Global temperature anomalies, 2016 and 2017
Here’s what the annual average history looks like now.
Those anomalies are calculated relative to a 1951-1980 baseline. If we adapt those to a 1880-1909 baseline, which is a closer match to the “pre-industrial” datum used as the basis for UNFCCC temperature targets. [The above image shows] how that looks, with the addition of a 42-point LOESS regression smoother.
The trend is now above the 1.0°C anomaly level relative to pre-industrial temperatures. The smoothed line shows remarkable linearity since 1980. Simply extending this trend to 2050, as shown by the dotted line, suggests that the 1.5°C threshold will be reached in about 25 years. We are now already halfway to 2.0°C and two-thirds of the way to 1.5°C.
Of course, abrupt changes in CO2 concentration trends (0r trends in other forcing agents) could bend the temperature trend curve one way or the other. However, there’s a lot of physical and economic inertia in the system and it looks like—short of a major geo-engineering intervention—1.5°C is now baked in over the next two or three decades.
Sorry, low-lying island states.
[The UK Met Office forecast for 2017 is] substantially down on 2016, but will be close to 2015 and it should end up well above the current third-warmest year in the Met Office record, 2014, at 0.61°C. It will fall back closer to the long-term trend line.