 the historical record by which you mean human historical record is highly overrated nigh worthless when you are talking about geological timescales even on topics with as short a timescale as climate there has been a significant recent increase in global coNUMBER concentrations the vast preponderance of the new coNUMBER in the atmosphere is due to human activity starting around the industrialization of europe and accelerating after wwii most scientists studying global climate change believe that these increased coNUMBER concentrations are the primary causal agent for increased global warming hence our interest in items of human time scale it is worth noting that underneath the receding glaciers deposited during the last major ice age they are finding substantial evidence of humans living in what was a nice temperate climate before the glaciers paved over their civilization the receding glaciers have turned into a bit of an archaeological treasure chest as they expose artifacts buried in and underneath them as they shrink that have been preserved by the ice for thousands of years i don t see any compelling reason to save the glaciers anyway particularly in light of the fact that their existence has always been transient most global climate change scientists would agree that temperatures in the past have often been much warmer than today the point of global warming isn t to save the earth the planet is not sentient the point is to understand and potentially reduce the impact of increasing temperatures on global human activity for anyone to insist that the current negligible fluctuations are anthropogenic just heaps one ridiculous assertion upon another i ll just stick with occam s razor for now the increase in atmospheric coNUMBER concentration is due to human activity it is generally accepted that increases in coNUMBER in a closed environment subject to solar heating retain more of that solar energy this is the current best explanation for the high temperature of venus if the coNUMBER concentration goes up globally which it has then theory states the earth should be retaining greater solar energy this process may be slow and may be difficult to monitor due to the variability of temperatures worldwide i encourage you to refute any part of this causal chain linking coNUMBER to eventual increases in global energy content part of which will be evident as heat jim 