Carbon dioxide is a gas molecule. It is used by plants to create oxygen, which is then used by us to respire. Similar to water vapor and methane, it is also a green house gas meaning that it traps heat from the sun which is helpful when it comes to keeping the earth warm.
The major causes of carbon dioxide emissions are anthropogenic activities such as deforestation and the burning of fossil fuels. Fossil fuels (which include oil, coal, and natural gas) are forms of stored solar energy, and burning them releases much of the carbon stored into the atmosphere. Trees use carbon dioxide for photosynthesis, and are also large carbon sinks. Like with fossil fuels, cutting down forests releases the carbon stored in the organism.
Carbon levels have been increasing by ~2.5 ± 0.1 ppm yearly. The annual increase in atmospheric carbon dioxide over the past 60 years is aproximatly 100 times faster than the earlier rate. The atmospheric concentration of Co2 have risen by 48% above pre-industrial levels in 1850 over the past 171 years because of human activity. It is predicted that the carbon levels will continue to increase we don't turn to sustainable and clean energy.
The US is generating electricity primarily from non renewable energy sources such as nuclear, coal, and natural gas. Non-hydroelectric renewable energy only makes up about 14% of the total generated electricity.
Wind (27%), hydropower (20%), wood biomass (17%), and solar power (12%) all make up a large percentage of the United States' total renewables consumption.
The still rising carbon levels have caused an increase in the earth’s global temperature. The earth’s temperature has been rising by 0.32 °F every 10 years since 1981 which is more than 2 times the rate in 1880 (0.13 °F). The rising temperature is causing the ice caps to melt, increasing the ocean's elevation. It is also affecting the ocean’s pH levels and causing it to become more acidic. This is harmful to the marine life as well. Plants and animals as well as ourselves are also being negatively impacted by all of these.
Many countries are already shifting towards cleaner energy sources (solar, wind, hydro, etc.) and implementing stricter regulations on fossil fuel use. There has been increased encouragement of green buildings and sustainable construction methods, and also more awareness around protecting marshes and other carbon sinks.
Although the rising carbon level poses a big issue, we as individuals can make choices in our everyday lives to reduce our carbon footprints. We can choose to bike or take public transportation instead of driving. We can purchase products made from recycled or renewable materials. We can lower our meat and dairy intake, and eat lower on the food chain. Furthermore, we can retrofit our homes to lower building related energy use.