With three quarters of the official measurements taken in 2019, it will be in place two of the hottest years in the world - a position that is unlikely to change in the last months of this year. It is an exceptionally high rating for a year 'without powerful El Niño', and therefore a strong indication of the worldwide rising temperature trend.
Halfway through the year it was already clear that by 2019 world average would be high on the list of warmest years. The American national weather service NOAA already gave it a 70 percent chance, based on January to June, that 2019 would be in place two or three - but not in place one, because 2016 still stood head and shoulders above it.
This was followed by the extremely warm month of July. In the Netherlands, the national heat record was broken, but worldwide temperatures were also exceptional: measurements of land and oceans, in the northern and southern hemisphere combined, made July 2019 the hottest month ever. Since that hot summer, the average temperature for 2019 has been in second place, and analysis of the expert website Carbon Brief makes it unlikely that this position will change in the end of the year.
(Source: Carbon Brief.)
Heat record is the sum of warming and strong El Niño
Record year 2016 remains firmly in place one. It was very warm that year, partly due to the powerful El Niño at the end of 2015. El Niño is a natural climate change, with the water on the surface of the Pacific temporarily warmer, which means that the atmosphere can lose less heat. La Niña is the cool counterpart; then in the Pacific Ocean a lot of relatively cold ocean water rises from the depth.
Years with a strong La Niña therefore often fall a bit cooler worldwide - while El Niño gives a temporary peak on top of the trend of rising temperatures worldwide due to climate change. El Niño was weak at the beginning of 2019, but for most of the year the situation in the Pacific was neutral, and at the end of the summer even a weak La Niña.
In the last five years, world temperature has risen by 0.2 degrees
This makes the high global temperature rating of this year significant: in the absence of a powerful El Niño or La Niña, global average temperature readings generally provide the best view of the underlying temperature trend. Together with the concentration of greenhouse gasses, this is accelerating, the World Meteorological Organization reported in September. In the last five years alone, 0.2 degrees has been added, just as much as in the ten years before.
The summer of 2019 brought more records that are associated with climate change. For example, the sea ice from the North Pole reached the second lowest point since the start of satellite observations above the area and there were exceptional wildfires around the North Pole.