Coffee, one of the most heavily globally traded agricultural commodities, has been categorized as a highly sensitive plant species to progressive climatic change. Here, we summarize recent insights on the coffee plant's physiological performance at elevated atmospheric carbon dioxide concentration [CO 2 ]. We specifically (i) provide new data of crop yields obtained under free-air CO 2 enrichment conditions, (ii) discuss predictions on the future of the coffee crop as based on rising temperature and (iii) emphasize the role of [CO 2 ] as a key player for mitigating harmful effects of supra-optimal temperatures on coffee physiology and bean quality. We conclude that the effects of global warming on the climatic suitability of coffee may be lower than previously assumed. We highlight perspectives and priorities for further Climatic Change (2019) 152:167-178 https://doi.# The Author(s) 2018research to improve our understanding on how the coffee plant will respond to present and progressive climate change.The current rise in atmospheric carbon dioxide concentration ([CO 2 ]) is one of the major drivers of global warming and climatic change. Atmospheric [CO 2 ] has increased approximately by 43% from the pre-industrial levels of 280 μL L −1 air in 1750 to current levels exceeding 400 μL L −1 air, and global mean surface temperature has increased by 0.85°C over the same period. Depending on the greenhouse gas emission scenarios, projections indicate that, at the end of this century, atmospheric [CO 2 ] might rise between 421 and 936 μL L −1 air, in parallel with a rise in global temperature between 0.3-1.7°C (best scenario) and 2.6-4.8°C (worst scenario), relative to 1986 (IPCC 2013 IPCC 2014). These long-term changes, coupled with climate variability, such as longer and unpredictable droughts and sometimes excessive rainfall, are expected to threaten the sustainability of agricultural production on a global scale, with consequences on the amount and quality of harvestable crops for the actual production areas (DaMatta et al. 2010).Plants sense and respond directly to rising atmospheric [CO 2 ] through an increase in net photosynthesis rate (A) and, frequently, a decrease in stomatal conductance (g s ), and this is the basis for the CO 2 fertilization effect on crops with corresponding increase in yields (Long et al. 2006;Ainsworth and Rogers 2007). Meta-analyses of free-air CO 2 enhancement (FACE) experiments have reported mean reductions in g s of 22% and increases in light-saturated (A) of 31% across a range of C 3 species for an increase in [CO 2 ] from approximately 366 to 567 μL L −1 air (Ainsworth and Rogers 2007). Increases in A with enhanced [CO 2 ] in the chloroplast of C3 plants are associated with a stimulation of the carboxylation rate of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), the rate-limiting step in photosynthesis at saturating light and current [CO 2 ] levels, and a concomitant reduction (or even suppression) of its oxygenation function, and thus the rate of photorespiration (Ainsw...

There are worldwide approximately 4.3 million coffee (Coffea arabica) producing smallholders generating a large share of tropical developing countries' gross domestic product, notably in Central America. Their livelihoods and coffee production are facing

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In Latin America, the cultivation of Arabica coffee (Coffea arabica) plays a critical role in rural livelihoods, biodiversity conservation, and sustainable development. Over the last 20 years, coffee farms and landscapes across the region have undergone rapid and profound biophysical changes in response to low coffee prices, changing climatic conditions, severe plant pathogen outbreaks, and other drivers. Although these biophysical transformations are pervasive and affect millions of rural livelihoods, there is limited information on the types, location, and extent of landscape changes and their socioeconomic and ecological consequences. Here we review the state of knowledge on the ongoing biophysical changes in coffee-growing regions, explore the potential socioeconomic and ecological impacts of these changes, and highlight key research gaps. We identify seven major land-use trends which are affecting the sustainability of coffee-growing regions across Latin America in different ways. These trends include (1) the widespread shift to disease-resistant cultivars, (2) the conventional intensification of coffee management with greater planting densities, greater use of agrochemicals and less shade, (3) the conversion of coffee to other agricultural land uses, (4) the introduction of Robusta coffee (Coffea canephora) into areas not previously cultivated with coffee, (5) the expansion of coffee into forested areas, (6) the urbanization of coffee landscapes, and (7) the increase in the area of coffee produced under voluntary sustainability standards. Our review highlights the incomplete and scattered information on the drivers, patterns, and outcomes of biophysical changes in coffee landscapes, and lays out a detailed research agenda to address these research gaps and elucidate the effects of different landscape trajectories on rural livelihoods, biodiversity conservation, and other aspects of sustainable development. A better understanding of the drivers, patterns, and consequences of changes in coffee landscapes is vital for informing the design of policies, programs, and incentives for sustainable coffee production.

The scientific community has recognized the importance of integrating farmer’s perceptions and knowledge (FPK) for the development of sustainable pest and disease management strategies. However, the knowledge gap between indigenous and scientific knowledge still contributes to misidentification of plant health constraints and poor adoption of management solutions. This is particularly the case in the context of smallholder farming in developing countries. In this paper, we present a case study on coffee production in Uganda, a sector depending mostly on smallholder farming facing a simultaneous and increasing number of socio-ecological pressures. The objectives of this study were (i) to examine and relate FPK on Arabica Coffee Pests and Diseases (CPaD) to altitude and the vegetation structure of the production systems; (ii) to contrast results with perceptions from experts and (iii) to compare results with field observations, in order to identify constraints for improving the information flow between scientists and farmers. Data were acquired by means of interviews and workshops. One hundred and fifty farmer households managing coffee either at sun exposure, under shade trees or inter-cropped with bananas and spread across an altitudinal gradient were selected. Field sampling of the two most important CPaD was conducted on a subset of 34 plots. The study revealed the following findings: (i) Perceptions on CPaD with respect to their distribution across altitudes and perceived impact are partially concordant among farmers, experts and field observations (ii) There are discrepancies among farmers and experts regarding management practices and the development of CPaD issues of the previous years. (iii) Field observations comparing CPaD in different altitudes and production systems indicate ambiguity of the role of shade trees. According to the locality-specific variability in CPaD pressure as well as in FPK, the importance of developing spatially variable and relevant CPaD control practices is proposed.

Pesticide risk indicators provide simple support in the assessment of environmental and health risks from pesticide use, and can therefore inform policies to foster a sustainable interaction of agriculture with the environment. For their relative simplicity, indicators may be particularly useful under conditions of limited data availability and resources, such as in Less Developed Countries (LDCs). However, indicator complexity can vary significantly, in particular between those that rely on an exposure-toxicity ratio (ETR) and those that do not. In addition, pesticide risk indicators are usually developed for Western contexts, which might cause incorrect estimation in LDCs. This study investigated the appropriateness of seven pesticide risk indicators for use in LDCs, with reference to smallholding agriculture in Colombia. Seven farm-level indicators, among which 3 relied on an ETR (POCER, EPRIP, PIRI) and 4 on a non-ETR approach (EIQ, PestScreen, OHRI, Dosemeci et al., 2002), were calculated and then compared by means of the Spearman rank correlation test. Indicators were also compared with respect to key indicator char-acteristics, i.e. user friendliness and ability to represent the system under study. The comparison of the indicators in terms of the total environmental risk suggests that the indicators not relying on an ETR approach cannot be used as a reliable proxy for more complex, i.e. ETR, indicators. ETR indicators, when user-friendly, show a comparative advantage over non-ETR in best combining the need for a relatively simple tool to be used in contexts of limited data availability and resources, and for a reliable estimation of environmental risk. Non-ETR indicators remain useful and accessible tools to discriminate between different pesticides prior to application. Concerning the human health risk, simple algorithms seem more appropriate for assessing human health risk in LDCs. However, further research on health risk indicators and their validation under LDC conditions is needed.

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