A characterization of the ammonia and hydrogen sulfide emissions generated by different production models in poultry farms of Costa Rica was carried out. It was found that egg production farms have the largest emissions since they mostly use management systems based on cages with pits which generates a high emission of ammonia (16 ppm). While the fattening farms had the lower emissions since they mostly use open systems, which are low ammonia emission models (6 ppm). There were no significant concentrations of hydrogen sulfide in the evaluated models, except when a mechanical removal of mounds of chicken manure, with several weeks of storage, took place. A peak of 163 ppm of hydrogen sulfide was observed during the process. The ammonia emissions were modeled for some farms using an atmospheric dispersion model, AERMOD (USEPA), to determine the impact in the surroundings. Using the results of the validated model, it was found that the ammonia concentrations around the farms met the local regulation for air quality. But in some cases is highly probable to exceed the odor threshold for ammonia, which is one of the main complaints of the population living around this kind of agricultural and livestock activities.

The Clean Development Mechanism (CDM) of the Kyoto Protocol, allows the non Annex 1 countries to receive projects that contribute to reducing greenhouse gas emissions and sustainable development in developing countries. The CDM, since its inception, has issued credits equivalent to 1.434.737.562 tons of CO2, distributed across 7.450 projects around the world, from 15 different sectors. Sectors 14 that allow forestry projects (such as reforestation and afforestation) have registered 53 projects to date; 19 of which are in Latin America. Nevertheless, the contribution of this sector currently represents less than 1% of CDM Certificates of Emissions Reduction (CERs) issued. In September 2013, through their National Forestry Financing Fund (FONAFIFO), Costa Rica registered their first CDM project with the United Nations Framework Convention on Climate Change (UNFCCC), after having complied with all the project cycle processes. The project, known as "Carbon Sequestration in Small and Medium Farms, Brunca Region, Costa Rica" was a project executed by FONAFIFO under their Environmental Services Payment Program. This project was developed in Pérez Zeledón, San José, Costa Rica in partnership with the Cooperative Corporation CoopeAgri RL. The total goal of the project is to reduce the greenhouse gas emission by 176,050 ton of CO2-e, in a period of 20 years and commercialize the CERs in the regulated carbon market.

Costa Rica is a privileged country due to its rich water availability; nonetheless, the water accessibility in terms of potable quality has become more and more scarce. Such situation implies a great challenge to guarantee its current and future supply to meet water´s increasing demands for its many purposes, considering the existing disparities among the country´s geographical regions and its different users. The current paper seeks to explore this dynamics and its future perspectives under the predicted climate change scenarios.