The five-year period from 2011 to 2015 has been the warmest five-year period on record globally, with 2015 being the warmest year on record to date.The period 2011–2015 was also the warmest on record for every continent except Africa. During this period, concentrations of the major greenhouse gases continued to rise and reached record levels for the instrumental period. The record high temperatures from 2011 to 2015,
along with the annual record set in 2015, are consistent with established long-term warming trends, the dominant cause of which is the emission of anthropogenic greenhouse gases. Year-to-year temperature fluctuations occur against the backdrop of the long-term warming trend, in particular as a result of El Niño and La Niña events. High temperatures have been accompanied by the continuation of long-term trends in other indicators that are consistent with warming, such as rising sea levels and declines in Arctic sea-ice extent and
in continental glaciers and ice sheets in Arctic and high-mountain regions.
The single most significant event of the period in humanitarian terms was the 2011–2012 famine in the Horn of Africa, to which drought in late 2010 and 2011 was a major contributor. More than 250 000 excess deaths in the Horn of Africa were attributed to this event by the Famine Early Warning Systems Network.
On shorter timescales, no single climate-related disaster in the period 2011–2015 was associated with
short-term casualties on the scale of some of the worst events of the previous decade, such as the 2003 European heatwave and Cyclone Nargis in Myanmar in 2008. However, many of the worst disasters of the period 2011–2015 still involved extreme weather and climate.