It is far too early to judge this year’s global temperature developments and their significance regarding the long-term warming trend.
The United Nations climate change conference, held in Bonn this year, is always the cue for press releases from the World Meteorological Office and the UK Met Office in which they give their assessment of the year based on 9-10 months of data.
Dealing with the El Nino of recent years (and don’t forget the ‘Pacific Blob’ before that) they have had difficulty with explaining what part of the record temperature was due to El Nino and natural, and what was anthropogenic. Now that the El Nino has subsided and temperatures have dropped a little the WMO and the Met Office are clearer about what is going on, but behind the headlines there are many contradictions.
According to the WMO: “The past three years have all been in the top three years in terms of temperature records. This is part of a long term warming trend,” said WMO Secretary-General Petteri Taalas.
The UK Met Office says; Although 2017 isn’t likely to break the record global mean surface temperatures set over the previous two years, climate scientists regard this year’s figure as noteworthy because it will be the warmest year in the series which hasn’t been influenced by an El Niño – the warm phase of the El Niño Southern Oscillation in the tropical Pacific.
So 2017 is significant because it hasn’t been influenced by the El Nino?
The recent El Nino was the strongest on record and took the global temperature way above what it was during the period from 2001 when there had been no statistically significant change. It’s a periodic weather event, and the global temperature was always expected to go straight up and come down again. Many at its inception proclaimed it was the start of a new global warming trend even though it was obvious what was happening. In any case its rate of temperature increase was far too rapid to be due to global warming.
Looking at the graph the WMO provided the recent El Nino is obvious (click on the image to enlarge). It is the only El Nino event, in this graph, that spans more than one year (although the graph is confusing). According to the WMO and the Met Office the temperature of the world in 2017 is independent of the El Nino, 2017 hasn’t been influenced by it is what they say. Does 2017 look unrelated to 2016 and 2015 to you? With the record amount of heat the El Nino pumped into the system should we have expected the Earth to cool within months. There are only two other El Nino events, in the early 1980s and in 1998, that we have for a comparison, and all have their differences.
Compare it to recent UK Met Office HadCRUT4 global temperature data (click on image to enlarge).
If the global temperature of 2017 was unrelated to the previous years then looking at pre-El Nino years it would entail a temperature jump of 0.13°C in three years – a substantial change. The years 2017 is a warm year and it is clearly not just a coincidence that it is adjacent to the recent record-setting El Nino years. It is far too early to judge its proper place and significance regarding the long-term warming trend.
However, Petteri Taalas, secretary-general of WMO, said at the Bonn conference that he saw little likelihood of the warming trend being reversed in the short term. “This trend can be expected to continue for the coming 50 years. In this system, once you reach a certain level it does not drop soon.” It will be interesting to see if the next few years bear out his certainty.