Fire has a role in ecosystem services; naturally produced wildfires are important for the sustainability of many terrestrial biomes and fire is one of nature's primary carbon-cycling mechanisms. Under a warming climate, it is likely that fire frequency and severity will increase. There is some evidence that fire activity may already be increasing in Western U.S. forests and recent exceptionally intense fire events, such as the Australian Black Saturday fires in 2009 and Russian fires in 2010, highlight the devastation of fires associated with extreme weather. The impacts of emissions from fires on global atmospheric chemistry, and on the atmospheric burden of greenhouse gases and aerosols are recognized although gaps remain in our scientific understanding of the processes involved and the environmental consequences of fires. While significant uncertainty remains in the long-term impacts of forest fires on climate, new sophisticated tools have recently become available (observational and modeling). These tools provide insight into changing wildfires and intentional biomass burning activity in the Anthropocene era that is marked by humans’ impact on Earth. The understanding of the impact of wildfires and intentional biomass burning emissions on the present and future climate is reviewed. Presently, fires and their emissions are controlled under fire management and emission reduction schemes. Under future climate conditions, significantly more effective controls on these fires seem necessary. Continued and improved monitoring to support and to demonstrate the effectiveness of the adopted measures, and further deepening of knowledge on the mechanistic and sociological factors that influence fires and their environmental impacts is highly needed. Wildfires and biomass burning are important for a range of international and domestic policies, including air pollution, climate, poverty, security, food supply, and biodiversity. Climate change will make the need to coherently address fires based on scientifically sound measurements and modeling even more pertinent.