June 19, 2010
Graph of the Day: Ocean Heat Content, 1955–2008
This figure shows changes in ocean heat content between 1955 and 2008. Ocean heat content is measured in joules, a unit of energy, and compared against the long-term average, which is set at zero. • In three different data interpretations, the long-term trend shows that ocean heat content has increased substantially since 1955. • Although concentrations of greenhouse gases have risen at a steady rate over the past few decades (see the Atmospheric Concentrations of Greenhouse Gases indicator on p. 14), the rate of change in ocean heat content can vary greatly from year to year (see Figure 1). Year-to-year changes are influenced by events such as volcanic eruptions and recurring ocean-atmosphere patterns such as El Niño.
