Greenhouse gases are those gases that contribute to the so-called "greenhouse effect." For the most part, greenhouse gases naturally occur in the environment. However, human activities have increased the quantities of greenhouse gases in the atmosphere.

How much of an effect does human influence really have?

Small, slow increases in the concentrations of greenhouse gases happened prior to the Industrial Revolution. Since the Industrial Revolution in the mid-18th century, the levels have skyrocketed. In the 1970s, greenhouse gas levels spiked dramatically, thanks to new processing techniques. For example, carbon dioxide concentrations increased by approximately 200 parts per million (ppm) since the start of the Industrial Revolution. Fifty ppm were noted from the 1700s to 1973. The next 50 ppm increase occurred from 1973 to 2006.

How is global warming related to greenhouse gases?

Most scientific communities agree that the sudden upswing in global warming is at least partially attributable to the increase in greenhouse gas concentrations in the atmosphere. While a basic tenet of statistical research is that correlation does not prove causality, there seems little doubt that the two events are linked in some way. Much research is currently underway throughout a variety of scientific fields in an effort to determine the specific links.

What happens next?

Scientists predict that even if we are able to bring worldwide greenhouse gas emissions down to an acceptable level, global warming will still progress to some extent. However, limiting greenhouse gas emissions will help to curb the damage done to the environment. If we do not take steps to limit greenhouse gas emissions, then the global effects could become catastrophic over the next hundred or so years.

Some weather experts warn that super storms like Hurricane Katrina could become more frequent and even more deadly. Katrina drew strength from an ocean that was just 2 degrees Fahrenheit about normal. Many other extreme weather events, from fires to tornadoes, can also be linked directly or indirectly to the effects of global warming. As the temperature continues to climb, worsening weather patterns can be expected.

What are some of the new technologies that are being explored to limit greenhouse gas emissions?

New technologies are being explored in a surprisingly vast array of different fields. Sustainable architecture is a new branch of architecture that applies the principles of sustainable design to the creation of new buildings. The goal is to replace traditional building materials and processes, which often contribute greatly to greenhouse emissions, with new ones that cause less impact on the environment. Examples of sustainable design details are on-site energy production such as wind and solar power and on-site rain harvesting for wash water. A so-called "green building" may also contain such built-in features as low-emitting windows, building materials that allow for more efficient heating and cooling, and deciduous trees on the property to block the sun in summer but allow it to penetrate during winter.

Sustainable architecture is an important part to reducing worldwide greenhouse gas emissions. However, another large piece of the puzzle is emissions related to cars, from the construction process to the refining of oil that is used for gasoline. New hydrogen powered cars, electric cars and hybrids help to reduce the emissions generated from each car significantly. However, due to the slowness of the new trend to catch on widely, these newer, cleaner cars cannot do the job by themselves.

Many communities have begun to move in the direction of alternative transport. Encouraging carpooling, which reduces the total number of Vehicle Miles Traveled, is a basic tenet that greatly assists with an overall reduction of emissions. However, in order to make a larger impact, alternative means of transportation must also be considered.

Some towns have begun to realize the importance of a clean, safe, and efficient transportation infrastructure. New Orleans, for example, although hampered by Hurricane Katrina, has begun a process of re-instituting the electric streetcars that used to carry passengers cleanly and efficiently throughout the city. Many cities have subway networks, and they are expanding their coverage. Other areas have begun to explore the possibility of high-speed light rail.

Many other new and exciting technologies are right around the corner in a myriad of industries. Working together, we can all do our part to reduce greenhouse emissions and help to combat their negative effects.