Greenhouse Gas Increases Are Leading to a Faster Rate of Global Warming

Joel Stronberg | Dec 11, 2014


Carbon dioxide (CO2) is the main contributor to climate change. In 2013, the global combustion of fossil fuels and the production of cement resulted in the emission of 36.1 billion tons of CO2, which was 61 percent over 1990 levels.1 (In terms of carbon, the emissions totaled 9.8 billion tons in 2013.) According to the most recent estimates, emissions in 2014 are projected to be 2.5 percent over 2013 levels.2 (See Figure 1.) In physical terms, this translates into the release of 37 billion additional tons of CO2 in the atmosphere.3 It is estimated that to keep the rate of Earth's warming below the 2 degrees Celsius threshold believed to be the temperature increase that will have severe and irreversible global environmental effects, total future emissions cannot exceed 1,200 billion tons.4

Greenhouse Gases Figure 1

According to the International Energy Agency (IEA), even “meeting the emission goals pledged by countries under the United Nations Framework Convention on Climate Change (UNFCCC) would still leave the world 13.7 billion tons of CO2— or 60 percent—above the level needed to remain on track for just 2ºC warming by 2035.”5 The IEA’s estimate will likely prove conservative, as most countries are in fact not on track to meet their stated reduction targets.6 The 2 degrees Celsius threshold could be crossed before 2041, absent significantly more aggressive global mitigation actions. At the current rate of atmospheric emissions of CO2 equivalents, the "quota" of 1,200 billion tons would be used up in less than a generation, although there is some disagreement on the exact timing of when this will happen.

The recently released Emissions Gap Report by the U.N. Environment Programme is a further warning: “In order to limit global temperature rise to 2°C and head off the worst impacts of climate change, global carbon neutrality should be attained by mid-to-late century."7 Reaching carbon net neutrality between 2055 and 2070 is, according to the report, essential to minimizing the risk of severe, pervasive, and in some cases irreversible climate change impacts.8

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