In independent studies, two Princeton University research teams recently identified surprisingly large sources of methane, a powerful greenhouse gas, being leaked into the atmosphere. Pound for pound, methane causes a far greater warming effect in the atmosphere than does carbon dioxide - 86-fold more heating over 20 years, and 35-fold more over the course of a century.

The very structures of cities play an important role in urban environments, from influencing residents' energy needs to affecting local climates and ensuring resilience against natural hazards. Developing new structures and maintaining existing ones are important challenges.

Lynn Loo

Complex materials and thin-film electronics

Princeton researchers are working to create technology that allows buildings to adapt to their occupants' needs. Devices such as smart windows developed by Loo regulate how much sunlight and solar heat enters the building to improve occupants' comfort and reduce heating, cooling, and lighting needs.

 Sigrid Adriaenssens

Engineering design framework for the future urban environment

Cities of the future will become increasingly dense, which necessitates highly efficient design. Princeton engineers are rethinking fundamental approaches to structures such as Adriaenssens' ultra-lightweight long-span bridges and buildings, which require a minimum of anchor points.

Claire White

Sustainable cement

Expanding cities will mean even greater use of concrete - a major source of greenhouse gas emissions - for buildings, sidewalks, and roads. Researchers at Princeton are working to make concrete more sustainable by replacing conventional cement with lower-energy alternatives including industrial byproducts and processed minerals, together with routes to permanently encapsulate carbon dioxide.

Forrest Meggers

Building systems design and integration, thermodynamics of the urban environment

Engineering researchers are designing low-energy building systems to harness geo- thermal power and heat transfer to make buildings more sustain- able, comfortable, and efficient.