English: This graph shows how short-term variations occur in the global temperature record. However, the graph still shows a long-term trend of global warming.

Climate change is defined as a change in the average conditions over periods of 30 years or more. On these time scales, global temperature continues to increase. This is shown on the graph as the red line. Over shorter time scales, however, natural variability (due to the effects of El Niño and La Niña events in the Pacific Ocean, for example, or volcanic eruptions or changes in energy from the Sun) can reduce the rate of warming or even create a temporary cooling.

From 1970 to 2010, for example, global temperature trends taken at five-year intervals range from decreases to sharp increases. This is shown on the graph by the blue lines. The most recent five-year period, from 2005 to 2010, included the largest solar minimum experienced since the Little Ice Age of the late 1700s and also occurred during a period when natural cycles were causing greater than average amounts of heat to be taken up by the oceans. These natural factors contributed to a temporary downward trend in temperature.

The graph is based on measurement data from NASA-GISS. This description is based on edited text from the cited public-domain source (Walsh, et al., 2013).