Human activities are altering the global climate system at rates faster than ever recorded in geologic time. Ample observational evidence exists for anthropogenic climate change including measured increased in atmospheric CO2, temperature and sea level rise. Biomass burning causes CO2 emissions of ~50% of those from fossil-fuel combustion and so are highly likely to influence future climate change. However, aerosols continue to be the least understood aspect of the modern climate system and even less is known about their past influence. Anthropogenic aerosols may have altered the global climate system for thousands of years as suggested by comparing late-Holocene greenhouse-gas concentrations to those from previous interglacials. The decrease in the spatial extent of forests beginning ~8000 yrs BP may be related to early agricultural activity including forest clearance through burning which should leave a quantifiable signal in climate proxies.We pioneered a ground-breaking technique for determining a specific molecular marker of biomass burning (levoglucosan) which can record past fire in ice cores and lake sediments. The research incorporates continuous ice and lake core climate records from seven continents with parallel histories of fire regime. These can provide essential insight into the interplay between climate and human activity, especially with the advent of agriculture. Key objectives include:1) How does biomass burning change through time and space?2) How do climate parameters respond to or correlate with changes in biomass burning?3) Did fires increase ~8000 and/or ~5000 years ago?4) Can natural and anthropogenic fires be differentiated? If so, how do fires and associated climate change ascribed to human activity differ from natural biomass burning?