted as a result of human activities, CO2 accounts for 56% of the total global warming potential of GHGs (IPCC 2007a). The concentration of CO2 in the atmosphere increased from a pre-industrial level of 279 parts per million by volume (ppmv) to 379 ppmv in 2005. An unprecedented increase of 36% in CO2 concentration was observed between 1750 and 2005.

Emissions of CO2, methane and nitrous oxide have increased in the last 25 years (Fig. 1.1a). In 2004, CO2 emissions from fossil fuels dominated, accounting for 57% of the total global CO2 equivalent GHG emissions (Fig. 1.1b) whereas those from deforestation, decay of biomass and peat accounted for about 19% (Fig. 1.1b) or 9.5 Gt (gigatonnes or billion tonnes). The CO2 emissions from land-use sectors have increased from 6.35 Gt in 1970, an increase of 0.126 GtCO2 annually, to 9.5 Gt in 2004. Over the 19th century and much of the 20th century, the terrestrial biosphere has been a net source of atmospheric CO2 (IPCC 2001a).

2000 2004

□ N2O from agriculture and others

□ CH4 from agriculture, waste and energy E CO2 from deforestation, decay and peat

□ CO2 from fossil fuel use

19.3

CO2 deforestation

57.4

CH4 14.3

CO2 fossil fuel use

CO2 deforestation

57.4

CO2 fossil fuel use

CH4 14.3

Fig. 1.1 (a) Trends in emissions of global anthropogenic greenhouse gases, 1970-2004, (b) share of different greenhouse gases (IPCC 2007c)

1970

1980

1990

1200 -1

1000-

800-

600-

400-

200-

A1FI

Fig. 1.1 (a) Trends in emissions of global anthropogenic greenhouse gases, 1970-2004, (b) share of different greenhouse gases (IPCC 2007c)

A1FI

Fig. 1.2 Projected atmospheric concentrations of CO2 under SRES marker scenarios (see Nakicenovic et al. 2000 for details of the scenarios)

IPCC Special Report on Emission Scenarios (SRES) (Nakicenovic et al. 2000) projects an increase in the atmospheric concentration of CO2 under all the six illustrative SRES scenarios (Fig. 1.2). The projected concentrations of CO2, the dominant anthropogenic GHG, in 2100 are likely to range from 540 to 970 ppmv, compared to 279 ppmv in the pre-industrial era (IPCC 2001a).

According to various SRES scenarios, a global warming by 1.8-4.0°C is projected by 2100 with land surface warmer than oceans, along with regional changes in precipitation and sea level rise (IPCC 2007a). Scientific evidence suggests that the projected climate change is likely to lead to increased water scarcity, droughts and high rainfall events, loss of biodiversity, shifts in forest types and reduction in food production in dry tropics with increased risk of hunger and flooding due to sea level rise. Some of the impacts such as loss of biodiversity and wetlands are irreversible (IPCC 2007b).

Mitigation and adaptation are the two approaches adopted by global scientific and policy community to address climate change. Mitigation is defined as the anthropogenic intervention to reduce the sources or enhance sinks of GHGs. Mitigation measures contribute to stabilization of atmospheric concentrations of GHGs, particularly CO2, at lower levels than projected, thereby reducing the magnitude and rate of climate change. Adaptation is adjustment in natural or human systems in response to actual or expected climatic stimuli and their impacts on natural and socio-economic systems. Adaptation is a necessary strategy to complement mitigation.

Addressing climate change requires scientific, technical and economic assessment of: (i) inventory of CO2 and other GHG emissions and removals from different sectors; (ii) contribution of different countries to the total global CO2 emissions and rise in GHG concentration, particularly that of CO2, in the atmosphere; (iii) different mitigation options and their mitigation potential, costs and benefits; and (iv) development, implementation and monitoring of mitigation projects, strategies and policies, particularly with reference to CO2. Mitigation opportunities exist largely in energy and land-use sectors. Land-use sector, the focus of this handbook, is critical to addressing climate change concerns through both mitigation and adaptation. Mitigation activities are likely to be implemented in most countries under diverse physical, biological and socio-economic situations, requiring diverse methods for estimation and monitoring of carbon sequestered and CO2 emissions avoided under different mitigation programmes and projects. This handbook focuses on such methods and guidelines for different land-use sectors as well as methods of carbon inventory for dominant land-use categories, namely forest land, cropland and grassland. Further, the handbook attempts to provide reliable, cost-effective, transparent and comparable methods for inventory of national CO2 emissions and removals as well as for monitoring carbon stock changes in carbon mitigation programmes and projects.

Guide to Alternative Fuels

Guide to Alternative Fuels

Your Alternative Fuel Solution for Saving Money, Reducing Oil Dependency, and Helping the Planet. Ethanol is an alternative to gasoline. The use of ethanol has been demonstrated to reduce greenhouse emissions slightly as compared to gasoline. Through this ebook, you are going to learn what you will need to know why choosing an alternative fuel may benefit you and your future.

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