According to a recent assessment by the National Oceanographic and Atmospheric Administration, or NOAA, the real key to climate change may lie not in accumulations of carbon dioxide in the atmosphere but in changes in regional ocean temperatures.

Since ocean temperatures may also be related to carbon dioxide levels, it's difficult to separate the anthropogenic (manmade) aspect of ocean temperatures from the purely natural ones. For example, is La Nina triggered by maximum amounts of carbon dioxide being sequestered in oceans, or is it purely a function of some other, less understood mechanism?

Scientists don't know for certain, but varying oceanic temperatures may also hold the key to predicting regional climate, at least in the United States, where the term "global warming" is now generating ridicule and disbelief among the residents of Alaska, Washington and Minnesota.

The NOAA assessment, one of many reports synthesized and coordinated by the U.S. Climate Change Science Program, has a long and less than memorable name (Reanalysis of Historical Climate Data for Key Atmospheric Features: Implications for Attribution of Causes of Observed Change). On a less didactic scale, the report describes the changing landscape of North America's climate over the past 50 years, and explains why such anomalies as massive snowfalls in Washington, chilling cold in Alaska and pre-1950s winter weather in Minnesota have become the norm rather than the exception.

"How can it be warming if it's this cold?" Ask Alaska residents beset by the worst cold snap in a decade. This, after last summer's record melt of sea ice caused an unprecedented heat wave.

We already know ‘global warming' was an unfortunate choice of titles. Now scientists are beginning to understand why. Warming is only part of an integral system of adaptations the earth takes on to cope with man's occupation of the planet. And it is these systems the new NOAA assessment hopes to condense into a predictive model for use in predicting future regional climate shifts.

According to Randall Dole, lead author and a scientist at NOAA's Earth System Research Laboratory in Boulder, Colorado, the major thrust of this assessment will allow improved climate variability predictions both in the near and long term. As noted in the study, some regional temperatures spiked sharply, while others remained normal. Drought worsened in some areas, while precipitation improved unexpectedly - in fact, disastrously, in the case of Washington state, where more than 30,000 people were evacuated last week as a result of melting record snow in the Cascades and equally record-breaking rain on the plain. Washington, which was previously experiencing drought from 2005 through 2007, now faces landslides, mudslides and avalanches.

As Dole points out, a general trend toward warmer ocean conditions - due to rising levels of greenhouse gases - does not preclude regional "cold spots", or extreme and unparalleled weather conditions. The trick is sorting out which are anthropogenic and which are part of a normal cycle, or perhaps purely anomalous.

Average continental warming of 1.6 degrees Fahrenheit has occurred over the last half-century, more than half of this rise due to an increase in carbon dioxide emissions. This has led, in many regions, to drought, reduced soil moisture and other water stresses. In the Southern hemisphere, for example, climate change seems to be taking a steady course toward rising land temperatures, drought, dropping water tables and creeping desertification. In the Northern hemisphere, and most especially North America, regional warming and drought in the Southeast seems to be offset by greater precipitation and completely unpredictable temperatures in the Northwest. At least, this was the pattern in 2007.

This new assessment is too untested to serve as an immediate predictive model, and scientists admitted they were not able to identify any long-term trends in rain or snow patterns, either regionally or by quantity. They did, however, note that the study - dubbed a retrospective analysis - has produced a higher-quality climate record, and the methods used to arrive at the new data allow them to more confidently state what mechanisms are driving the extreme weather patterns of the last few years. These mechanisms include ocean currents like El Niño (tied to Northwest drought), La Niña (linked with Colorado wildfires), the Pacific Decadal Oscillation (another Northwest influence), the North Atlantic Current (whose failure may be linked to colder conditions in the UK), and the effects of carbon dioxide-saturated cooling oceans on phytoplankton.

NOAA, whose mission is to observe, understand and predict earth and climate changes, will undoubtedly find this new assessment a valuable tool in its arsenal of predictive instruments. Like any tool, however, its correct use will depend on the astuteness of the users, the accuracy of the data (which goes back to the 1600s), and an almost intuitive ability to spot trends.

In the meantime, says the NOAA, expect warmer-than-normal temperatures in the central part of the country, and a continuation of drier-than-normal conditions across the Southeast. In the absence of either El Nino or La Nina, the West Coast can expect temperatures all over the board, but drought is still in the picture.

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Ocean Seeding: The Good, the Bad, the Moratorium
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