Understanding role of climatic parameters and adaptation strategies in agriculture productivity of South Asian countries

ABSTRACT

South Asia, a most populated region has varied geography ranging from higher mountains to low lying coastal areas but economies are primarily dominated by agriculture. Chiefly dependent on agriculture for livelihood make the region highly vulnerable region to changing climate and cause threats to financial, ecological and social systems. Ever increasing population, put higher pressure to food security influenced by global climate change. The climate-induced variables disturb macroeconomic factors like food consumption and GDP as well as microeconomic factors like food prices and crop production. The impact of changing climate on crop production, yield and in climate variable, specifically temperature and rainfall, are addressed in this chapter. The positive and negative trends observed on crop yield are, 85% reduction for rice and maize yield in Afghanistan, up to 60% reduction in wheat yield in Bangladesh, 20–25% cotton yield loss in India, while 58% increase in sugarcane production in Pakistan. The economic losses face by South Asian countries are predicted to be 9.4% for Bangladesh, 6.6%for Bhutan, 8.7% for India, 12.6% for the Maldives, 9.9% for Nepal, and 6.5% for Sri Lanka. The implication of existing policies with research and development, market-based strategies and community-based options are necessary to enhance better results.

KEYWORDS:

• Agriculture
• Climate change
• GDP
• Food security
• Temperature
• Rainfall

1. Introduction

The term‘Climate’ refers to long-term weather conditions of any particular region such as wind flow, atmospheric pressure, humidity, rainfall behavior, temperature, and so on, and statistical change in these basic conditions for specific time period is termed as ‘climate change’ (Hussain et al., 2018). Climate change is a global phenomenon associated with extreme weather events (IPCC, 2007; Karl et al., 2009). The term climate change is not new to the world because of its global, regional and local impacts that is the reason world is concerning more about climate change (Kayani et al., 2018; Liu et al., 2018).

According to United Nation Framework Convention on Climate Change (UNFCCC, 2007), climate change is actually the fluctuation in the weather behavior for prolong time ranging from several years to many decades. The most visible effects of changing climate are variation in rainfall pattern, increasing average temperature, glacier melting, rising sea levels, crop diseases, specie invasions, weather related disaster and so on. InIntergovernmental Panel on Climate Change(IPCC) Fifth Assessment Report (2014), the prime responsibility of changing climate was given to greenhouse gases (GHGs) and Yousaf et al. (2017) claimed that the human activities are the major source of GHGs emissions and causing global warming. The human activities involved are industrial processes (Benhelal et al., 2013), fossil fuel burning (Yousaf et al., 2017), vehicular discharge (Bernabeo et al., 2018) and agriculture (Huang et al., 2016). In IPCC fourth and fifth assessment report it is compelled that by increase in GHG emissions the world’s temperature is rise by 0.8ºC from beginning of 20^th century and it is expected to increase by 2.4–6.4ºC by the end of twenty-first century, without carbon mitigation (Intergovernmental Panel on Climate Change, 2014; IPCC, 2007).

In comparison with last ice age and today’s climate the temperature difference is 6°C, result in glacier melting, rising sea level and diminution of soil moisture (Senapati et al., 2013). Since 1950, warm days and nights are increasing day by day; the intensity, extent and frequency of heat waves are increasing. Climate change also alters the precipitation timing and pattern, with low and heavy precipitation at different regional variations (Field et al., 2012). In short, climate change is rising global temperature; affect cloud cover and precipitation pattern; melting glaciers, thinning ice cover, rising ocean water acidity and temperature, and many more.

With high confidence, the land is, at the same time, source and sink of CO₂ (Intergovernmental Panel on Climate Change, 2019). Globally from 2007 to 2016, 23% (12.0 ± 3.0 GtCO₂e/year) of emissions caused due to anthropogenic activities in agriculture, forestry, and other land use (AFOLU) with almost 13% carbon-dioxide, 82% nitrous oxide and 44% methane. Intergovernmental Panel on Climate Change (2014) emphasizes in Fifth Assessment Report (AR5) that in coming 50 years agriculture is the most climate sensitive sector (Mendelsohn, 2001) in entire globe due to climate change. Agriculture is one of the most climate vulnerable sectors of the economy because climate is a direct input to agricultural production (Gupta et al., 2014). Agricultural sector is at the top of the list of affected communities by climate change, although agriculture is contributing only 10% of annual CO₂ emission because of high dependency on climate driven elements such as unpredictable climate crisis, increase temperature, enhance water-related risks, frequent events and decrease summer precipitation (Fuhrer et al., 2013; Maskrey et al., 2007). So, it is important to comprehensively study the role of climatic parameters on agricultural sector. Furthermore, the adaptation and implication of different strategies to improve the agricultural yield and productivity in response to climate change are also important to study broadly. The study objective is (i) to understand the influence of climatic parameters especially temperature and precipitation on the yield of different agricultural crops of South-Asian Countries, (ii) to suggest some strategies adaptation for different crops that are vulnerable to climate change specifically in South-Asian Countries.

2. Impacts of temperature and precipitation on agriculture sector

The changing climate impacts are different and diverse, may be minor or major, favorable or unfavorable to the agriculture depend on spatiotemporal conditions. Increased heat, reduced cold, rising seas, CO₂ fertilization cause faster crop growing, strict droughts, disease spread and sometimes species extinction at extreme cases are the impacts usually observed but the important thing is to assess the change in balance, good or bad and the other associated impacts (Tol, 2018). The major pressure on food production is climate change and variability among climate factors in global farming regions. Both temperature and precipitation are inducing factors, which are drastically affecting the climate sensitive agriculture sector and productivity of crops (Kyei-Mensah, Kyerematen and Adu-Acheampong, 2019). Temperature variability shrinks global yield and crop production, correspondingly, precipitation variability reduces the yield of traditional crops, damaged the standing crops, enhanced crop diseases events and cause reduction in soil fertility (Kashaigili et al., 2014; Kurukulasuriya & Rosenthal, 2013; Olesen et al., 2011; Zhao et al., 2017).In addition, changing temperature and rainfall pattern affect the evapotranspiration rates and alter the water availability for irrigation, respectively (Adams et al., 2001).

Specific temperature range for each crop is necessary for healthy process of photosynthesis and crop physiological mechanism; however, increase in temperatures even for few hours cause the disruption in these mechanisms especially for sensitive parts, for example reproductive parts, and thus impacting the crop yield. It was predicted that increase in extreme heat events cause in the reduction of crop yield up to 15% by 2030. It is evident in historical analysis, from 1980–2008 there is an obvious reduction of the crops of wheat and maize up to 5.5% and 3.8% respectively. Scientists have also predicted that the yield of rice and wheat would be decline 8% approximately after every single degree Celsius increase in temperature. Potato production is also affecting, globally, because potatoes are suitable to grow in cooler temperatures (Doreen, 2014). Recent studies demonstrated that, globally the rise in temperature for each degree-Celsius result in the yield reduction of 6.0 ± 2.9% of wheat, −7.4 ± 4.5% of maize, 3.2 ± 3.7 % of rice and 3.1% of soybean (C. Zhao et al., 2017). According to economic study of Nelson et al. (2009), the impact on crop production and yield would greatly affect the crop prices specifically for highly fed crops like wheat, rice, maize, etc. and hence the import price in South Asia will increase up to 15 billion dollars per year. The rising unpredictable rainfall pattern and variable seasonal precipitation badly influence the soil water availability for crop, loss by floods and drought become a serious issue to farmers of the South Asia and policy makers as a threat to food security (Mumo et al., 2018; Taneja et al., 2019; Wang et al., 2019; Wang et al., 2018). An important note while discussing impacts of climate change on agriculture, economic losses and damages bear by small hold farmer, and their community would address and aid by government and policy makers to stop migration/displacement due to crop failure and transformation from major staple crops and to make measures to enhance economic gains (Doreen, 2014).

3. Agriculture and food security in South Asia at a glance

South Asian region, chiefly dependent on agricultural-based economies, is considered as the most vulnerable region in the world, disturb the food production and make agricultural production and growth crucial due to changing climate causing food insecurity, negative affect on regional economies and intensive threats related to financial, ecological and social systems (Bandara & Cai, 2014; Mirza, 2011). South-Asia has the fastest growing economy but the region is densely populated and climatically threatened and situation get worsened by locality, topography, socio-political influences, literacy rate, unskilled labors, economic prosperity, poverty and dependency of livelihood on nature (Hirji, Nicol, & Davis, 2017; Anup et al. (2013).

South-Asia covered a total area of 513,790 Km² with the population of 1653 million people with 450 million US Dollars Gross Domestic Product (GDP). According to De La et al. (2018), there are 274.5 million people in South Asia that are live in extreme poverty conditions. Only 2.62% of world’s GDP is fulfilled by South Asia, though South Asia has population of 23.24% relative to the entire globe. Agriculture is the major source of livelihood in this region but dominated by smallholdings in such a way that in India and Pakistan comprise 1.41 hectare and 3.0 hectare, respectively, Sri Lanka and Nepal have 1.0 hectare and Bangladesh have only 0.5 hectare (Jaspal et al., 2014). As the high dominancy is of micro-scale farmers that means the economic viability of region is highly vulnerable to changing climate because the farm-size under 2 ha is proved to be economically profitable and proper policy design to finance agriculture is crucial (Dev, 2012; Amjath-Babu; Amjath-Babu et al., 2019).

Although the agriculture is an important sector in South Asia for contribution in livelihood and GDP, but the earning capacity in this sector of every third person is less than 1.25 US dollars/day (Anik, Rahman and Sarker, 2017). The total livelihood capacity in agriculture and percentage GDP contribution of agriculture (Table 1) for South Asian region specify that obvious decline in GDP probably due to uncertain climate trends (Asian Development Bank ADB, 2019; Doreen, 2014).

Table 1. Percentage of labor force and GDP contribution in agriculture over a period of 2000 to 2018

Year	Country	Afghanistan	Bangladesh	Bhutan	India	Maldives	Nepal	Pakistan	Sri Lanka
2000	Labor	69.6	50.8	46.5	59.9	13.7	–	48.4	36.0
	GDP	43.7	25.5	27.4	23.0	6.9	39.6	27.4	17.6
2005	Labor	69.6	48.1	43.6	56.1	15.9	–	43.0	32.8
	GDP	35.2	20.1	23.2	18.8	8.7	35.2	24.4	11.8
2010	Labor	–	47.5	59.4	53.2	4.3	64.0	45.0	32.5
	GDP	28.8	17.8	17.5	18.2	6.1	35.4	24.3	9.5
2018	Labor	39.5	40.6	54.0	–	9.0	21.5	38.5	25.5
	GDP	21.4	13.8	18.3	16.1	6.6	28.1	24.0	8.6

Source: Asian Development Bank, 2019.

According to FAO, WFP, and IFAD (2012), South Asia has largest number of food insecure people with an estimation of 300 million undernourished individuals. South-Asia is already facing developing economies, food insecurity and population bomb so in this scenario climate change is the additional stress to agricultural system (Doreen, 2014). In South Asian regions, agriculture is vital for food security and minimizing poverty, still climate change is an obstacle to obtain food security and poverty reduction in this region (Ali and Erenstein, 2017). Globally, the production of crops in South Asia is important for food security as it is contributing in production of 18% and 31% of world’s wheat and rice, respectively (Doreen, 2014). Lasco (2014) impelled that impacting agriculture means risk to food production in so many ways like changing precipitation pattern and rising temperatures affecting crop production and composition, increased irrigation requirement, cropping season (Ali and Erenstein 2017), unpredictable heavy rainfalls damage farm land and crops, and also the random and the recurrent climatic events contribute additional to crop losses. In face of changing climate, South Asian farmers are changing sowing, irrigation and harvesting pattern, cultivation techniques, cropping patterns, use transient crop varieties and agroforestry and adapt their farm level management practices to manage crop production parallel to rapid population growth (Henne et al., 2018; Tripathi & Mishra, 2017). Still there is a need to adapt cropping and agricultural resilience to protect the system from adverse climate stimuli in South Asian region with developing economies.

4. Effect of temperature and precipitation on South Asian’ agricultural productivity

4.1. Case of Afghanistan

Afghanistan is geographically landlocked country. From southwest to northeast, Afghanistan is located at arid sub-tropics between 29° and 37º north of equator, surround by Hindu Kush mountainous area that further divides the country in various highlands and deep valleys. The soil, topography, vegetation and climate may alternate in the whole region; this heterogeneity in the region also creates different agricultural systems (Library of Congress-Federal Research Division., 2017). Summers are hot and dry while temperature drops below freezing in winters. It is raining and snowfall from October to April. In summers, majority of agriculture depend on rainfall and snowmelt APPRO (Afghanistan Public Policy Research Organization) (2014). The three decades of conflict and political turmoil disturb farming system and sector’s capacity, and hence minimize the economic growth and employment rate (Asian Development Bank ADB, 2016).

The major crop type in Afghanistan is 80% of wheat production (Aich et al., 2017). According to United Nations Development Programme (UNDP, 2018), 80% of Afghanis are depending on rain-fed agriculture and cattle-grazing for their livelihood; both are vulnerable to increase in temperature and irregular rainfall pattern. Agriculture in Afghanistan is accounts for 61% of total country’s economy with 44% of employment source (World Food Progamme WFP, 2016). The mean annual temperature in Celsius is 14.0 and annual precipitation of 312 mm for Afghanistan (Aich et al., 2017). Afghanistan has 70% of both irrigated and rain-fed cultivation lands (FAO, 2018). The rise in annual temperature observed in Afghanistan is 0.6ºC since 1960 (Aich et al., 2017). Wheat, cool season crop, is the largest cereal crop produced in Afghanistan about 80% and remaining 20% is rice, barley and maize (World Bank, 2010). The other eminent horticulture crops are grapes, apples, apricot, almonds, pistachio, melon and pomegranate, which add 1.4 US dollars to GDP with major country’s export. Agriculture is an area of continuous growth for Afghanistan but majority dependency is on rain-fed agriculture make this sector vulnerable to climate crisis. So, Afghanistan needs to strengthen their adaptation measures to enhance water management, agricultural research and development, better disaster risk management and preliminary warning systems (Asian Development Bank ADB, 2016).

4.2. Scenario in Bangladesh

Bangladesh, flat and low-lying country, located on Bay of Bengal at north-east of Indian sub-continent. The climate is humid, tropical and warm in all the year with the average temperature of 25ºC. The country exhibit four seasons that are (i) the warmest period pre-monsoon from March to May, (ii) rainy season the monsoon from June to September, (iii) pre-monsoon and (iv) cool and dry sunny season from December to February (Ahmed & Suphachalasai, 2014). Precipitation pattern is moderate to high with flooded monsoon season (Sikder & Xiaoying, 2014). Almost 80% of total precipitation happen in monsoon with average rainfall of 2,320 mm ranges from extreme northwest to northeast from 1,110 mm to 5,690 mm. The temperature is ranging from 4°C to 43°C with mean temperature of 25°C. In Bangladesh, the temperature is expected to increase by the end of twenty-first century, the change is predicted to be; 0.9–1.9°C by 2030, 1.6–2.5°C by 2050 and 2.9–4.2°C by 2080 (M. Ahmed & Suphachalasai, 2014).

Agriculture is playing vital role in country’s economy with more than half that is 55% of total bengaline population depends for their livelihood on agriculture and contributed 17.22% in GDP (Hossain et al., 2019). The total cultivable land in country is approximately 8 million-hectare give annual food production of 31.9 million ton. Bangladesh has fertile soil and produce rice, jute, wheat, maize, potato and vegetables in the country. Although Bangladesh is rich with fertile land but rapid urbanization, reduce 1% of agriculture land per year. Besides that, the climate shocks of floods, droughts, storms and cyclone make agriculture sector more vulnerable and harm the country’s economy (Ahmed & Suphachalasai, 2014).

The crop agriculture is the primary source of food security and economy for both rural and urban populace (Hossain et al., 2019). There are two cropping systems namely Rabi and Kharif. Rabi crops from mid-November to mid-March include Boro rice, potato, wheat, oilseeds, pulses and winter vegetables and Kharif crops; kharif-I from mid-March to mid-July and kharif-II from mid-July to mid-November include Aman and Aus rice, jute and summer vegetables (Hossain et al., 2019). The rice, comprises 95% of total crop, is the largest crop in Bangladesh produced. Rice is chief crop accounts for 77% of agricultural land use with 1/6^th of national income. The other crops accounts for 2.50 of wheat and 4.74% jute, 3.07% potato and other (10.24%). Jute production is accounts for 26% of agricultural production (Hossain et al., 2015). Hossain et al. (2019), conclude that by 1°C rise of temperature in wet season help in economic gain of 15.64 US dollars per hectare and in dry season cause economic loss of 0.22 US dollars per hectare.

4.3. Case of Bhutan

Bhutan is placed between 26º 42´ N and 28º 14´ N latitude and 88º 44´ E 92º 07´ E in the southern slope of Eastern Himalayas, with temperature varies from > 20ºC in South to below zero in the high Himalayas (Chhogyel & Kumar, 2018; World Food Progamme WFP, 2016). The climate ranges from alpine in the highlands, temperate in the foothills of Himalayan valleys and humid and subtropical in the southern plains, which are responsible for varying temperature in different parts of country (Ahmed & Suphachalasai, 2014). Bhutan is an agrarian country and serves as major source of employment and livelihood to almost 70% of Bhutanese in which 56% are farmers and others are involved by indirect means (WBG, World Bank Group, 2016). The contribution of agriculture in Bhutan’s GDP is 17.37% in 2017 (Plecher, 2020). Due to topographic and geographical uniqueness, the country has limited cultivable land of 2.93%. Bhutan’s 13% land is arable, and 27% land is cambisol or fluvisol (Chhogyel & Kumar, 2018).Arable land is a land that has capability of being ploughed and used to grow crops. Combisol are also good agricultural land that mainly occur in the temperate and boreal regions. Fluvisol are very young soil land and found in all the climatic zones and on all the continents. Country’s total area of 38,393 km² is divided into six agro-climatic zones namely; warm temperate, cool temperate, alpine, sub-tropical, wet sub-tropical and humid sub-tropical, with rainfall variation from <650 mm in alpine to >5500 mm in wet sub-tropical region and also 0.5–0.6ºC decrease in temperature with increasing altitude (WBG, World Bank Group, 2016).

Bhutan will predicted to experience peak warming temperature by 2050s with rise in rainfall and change in spatial pattern of monsoon (Katwal et al., 2015). By the end of 21^st century, temperature is predicted to increase 1.5–1.9°C by 2030, 2.2–2.6°C by 2050 and 3.3–4.5°C by 2080 and rainfall is predicted to deviate by −3.3–4.1% in 2030, −1.1–6.4% by 2050 and 0.1–1.1% by 2080. The agriculture in the region is primarily monsoon precipitation dependent. Hence, the change in climatic conditions cause crop failure and affect the rural livelihood. As 31% of agriculture in the country is on slopes, with rise in temperature the glacial retreating damage the agricultural land, extensive land sliding and eventually lead to economy loss to the farmers (Ahmed & Suphachalasai, 2014).

4.4. India’s situation

India is the largest of South-Asia and 7^th largest country in the world by size with an area of 3.288 million km² and coastline of 7500 km (FAO, 2017). India is among largest agrarian economies of the world with almost half of the population linked with this sector for their livelihood (M. Ahmed & Suphachalasai, 2014; Madhusudhan, 2015). Agriculture in India contributes 14% and 23% in GDP and 35% in (Defra, 2012; FAO, 2017; Kumar & Gautam, 2014). In India, crops are classified by two varieties, rabi; the winter crops and kharif; the rainy season crops. The winter crops include barley, wheat, gram, mustard and peas, the winter rainfalls because of western temperate cyclone help in winter crop production. The rainy season crops include rice, pulses, maize, sugarcane and groundnut, are sown in early monsoon. The changed temperature and rainfall patterns cause floods and droughts cause crop failure, damage to standing crops and related economies (Ahmed & Suphachalasai, 2014).

Climate is humid to dry in tropical South to temperate alpine in north; provides agro-ecological diversity (Kumar & Gautam, 2014). The average precipitation is 1,170 mm and the temperature varies from South to north in the country. The temperature forecast is 0.6–2.4°C, 1.1–3.5°C and 1.9–6.2°C by 2030, 2050 and 2080, respectively. Likewise, the precipitation forecast for 2030 is −39.2–16.3%, −33.2–29.7% for 2050 and −42.5–33.3% for 2080 (Ahmed & Suphachalasai, 2014). India face 23 droughts till 2009 with increased frequency in seasonal variations including more warmer winters and high temperatures and would experience loss in agriculture for up to 40% by 2080s (Kumar & Gautam, 2014).

4.5. Case of Maldives

Surrounded by 26 low-lying coral isles, having elevation of 2.4 m, archipelago of 1192 islands is Maldives, contains 3.1% of world’s coral reefs. It is placed in Indian Ocean extended from 7º N to 0.5º S of equator, at South of India. The total of the land area is 870 km². The soil is alkaline in nature because of coral sand and hence bounds the agricultural production (Stevens & Froman, 2019; Stojanov, Duží, Němec, et al., 2017). Maldives comprise humid and warm tropical climate with two monsoon seasons; the wet monsoon from May to November and dry monsoon from January to March. The temperature is predicted to raise by 0.8–1.09°C by 2030, 1.3–1.6°C by 2050 and 2.2–3.3°C by 2080. However, precipitation will forecasted to increase by 7.7–18.7% in 2030, 11.3–16.2% in 2050 and 23.7–30.5% in 2080 (Ahmed & Suphachalasai, 2014). The climate is tropical with average temperature of 28ºC and variation of 23–31ºC (Stevens & Froman, 2019; Stojanov, Duží, Němec, et al., 2017). The precipitation varies from north to South from average, 1,700 mm/year to 2,350 mm/year, respectively with humidity ranges from 75% to 83% (Stojanov, Duží, Kelman, et al., 2017). Agriculture includes coconut, fishery with the contribution in GDP is 1.6%, and almost all of the other food items are imported from other countries (FAO, 2012). However, fishery comprises 99% of Maldives’ export (Zameel, 2019). In Maldives, the agricultural land is only 10%, pasture 3% and forest 3% as well (Stojanov, Duží, Kelman, et al., 2017). The climate shocks to the agriculture system is worsen by scare water reserves and poor soil structure of archipelago (Ahmed & Suphachalasai, 2014).

4.6. Situation in Nepal

Nepal, another agriculture dominant land in South Asia, lies 280º N and 840º E, in between; India in the east, west and South and China in the north (Paudel, 2016). Nepal’s spread at an area of 147,181 km², divided into five geographical regions including Terai (23%), Siwalik, Himalaya (35%), mid-hills and high hills (42%) (Paudel, 2016). Agriculture is the major source of Nepalese economy providing 66% of employment to total population. The total land used for cultivation/agriculture is 3,091,000 ha, attributed for 38.15% of GDP (Malla, 2008). The agricultural process is primarily depend on ice, snow and glacial melts (Ahmed & Suphachalasai, 2014).

The average precipitation is 1500 mm with two rainy seasons that is summer from June to September and winter from December to February. The monsoon season accounts for 75% of total precipitation (Ahmed & Suphachalasai, 2014). The average temperature increased in Nepal by 0.06ºC/year with 0.04ºC for Terai and 0.08ºC for Himalayas every year. It is predicted that temperature will increase by 0.5–2ºC, 1.3–3.8ºC and 1.8–5.8ºC with variation in precipitation by −34 to + 22%, −36 to + 67% and −43 to + 80%; by 2030, 2060 and 2090, respectively (Bhusal, 2019). Almost 26.5% of land is attributed for cultivation; upon which 80% people is dependent for employment (Dhakal et al., 2016)

4.7. Case of Pakistan

Among South Asian countries, Pakistan is the second largest country with an area of 881,889 km² and fifth most populace country in the world with 219,382,000-population size (Ziring & Burki, 2020). Pakistan is among highly vulnerable country because of climate crisis and fluctuating weather with ranking of seven in Global Climatic Risk Index (GCRI) for 1997–2016 (Kiani & Iqbal, 2018) and according to world bank Pakistan is 12th utmost exposed country to changing climate (Ali et al., 2017). The climate is ranges from subtropical arid to semi-arid and temperate to alpine. The precipitation varies from 100 to 2000 mm mainly from June to September across the countryside (McDermid et al., 2015). Pakistan is agrarian country with contribution of 21% of agriculture to GDP and provides employment to 62% of population (Kiani & Iqbal, 2018). Pakistan is mainly located in an arid region with low precipitation and high temperatures (Ahmed et al., 2018). The main crops are wheat, cotton and rice grown at different agro-ecological zones of the country with diversified hydrological, soil and climate conditions. The growing seasons are two in Pakistan; the first is from April to December-kharif and the second is from October to May-rabi. The rainfed agriculture is grown by southwest monsoon (McDermid et al., 2015). The temperature and rainfall show constantly increasing and decreasing trend since start of 20^th century, the rising temperature cause increased evapo-transpiration demand for crops for up to 10–30% (Ullah, 2017). Agriculture systems in Pakistan is worsen by population and urbanization pressure as it decrease the production and profitability of crops (McDermid et al., 2015).

4.8. Scenario in Sri Lanka

An island of area 65,610 km², in Indian Ocean, is Sri Lanka. It is a land of almost 20.5 million populations with GDP per capita of 2400 US dollars. For 2500 years, Sri Lanka is an agrarian base country with agriculture as a backbone of economy having 70% population living in rural areas; 71% have < 1 hectare land holding whereas 66% have rain-fed cropland, making region more vulnerable to climate extremes. The mean temperature is 27°C in lowlands and 15°C in highlands whereas the average rainfall is 2,000 mm. The temperature forecasted to increase in Sri Lanka by 1.0–1.0°C for 2030, 1.3–1.8°C for 2050 and 2.3–3.6°C for 2080 and the rainfall patterns for the country is predicted to increase as 3.6–11.0% in 2030, 15.8–25% in 2050 and 31.3–39.6% in 2080 (Ahmed & Suphachalasai, 2014). Agriculture is important sector to in economy with the contribution of 12% in GDP. The total land is divided into three agro-ecological zones, which are 4.17, 1.54 and 0.85 million hectares as dry zone, wet zone and intermediate zone in Sri Lanka, respectively (Esham & Garforth, 2013).Agriculture contribution to GDP is 78% in which 13.4% is attributed for rice, 10.1% for tea and 10.9% for coconut (Zubair et al., 2015). The climate change impacts on agriculture are exacerbate by socio-economic conditions, poverty level, low literacy levels, irrigation water availability and political influence (Ahmed & Suphachalasai, 2014). All the impacts of changing climate on crops with change in temperature and rainfall on major crops of South Asian countries, except Maldives due to less availability of data, is discussed in Table 2.

Table 2. Effect of temperature and precipitation on major crops of South Asian countries

Country	Temperature and precipitation	Crops	Impact	Feedback	References
Afghanistan	High temperature up to 5ºC in overall region; precipitation reduces 100mm and more by 2050; Increase in temperature between 2–6ºC; drier conditions with 10-40mm reduced rainfall pattern (Savage et al., 2009; Sharma et al., 2015)	Rice, Maize	85% loss of production of rice and maize since 1998–2005	Negative	Savage et al. (2009)
		Wheat	Loss of 7.7% of yield	Negative	Sharma et al. (2015)
Bangladesh	0.20ºC increase in temperature per decade; reduction in −0.75 and −0.55mm in pre and post monsoon seasons, respectively, with decline in precipitation pattern from 2011–2020 up to 153mm (Rahman & Lateh, 2017)	Wheat	Production loss of 60% of achievable yield; by 2050 yield is reduced of 32%	Negative	Hossain and Teixeira da Silva (2013).
		Jute	Gain in production that is 0.87% but loss in yield for up to 0.22%, in 2014–2015 compared to last year 2013–2014	Positive production but negative yield	Bangladesh Bureau of Statistics (2015)
		Rice	Production loss of average 7.4% since 2005–2050; 8–17% Production losses by 2050; 40% Aman rice production losses by 2005–2006; Yield loss of 12.67%	Negative	Sikder and Xiaoying (2014); Amin et al. (2015); Nahar (2016)
Bhutan	Dry spells and winter temperature rises at higher 3.5 to 4.0ºC (UNDP, 2011) Precipitation nearly zero in winters and increase gradually up to 280mm to 500mm in July (Shahnawaz & Strobel, 2015)	Potato	Yield loss of 5606.7 to 3763.0 kg/acre from 2004 to 2013	Negative	WBG, World Bank Group (2016)
		Wheat	Yield increased by 552.7 to 787.7 kg/acre from 2004-to 2013, respectively	Positive	WBG, World Bank Group (2016)
		Rice	Yield increased by 1166.1 to 1555.6 kg/acre from 2004-to 2013, respectively; Yield increases up to 10% that is positive trend for year 2020s and 2050s	Positive	WBG, World Bank Group (2016); Knox et al. (2011)
		Maize	Yield loss of 1679.1 to 1297.9 kg/acre from 2004-to 2013, respectively	Negative	WBG, World Bank Group (2016)
India	Temperature increase by 0.48C and precipitation decrease by 26mm from 1960–2016 (Hari et al., 2018)	Maize	Yield loss by 10–30%	Negative	Aryal et al. (2019)
		Cotton	yield loss by 20–50%	Negative	Araya (2007)
		Rice	Yield loss by 6–8%	Negative	Aryal et al. (2019)
		Wheat	Yield loss of 1.5–5.8%; yield reduced to 5.2% from 1981–2009	Negative	DEFRA (2012); Aryal et al. (2019)
Nepal	Temperature increase by 0.02ºC/year with decrease in precipitation by 10.21mm annually for past 30 years (Dhakal et al., 2016)	Chick pea	Severe winter cause yield loss of 38%	Negative	Dhakal et al. (2016)
		Mustard seed	Severe winter cause yield loss of 11.2%	Negative	Bhusal (2019)
		Potato	Severe winter cause yield loss of 27.8%	Negative	Bhusal (2019)
		Barley	By winter drought assessment yield loss by 17.3%	Negative	Dhakal et al. (2016)
		Wheat	Yield increase by 8.6%; by winter drought assessment yield loss by 14.5%	Positive; Negative	Acharya and Bhatta (2013); Dhakal et al. (2016)
		Rice	Yield increase by 17.1%	Positive	Acharya and Bhatta (2013)
Pakistan	Rise in temperature up to 1.05°C and rainfall decline by 3.5mm (Baig & Amjad, 2014)	Other crops	yield loss by 17–3%	Negative	Ahmed et al. (2019)
		Sugarcane	production increase by 58% from 1973 to 2013	Positive	Zhao and Li (2015)
		Oilseeds	yield loss by 15–4%	Negative	Ahmed et al. (2019)
		Cotton	yield decreaseby 8%	Negative	Ahmed et al. (2019)
		Maize	yield decrease by 5%; loss by 27%	Negative	Ali et al. (2017); Ahmed et al. (2019)
		Wheat	yield decrease for up to 1.9% during period 2013–2015; yield loss by 50%	Negative	Ali et al. (2017); I. Ahmed et al. (2019)
Sri Lanka	Temperature increase by 2.4°C with rainfall increase by 106mm in 2070–2099 compared to 1961–1990 (Esham & Garforth, 2013)	Tea	Yield reduces by 10%	Negative	Esham and Garforth (2013)
		Rice	Production loss of 14–28% due to drought	Negative	Wijeratne et al. (2007)

5. Adaptation possibilities against changing climate

In the entire above-discussed scenario, adaptation strategies are necessary to beat adverse climate shocks and to build resilience that will result in building communities and stronger regional economies. A major challenge for adaptation processes in agriculture is including socially and economically deprived groups in which first is gender like women contributing in crop productions, cultivations and animal development and second is marginalized farmers which are forced to migrate in search of off-farm activities. This group of farmers are confronting hurdles because of illiteracy, lack of access to information and inequalities. By integrating policy and institutions and by training and capacity building enable women and economically viable farmers to adapt to climate change (Khatri-Chhetri & Aggarwal, 2017). The main difficulty in adapting strategies includes illiterateness, bad economic status, and lack of social services, poor topography and inefficient adaptive capacities of the region (Khanal et al., 2019).

As farmers are the first to face changing climate so they need to adapt their farming practices and system against climate crisis (Shahzad et al., 2021). Increase in intensity of unpredictable rainfalls, low frequency of rains and longer dry spells as well as loss of standing crops and harvest due to frequent natural hazards including drought and floods; are the major risks on which are always at verge (Li et al., 2010; Thomas et al., 2013). Minimizing these impacts adaptation is important component in reaction to climate risks; as without adaptation practices these adverse impacts found more inimical to agriculture (Ali and Erenstein, 2017). Climate change is adversely impacting the agricultural (Kipling et al., 2019; Thornton et al., 2018) however, effective adaptation strategies based on traditional knowledge, farmer’s perception, farm type, economic capacity of farmer and local climate, and the integration of primitive knowledge at local farm with expert opinions, make it possible to reduce negative climate impacts (Aryal et al., 2019). The adaptation should be of such characteristic that it helps to reduce greenhouse gas emission as well as increase farmer’s crop production and yield with less economic implication. South-Asia has wide range of argo-climatic zones with developing economies so the adaptation and mitigation strategy should be cost effective and adaptable to small hold farmer too and help in reducing GHG emissions. Rain water harvesting, improved drainage system, flood control parameters in flood-prone area, zero tillage save up to USD 79/ha with reduced GHG emissions (Aryal et al., 2015), alternative land use, agroforestry, use of heat and drought tolerant seeds, use of shade trees, use of alternative crops, and so on (Wichern et al., 2019) are some options adopted at individual farm level, society level as well as regional and national level. Farmers and researchers to cope-up with climate stresses, explores many of the climate adaptation strategies. The crop-wise adaptation practices conducting in many regions of South Asia are stated in Table 3.

Table 3. Adaptation practices in major crops of South Asian countries

Country	Adaptation	Crop	References
Bangladesh	Use of System of Rice Intensification (SRI) to enhance rice yield improve 64% of yield relative to conventional methods	Rice	Barrett et al. (2016)
India	Ring pit planting compared to conventional flat planting, yield increase by 64%	Sugarcane	Yadav and kumar (2005)
	Argro-foresty, using prosopis cineraria as wind barrier; integrated weed management	chickpea	Raj and Lal (2014); Ratnam et al. (2011)
Nepal	Nutrition management, raised bed cultivation	Maize, Wheat	Sherchan and Karki (2005); Lauren et al. (2006)
Pakistan	Use of drought and heat tolerant cultivars	Cotton wheat	Khan et al. (2015) Minhas et al. (2018)
Sri Lanka	SRI to improve yield	Rice	Namara et al. (2003)

2021 It is evident that improved livestock management and paddy production as well as improved crop-land management help to mitigate 9% of CO₂ and 2% of NO₂. An ideal mitigation and adaptation strategy is the one, which give higher productivity; climate smart agriculture (CSA) is an ideal strategy to reduce the impact of climate crisis (Jat et al., 2016). Climate resilient agriculture (CRA) is a branch of CSA to improve agricultural resilience, focuses on the reduction of GHG emissions. This approach help to cope up with vulnerability of climate shocks and improve adaptive capacity, rise in economy and food security (Pound et al., 2018).

According to Acharjee et al. (2019), shifting dates for crop plantation would found helpful as an adaptation strategy against unpredictable climate change especially to reduce irrigation water demand but found not a healthy option at Indo-Gigantic plain due to low winter temperatures. Like Acharjee et al. (2019), Brouziyne et al. (2018) also demonstrate shifting practice of crops as climate smart adaptation by early sowing date to avoid temperature thresholds at season end along with no tillage practice no that the soil biota and moisture will conserve for crops planted. Some other options available for adaptation are using variety of crops and species, shifting seasonal dates, changing water and irrigation pattern, agroforestry, and so on. It help to promote the decline of food security crisis, pinpointing vulnerabilities, guarding genetic resources, establishing agricultural communication, change topography of land and/or farming system, institutional and governmental policies and benefits from micro-climate and ecological services (Food and Agriculture Organization FAO, 2007).

These changing weather conditions demand intense endeavor to deal with climate-related risks in developing world, but few constraints refrain fruitful strategies to be accomplished includes, lack of economic resources, poor access to information and knowledge, limited technological advancement and lack of access to other resources, as well as, dependency on natural resources and majority of rain-fed agriculture. South-Asia’s larger region based on mountains or dry land has more supplementary challenges with few controlling options against climate crisis. If above discussed strategic frameworks amalgamate with other aspects, like institutional involvement, decision making, tenure and ownership, governance arrangement, resource allocation, risk analysis, livelihood elements, ecosystem elements, integrated farming system of livestock, fisher, cropping, etc. and technological integration with adaptation processes, the response for reducing impact would boost up (Food and Agriculture Organization FAO, 2007). The biggest problem is economical constrains, funded by some international bodies, like Least Developed Country Fund (LDCF), to meet the cost of adaptation to the countries more prone to climate risks as agriculture requires large amount of investment which is difficult for economically viable small holder famer with an average farm size of 0.5 hectare. For the major and repeated problem of economy in the developing world, some estimation of financial assistance of South Asian countries for adaptation practices for year 2015–2030 (Aryal et al., 2019) are given in Table 4.

Table 4. Estimation of financial needs for agriculture

Estimated cost needs	Afghanistan (USD)	Bangladesh (USD)	Bhutan (USD)	India (USD)	Nepal (USD)	Pakistan	Sri Lanka (USD)
Agricultural Adaptation cost/ha/year	138 billion	116 billion	29 billion	69 billion	67 billion	72 billion	111 billion
Adaptation to disaster	16.3 billion	42 billion	51.12 billion	332 billion	10.1 billion	97 billion	9.99 billion

On that account, the absence of proper adaptation actions and maladaptation practices against climate change will drop South Asian annual GDP to approximately 1.8% by 2050 and 8.8% by 2100. The economic losses face by South Asian countries are predicted to be 9.4% for Bangladesh, 6.6% for Bhutan, 8.7% for India, 12.6% for the Maldives, 9.9% for Nepal, and 6.5% for Sri Lanka. Therefore, by abrupt climate change in South Asian region cause livelihood, productivity and food security of the region vulnerable without suitable adaptation measures (Aryal et al., 2019).

6. Policy implications

The adaptation policies, with long-term concerns, are necessary at that point when erratic climatic patterns are increasing at high speed and continue to intensify by the end of twenty-first century. The long-term adaptation policies are necessary for addressing unpredictable climate crisis, are the way in which climate policies are planned and executed to minimizing the impact of changing climate for periods between 30 and 100 years (Vij et al., 2017). Therefore, sound decisions are only made when policymakers understand the nexus between climate change and its impact on agricultural yield and production and designed and implement in such a way to overcome climate related issues in agriculture (Zhou et al., 2019). For flexible policy consideration, the governance should include 4Rs, which is revitalization, resilience, reflexivity, responsiveness, necessary for up, downscaling the impacts at local, and trans-boundary level (Termeer et al., 2015). In developing world like South-Asia when theoretical polices put toward implementation phase things gone wrong generally. For this purpose, integration of farmer’s opinion and experience, institutional behaviors and policy actors should be assured (Chaudhury et al., 2016). The action needed is to strengthen adaptive capacity and strive against the water demand and supply due to increase in temperatures and erratic rainfall behavior, therefore, implementation of existing policies with adequate farmers training and financial assistance is required. The results would be fruitful as it convinces state actors and other related stakeholders to take part in challenging climate change and take measures to reduce vulnerability in agriculture sector (Iglesias & Garrote, 2015). In Bangladesh, Bangladesh Climate Change Strategy and Action Plan (BCCSAP) 2009 and National Adaptation Program of Action (NAPA) 2005 and 2009 are the initiatives taken in this sector. By the planning and integration of Ministry of Agriculture, Ministry of Water Resources, Ministry of Environment and Forestry, Ministry of Finance and Ministry of planning, adaptive policies are being organized and implemented to bring coherence. Focusing on mega issues in agriculture and little emphasis on micro-climatic conditions, the BCCSAP and NAPA focuses on water, infrastructure, health, disaster and food security with other sectorial policies (Vij et al., 2017).

As a policy intervention in agriculture sector India adopt National Action Plan on Climate change (NAPCC) and established funds National Adaptation Funds on Climate Change (NAFCC) with the mission to strengthen sustainable agriculture, green India, Himalayan ecosystem, national water and strategic knowledge on climate change. By this state and multiple actors are able to achieve required objectives to cope up with changing climate scenario. Nepal integrate NAPA and Climate Change policy in face of changing climate. Although these policies are not strong, Nepal is now working on national action plan and village level adaptation projects to fortify agriculture, forestry, water, health, etc (Vij et al., 2017). Pakistan practice National Climate Change Policy (NCCP) and coordinating different adaptation policies at national and local level. The policy is blended with other state policies to explore food security issue, water related problems, etc (Vij et al., 2017).

While discussing about the problems still exist is due to policy failures and for which changes in policies are required to able to run on sustainable pathway. Some policy options are also adopted to strengthen already existing policy frameworks. The first thing is the implication of national policies with added strive in education and research and development to get sustainable results. There is lowest number of agriculture institutes in South Asia. The investment in agricultural research is very low in South Asian countries; Bangladesh (0.25%), India (0.50%), Pakistan (0.58%). This initiative gives rise to extensive training and building community awareness, enhanced interest to protect common environmental resources, empowerment of women who are the major contributor to agriculture, better outcomes and collaboration of scientific knowledge and skills. The second is the ‘true market pricing’ to avoid over use as well as wastage. It includes pricing of groundwater resources, fertilizers, composts, machinery, and so on. The productive results are being obtained as it reduces the loss of global commons and to prevent against changing climate. Last but not least community involvement is mandatory. This combined community actions provides positive contribution to fight against changing climate in South Asian counties (Alauddin & Quiggin, 2008).

7. Conclusion

Climate change is real and in countries like South Asian countries impacting generally negative on agriculture yield and production by any change in temperature and precipitation and damaging developed economies. In this chapter, different impact of rainfall variation and temperature deviations are discussed and illustrate different adaptation strategies as well as economic estimation for their adaptation needs. The long-term adaptive policies would be necessary at all possible sectorial levels to combat changing climate. As a result, it is difficult to specify the changing climate impacts and seems unfeasible. An area for future research is other climate variables other than temperature and rainfall like humidity, evapotranspiration rate, and so on, would be accessed.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

All data related to this manuscript is included in the main text.