Econintersect: A report published last month by the NASA indicates that solar activity is secondary to other causes in accounting for the current energy increase for the earth over time. There has been a minimum in solar flares activity during the time period 2005 – 2010. During that interval the earth absorbed 0.58 W per square meter more energy than it emitted. The reduction in absorption due to lower solar activity was 0.25 W per square meter. On this basis it appears that abnormally low solar activity does reduce the rate of global warming but does not reverse it. The reduction for the low activity period 2005 – 2010 was about 30%.
From the article in R&D Magazine:
A new NASA study underscores the fact that greenhouse gases generated by human activity—not changes in solar activity—are the primary force driving global warming.
Of course, without significant further examination of research data, the statement above cannot be supported. The study does define the secondary significance of solar activity variation in influencing rising global temperatures. The study does nothing to further specify what the cause actually is.
The advent of the satellite age has enabled geographically wide ranging data to be collected on the earth’s thermal profile. The graph below shows the solar energy profile for Earth over recent decades using satellite measurement systems.
A paper just published by the University of Colorado Institute of Arctic and Alpine Research led by Prof. Gifford Miller shed some light on longer range variations in global temperatures. From Scientific Computing:
The new study suggests that the onset of the Little Ice Age was caused by an unusual, 50-year-long episode of four massive tropical volcanic eruptions. Climate models used in the new study showed that the persistence of cold summers following the eruptions is best explained by a sea ice-ocean feedback system originating in the North Atlantic Ocean.
“This is the first time anyone has clearly identified the specific onset of the cold times marking the start of the Little Ice Age,” said Miller. “We also have provided an understandable climate feedback system that explains how this cold period could be sustained for a long period of time. If the climate system is hit again and again by cold conditions over a relatively short period — in this case, from volcanic eruptions — there appears to be a cumulative cooling effect.”
The Little Ice age began abruptly between 1275 and 1300 AD, according to the new study and resulted from the eruption of just four massive volcanos. The cooling results from those eruptions had a long lasting cummulative effect for several hundred years. Of course later volcanic eruptions such as the monstrous 1815 eruption of Mount Tambora in what is now Indonesia added to the effects of the earlier activity. Tambora created the year without a summer for 1816 in the northern hemisphere. In northern Vermont, where this editor grew up, it snowed every month of the year in 1816 and 120 years after the fact old timers still talked about 1800 and froze to death, in stories handed down from their grandparents.
See the two articles by Fabius Maximus below for a review of some other recent details on global warming.
Despite low solar activity, Earth’s energy budget out of whack (R&D Magazine, 31 January 2012)
Answering Long-standing Questions about Enigmatic Little Ice Age (Scientific Computing, 3 February 2012)
Good News! Global temperatures have stabilized, at least for now. (Fabius Maximus, 3 February 2012)
What can climate scientists tell about the drivers of future warming? What can we expect? (Fabius Maximus, 6 February 2012)
Mini Ice Age? (GEI News, 20 June 2011)