How were cities distributed globally in the past? How many people lived in these cities? How did cities influence their local and regional environments? In order to understand the current era of urbanization, we must understand long-term historical urbanization trends and patterns. However, to date there is no comprehensive record of spatially explicit, historic, city-level population data at the global scale.

The major mosquito vectors of human diseases have co-evolved with humans over a long period of time. However, the rapid growth in human population and the associated expansion in agricultural activity and greater urbanisation have created ecological changes that have had a marked impact on biology of mosquito vectors.

Living with fire is a challenge for human communities because they are influenced by socio-economic, political, ecological and climatic processes at various spatial and temporal scales. Over the course of 2 days, the authors discussed how communities could live with fire challenges at local, national and transnational scales. Exploiting our diverse, international and interdisciplinary expertise, we outline generalizable properties of fire-adaptive communities in varied settings where cultural knowledge of fire is rich and diverse.

Agroforestry is a traditional and ancient land use practice, having deliberate integration of trees with crop and livestock components. In India, agroforestry practices are prevalent in different agro-ecological zones and occupy sizeable areas. These practices have great potential for climate change mitigation through sequestration of atmospheric CO2. Carbon sequestration potential was studied in four districts of Gujarat (Anand, Dahod, Patan and Junagarh), for which field survey was conducted to collect primary data on existing agroforestry systems.

Wildfire has been an important process affecting the Earth's surface and atmosphere for over 350 million years and human societies have coexisted with fire since their emergence. Yet many consider wildfire as an accelerating problem, with widely held perceptions both in the media and scientific papers of increasing fire occurrence, severity and resulting losses. However, important exceptions aside, the quantitative evidence available does not support these perceived overall trends.

The practice of horizontal high-volume hydraulic fracturing (fracking) has become widespread in many areas of the United States, yet the regulatory landscape for local governments is highly variable and legally uncertain. We do not have a clear idea of what fracking-related policies local governments are adopting, nor how factors such as local government capacity influence policy adoption. We survey 140 local government officials in shale gas drilling areas in four states: Colorado, Louisiana, North Dakota, and Pennsylvania.