Many of you have probably read that February produced the most abnormally warm temperatures in the instrumented record, and by a fairly large margin. The cause of this extreme warmth is the combination of global warming and El Nino. The trace below shows the global average temperature anomaly for the month of February since 1890, as analyzed by the Japan Meteorological Agency (JMA). Note the El Nino fueled spike in 1998, toward the end of the last "uber" El Nino, and then in 2016, consistent with the current "uber" El Nino.
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| Source: JMA |
Once the current "uber" El Nino wanes, global cooling is coming, at least relative to where we sit right now. That cooling, however, will reflect short-term climate variability and will be temporary.
In my post
Locally Dense Snow and Globally High Temperatures back in November, I made made the prediction that such a drop in temperatures, as occurred following the last Uber El Nino in 1997/98, you will hear people claiming a global warming hiatus once again. Ethan Siegel made
a similar prediction today in Forbes. When that happens, don't be fooled. In terms of long-term trends, global warming is the signal, and the year-to-year ups and downs in global temperatures the noise.
Year-to-year variability coupled with measurement uncertainty does make it difficult to track global warming on annual timescales, however I disagree that we need to wait ~15 years for every atmospheric spike to see if it is continuing like Siegel states. We should be estimating the heat content of the entire climate system, where warming has been shown to be dominated by ocean warming, which has far less 5-10 year variability: https://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/.
ReplyDeleteYes, beware the "pseudo-scientists for hire" who usually are directly or indirectly funded by energy or political organizations whose only goal is to cast some sort of doubt on the undeniable warming trend, to delay any meaningful measures to be put in place. The bogus "warming ended in 1998" was run its course so much that even the die-hard denialists have a hard time with that one. No doubt they will feel invigorated by any descent from our current levels. The true question to ask then is when will any year be cooler than anything before 1997?
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