Environmentally speaking, the problem occurs when an atom of carbon combines with two atoms of oxygen to form carbon dioxide (CO2), which is released into the atmosphere as a gas via respiration by people and animals, by volcanic eruptions and, more importantly, by the combustion of fossil fuels, deforestation and some manufacturing processes.
Although carbon dioxide is considered a trace gas in the atmosphere, its concentration has been rising steadily over the past century, along with other greenhouse gases. In the upper atmosphere, these gases absorb infrared radiation from the sun, trapping heat and creating an imbalance in the earth's temperature.
In January, ground broke on Masdar City, a six-square-kilometer (3.72 square miles) community located in Abu Dhabi, in the United Arab Emirates on the Arabian Peninsula. When completed in 2016, Masdar City will be the world's first zero-carbon, zero-waste community.

On a greater scale, the country of Costa Rica recently announced that it intends to be completely carbon neutral by the year 2021. The country plans to achieve its goal by reducing reliance on fossil-fuel-fired power plants, and generating more power from alternative methods such as wind and geo-thermal. In addition, it will promote the use of hybrid vehicles and increase tree plantings to offset carbon emissions. Like the Masdar City Initiative, it's an indication of what's possible when individuals, communities and industries work together. For more information: www.masdaruae.com (the Masdar Initiative) or www.visitcostarica.com (the official site of Costa Rica).