As gas prices rise, people tend to shift from driving personal vehicles to using public transit. However, the extent of this change and the interplay between fuel price spikes and transit usage are not precisely known.
Travel demand and vehicle use rates have generally increased from the 1970s through the early 2000s. These trends often inform projections about global energy growth, increases in greenhouse gas emissions and climate change scenarios.
The rise of antimicrobial-resistant bacteria is among the greatest emerging public health problems. Resistance, acquired by bacteria through natural selection, has been accelerated by the improper use of antibiotics. Because such strains can be resistant to even newer, more powerful compounds, their infections are associated both with higher disease and death rates and with greater economic tolls on health care systems.
Since the 2001 invasion of Afghanistan and the 2003 start of the Iraq war, hundreds of thousands of U.S. soldiers have served increasingly long and difficult deployments overseas. Beyond the physical risks troops face, their absence can have significant negative impacts on family members.
Since the Endangered Species Preservation Act was signed into law in 1966, local and global endangered species lists have emerged as useful tools for protecting threatened animal and plant populations. Prioritizing resources is essential, however, and local situations don’t always reflect global realities — a species could be threatened in one area but plentiful overall, or locally plentiful but in danger worldwide.
Phytoplankton are microscopic, free-floating plants that form the basis of the aquatic food chain. They also account for half of all photosynthetic activity, and thus produce much of the atmosphere’s oxygen. Changes in the level of phytoplankton activity would have important implications on the health of the entire ecosystem, including human life.
Sustainable water management refers to managing resources in a way that the water needs of present and future generations as well as the broader ecology are met. While the concept of sustainability has received considerable attention, actual efforts have been limited as population growth has continued.
While increasing energy efficiency has considerable benefits, significant barriers exist. Efficiency potential is spread throughout millions of individual homes and businesses, requires upfront investments and shows returns only over time. This makes efficiency no one’s first priority.
High-occupancy vehicle lanes are intended to both speed traffic and improve air quality. This is done by dedicating a lane to cars with two or more occupants, thus reducing the number of vehicles traveling on the road. This both speeds traffic flows and reduces pollution. Some have argued, however, that if underutilized, such lanes can create congestion.
While national pedestrian fatalities in 2008 declined by 16% from a decade earlier, that year car crashes caused 4,378 pedestrians deaths and injured 69,000 pedestrians. Urban areas were consistently found to account for a larger proportion of such deaths and injuries.
