Climate change and agriculture are interlinked and affect each other globally. The global population continues to rise while food and nutritional insecurity remain main global challenges facing humanity. Traditional agriculture methods need transformation to climate smart agriculture (CSA) approaches that have potential to improve food production amidst climate change realities. The review aimed at evaluation of published literature on CSA, establishment of CSA linkages with national development plans for Uganda and Ethiopia, African Union Agenda 2063, UN Sustainable Development Goals and CSA contribution to biodiversity conservation across the globe. Additionally, the review aimed at identifying opportunities and challenges of CSA in the 21 st Century and recommend possible options for all stakeholders for improved income, environmental conservation, and food and nutritional security. Literature search from 2000-2019 was carried out using key words and key phrases in relevant journals and authentic websites. It was found out that CSA supports three pillars: 1) Sustainably increasing agricultural productivity and incomes, 2) Adapting and building resilience to climate change, 3) Climate change mitigation and contributes to Biodiversity Conservation and management. CSA approach has potential to improves food security and farmers' income. CSA has a vast number of opportunities that include availability of crop genetic diversity, availability of interested CSA researchers, gene banks for genome resources for CSA crop enhancement; enhanced technology for CSA practices that can be accessed by farmers and vibrant research organizations and donor agencies interested in promoting CSA approaches. CSA challenges were identified to include: limited technical and financial capacity and negative attitude from smallholder farmers. It was concluded that CSA approach is a better option for the present and centuries to come farmers across the globe for the attainment of the United Nations (UN) Sustainable Development Goals (SDGs) 2015-20130, UN Agenda 2063 and national development plants of most African countries including Uganda and Ethiopia. The review recommended that capacity building for farmers and researchers need to be done and governments and donor agencies should provide soft CSA loans to farmers to supporting CSA practices and technologies in all developing countries and the approach should be adopted by all the farmers and be promoted by all stakeholders at all levels in both the present and future centuries.