Preface Firstly, we convinced ourselves that there is a need for a book on “Climate Change and Greenhouse Gases Emissions’ for student at universities. A few text books on “Climate Change and Greenhouse Gases Emissions”, particularly in agricultural sector are available. One of the special features of this book is that most of the data presented and discussed are the outcome of research works done by scientists both under national and international perspectives. Written in a simple language, the book presents the principles, practices along with key messages on different relevant issues on climate change and greenhouse gases (GHGs) emissions in agriculture. Chapters also contain probable questions and few solved problems. It is primarily intended for use as text book at undergraduate and postgraduate levels, but it can also be used by researchers of environmental sciences and allied disciplines. The other important feature of the book is that techniques of GHGs measurements at field level with examples are presented which could be useful for practical studies. The book should give students a good foundation in climate change studies and inspire them to take up further studies in the advanced arena of environmental sciences. The chapters systematically cover the major areas of climate change and GHGs emissions in agriculture. The basic concept of weather, climate, climate change, climate variability, the cause and effect relationship between GHGs emission and climate change is introduced in Chapter 1. In Chapter 2, the details on causes of climate change including natural and anthropogenic, net feedback mechanisms, carbon cycle and evidences of climate change are described. The chemistry of GHGs, radiative forcing and energy balance, mechanism of major GHGs emissions from agriculture, contribution of agriculture to GHGs emissions and sector wise emissions are discussed in Chapter 3. The techniques of measurement of GHGs at field level employing manual chamber, automatic chamber, infrared gas analyser, photoacustic spectroscopy, eddy covariance techniques are elaborated in Chapter 4. It is a unique chapter which has both theoretical and practical application. This chapter also has a specified section for equations needed for GHGs estimation and few interesting solved problems using field level data. The small but important chapter is Chapter no. 5, which deals with the issues of impact of climate change on agriculture, environment and food security. This chapter also contains the predictions of climate change consequences on agriculture as a whole and impacts on Indian agriculture in particular. The heart of the book is Chapter 6, which deals with the mitigation of GHGs emissions and climate change. This chapter emphasises on the principles of mitigation of GHGs emissions, mitigation strategies, adaptation strategies to climate change, Climate Resilient Agriculture (CRA) and Climate Smart Agriculture (CSA). In the penultimate Chapter 7, we tried to critically put the economics of GHGs emissions along with the history of ‘climate change policies’ and the ongoing debate on climate change mitigation and food security dilemma. In the preparation of the book, we received ungrudging help from ICARNational Fellow Project, ICAR-NRRI, Cuttack and number of scientists and well wishers. Those whom we wish to mention are: Dr T Mohapatra, Dr S.C Datta, Dr H Pathak, Dr P Swain, Dr M J Baig, Dr, Ch. Srinivasa Rao, Dr T Adak, Dr D Bhaduri, Dr D Mandal, Dr D Chakraborty, Dr A Bhatia, Dr N Jain, Dr S Kartykeyan, Dr M C Manna, Dr R Saha, Dr D Burman, Dr S Pal Majumdar, Dr B Majumdar, Dr S Neogi, Dr K S Roy, Mr S R Padhy, Miss P P Padhi, Miss U Nandy, Mr M Das from ICAR-NARS system. We have duly acknowledged the sources of the diagrams and tables that have been reproduced from other sources and publications.

1.1 Weather Firstly, what is weather? Simply, the conditions in the atmosphere above the earth is called weather. It refers to the conditions such as wind, rain and temperature, prevailing at a particular location during periods of hours or days. We often ask “what’s the weather like today”? Any individual can answer to this question as it requires only a short term experience or say exposure to the atmosphere. The TV news forecasters predict weather each day and inform about the temperature, cloudiness, humidity, or possibility of storm in the next few days. Weather is localised, say, it’s a hot and cloudy weather in one part of the country and dry and windy on the other part. 1.1.1 What are the factors that influence weather? Before we try to understand the factors that influence weather, we must understand what the components that describe a weather conditions are? Is it the rains, or the air temperature or both? The answer to this question is not so easy, and it’s a bit complicated. There are many components that constitute weather. Weather components include rain, cloud cover, sunshine, winds, hail, snow, sleet, storms, thunderstorms, heat waves and many more. These components are sometimes referred as weather parameters or climate elements. Each of these components define weather patterns of a particular area. These components determine the status of local atmospheric conditions. Again, as a basic definition, weather is the state of the atmosphere and majority of weather phenomena occur in the lowest layer of the atmosphere, called as the troposphere. Does it mean that ground conditions such as the topography, water bodies and vegetation of a particular area has nothing to do with it? No, it is not so. The state of the atmosphere is subjected to various processes taking place not only in the atmosphere but also in the ocean, the sea-ice, the vegetation, etc. Weather parameters or the components of weather form a sequence of events, and the influences are far reaching and they do not remain solely in the atmosphere. For example, terrestrial radiation impacts the air temperature, air pressure and humidity. The terrestrial location also influences the cloud formation. The clouds may or may not turn into precipitation depending on the outcome (cloud or rain), which is by and large governed by troposphere. Likewise, a lack of precipitation affects not only weather conditions, but also soil moisture conditions that may result in lowering of water levels (ground water table) in soil. Wind speed and direction are governed by the atmospheric pressure and air temperature. So, all these parameters or components are interrelated and the weather conditions are the outcome of their interactions. Therefore, we can say that, the three main components of weather are temperature, precipitation and solar radiation. These components are influenced by different factors.

Climate change is caused by both natural as well as anthropogenic causes and it has been changing since the inception of earth-atmosphere (Figure 2.1). In a broader sense, anthropogenic activities (human activities) also must be considered as natural one in longer time scale as human and their activities are also a part of natural-ecosystem-functions. Among the natural phenomena, volcanic eruptions and continental drifts significantly affect the earth’s precipitation and temperature. A huge volume of CO2 is released due to volcanic eruption at a little span of time-period which heated up the earth-atmosphere. Climate variability is primarily governed by rise in sea temperature, movement of warm water from the Western Pacific towards Peru, and El Nino which occurs at an intervals of 3-7 years. Climate variability also influenced the alteration in temperature and precipitation world wide. And persistent climate variability cause long term climate change. Therefore, basically three drivers that causes climate change are, the alteration in the energy of sun received by earth-atmosphere (natural causes), variations of ref lectivity of earth-surface- atmosphere system (natural as well as anthropogenic causes) and fluctuations in the greenhouse effect (natural as well as anthropogenic causes).

3.1 Chemistry of greenhouse gases (ghgs) Greenhouse gases (GHGs) are atmospheric-gases that have capabilities to absorb and radiate-back the infrared (IR) radiation in the earth-atmosphere system (Figure 3.1). In this process the atmospheric-gases absorb and radiate- back IR radiation in lower atmosphere effectively emitting and absorbing heat energy heat energy. They maintain the heat budget of earth-atmosphere and keep our plant warm. If we typically see the chemistry of those gases, the key point is that they should have dipole moments. This is the property which makes them capable to absorb and radiate-back the range of IR radiation. In a molecule when valence-electrons are not equally shared in a bond between the two atoms, a slight positive charge is developed above one atom and a negative charge on the other atom. That charge difference of the different atoms in a molecule generates the dipole moment. For instance, in water vapour (H2O- vapour), an unequal sharing of electrons and or separation of charge causes dipole moment. In H2O, the centre has a positive charge at the hydrogen atoms and negative charges are located on the oxygen atom. The magnitude of dipole- charges, vibration and stretching of O-H bond generates certain frequency of the oscillating dipole moment that actually regulates the absorption capacity of IR radiation by H2O vapour.

The measurement of greenhouse gases (GHGs) has been started during middle of the last century. Initially, CO2 and water vapour were measured with other common meteorological variables like temperature, sunshine hours, rainfall, humidity etc., for monitoring the weather condition and pollution. The absolute or relative concentrations of gasses in atmosphere are used to measure basically for monitoring purpose. However, limited studies were dealt with actual gaseous exchanges of fluxes. The concern about gaseous flux measurement and GHGs-exchanges started after 1900s when people got concerned about anthropogenic pollution, environmental sustainability and climate change issues. The GHGs-exchanges in earth-atmosphere systems primarily occur due to change in meteorological variables, soil responses and physiological activities of crops. If we are interested for environmental data inventories, then absolute GHGs concentrations of atmosphere at a specific time is required. However, presently researchers, students, environmentalists, climate scientists are primarily interested for quantitative data on GHGs fluxes and or GHGs-exchanges. They want to know what and how much quantity of a particular GHG is emitting from unit area at unit time. Flux refers to the amount of any gas emitted per unit area per unit time. The dimension of that is M A-11 T-1. (Where, M= Mass/ Quantity; A= Area; T= Time). The SI unit of flux is g m2s-1. Therefore, flux is a vector. It has magnitude as well as direction. As for example positive flux of CO2 from earth surface means, CO2 is moving out from earth surface to atmosphere. If it moves in opposite direction then the flux would be negative. In that case CO2 gas may be absorbed by the soil surface from adjacent atmosphere. Similarly, GHGs fluxes of earth surface are either positive or negative. Generally, positive GHGs flux refers to emission of GHGs from earth to atmosphere and vice versa.

5.1 Impact of climate change on agriculture Climate change has both positive and negatively impact on agriculture, food security and land degradation. Climate change could exacerbate the land degradation processes by increases in rainfall intensity, drought frequency and severity, dry spells, f looding, heat stress, sea-level rise and permafrost thaw. The 1/4th of ice-free land area in the world is prone to human-induced anthropogenic degradation (Certini and Scalenghe, 2011; Hooke et al., 2012). Soil erosion rate is 20-100 times faster than that of soil formation in agricultural field. The erosion rate is least is zero-tillage (non-disturbed field) and maximum at conventional intensive tillage practices. Climate change further exacerbates the land degradation. The permafrost areas, dry-lands, low-lying coastal regions, river deltas are more vulnerable. The occurrence of drought in dry-land was increased by around 1% per year during 1961-2013 periods. On an average 380-620 million people globally experienced desertification who lived in dry-land areas (1980s and 2000s) in South and East Asia, North Africa, Middle East, Sahara region, and Arabian peninsula. Moreover, people who are already living in degraded/ desertified regions are more negatively affected by climate change. Specifically, the land surface air temperature has increased about twice as much as the global average temperature since the pre-industrial era. The land-surface air temperature has increased relatively higher than the world’s average surface (land and ocean) temperature since the pre-industrial era (1850-1900). The average land-surface air temperature has enhanced by 1.53°C (1.38-1.68°C), whereas, world’s surface (including land and ocean) air temperature has enhanced by 0.87°C (0.75-0.99°C). Subsequently, global warming triggered the frequency, intensity and duration of heat waves and related damage. The direct and indirect impacts of climate change on global agriculture is summarised below for an overall idea about the importance of the issues.

What is mitigation of GHGs emission? We must be clear about the answer of this fundamental question. In simple term, the mitigation of GHGs emission is the way or means by which the emission of those gases could be reduced. As we know from the previous chapters of this book that the GHGs emission could be occurred from natural as well as anthropogenic activities. Natural activities included volcanic eruptions, ocean current fluctuations, continental drifts which are responsible for emission of huge amount of CO2 and other GHGs. The reduction of emissions from those natural activities is beyond our capabilities. However, the human induced emissions of GHGs emission could be reduced. We studied in previous chapters that fossil fuel burning, industrial and energy sector pollution, deforestation, land use change and agricultural could contribute to GHGs emission considerably. Mitigation techniques are different for each of those sectors that governed by lot of interrelated factors. In actual sense, the mitigation of GHGs emission should includes all the measures that can curtail the anthropogenic emission from all sectors. But that is out of the scope of this book. In this book, we specifically address the mitigation principles, options and efficiency of different techniques/ practices in agriculture only. In that aspect, the mitigation of greenhouse gases emissions in agriculture is defined as “the means and ways by which emissions of GHGs could be reduced from agriculture”. The ways and means actually referred to the techniques and practices and their amalgamation in agricultural sector both in production, processing and consumption aspects. So, mitigation is not only a techniques or combination of techniques it is actually an integrated approach for reducing greenhouse gases emission from agricultural systems. Primarily, there are two complementary approaches for mitigation of GHGs emissions from agriculture. Those two approaches are (i) supply-side and (ii) demand- side options or pathways. The supply-side approaches includes scientific land- use-changes, improvement of crop management, better livestock management practices, enhancing carbon storage in biota, soil carbon sequestration, significant substitution of fossil fuel by bio-fuels and use of renewable energy in agriculture. On the other hand, demand side approaches, taken in to account of shifting in the dietary pattern from non-vegetarian to vegetarian, curtail down the food loss and waste, and reducing the supply-chains (Figure 6.1). We can see, most of the approaches in supply-side are technology driven, while, approaches in demand-side are socio-economical and or policy driven. In this chapter we would thoroughly discuss the principles of mitigation, options of mitigation, mitigation cum adaptation approaches to reduce GHGs emission and climate change and few strategies to cope up with the vagaries of climate change.

7.1 Economics and Valuation of ghgs emissions Since the late 20th century, it has been largely accepted that cause of high concentration of GHGs in atmosphere is induced by human activities. Greenhouse gas emissions and related climate change has opened up debate on overall economic losses and ways to reduce these loses. Moreover, apart from curbing monetary losses; the global political leaders as well as reputed economists are looking towards making money by saving the emissions. Recently, the researchers have started to emphasize on the actual value added to the ecosystem by curbing emissions, discrete of the economic benefits. This section will discuss the economics and ecosystem services related to the management of GHG emissions. Origin The initiative to curb the emissions started in 1992 with the United Nations Framework Convention on Climate Change (UNFCCC) at the Earth Summit in Rio de Janeiro. The Convention took place from 3 to 14 June, 1992. The UNFCCC is an international environmental treaty designed to “stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system”. The UNFCCC had non-binding limits on greenhouse gas emissions for individual countries and the framework was only meant for formulating precise international treaties (called “Protocols” or “Agreements”). It contained no execution mechanisms, however, it considered some negotiations and suggestions to formulate the action plans and regulation guidelines under UNFCCC to fulfill the objective of reduction of GHG emissions to the desired level.

Glossary Adaptation Capacity: It is the intrinsic adaptive ability of crops and animals to cope up with climate variability. Aerenchyma: A soft plant tissue containing air spaces. Aerosol: A colloidal suspension of particles dispersed in air or gas. Anthropogenic activities: An effect or object resulting from human activity. Carbon cycle: It is the combination of different chemical pathways through which carbon f lows between the earth-atmosphere systems. Carbon sequestration: It is the process of storing carbon either in soil, plant, geological rocks or ocean for a longer period of time Clean Development Mechanism (CDM): It is to promote clean development with sustainability through emission reduction projects in developing countries. Climate Change: Climate change is refers to considerable and relatively persistent changes in the global climate. Climate index: Climate index referred to the estimated values used to elaborate the state and the changes in the climate systems. Climate Resilient Agriculture (CRA): It means the ability of the agricultural system to bounce back to its original when subjecting to certain climatic-stresses. Climate Smart Agriculture (CSA): It is an holistic and integrated approach which considers three basic component of development, techniques, policy and infrastructure (investment) to achieve sustainable development in agricultural for food security under climate change scenarios.