In the last two decades, an increasing number of studies have documented the climate variability and its effects on biotic and abiotic level. However, recent catastrophic climate events (such as heat waves, droughts, floods, extreme winds / or hurricanes, ocean deoxygenation) happening in the last decades have increased the interest of population and stakeholder to considers the environmental, social and economic impacts of climate variations in South America.

Extreme weather events and their impacts on the environment and society are considered one of the greatest challenges of the century. For example, it is well reported that during moderate-to-intense ENSO events, more than 50% of the entire South American hydrology is markedly affected; floods in the northern coast of South America and a decrease in water availability in the Andean region are a good example of connectivity. Water resources from mountainous regions of South America are vital to natural ecosystems, the human economy and living in the adjacent lowlands at arid and semiarid regions of the continent. Climate change has also brought evidence of different processes in continental areas such as glacier retreatment and desertification. Those processes are linked to global circulation patterns that are particularly sensitive to changes in global climate; seemingly small changes in the global circulation can lead to high pressure system expansion or contraction threatening entire populations in many South America countries. In this sense, the South America is affected by the spatio-temporal variations in Hadley and Walker's cell. The variability on interannual and multidecadal modes depends on climate phenomena such as ENSO (El Niño Southern Oscillation) and IPO (Tripole Index for the Interdecadal Pacific Oscillation), where Walker's cell plays a very important role, as well as mechanisms such as the High-Pressure System of the South Pacific. However, the role of natural variability in the possible impacts derived from climate must be considered to understand their role and major changes in the future impacts and climatic event.

Therefore, studies with paleoenvironmental approach are necessary due that are the only ones that can bring information on these processes. First, because there are almost no climate records in South America beyond 1970CE, and second, because in addition to climate information, these are sensitive to environmental changes, and can give us an idea of the consequences of their impacts. In this sense, we will use high-resolution multiproxy reconstructions to analyze the impacts of extreme weather events on fragile ecosystems on the west coast of America linked to climate variability and under current climate change through past evidence with the aim of identifying atmospheric patterns commons and their teleconnections. Furthermore, our efforts will focus on Colombia, where the climate records are few and because the results will allow test various hypotheses of changes in the atmospheric circulation linked to variability and climate change and its extreme events. This team has while experience in the study of climate variability at South America, using environmental archives (I.e. tree rings, marine records, speleothems) and multiproxy approach, mainly those related to regional variability of precipitation, aeolian erosion, wind patterns and upwelling system, all these over strategic ecosystems of South America. Therefore, this is an emerging team that might be link between past events and currents climate impacts.

Thereby, the challenge is to contribute to the reduction of uncertainty, which will allow the collection of information to support decision-making regarding adaptation to climate change and provides greater statistical confidence to models. In this way, this project seeks to study from an angle of current and environmental reconstruction the climatic impacts related to their extreme events associated on sensitives ecosystem of Colombian, Peru, and Chile along the Eastern Pacific Coast.

Période de soutien : 2021-2023