ELEMENTAL-CLIMATERegional ProjectsProject duration: May 2021 to May 2024IntroductionThe ELEMENTAL-CLIMATE projectwill identify and quantify the changes driven by climate change in elementomes in environments (soil and water), organisms, ecosystems and agroecosystems,will identify, codify and quantify the unknown feed-back effects of these biogeochemical changes on climate change, mainly throughout its impacts on the elemental composition, structure and functioning of organisms, communities, ecosystems, andwill identify, codify and quantify the profound but uncertain effects of these biogeochemical and stoichiometric environmental changes on food security.Accomplishing these four objectives will fill the large gap in our knowledge of elementome changes and their implications. We will especially focus on tropical, arid, semi-arid (Mediterranean, Sahel,..) and cold habitats, both because of their key role in the biosphere and human society and because they are especially sensitive and likely to be affected by anthropogenic shifts in environmental and organismal elementomes. The results of this project will be also very useful for international strategies based on the Millenium Assessment agreements, including a better assessment of the capacity of carbon fixation of terrestrial ecosystems and therefore better projections of climate change by IPCC. The results will also be useful for international organizations such as UN and FAO and their policies.