DeltaPilot Posted June 24, 2013 Share Posted June 24, 2013 Ok, I'd like just a bit of help refuting this comment on a blog I participate at. This is a post from one of the threads there in which we are discussing climate change. I see this often and honestly dont really know how to reply to this without helping folks understand the IMPACT CO 2 levels now have or are having on warming. "Here is a graph from very recent geological time. From the chart it appears there is a warming cycle about every 90,000 years. It also appears that we are just past the peak of the most recent warming event. At the same time CO2 has increased dramatically and yet over the same period the temperature has decreased. Please help me understand how this fits in with your understanding that man is possibly the "source" of recent warming? " Then there is this link......wonder what the opinions of folks here are on it...... Dr Roy Spencer, http://tucsoncitizen.com/wryheat/2013/04/19/global-temperature-continues-divergence-from-model-predictions/ Link to comment Share on other sites More sharing options...
skierinvermont Posted June 24, 2013 Share Posted June 24, 2013 The scale of the graph is too fine to see the necessary detail. The last 10,000 years are all smushed together and you can't tell what is really happening. The huge spike in CO2 on that graph occurs at the same time as a spike in temperature. You just can't see the temperature line. Over the last 10,000 years CO2 concentration stayed between 260 and 280ppm until the 19th century when human emissions caused it to begin to increase. The current level is near 400ppm. Since the 19th century, as expected, global temperature has warmed about 1C and would probably warm an additional ~.5C even if CO2 concentration stopped rising. There is no period of cooling during which CO2 concentration increased. There does appear to be some slight increase from 260 to 280ppm over the last 10,000 years prior to the 19th century. And during this time period global temperatures peaked about 7,000 years ago. The change in CO2 was fairly small and there were significant changes in orbital parameters that caused cooling after 7,000BP.. Link to comment Share on other sites More sharing options...
Snow_Miser Posted June 24, 2013 Share Posted June 24, 2013 Then there is this link......wonder what the opinions of folks here are on it...... Dr Roy Spencer, http://tucsoncitizen.com/wryheat/2013/04/19/global-temperature-continues-divergence-from-model-predictions/ I think it's pretty clear evidence that Climate Sensitivity has been overestimated. In the Tropical Troposphere, where the Climate Models predicted the most warming to occur because of the negative lapse rate feedback related to the positive water vapor feedback, we can see that models have grossly overestimated the rate of warming here. This means that both the water vapor and lapse rate feedbacks are closer to zero than the GCMs suggest, and thus, Climate Sensitivity is likely lower than 3.2 Degrees C. This has been documented in paper after paper that the models exaggerate the vertical amplification to a significant degree. Link to comment Share on other sites More sharing options...
Jonger Posted June 24, 2013 Share Posted June 24, 2013 Ok, I'd like just a bit of help refuting this comment on a blog I participate at. This is a post from one of the threads there in which we are discussing climate change. I see this often and honestly dont really know how to reply to this without helping folks understand the IMPACT CO 2 levels now have or are having on warming. "Here is a graph from very recent geological time. Global_Temp_-_CO2_Level.jpg From the chart it appears there is a warming cycle about every 90,000 years. It also appears that we are just past the peak of the most recent warming event. At the same time CO2 has increased dramatically and yet over the same period the temperature has decreased. Please help me understand how this fits in with your understanding that man is possibly the "source" of recent warming? " Then there is this link......wonder what the opinions of folks here are on it...... Dr Roy Spencer, http://tucsoncitizen.com/wryheat/2013/04/19/global-temperature-continues-divergence-from-model-predictions/ This was the cause to all those cycles you have on the OP, co2 is a feedback, not the cause of PAST warming and cooling. http://en.wikipedia.org/wiki/Milankovitch_cycles Link to comment Share on other sites More sharing options...
Snow_Miser Posted June 24, 2013 Share Posted June 24, 2013 This was the cause to all those cycles you have on the OP, co2 is a feedback, not the cause of PAST warming and cooling. http://en.wikipedia.org/wiki/Milankovitch_cycles Yep, exactly. The cause of past warming/cooling is astronomical factors. Link to comment Share on other sites More sharing options...
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