ANSWER: 2017
Explanation:
The first half of this year was the second hottest - just behind 2016 - in 137 years of modern record-keeping on Earth, as per scientists.
The average temperature across global land and ocean surfaces was 0.91 degrees Celsius above the 20th century average of 13.5 degrees Celsius.
This was the second highest value for January-June in the 1880-2017 record, behind the record year of last year.
Last month was the third hottest June, according to the US National Oceanic and Atmospheric Administration (NOAA) global temperature dataset record.
The June temperature across global land and ocean surfaces was 0.82 degrees Celsius above the 20th century average of 15.5 degrees Celsius.
This was the third highest value for June in the 138-year period of record, behind 2016 and 2015.
Last month marks the 41st consecutive June and the 390th consecutive month with temperatures at least nominally above the 20th century average.
The monthly analysis by scientists at NASA’s Goddard Institute for Space Studies (GISS) is assembled from publicly available data acquired by about 6,300 meteorological stations around the world, ship- and buoy-based instruments measuring sea surface temperature, and Antarctic research stations.
The modern global temperature record begins around 1880 because previous observations didn’t cover enough of the planet.
