The Earth’s surface is warming primarily because of human generated greenhouse gasses, mainly CO2, being added to the atmosphere. Several agencies and organizations track this by combining data from surface thermometers and sea surface temperature measurements. The Japan Meteorological Agency is one such group, and they have just released their updated monthly data for October.
The graph above shows the average surface temerature for the month of October for the entire period of their data set (1891 to the present). Not only is October 2015 the warmest October observed, but it is way warmer than previous Octobers.
This isn’t the biggest jump observed. If you look at the earlier data, you can see other jumps of simlar (or in one or two cases, greater) magnitude. These, including this year, are all En Niños. During an El Niño, heat that has been stored up for the previous several years in the Pacific Ocean is released because of temporary changes in sea currents and trade winds.
Here is the important thing to note about this set of data. The present El Niño is a big one. But several of the earlier El Niños were also big ones. But with each big El Niño, we see an increase in temperatures over the previous El Niños. Keep this in mind when the following two things are brought to your attention: 1) We are breaking all sorts of records with tropical storms, heat waves, and other dangerous weather, but 2) this is expected since it is an El Niño year.
The breaking of numerous records in not expected in an El Niño year. For many of these observations, we do expect to be more likely to break a record during any given El Niño, but records would also be broken, and set for the long term, during an earlier strong El Niño. But, with global surface temperatures marching ever upwards, a year like the present one is likely to break even those older El Niño enhanced records, because of global warming.
The present El Niño is expected to last into next year.
Over the coming days some of the other agencies that track global warming will come out with their data for October. Stay tuned.