Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

Politics : Evolution -- Ignore unavailable to you. Want to Upgrade?

To: longnshort who wrote (33749)	3/2/2013 7:35:56 PM
From: Solon	1 Recommendation Read Replies (1) \| Respond to of 69300

"and the sun had zero input" LOL!! Now now...let us not get carried away. -g- But when dealing with a question of Science, it is alaways best to go to the Scientific Research. solar-center.stanford.edu "...Finally, the role of solar variability in climate change has received much public attention because reliable estimates of solar influence are needed to limit uncertainty in the importance of human activity as a potential explanation for global warming. Extensive climate model studies have indicated that the models can only reproduce the late twentieth century warming when anthropogenic forcing is included, in addition to the solar and volcanic forcings [IPCC, 2007]. The change in solar radiative forcing since 1750 was estimated in the IPCC [2007] report to be 0.12 W m-2, corresponding to an increase in TSI of 0.69 W m-2. A value of 0.24 W m-2 solar radiative forcing difference from Maunder Minimum to the present is currently considered to be more appropriate. Despite these uncertainties in solar radiative forcing, they are nevertheless much smaller than the estimated radiative forcing due to anthropogenic changes, and the predicted SC-related surface temperature change is small relative to anthropogenic changes..." ALSO solar-center.stanford.edu Solar Variability & Global Warming During the initial discovery period of global climate change, the magnitude of the influence of the Sun on Earth's climate was not well understood. Since the early 1990s, however, extensive research was put into determining what role, if any, the Sun has in global warming or climate change. A recent review paper, put together by both solar and climate scientists, details these studies: Solar Influences on Climate. Their bottom line: though the Sun may play some small role, "it is nevertheless much smaller than the estimated radiative forcing due to anthropogenic changes." That is, human activities are the primary factor in global climate change. Solar irradiance changes have been measured reliably by satellites for only 30 years. These precise observations show changes of a few tenths of a percent that depend on the level of activity in the 11-year solar cycle. Changes over longer periods must be inferred from other sources. Estimates of earlier variations are important for calibrating the climate models. While a component of recent global climate change may have been caused by the increased solar activity of the last solar cycle, that component was very small compared to the effects of additional greenhouse gases. According to a NASA Goddard Institute for Space Studies (GISS) press release, "...the solar increases do not have the ability to cause large global temperature increases...greenhouse gases are indeed playing the dominant role..." The effects of global climate change are apparent (see section below) despite the fact that the Sun is once again less bright during the present solar minimum. Since the last solar minimum of 1996, the Sun's brightness has decreased by 0.02% at visible wavelengths, and 6% at extreme UV wavelengths, representing a 12-year low in solar irradiance, according to this NASA news article (April 1, 2009). Also, be sure to read this more recent article: 2009: Second Warmest Year on Record; End of Warmest Decade. For January-June of 2010, the global temperature average was 57.5 degrees Fahrenheit - the warmest first half-year since records began in 1880, though it remains yet to be seen whether the next six months will make this year the warmest on record. (Link: First Half of 2010 Warmest on Record). Still, according to NOAA, "each of the 10 warmest average global temperatures recorded since 1880 have occurred in the last fifteen years" - Link. More data available on NOAA's State of the Climate Website where you can view monthly climate reports. Trends & Effects; Scientific Studies Image created by Robert A. Rohde / Global Warming Art globalwarmingart.com The United Nations Intergovernmental Panel on Climate Change has been studying global warming for years. Their most recent report, issed in February 2007, (see Climate Change 2007: The Physical Science Basis (summary for policymakers), U.N. Report Confirms Human Activity to Blame for Earth's Warming Climate (from Voice of America), and Intergovernmental Panel on Climate Change), concludes that "The global increases in carbon dioxide concentration are due primarily to fossil fuel use and land-use change, while those of methane and nitrous exide are primarily due to agriculture." The report goes on to note that these findings come with a "very high confidence rate [words emphasized in italics in the report summary] that the globally averaged net effect of human activities since 1750 has been one of warming." The primary place where scientific studies related to global climate change are reported is the American Geophysical Union (AGU). Based on the outcome from a considerable number of studies in various fields related to global climate change, the AGU has issued a statement: Human Impacts on Climate. The American Meteorological Society, which promotes the development and dissemination of information and education on the atmospheric and related oceanic and hydrologic sciences, has also issued a statement on global changes. For more information on the impact of global climate change, see the "Impacts, Adaptation and Vulnerability" section from the IPCC Fourth Assessment Report: Climate Change 2007. You can find the technical summary here. Additional discussion on current and potential future effects and feedback mechanisms can be found here: Effects of global warming.