November 3rd hottest on record despite La Niña

Source: RobertScribbler

The chart doesn't show the absolute temperature, it shows the anomaly.  Temperature anomalies are calculated by taking the temperatures for a place for each month  and then subtracting the average temperature for each month.  The base period for which the average is calculated differs for each authority, but the shape of the resulting charts is pretty similar.   V shows a significant volcanic eruption, m shows the sunspot minima and M the sunspot maxima.  There is some evidence that eruptions reduce temperatures (1911, 1982) but very little evidence a priori that the solar cycle has any impact.  One would expect sunspot minima to correspond to lower anomalies and vice versa with maxima, and there seems to be no relationship.

The lowest anomalies (the coolest periods) are at the beginning of the chart, the highest at the end, a clear sign of the rising temperature trend.  Because of random fluctuations, it's not a smooth transition from dark blue through yellow to pink.  March 1900, for example, was relatively warmer than the other months in 1900.  That doesn't mean it was warm, just that it was warmer than March is on average.

With data available for January through November this year it seems 98% likely that 2017 will edge out 2015 to be the second hottest year since the 1880s, despite a La Niña, which should cool the global atmosphere.  After the previous strong El Niño in 1998, global temepartures dropped significantly.  See how the long sequence of red squares in 1998 didn't happen again until 2005.  This time, despite a La Niña, temperatures have dropped only a little.  This is not good.

Big declines in CO2 emissions won't start for another decade, which means that global temperatures will keep on rising for at least that long.  The trend increase has been 0.2 degrees C per decade--they'll need one more colour on this chart.  The eruption of Mt Agung in Indonesia may lower temperatures for a while, as has happened with previous volcanic eruptions, but it won't last.  Look for lots more pink and black on this chart as it is updated over the next 10 years.  And keep the pressure up on your elected representatives.  If we had started reducing emissions 2 decades earlier we wouldn't be in the fix we are now.  We don't want another 2 decades of delay and denial.