Some remarks on the recent record warmth

UPDATE: The global temperature seems to have been taking quite a hit over the past two months, as it fell rapidly from April to May, and from May to June (this is according to UAH satellite data, RSS data is not yet public at the time of writing). This raises the interesting possibility of 2016 not being the warmest year on record in the satellite data, because it probably will be in surface temperatures.

UAH global tropospheric temperature data

Let me first say that if humans were the only input on the climate system, then we would probably see a steady warming and every month and year would be a new record. That global temperatures have been rising is not a

Recent RSS global lower tropospheric temperature data

HadCRUT4 global surface temperature data

surprise to me. However, the climate system isn’t linear and we are definitely not the only factor. That being said, I believe that human-caused global warming will not manifest itself (and hasn’t) as sudden, enormous jumps in temperature. It is more likely, in my opinion, to be represented as a steady warming of the climate system from human input of greenhouse gases, urbanization, land use change, etc. The idea that human-induced climate change is responsible for temperature jumps like those above is absurd. I don’t think that

Global temperatures from 2015 until present

Global temperatures from 1997 to 1999 – Note the similarities

without human influence we’d be seeing a temperature increase like the one above, but claiming that humans are responsible for this kind of a jump is ridiculous, especially when we have seen jumps like this in the past precisely during an El Nino event, such as during the El Nino of 1997-1998, which was (as is this current one) one of the strongest such events on record. So, while humans are definitely responsible for a significant part of the warming we’re seeing and have seen in the past 150 years and because of humans we will experience more record temperatures, El Nino is the dominant cause of this temperature jump. In addition, if there hadn’t been an El Nino over the past two years, the earth may have cooled due to the combined effect of various natural effects, such as low solar activity and declining PDO and AMO. This is not to say that natural forces will always overwhelm human warming, but over multiyear and even longer periods, natural variability (which is still very poorly understood) can cancel or even reverse the human-caused warming.