The purpose of this article is to describe the present context of interactions between global climate changes and agriculture in Brazil . The contributions of agriculture towards worsening greenhouse effect and climate changes, and the impact of climate changes on the Brazilian agriculture are discussed. The focus is on the definition of future agricultural scenarios based on mathematical models that represent the processes involved in productive systems. Several aspects of the problem are presented as well as ways of dealing with them in a multidisciplinary research network. And finally, Embrapa's institutional approach is given as an example, as it proposes to analyze the agricultural and forestry systems as well as measures of mitigation and adaptation based upon risk analyses and environmental, social, and economic sustainability, seeking to cooperate in the definition of public policies that would seek ways of concretely financing and implementing such measures. Even though this article is not a review of scientific literature, it seeks to touch upon the most relevant issues of scientific discussions on the theme of the relation between agriculture and climate changes.