Friday, July 21, 2006
More sudden climate change
Who doesn't think it wouldn't be "lush and populated" today if it weren't for George Bush?
3 Comments:
By 
GreenmanTim, at
Fri Jul 21, 11:02:00 AM:
Seems to me the onset of a wetter Sahara corresponded with the retreat of the ice sheets across the northern hemisphere. At the height of this wetter period, around 8,200 years ago, an abrupt ocean temperature change happened in the North Atlantic, brought on by the melting of the icesheet that covered the Great Lakes. Specifically, this affected the Gulf Stream, causing average temperatures to drop across much of the northern hemisphere.
http://news.mongabay.com/2006/0629-flood.html has the story.
Not sure that our President had much to do with that historic climate change event one way or the other, but his and our actions or lack thereof during the present one deserve scrutiny.
By Purple Avenger, at
Fri Jul 21, 05:17:00 PM:
How much has the sun's output increased over the past 300 years Tim?
By GreenmanTim, at
Fri Jul 21, 10:55:00 PM:
Here is what NOAA has to say on that score:
"The Sun is the heat engine that drives the circulation of our atmosphere. Although it has long been assumed to be a constant source of energy, recent measurements of this solar constant have shown that the base output of the Sun can vary by up to two tenths of a percent over the 11-year solar cycle. Temporary decreases of up to one-half percent have been observed. Atmospheric scientists say that this variation is significant and that it can modify climate over time. Plant growth has been shown to vary over the 11-year sunspot and 22-year magnetic cycles of the Sun, as evidenced in tree-ring records.
While the solar cycle has been nearly regular during the last 300 years, there was a period of 70 years during the 17th and 18th centuries when very few sunspots were seen (even though telescopes were widely used). This drop in sunspot number coincided with the timing of the little ice age in Europe, implying a Sun- to-climate connection. Recently, a more direct link between climate and solar variability has been speculated. Stratospheric winds near the equator blow in different directions, depending on the time in the solar cycle. Studies are under way to determine how this wind reversal affects global circulation patterns and weather.
During proton events, many more energetic particles reach Earth's middle atmosphere. There they cause molecular ionization, creating chemicals that destroy atmospheric ozone and allow increased amounts of harmful solar ultraviolet radiation to reach Earth's surface. A solar proton event in 1982 resulted in a temporary 70% decrease in ozone densities."
More at http://www.sel.noaa.gov/primer/primer.html.
Regarding climate change and whether we have anything to do with it, you can find just about anything you want to support an opinion you already hold on the Internet so keep those minds open and don't forget to test the null hypothesis.
