Global Temperature Update: April 2011
So far this year the satellite temperature data have measured temperature anomalies of less than 0.1 °C. April is the first month to show an anomaly of > 0.1 °C. The actual number came in at 0.12 °C. That is the anomaly temperature though. April is much more interesting for other reasons. It is one of the two months per year when the average actual temperature increases by 1 °C. That is because the NH is warming up from the winter and the NH drives the yearly variation in the Earth’s temperature.

(Brown) Measured Global Temperature, (Green) Average Global Temperature, (Purple) Temperature Anomaly
As can be easily seen in this chart, the Earth is rapidly warming up from the NH winter, but the difference from the average temperature is very small. 2011 is looking very much like 1980 for the satellite temperature anomaly. That is the last time the actual temperature was so close to the average this far into the year.
2011 is a pretty normal April for temperature anomaly.
More interesting is the 10 year trend in April temperatures. Both satellite sources are showing a negative trend in temperature for the past 10 years.

10 Year trend in temperature by source. Both satellite methods are detecting the decreasing April temperatures around the world.
Certainly a 10 year decreasing temperature trend is not predicted by the theory of global warming. While there have been two La Nina’s in the past 4 years, it was El Nino’s that drove the big spike in warming in 1998. Now that the trend has reversed it is interesting to see how the ENSO gets the blame for the cooling, but not for the previous warming.
The big warm spot on the Earth in April was over Russia. That fits in perfectly with the early snow melt that was experienced in the same location this year over the past month.
The warmth in Eurasia was balanced by cool weather in North America. Otherwise not much stands out location wise.
More and more it is becoming apparent that there is not so much as a trend as an oscillation of a bi-modal behavior. It was only in the transition between modes that the idea of global warming caught traction. For 10 years now the trend has not been in favor of global warming.
Tags: Global Temperature






The objective, according to GISS scientists, is to provide an estimate of temperature change that could be compared with predictions of global climate change in response to atmospheric carbon dioxide, aerosols, and changes in solar activity.