Ahead of the forthcoming global intergovernmental climate meeting in Paris, scientists met in Paris in July at a large scientific conference calling for an ambitious agreement aimed at holding global warming to 28C. With agriculture, forestry, and other land use contributing 24% of total greenhouse gas (GHG) emissions (2000–2009), there is potential for significant ecosystem-based mitigation benefits. Similarly, maintaining healthy ecosystems represents, in many situations, the most efficient way of adaptation. This paper highlights some scientific aspects, as presented at the conference, related to ecosystem-based adaptation and mitigation. It calls for enhanced cooperation between scientists, policy makers, and other stakeholders.