Thoughts on Global Warming

If increased release of green house gasses into the atmosphere is the cause of the planet warming up then why have we not seen a constant temperature increase over the last 400,000 years since man started to introduce additional CO2 into the atmosphere? I agree at first the increase would be small. But since fire was first used by man,we have been adding more and more CO2 into the atmosphere than would of been introduced otherwise and since increased levels of CO2 raise the temp then we should be seeing a steady rise in temperature from that point forward. But that is not the case.

From 1910 to 1940 the global emissions of CO2 increased from 500,000 tons per year to 1 billion tons per year and global temps went up about 0.9F Yet from 1940 to 1980 global CO2 emissions went from 1b tons to 5b tons, and global temperatures went down about 0.9F. If CO2 emissions are to blame, why the drop in temperature when emissions were increasing faster? Of course from 1977 to 2000 we again experienced another warming. But since 2000 temperatures seem to be dropping again. Since the beginning of the Industrial Revolution we have had periods of warming and cooling. If increasing CO2 was the cause of warming and with the increase of CO2 pumped out since the beginning then there should not be any cooling periods since there were no periods of decreasing CO2 output.

Isn't it more plausible that the sun with a mass a million times that of the earth that is responsible for almost all of the thermal energy on this planet could through uneven emissions of radiation cause the global temperature to fluctuate? Isn't that a more plausible option? That along with the "wobble" in the earth's orbit seems to be a much more plausible explanation of the climate change that went on long before we started adding CO2 to the atmosphere?

The history of climate change over the last 1000 or even 500 years does not indicate that humans have that much control over climate. We have had cool periods and warm periods and all the time we have been polluting the atmosphere. I think that the wobble in the earth's orbit and the changes in the thermal output of the sun are more likely the cause of global temperature changes. We have massive evidence of climate change on this planet on scales that dwarf what has happened over the last 100 years. Yet humans were not even here for most of these changes.