perfluorotributylamine (PFTBA), of the three most common anthropogenic GHGs, the one that garners most attention is carbon. That it because it is the most abundant and the single biggest driver of climate change.
As of February 2015, NOAA's Mauna Loa observatory in Hawaii recorded concentrations of atmospheric carbon of more than 400 parts per million (ppm). This is the highest concentration of CO2 in at least 800,000 years. CO2 emissions have risen 102 ppm since the dawn of the industrial revolution with over 90 percent occurring in the last century. Human activity is radically altering the chemical composition of the atmosphere and this has dramatic implications for our climate.
According to the most recent IPCC report, we need to see substantial cuts in greenhouse gas (GHG) emission to keep temperature increases within acceptable limits (the upper threshold limit is 2 degrees Celsius above pre-industrial time times). We specifically need to see GHG emission reductions between 40 and 70 percent by 2050 compared to 2010 levels.
The IPCC report indicated that emissions continued to increase despite emissions reductions efforts. In 2013, a total of 36 billion tons of carbon dioxide were pumped into the air. According to the EIA CO2 emissions in the US alone increased to 5.38 billion tons representing a 2 percent increase over the previous year.
According to the Trends in Global CO2 Emissions Report, released in 2014, China, the US and Europe are responsible for more than half (55 percent) of global carbon emissions in 2013.
China is the global leader at 10.3 billion tonnes of CO2 or 29 percent of the global total representing an increase of 4.2 percent over 2012. The United States is responsible 5.3 billion tonnes CO2 or 15 percent of the global total representing an increase of 2.5 percent over 2012. The European Union generated 3.7 billion tonnes CO2 or 11 percent of the global total representing a 1.4 percent increase over 2012.
The situation did not improve in 2014. According to a study in Nature Geoscience, at the end of 2014, GHG emissions were expected to reach a record high of over 40 billion tonnes in 2014. That is a 2.5 percent increase over 2013 levels.