**3. Climate-smart agriculture in drylands**

Climate-smart agriculture can be defined as agriculture that sustainably increases productivity, resilience (adaptation), reduces/removes GHGs (mitigation), and enhances achievement of national food security and development goals [2, 31–33]. Making agriculture climate-smart is one of the means to tackle climate change and its impacts which is the focus of Sustainable Development Goals (SDGs) (Goal 13) and complements SDGs 1 and 2. Agricultural development in drylands is a victim of climate change impacts. It is anticipated that higher temperatures could reduce crop yields by 10–20% in Sub-Saharan Africa by 2050. In return, unsustainable agricultural development is one of the causes of climate change as it is responsible for 10–12% of anthropogenic GHGs emissions each year and much more (30%) if human beings take into account the clearance of forests to make way for crops and livestock [34, 35]. Agricultural development must be effective in terms of food production,

reducing GHGs emissions and helping farmers adapt to climate change [36, 37]. To build the resilience of drylands, it is essential to make agricultural land management practices more sustainable; improving grassland management so as to enhance carbon sequestration; reforestation and restoration of dryland forests; improving the efficiency and productivity of livestock by rearing improved breeds and transforming high emitter livestock (*e.g.* cattle) to lower emitter ones (*e.g.* chickens); improving livestock feeds [2].

Climate change requires environmental conservation and global partnerships that are related to two of the Millennium Development Goals (MDGs): ensure environmental sustainability and develop a global partnership for development [38]. These have been strongly strengthened in the SDGs under goals 15 and 17 [39]. Parry [40] stated that climate change is a binary development issue. In the first case, unsustainable development, in the past and present, is the root cause of climate change. In the The second case, sustainable development is certainly a necessary, and probably sufficient condition for overcoming this challenge (**Figure 3**). Portfolios of mitigation and adaptation strategies to unsustainable development will not result in the right co-benefits. Rather sustainable transformations are important for the case in point [41, 42]. For instance, Denmark has reduced GHGs emissions by 28% in 1990–2009 because of a 31% reduction in N2O emissions due to improved use of manure and a 40% reduction in the use of inorganic fertilizer in 1990–2000, with a further consensus to reduce GHGs emissions from agriculture by 50–70% without a decrease in food production [43]. Ethiopia has also planned to follow similar trends through its climate resilient green economy strategy. This creates a win-win situation between climate change and agricultural development [28, 44, 45].

Land degradation and human population growth in the drylands of Ethiopia, exacerbated by climate change such as severe droughts, have greatly impaired the country's economic and social development and its food security status. It is clear that combating desertification and land degradation, and mitigating the effects of drought are the basis for accelerated sustainable development, poverty reduction and insuring food security in Ethiopia. This requires the realization of strong partnership building and commitment at regional and international levels. Cognizant of this fact, the

#### **Figure 3.**

*The climate change and agricultural development relationships (negative signs before GHGs indicate emission reduction and the yellow arrows show negative impacts on each other & positive signs before GHGs indicate emission enhancement and the green arrows show win-win). The strategies that help to make such transformations are described in Sections 3.1 to 3.4 below.*

Ethiopian Government was one of the pioneering governments to accept and endorse the Great Green Wall for the Sahel and Sahara Initiative (GGWSSI) and was ready for its implementation [46].

#### **3.1 Grazing land management**

Drylands are characterized by low and highly variable precipitation and warm temperatures. Livestock grazing is the predominant type of land use, providing a livelihood for a considerable number of people [47]. Optimal rangeland management depends on (i) the current state of the vegetation; (ii) the observed rainfall; and (iii) optimizing the stocking density and rate to reduce emission of GHGs, particularly methane. The stocking density refers to the number of livestock per hectare of rangeland while the stocking rate refers to the ratio of livestock to available forage on the pasture in a given year [48].

The livestock population of Ethiopia, which reached more than 160 million heads in 2011 and more than 224 million heads in 2020 [49, 50], is the largest in Africa and the 10th in the world. It constitutes a large component of the Ethiopian agricultural sector and is well integrated with the farming systems in general and provides the sole means of subsistence for the herders in the lowlands in particular. More than 50% of Ethiopia's land is utilized for grazing and browsing. Herders in the lowlands take the lion's share of this figure. Even if the world share of non-CO2 emissions from the livestock sector of Ethiopia is the minimum as shown in **Figure 4** [28, 51], sector-wise Ethiopia's emission profile is dominated by emissions from agriculture contributing about 80% of the total. Whereas gas-wise it is dominated by CH4 contributing 80% of the total CO2 equivalent emissions in 1994 [52] and most of this contribution is from less productive livestock. Even in current times, cattle take more than 80% of the share of CH4 emission in Ethiopia [53, 54]. Based on IPCC [55] guidelines, methane emissions from enteric fermentation are estimated using equation 1 for eight major livestock subcategories in Ethiopia (**Table 3**). The livestock subcategories are donkeys, camels, cattle, goats, mules, sheep, horses and poultry. Livestock population data for each subcategory is from CSA [49, 50]. The emission factors attributed to each livestock subcategory for enteric fermentation are all IPCC default values ascribed for Ethiopian conditions. The methane emissions resulting from equation 1 are then multiplied by 21, the global warming potential for methane at 100 years in the atmosphere, to yield the carbon dioxide equivalent in tonnes of CO2e (**Table 3**). In order to optimize methane emissions while there is an increasing livestock population [50], there is a need to settle climate smart livestock production with proper rangeland management, improved feed and highly productive livestock breeds. If Ethiopia's livestock production is climate-smart and reduces emissions by 38%, the emission from the eight livestock subcategories (**Table 3**) is less 16,929,022 tCO2e and 24,583,413 tCO2e than conventional livestock production in 2011 and 2020 respectively. The Ethiopian Climate-Resilient Green Economy strategy states that, in agriculture, higher livestock productivity has the potential to reduce 45 x 10<sup>6</sup> tonnes of CO2e emissions a year in 2030 [28]. Grazing lands are considered an important carbon sink-storing 10–30% of the global soil organic carbon. Improved grazing management on rangeland, such as species management, irrigation, rotational grazing, and fertilization, is expected to capture a significant amount of carbon. Studies indicated that there are potential soil carbon sequestration rates of 0.6 - 1.3 tCO2e ha−1yr−1 from these improved managements [57].

**Figure 4.** *Global non-CO2 emission from the livestock sector (Ethiopia's contribution Ethiopia is 0.065 Gt CO2-eq) (Source: [51]).*

$$E = \frac{EFt \* Nt}{1000} \tag{1}$$

**Where:** E is methane emissions from enteric fermentation, tCH4/year; EFt is emission factor for the defined livestock population, kg CH4/head/yr; Nt is the number of head of livestock species/category in the country, t is species/category of livestock Emission CO2e /year (tonnes) = CH4 emission/year (tonnes) \* 21 (Global Warming Potential for CH4).

#### **3.2 Water management**

Water and desertification are the most optimizing factors to foster economic, social and environmental development in the drylands and that the sustainable utilization of water resources is a priority at regional and national scales [58]. Climate change will have enormous effects on the hydrological cycles in drylands with less total rainfall, drier soils but with increased risks of floods from increased frequency and intensity of storm events [4]. There should be a need to enhance physical and economic water productivity. The former is defined as the ratio of the amount of agricultural output to the amount of water used and the latter is defined as the value derived per unit of water used [13].

