Thursday, September 18, 2014

Is global warming really occurring? It depends upon where you live

I generally accept the National Oceanic and Atmospheric Administration website as a “reliable” source for  latest local weather happenings, although it can’t help but be wrong on occasion; the day we saw almost an inch-and-half of rainfall over an 8-hour period last month, there was supposed to be only a “slight”—20 percent—chance of rainfall. Still, on my way there the NOAA provides some interesting stories explaining (or trying to) what is going on with Nature.

For example, it is now being reported that action on an international scale to confront ecological problems may actually work, if given enough time. Three decades ago the Montreal Protocols was signed off on by most nations to combat the depletion of the ozone layer, which protects the earth from ultraviolet radiation (the kind that causes skin cancer). The use of chlorofluorocarbons (CFCs) and halons (chemicals used to deter the combustion process in fires) were to be phased out by 2000. It is not clear how much the ozone has recovered, however, only that there are now a significant decrease in ozone-depleting chemicals in the atmosphere. 

On the other hand, it is noted that chemicals that replaced CFCs and halons—such as hydrofluorocarbons (HFCs)—“are potent greenhouse gases and could contribute substantially to climate change in the coming decades,” emphasizing “the complex connections between ozone layer recovery and climate change, he said. For example, some of the replacements for ozone-depleting substances are safe for the ozone layer but cause climate warming.” One is reminded of all those drug commercials on television where the “benefit” is barely mentioned as the list of potential “side-effects”—including death—goes on, and on, and on.

Anyways, August was a hot month around here. According to NOAA statistics, Seattle saw the second highest average high temperatures on record, and the Northwest in general was well above normal both in temperature and precipitation since January (the latter reported in Seattle was also a near record total). In fact, the entire western Pacific coast all the way to Alaska reported record or near record temperatures, due to the El Nino effect; California had its hottest Jan-Aug on record, and  in southern California, Pacific water temperatures of 75 degrees were recorded. 

This has not been good news for California, which has seen the lowest three-year precipitation levels since 1895, when the need for water was obviously much lower. “Spring snowpack conditions helped set the stage for a brutal summer, according to NOAA. “The fifth and final snow survey of the season in May 2014 recorded snowpack at only 18 percent of average statewide. By the end of the month, the Sierra snowpack water equivalent decreased to almost zero. Current reservoir conditions show most of the state’s reservoirs below 50 percent of their total capacity. Many are also below 50 percent of their historical average capacity.”

The state has been forced to pump groundwater to make up most of the difference. Groundwater comes from precipitation that is too much for the upper layers of soil to hold, percolating downward until it encounters dense rock to form aquifers from which water can be drawn to the surface for human consumption. Unfortunately for California, since this source of water is dependent for its “recharge” by precipitation, the drought has brought to the fore the question of how much water is left in these aquifers. In fact, very little is known about how much water actually resides in them; all that is known is that a huge amount of water has been drained from them.

But while the West has seen spectacularly high temperatures, the rest of the country—particularly east of the Mississippi River—have near record low average temperatures since January. In August, the temperature variation between the west and the eastern seaboard could not be any more stark. Precipitation levels also showed wide variation even on the east coast, while one New York locale saw an astonishing 13.57 inches of rain fall in one 24-hour period in August, Georgia has seen drought conditions continue over most of the state. 

All this is, of course, food for fodder for opponents of the concept of global warming, but not to “worry.” The Global analysis of worldwide temperatures still point in that direction:

“The average temperature across the world's land and ocean surfaces during July 2014 was 0.64°C (1.15°F) above the 20th century average, the fourth highest for July on record. The record warmest July occurred in 1998, with a temperature that was 0.73°C (1.31°F) higher than average. Eight of the 10 warmest Julys have occurred within the past 10 years (2002 also ranks among the 10 warmest). Additionally, July 2014 marked the 38th consecutive July and 353rd consecutive month with a global temperature above the 20th century average. The last below-average global temperature for July was July 1976 and the last below-average global temperature for any month was February 1985. With the exception of February (21st warmest), each month during 2014 to date has ranked among the four warmest compared to its respective month.”

We out here in the Pacific Northwest will enjoy it while it lasts. How long will this fine summer weather last—or better yet, will it carry into the normally miserable months of rain and cold? NOAA is less certain than it was that the EL Nino effect—when Pacific trade winds drop, which allows warm water to linger in the eastern Pacific rather than travelling west—will continue into the Fall and Winter, with a 60-65 percent chance that a weak effect will occur.

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