Juan Mauricio Bedoya-Soto

Understanding the vulnerability of coffee production to shifting climate patterns is a global concern. In the Colombian Andes, specifically within the Chinchiná river basin (CRB), where the local economy relies heavily on coffee production, we investigate how coffee serves as a mediator between the El Niño-Southern Oscillation (ENSO) and local producers. Our qualitative/quantitative study at nine coffee farms focuses on the strong events of El Niño and La Niña during 2009–2010, 2010–2011, and 2015–2016. Monthly data from ground-based pluviometers and CHIRPS satellite-derived rainfall data, covering the entire study area, are integrated. Coupled with an examination of land surface temperature and vegetation activity using MODIS, we unveil relationships between climate, geography, and vegetation in this coffee-production zone. Orographic features significantly impact rainfall, concentrated in the most susceptible yet most suitable coffee area, which is also vulnerable to pest infestations enhanced by climate extremes. This research sheds light on socioeconomic and environmental dynamics, enhancing our understanding of how climate variability impacts production of coffee in the CRB.

The contribution of intraseasonal variability (10- 90 days) in OLR data across Northern South America, Central America, and Mexico was studied. This variability is driven by planetary and tropical oscillations, including Kelvin waves, Tropical Easterly Waves, Mixed Rossby-Gravity Waves, and the Madden-Julian Oscillation, which display distinct signals in the wavenumber—frequency power spectra. Using the Wheeler-Kiladis methodology (1999) and the spatial EOF analysis for local activity index and composites by Mounier (2007), our findings reveal that intraseasonal variability accounts for 10% to 35% of the total variance, depending on the specific location, with Kelvin waves being the largest contributors to the OLR variance in the study region. This methodology allows to propose a local index for each coupled convective wave aiming to classify as convection inhibiting (dry) and convection favoring (wet) days events. The annual cycle of these dry and wet events for each wave show interesting patterns like a predominance of Tropical Easterly Waves and Mixed Rossby-Gravity Waves during the boreal summer and major Kelvin waves occurring during May and April.

This work is a second part contribution of the effect of intraseasonal oscillations on precipitation over the study region. The index generated for each wave (Part I) allow to classify events like convection inhibiting (dry) and convection favoring (wet) days and correlate with precipitation data from ERA5 and CHIRPS. Results show positive and negative precipitation anomalies across the region associated with each oscillatory process, which can be linked to anomalies in moisture transport and convection within the atmospheric column. During wet days, the Tropical Easterly Waves contribute up to 20% of precipitation over Caribbean Sea and eastern Pacific (and western Mexico), while the Kelvin waves accounts for 15% over the tropical eastern Pacific. On the other hand, Mixed Rossby-Gravity waves accounts for 15% of precipitation over the eastern Pacific (10°N - and western Mexico) during wet days and, 12% of precipitation on the Pacific coast of Central America during dry days. Finally, the Madden-Julian Oscillation contributes nearly 15% of precipitation over the Pacific coast of Mexico and Central America during wet days. These findings offer new insights into the spatial and temporal patterns within the region related to these intraseasonal oscillations.

Air pollution includes particle-bound polycyclic aromatic hydrocarbons (PAHs), which eventually reach the placenta, triggering adverse perinatal outcomes through long-term exposure. Lately, air pollution has increased over the Metropolitan Area of Medellin-Colombia (MAMC), but its effects on pregnancy are still unknown. In this research, a real-time analysis of total airborne PAHs was made using a photoelectric sensor for residential places influenced by the industrial and traffic sources affecting the southern and northern MAMC during the second peak of the bimodal tendency for PM2.5 emissions in this region. Additionally, individual PAHs were analyzed by GC/MS coupled with pressurized hot water extraction methodology. The data were applied using an inhalation intake model to assess pregnancy exposure. The average concentration of PAHs in the southern MAMC was three times higher than in the northern MAMC, where the missed abortion rate has been 1.4 times higher according to the database. Previous research indicates that PAHs act as endocrine-disrupting chemicals (EDCs) during pregnancy and that even heavy congeners could reside in umbilical cord blood. Finally, the annual series of missed abortion rates in the MAMC exhibited a significant correlation with the annual average levels of PM2.5, which were associated with PAHs through correlation analysis (r² = 0.69, p < 0.01). While this significant correlation does not imply causality, our results suggest an important connection between both variables, opening a gap for a deeper understanding of how regions with high PAH convergence influence the missed abortion rates in MAMC.

The Colombian Andes (CA) are located over the northwestern corner of tropical South America (NW‐TropSA), where land and atmosphere interchange moisture and energy in a complex way owing to the orographic influence on the recycling of moisture over land. We aim to understand where and when water vapor evaporated from land turns into rainfall through moisture recycling, using the Water Accounting Model‐2layers (WAM‐2), an offline model to track atmospheric moisture forced with data from ERA‐5 at its native 0.25° resolution during 1980–2020. We define the spatiotemporal distribution of sources (high evaporation recycle ratios, ϵ _C ) and receptors (high precipitation recycle ratios, ρ _C ) of continental moisture at diverse timescales, including monthly, seasonal, annual and interannual (ENSO). Referring to the regional runs of WAM‐2 over NW‐TropSA (4°S–12°N/80°W–66°W), at elevations above 1,000 m.a.s.l., the CA has a mean annual ρ _C of 11% (ranging 6%–16%) and a mean annual ϵ _C of 35% (ranging 27%–40%). Moisture recycling in the CA exhibits a strong annual cycle over the region. The seasonal dynamic of moisture recycling shows two clear‐cut sources of moisture: the eastern foothills of the Eastern and Central ranges of the CA. Both foothills are also regions of high rainfall, although moisture recycling mechanisms differ. Sources of continental moisture grow spatially during September‐October‐November and March‐April‐May. The seasonal availability of moisture recycled coincides with regions where orography interacts with low level jets sourcing humidity. At interannual timescales, sources and receptors of continental moisture in the CA are modulated by the extreme phases of ENSO.

At about 4,000 years ago the earth’s global climate underwent significant transformations resulting from changes in solar insolation. Manifestations of this change are relatively well known in higher latitudes, however, in the American tropics these are still not fully identified or understood. Recent paleo-environmental reconstructions based on paleolimnological and vegetational histories of two Colombian Andean sites suggest that between ~4,150 and 2,500 yr BP the Eastern Cordillera (EC) witness wetter anomalies, while the Western Cordillera (WC) suffered from drier anomalies between ~3,700 and 1,750 yr BP. Results from analyses of modern precipitation series from weather stations close to the study sites indicate that the long-term mean annual cycle of precipitation in both sites is out-of-phase and that precipitation anomalies on the western (eastern) site are negatively (positively) correlated with sea surface temperatures in the tropical Pacific (Tropical Atlantic). Hence that we propose that both oceans warmed up during the late Holocene, likely from a more active ENSO and ENSO flavours. With the current global rise in atmospheric temperature and the warming of tropical oceans, this study sheds light on possible anomalous effects on precipitation over the northern Andes.

At about 4,000 years ago the earth’s global climate underwent significant transformations resulting from changes in solar insolation. Manifestations of this change are relatively well known in higher latitudes, however, in the American tropics these are still not fully identified or understood. Recent paleo-environmental reconstructions based on paleolimnological and vegetational histories of two Colombian Andean sites suggest that between ~4,150 and 2,500 yr BP the Eastern Cordillera (EC) witness wetter anomalies, while the Western Cordillera (WC) suffered from drier anomalies between ~3,700 and 1,750 yr BP. Results from analyses of modern precipitation series from weather stations close to the study sites indicate that the long-term mean annual cycle of precipitation in both sites is out-of-phase and that precipitation anomalies on the western (eastern) site are negatively (positively) correlated with sea surface temperatures in the tropical Pacific (Tropical Atlantic). Hence that we propose that both oceans warmed up during the late Holocene, likely from a more active ENSO and ENSO flavours. With the current global rise in atmospheric temperature and the warming of tropical oceans, this study sheds light on possible anomalous effects on precipitation over the northern Andes.