– how do greenhouse gases fare?
The American Meteorological Society (AMS) has just released the State of the Climate Report for 2014. The report confirms the continuing trend of a gradually warming planet with 2014 recorded as the warmest year on record. Accordingly, sea surface temperatures and global sea levels were at a record high.
What is the state of greenhouse gases? In particular, long lived greenhouse gases (LLGHG) such as carbon dioxide and methane?
(suggested link: Gas Sensing Technology for Measuring Atmospheric and Dissolved Gases)
carbon dioxide (CO2)
“The global average CO2 mole fraction at Earth’s surface in 2014 was 397.2 ± 0.1 ppm, an increase
of 1.9 ppm over the 2013 global mean.” – p. 39 (see reference at end of this post)
“The global growth rate of CO2 has risen from 0.6 ± 0.1 ppm yr−1 in the early 1960s to an average of 2.0 ± 0.1 ppm yr−1 during the past 10 years.” – p. 40
“Based on NOAA background air sampling sites the 2014 globally averaged CH4 mole fraction at Earth’s surface was 1822.9 ± 0.8 ppb. The increase of 9.2 ± 0.9 ppb from 2013 to 2014 is larger than the CH4 growth rate in other recent years.” – p. 40
“The rate of CH4 increase slowed from more than 10 ppb yr−1 in the 1980s to nearly zero in the early 2000s, then increased to ~6 ppb yr−1 since 2007” – p. 40
nitrous oxide (N2O)
“The mean global atmospheric N2O mole fraction in 2014 was 326.9 ± 0.1 ppb, an increase of 1.0 ppb from 2013…
The average N2O growth rate since 2010 of 0.95 ppb yr−1 is higher than the 0.75 ppb yr−1 average over the previous decade.” – p. 40
NOAA annual greenhouse gas index (AGGI)
“Trends in the combined direct radiative forcing by five major LLGHGs (CO2, CH4, N2O, CFC-11, and CFC-12) and 15 minor gases are summarized by the NOAA Annual Greenhouse Gas Index (AGGI; Hofmann et al. 2006; www.esrl.noaa.gov/gmd/aggi/). This index represents the cumulative radiative forcing by these gases for each year, relative to the Kyoto Protocol baseline year of 1990. The AGGI does not include indirect radiative forcings (e.g., influences on ozone and water vapor). In 2014, the 5 major LLGHGs and 15 minor gases contributed 2.94 W m−2 of direct radiative forcing …, 0.035 W m−2 (1.2%) greater than in 2013. The 2014 AGGI of 1.36 indicates a 36% increase in the direct radiative forcing by these gases since 1990.”
Source: Fig.2.36, State of the Climate Report 2014, AMS (see reference below).