Weather and Climate Are Different

Weather is not the same as climate.  Like surf can be high then low, but doesn’t indicate whether the tide is ebbing or flowing, weather on short time scales does not indicate climate change.  Long trends do.  Many things can affect weather.  One important condition is that in El Niño years the temperatures tend to increase.Weather vs Climate

This can be seen on the figure on the right.  The monthly average varations are weather changes, up and down.  The big spike at 1998 is an El Niño year, which also shows in the annual average.  But if one looks at the five year average, which will tend to better show long term trends, the trend is upward.  Note also that when Mt. Pinatubo Volcano erupted in 1993-4 there is a decrease in temperature caused by shading from the volcanic ash spreading around the globe.

Figure from Global Warming Art.

Click on figure to enlarge.

Why Are Some Places Colder Not Warmer?

If you live in the northeastern and midwestern U.S. you might think winters are colder.  But if you live in California you definitely wouldn’t. Even long term, although many areas will eventually be warmer,  depending on local conditions, some areas can be cooler.  The effect of climate on global weather is still poorly understood.  It is hypothesized that the warming may affect the polar vortex, which  is essentially a wind which spins around the north pole.  Meteorologists have observed that the polar vortex has tended to slow in some winters in the recent past, which then sags down into the northeastern US, bringing Arctic cold with it.  Air T Anomalies

More generally, temperatures seem to be warming in the northern polar region, and cooling in the temperate northern latitudes.

Figure from NOAA/ESRL Physical Sciences Division

Click on figure to enlarge.

As Dr. James Overland, 30 years with NASA, said,

“In December 2009, the Arctic was 9 degrees F warmer than normal, and mid-latitude continents were 9 degrees F cooler than normal, with record cold and snow conditions in northern Europe, eastern Asia and eastern North America,”