In January 2020, it was estimated that over 66,000 persons were experiencing homelessness in Los Angeles, but only 21,000 housing units were available. How should those experiencing homelessness be prioritized for receiving these scarce resources?

One of the major problems that has emerged during the COVID-19 pandemic is that hospitals and states have more cases than they have resources to respond to and treat positive patients (e.g., not enough personal protective equipment [PPE], not enough ventilators, not enough doctors, not enough nurses). When there’s not enough resources to treat everyone, who should receive them? How should a hospital decide this?

The current rate of species extinctions is estimated at 10 to 100 times greater than any of the prior mass extinction events in the history of Earth. Erosion of biodiversity due to human activity has been increasingly observed, and the persistence of many species is threatened by habitat loss due to human land use and climate change. One of the key strategies for preserving biodiversity requires purchasing or leasing land to protect it from human-induced degradation. With limited funds, how should conservationists buy parcels of land to preserve biodiversity?

In recent years, there have been an increasing number of natural disasters such as mudslides, wildfire, earthquakes, and floods, all of which had major effects on individual lives and infrastructure; causing devastation to local communities. Natural disasters cost the US on average $100 billion each year, and the number of people affected continues to grow. Given current trends in environmental change and human population growth, such disasters are likely to increase in frequency, severity, and distribution. How do we prepare informed, effective, and efficient disaster plans?

When life-threatening illnesses and injuries occur, Emergency Medical Services (EMS) provide immediate care to patients through pre-hospital treatment, ambulance transportation, and emergency care. At times, there are more emergencies than the number of ambulances and hospital resources. In these situations where there is a limited number of EMS resources and time is of the essence, how should an EMS system decide to route its ambulances?