It is well known that the earth has gone through heating and warming trends… I posted all that in the last global warming thread. What I think you are finding misleading is the (rate)…. Most heating periods took place over thousands of years not a couple hundred…
The basis of global warming is that the earth is heating up to quickly not that it is heating up… The reason it is heating to Quickly is do to green house gases that retain heat…
Maybe this will clear some things up.
Climate is influenced by many factors, both natural and human. [7] Things that increase temperature, such as increases in heat-trapping emissions from cars and power plants or an increase in the amount of radiation the sun emits, are examples of “positive” forcings or drivers. Volcanic events and some types of human-made pollution, both of which inject sunlight-reflecting aerosols into the atmosphere, lower temperature and are examples of “negative” forcings or drivers. Natural climate drivers include the sun’s energy output, aerosols from volcanic activity, and changes in snow and ice cover. Human climate drivers include heat-trapping emissions from cars and power plants, aerosols from pollution, and soot particles.
In their search for clues, scientists compared two natural drivers of climate (solar changes and volcanic aerosols) and three human drivers of climate (heat-trapping emissions, aerosol pollution, and ozone depletion), altering these one at a time in their sophisticated models. Changes in the sun during the twentieth century have warmed both the troposphere and stratosphere. But human activities have increased heat-trapping emissions and decreased stratospheric ozone. This has led to the troposphere warming more because the increase in heat-trapping emissions is trapping more of Earth’s outgoing heat. The stratosphere has cooled more because there is less ozone to absorb incoming sunlight to heat up the stratosphere. Both these effects combine to shift the boundary upward. Over the period 1979-1999, a study shows that human-induced changes in heat-trapping emissions and ozone account for more than 80 percent of the rise in tropopause height. [10] This is yet another example of how science detectives are quantifying the impact of human activities on climate.