DKos front-page http://www.dailykos.com/... reports jolting research that current CO2 levels are a 15 Million Year Record. This is not a record that mankind gets an award for.
During the second half of the Twentieth Century, solar intensity was significantly rising, and so were atmospheric Carbon Dioxide gas (CO2) concentrations primarily due to industrial emissions. ( http://en.wikipedia.org/... , ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_mm_mlo.txt , http://en.wikipedia.org/... )
Since CO2 levels were rising rapidly, many great scientific minds and resources dedicated themselves to modeling the probable results of atmospheric increase of CO2 on the global climate. The studies of a vast consensus of climate scientists concluded a powerful and dramatic future heating impact. ( http://en.wikipedia.org/... )
In 2007, the 4th IPCC report presented a range of model forecasts. Since 2007, often climate scientists have warned that some actual observations appear significantly worse than the already dire IPCC Assessment's worst case. ( http://www.wunderground.com/... )
A few self-purported scientists sometimes suggest that the increase in solar output during the second half of the 20th century was the dominant cause of global warming. Observations continue to show they were miserably wrong. Measurements and models are converging to show the far more powerful connection between CO2 and climate. Good climate scientists in the past couple of decades may have, in reaction, downplayed solar cycles as of negligible importance on observed earth surface temperatures. This seems foolish. The Little Ice Age ( http://en.wikipedia.org/... ) appears to have actually happened, and to have happened as a result of a very weak solar cycle/macro-cycle. ( http://en.wikipedia.org/... )
Our current Solar Cycle 24 (now apparently at late-minimum) is remarkable in falling below 1913's minimum, putting itself in a class with cycles that likely precipitated The Little Ice and AND all the grandparents' stories about such very snowy, snowy, cold winters decades ago.
The solar cycle seems to have a quite noticeable but temporary climate effect, and if the current CO2 level (387 PPM) were equal to the year 1650's level (<280 PPM ??), we might be having another "little" ice age now. That, however, is speculative, but most definitely is not occurring!</p>
What is actually happening is that Arctic ice extent is menacing its record-low levels achieved in 2007 ( http://nsidc.org/... ).
Click here to see graph of Arctic sea ice updated near-daily by the National Snow and Ice Data Center:
NSIDC says ( http://nsidc.org/... ):
However, ice extent was still 1.68 million square kilometers (649,000 square miles) below the 1979 to 2000 September average (Figure 2). Arctic sea ice is now declining at a rate of 11.2 percent per decade, relative to the 1979 to 2000 average (Figure 3).
The people who look at data who said the Arctic might melt quickly also warn Greenland is not likely to lag far behind in melting due to loss of surface albedo (a strong positive feedback: http://en.wikipedia.org/... ); then we have sea level rises far worse than Americans appear to be anticipating.
You should keep a close eye on NSIDC's public data: http://nsidc.org/... . We are already or imminently heading upward toward a new solar-cycle maximum (2011-2014?) -- which I believe data trends suggest will make the following solar minimum irrelevant for a once-again dark-watered, heat-absorbing, ice-less Earth. This is an Earth that Homo sapiens has never walked upon. But, there would be a bunch less land to walk on anyway.
This time it won't be as easy as building an Ark.