Observing & Predicting

July 2014

  • As the assessment now known as the BAMS State of the Climate report pushes into its third decade, international participation is at an all-time high. From atmospheric chemists to tropical meteorologists, more than 420 authors from institutions in 57 countries contributed to this year’s report.

  • The annual average concentration of carbon dioxide (CO2) in the atmosphere stood at 395.3 parts per million (ppm) in 2013—a 27 percent increase compared to conditions before the Industrial Revolution. On May 9, 2013, the daily average concentration of CO2 surpassed 400 ppm for the first time at the Mauna Loa Observatory in Hawaii.

  • Observing temperature patterns in the lower stratosphere gives scientists clues about our planet’s changing climate. Global average temperatures in the lower stratosphere for 2013 were slightly below the 1981–2010 average.  

  • The globally averaged sea surface temperature in 2013 was among the 10 highest on record, with the North Pacific reaching an historic high temperature. ENSO-neutral conditions and a negative Pacific Decadal Oscillation pattern had the largest impacts on global sea surface temperature in 2013.

  • Upper ocean heat content has increased significantly over the past two decades. An estimated 70 percent of the excess heat has accumulated in the top 2,000 feet of the ocean, and the rest has flowed into deeper ocean layers.

  • In 2012—for the 23rd consecutive year—mountain glaciers worldwide lost more mass through melting than they gained through new snow accumulation. The retreat of the majority of mountain glaciers worldwide is one of the clearest signs that climate is warming over the long term.

  • 2013 continued a trend of water vapor in the surface atmosphere increasing over land and ocean relative to the 1970s, while the atmosphere over land becomes less saturated. 

  • In 2013, global average sea level was 1.5 inches above the 1993-2010 average, which is the highest yearly average in the satellite record (1993-present). Overall, sea level continues to rise at a rate of one-eighth of an inch per year.

  •  Arctic sea ice extent shrunk down to 2.0 million square miles (5.1 million square kilometers) in September 2013—18 percent below the 1981-2010 average, but larger than record low set in 2012.

  • While the Northern Hemisphere’s snow cover on land ranked as the 13th most extensive on record in 2013, snow cover extent at the end of the cold season has dropped by 19.9 percent per decade since 1979 relative to the 1981-2010 average.

  • Globally-averaged surface temperature for 2013 was 0.36 - 0.38° Fahrenheit above the 1981–2010 average, placing it among the top 10 warmest years since record-keeping began. 

  • From the strongest typhoon ever observed to historically high atmospheric carbon dioxide levels, the State of the Climate in 2013 report provides a complete rundown on the state of Earth's climate and how it is changing.