Originally posted by sylas
On the other hand, in an extensive footnote in an article here (see footnote #10), an author lists four major factors that could indicate cooling rather than warming in the near future. I will excerpt from the article only the PDO factor, because that is the one that Roy Spencer identifies as the primary driver of natural climate change ― as opposed to IPCC AGW theory.
Cool Pacific Decadal Oscillation
The Pacific Decadal Oscillation refers to cyclical variations in sea surface temperatures that occur in the North Pacific Ocean. (The PDO is often described as a long-lived El Niño-like pattern.) PDO events usually persist for 20 to 30 years, alternating between warm and cool phases.
From 1977 to 1998, during the height of “global warming,” North America was in the midst of a warm PDO.
But the PDO has once again resumed its negative cool phase, and, as such, represents the first climate driver in the Triple Crown of Cooling. With the switch to a cool PDO, we’ve seen a change in the El Nino/Southern Oscillation (ENSO), which alternates between El Nino (warm phase) and La Nina (cool phase) every few years. The recent strong El Nino that began in July 2009 is now transitioning to a La Nina, a sign of cooler temperatures ahead.
“We’re definitely headed towards La Nina conditions before summer is over, and we’re looking at a moderate to strong La Nina by fall and winter, which ... should bring us cooler temperatures over the next few years,” predicts Joe D’Aleo, founder of the International Climate and Environmental Change Assessment Project (ICECAP) and the first director of meteorology at the Weather Channel.
He is not alone in his forecast. Bastardi also sees a La Nina just around the corner.
“I’ve been saying since February that we’ll transition to La Nina by the middle of the hurricane season. I think we’re already seeing the atmosphere going into a La Nina state in advance of water temperatures. This will have interesting implications down the road. La Nina will dramatically cool off everything later this year and into next year, and it is a signal for strong hurricane activity,” Bastardi predicts.
The difference in sea surface temperature between positive and negative PDO phases is not more than 1 to 2 degrees Celsius, but the affected area is huge. So the temperature changes can have a big impact on the climate in North America.
The Pacific Decadal Oscillation refers to cyclical variations in sea surface temperatures that occur in the North Pacific Ocean. (The PDO is often described as a long-lived El Niño-like pattern.) PDO events usually persist for 20 to 30 years, alternating between warm and cool phases.
From 1977 to 1998, during the height of “global warming,” North America was in the midst of a warm PDO.
But the PDO has once again resumed its negative cool phase, and, as such, represents the first climate driver in the Triple Crown of Cooling. With the switch to a cool PDO, we’ve seen a change in the El Nino/Southern Oscillation (ENSO), which alternates between El Nino (warm phase) and La Nina (cool phase) every few years. The recent strong El Nino that began in July 2009 is now transitioning to a La Nina, a sign of cooler temperatures ahead.
“We’re definitely headed towards La Nina conditions before summer is over, and we’re looking at a moderate to strong La Nina by fall and winter, which ... should bring us cooler temperatures over the next few years,” predicts Joe D’Aleo, founder of the International Climate and Environmental Change Assessment Project (ICECAP) and the first director of meteorology at the Weather Channel.
He is not alone in his forecast. Bastardi also sees a La Nina just around the corner.
“I’ve been saying since February that we’ll transition to La Nina by the middle of the hurricane season. I think we’re already seeing the atmosphere going into a La Nina state in advance of water temperatures. This will have interesting implications down the road. La Nina will dramatically cool off everything later this year and into next year, and it is a signal for strong hurricane activity,” Bastardi predicts.
The difference in sea surface temperature between positive and negative PDO phases is not more than 1 to 2 degrees Celsius, but the affected area is huge. So the temperature changes can have a big impact on the climate in North America.
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