What global warming looks like

Climate scientists have warned that climate change will bring more heat waves, more droughts, more torrential downpours, more wildfires and worse storms. Sound familiar?  This year in the U.S., more than 2 million acres have burned in wildfires, more than 100 million people were under extreme heat advisories by end of June, and two-thirds of the country was in drought while deluge flooding has occurred in several states.This may be what global warming looks like at the personal level.  See Summer ‘what global warming looks like’.

Warmest March in U.S.

More than 15,000 warm temperature records were broken during March in the U.S. and the warmer-than-average conditions created an environment favorable for severe thunderstorms and tornadoes. There were 223 tornado reports during March, which averages 80 tornadoes annually. (This according to NOAA's Storm Prediction Center.)  See: U.S. Records Warmest March; More Than 15,000 Warm Temperature Records Broken.

Cold winters caused by warmer summers

Not so surprising since warmer air holds more moisture. Scientists offer an explanation for the harsh winters recently experienced in the Northern Hemisphere - increasing temperatures and melting ice in the Arctic regions produce more snowfall in the autumn months at lower latitudes.

See Cold Winters Caused by Warmer Summers, Research Suggests

October snow in western PA

Somewhat rare, October snow covers grass and foliage in western Pennsylvania. Even so, temperatures have been above normal, especially at night for this time of year. Remember, warmer air holds more moisture.

Observational evidence

I had a conversation recently with someone who claimed that "global warming theory" is not supported by observational evidence. It's true that on any given day or week in your own neighborhood, what you see cannot necessarily be linked to climate change, as weather and climate occur on two entirely different scales. Weather is short-term while climate trends are detected over much longer periods (like 30 years at minimum) so particular weather events are not really evidence of global warming, but the longer-term patterns are.

I see plenty of observational evidence around the world that's being reported on longer term patterns. For example, in today's news, Europe's Worst Drought In 100 Years Is Getting Worse says that England is the driest it's been since 1910 and the warmest since 1659.

For more on recent climate trends, see NOAA: 2010 Tied For Warmest Year on Record.

2010 could be a record hot year

2010 is shaping up to be one of the hottest years on record according to NASA data. Record high temperatures have been set recently in various countries around the world.
See NASA: First half of 2010 breaks the thermometer — despite recent minimum of solar irradiance.

Tropical Pacific has switched from warm to cold

La Niña has recently taken hold over El Niño. During a La Niña, trade winds in the western equatorial Pacific are stronger than normal, and cold water that normally exists along the coast of South America extends to the central equatorial Pacific. La Niñas change global weather patterns and are associated with less moisture in the air, resulting in less rain along the coasts of North and South America. They also tend to increase the formation of tropical storms in the Atlantic. See Adios El Niño, Hello La Niña?