Climate Change

At the 2009 U.N. Climate Change Conference in Copenhagen, concern focused on the global climate impacts of land-use changes such as deforestation. While the conference sought to establish regulations on emissions resulting from land-use changes only for rapidly growing countries, growth and urbanization in more developed nations also plays a role.

Cap and trade is a market approach for reducing greenhouse gas emissions. The government sets a cap for a particular pollutant and then allows companies to negotiate among themselves on how to meet the limit; those that are most efficient at reducing emissions are rewarded for doing so.

In the past, studies of large-scale changes to the Earth’s oceans have been restricted both by the limited nature of physical sampling and the reality that often these changes occur over great lengths of time.

The general public continues to perceive a large degree of uncertainty among scientists on issues relating to climate change. A May 2011 survey sponsored by Yale University and George Mason University, for instance, showed that only 39% of the public believes that most scientists agree on global warming (up from 34% in 2010.)

Coal currently provides more than half the United States’ electricity. Because burning a single ton of coal can create more than two tons of CO₂, a primary contributor to climate change, a technique known as carbon capture and storage (CCS) is under development.

Hydropower accounts for two-thirds of all renewable electricity production in the United States. A 2008 paper by the University of Missouri at Saint Louis, “The Potential of Water Power in the Fight Against Global Warming,” discusses the potential for hydropower in reducing U.S. greenhouse gas emissions.

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.

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.