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Stealth Hunter · 03-13-10, 03:20 PM

Continuing on topic.

One of the most important bits of evidence touched upon are global surface temperature trends. The global average surface temperature fluctuates over time, but in recent decades it has increased dramatically. From 1920 to the present, Earth’s average surface temperature has increased by 1.4*F. According to the National Academy of Sciences, this change is the largest global temperature rise in at least the last 2,000 years and may steal the record from the last 5,000 years. The sharpest rise occurred between 1975 and 2005, when temperatures rose steadily by about 1*F on average.

The recent increase in concentration of carbon dioxide in the atmosphere is the result of human activities, as we discussed earlier- mainly the burning of fossil fuels. As the concentration of CO2 in the atmosphere has increased, so has the average surface temperature (to reiterate). The relationship between atmospheric CO2 concentration and surface temperature is shown here for the past 150 years.

The quality sucks, but the red line represents surface temperature, the pink outline represents the uncertainty range, the blue line represents CO2 concentration. The graph begins in 1845 and ends in 2005, and each number along the bottom represents an elapsed interval of 20 years.

Source for CO2 concentration data: Keeling, C.D. and T.P. Whorf, 2005. Atmospheric CO2 records from sites in the SIO air sampling network. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. DOE, Oak Ridge, Tenn., U.S.A.

Source for temperature data: Brohan, P., I. Haris, S.F.B. Tett, P.D. Jones, and J.J. Kennedy, 2006. Uncertainty estimates in regional and global observed temperature changes: a new dataset from 1850. Journal of Geophysical Research, p. 111, 2003.

Over the last 400,000 years.

Again, the quality is bad, but the red line represents Antarctic surface temperature, the blue line pre-industrial atmospheric CO2, the yellow-orange line human-contributed atmospheric CO2. Intervals along the x-axis go for 50,000 years each, starting 400,000 years ago and ending in the present. This data was also collected by C.D. Keeling and T.P. Whorf, published on pages 121-126 of issue #398 of Nature magazine in 2000.

The graph below this section of paragraphs compares measurements of the Earth’s past temperature variations (shown by the black line) with simulations of past temperature variations (shown by the red and blue lines) in order to determine whether the major changes in temperature were caused by natural or human-caused factors.

The black line shows observed surface temperature variations from the average. The blue and red lines show computer model results when past temperatures are simulated including different drivers of the climate system. Natural drivers include solar radiation and volcanic emissions, while anthropogenic (man-made) drivers include man-made greenhouse gases and sulfate aerosols. The blue line shows variation when natural drivers are included in the calculations, while the red line shows variation when both natural and anthropogenic drivers are included.

This graph shows that the combination of natural and anthropogenic drivers (the red line) provides a better match to the observed temperatures (black line) than only natural drivers (the blue line).

Natural drivers alone can explain much of the temperature change in the first half of the century, as demonstrated by the similarity between the black and blue lines during that time period. As can be seen with the close match between the red and black lines, human-produced drivers strongly dominated the temperature change in the latter part of the 20th century.

It's of somewhat better quality. The source: Meehl, G.A., W.M. Washington, C.M. Ammann, J.M. Arblaster, T.M.L. Wigley, and C. Tebaldi, 2004. Of Models and Men. Journal Collective of Scientific Minds, p. 44, found in the January 2005 edition.

The graph below shows the heat content of the ocean measured at three depths: from 0-300 meters (red line), from 0-700 meters (blue line), and from 0-3000 meters (gray line). Each line on the graph corresponds to measurements taken at one of these three depths and shows a gradual increase in heat content over time. Warming of the oceans has many consequences, including sea level rise, coral bleaching, loss of sea ice, intensification of hurricanes, and higher coastal storm surges. Taken together with the graph below, this shows that increased temperatures have been observed at Earth’s surface and in the oceans.

Source: Levitus, S., J. Antonov, and T. Boyer, 2005. Journal of Geophysical Research, p. 66, 2005.

Tonight, I'll cover the issue of impacts of the enhanced greenhouse effect, climate change, and global warming.

03-13-10, 03:20 PM	#180
Stealth Hunter Silent Hunter Join Date: Nov 2006 Location: Y'ha-Nthlei Posts: 4,262 Downloads: 19 Uploads: 0	Continuing on topic. One of the most important bits of evidence touched upon are global surface temperature trends. The global average surface temperature fluctuates over time, but in recent decades it has increased dramatically. From 1920 to the present, Earth’s average surface temperature has increased by 1.4F. According to the National Academy of Sciences, this change is the largest global temperature rise in at least the last 2,000 years and may steal the record from the last 5,000 years. The sharpest rise occurred between 1975 and 2005, when temperatures rose steadily by about 1F on average. The recent increase in concentration of carbon dioxide in the atmosphere is the result of human activities, as we discussed earlier- mainly the burning of fossil fuels. As the concentration of CO2 in the atmosphere has increased, so has the average surface temperature (to reiterate). The relationship between atmospheric CO2 concentration and surface temperature is shown here for the past 150 years. The quality sucks, but the red line represents surface temperature, the pink outline represents the uncertainty range, the blue line represents CO2 concentration. The graph begins in 1845 and ends in 2005, and each number along the bottom represents an elapsed interval of 20 years. Source for CO2 concentration data: Keeling, C.D. and T.P. Whorf, 2005. Atmospheric CO2 records from sites in the SIO air sampling network. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. DOE, Oak Ridge, Tenn., U.S.A. Source for temperature data: Brohan, P., I. Haris, S.F.B. Tett, P.D. Jones, and J.J. Kennedy, 2006. Uncertainty estimates in regional and global observed temperature changes: a new dataset from 1850. Journal of Geophysical Research, p. 111, 2003. Over the last 400,000 years. Again, the quality is bad, but the red line represents Antarctic surface temperature, the blue line pre-industrial atmospheric CO2, the yellow-orange line human-contributed atmospheric CO2. Intervals along the x-axis go for 50,000 years each, starting 400,000 years ago and ending in the present. This data was also collected by C.D. Keeling and T.P. Whorf, published on pages 121-126 of issue #398 of Nature magazine in 2000. The graph below this section of paragraphs compares measurements of the Earth’s past temperature variations (shown by the black line) with simulations of past temperature variations (shown by the red and blue lines) in order to determine whether the major changes in temperature were caused by natural or human-caused factors. The black line shows observed surface temperature variations from the average. The blue and red lines show computer model results when past temperatures are simulated including different drivers of the climate system. Natural drivers include solar radiation and volcanic emissions, while anthropogenic (man-made) drivers include man-made greenhouse gases and sulfate aerosols. The blue line shows variation when natural drivers are included in the calculations, while the red line shows variation when both natural and anthropogenic drivers are included. This graph shows that the combination of natural and anthropogenic drivers (the red line) provides a better match to the observed temperatures (black line) than only natural drivers (the blue line). Natural drivers alone can explain much of the temperature change in the first half of the century, as demonstrated by the similarity between the black and blue lines during that time period. As can be seen with the close match between the red and black lines, human-produced drivers strongly dominated the temperature change in the latter part of the 20th century. It's of somewhat better quality. The source: Meehl, G.A., W.M. Washington, C.M. Ammann, J.M. Arblaster, T.M.L. Wigley, and C. Tebaldi, 2004. Of Models and Men. Journal Collective of Scientific Minds, p. 44, found in the January 2005 edition. The graph below shows the heat content of the ocean measured at three depths: from 0-300 meters (red line), from 0-700 meters (blue line), and from 0-3000 meters (gray line). Each line on the graph corresponds to measurements taken at one of these three depths and shows a gradual increase in heat content over time. Warming of the oceans has many consequences, including sea level rise, coral bleaching, loss of sea ice, intensification of hurricanes, and higher coastal storm surges. Taken together with the graph below, this shows that increased temperatures have been observed at Earth’s surface and in the oceans. Source: Levitus, S., J. Antonov, and T. Boyer, 2005. Journal of Geophysical Research, p. 66, 2005. Tonight, I'll cover the issue of impacts of the enhanced greenhouse effect, climate change, and global warming.