Global Warming- Scientific Method and History

There has been a great deal of talk in the press as of late about Global Warming and as a devote follower of the Scientific method....I'm a skeptic. The Scientific method has 4 parts. 1. Observation-observe a phenomenon or problem 2. Hypothesis- derive a hypothesis to explain the phenomena 3.Prediction- logically predict how the hypothesis will perform using past and present events 4. Experimentation- perform experiments and analyze data to prove or disprove your hypothesis. Most of what I hear today stops with steps 2 . No one has used step 3 to explain warming after prior ice ages or experimentation to show that man is causing each of these global warming periods.
So here we are 1. Is the Earth getting warmer? I think the answer is yes. We are now in a warming period coming out of the "little ice age" a cooling period that followed the "Medieval Climate optimum" It's important to note that this occurred prior to the development of the internal combustion engine. The earth is now in the 2nd interglacial period which are about 100,000 years apart. 2. Is human activity causing this warming? The idea that man effects the weather is not new. Our history is replete with the sacrificing of our fellow man or woman( in the case of the proverbial virgin) to appease the weather God. In 1896 a Swedish scientist published a new idea. As humanity burned fossil fuels such as coal, which added carbon dioxide gas to the Earth's atmosphere, we would raise the planet's average temperature. In the 1970s scientists said that the accumulation of CO2 , dust and smog would actually block out sunlight and start Global Cooling. Today we have come full circle again and the thought is that the internal combustion engine is causing an increase in CO2 that produces the so called "Hockey Stick" graph showing a change in temperature linked to human activity. In this study going back 1000 years it shows a dramatic warming in the 20th century. "The term "Hockey Stick" was coined by the former head of NOAA’s Geophysical Fluid Dynamics Laboratory, Jerry Mahlman, to describe the pattern common to numerous proxy and model-based estimates of Northern Hemisphere mean temperature changes over the past millennium. This pattern includes a long-term cooling trend from the so-called "Medieval Warm Period" (broadly speaking, the 10th-mid 14th centuries) through the "Little Ice Age" (broadly speaking, the mid 15th-19th centuries), followed by a rapid warming during the 20th century that culminates in anomalous late 20th century warmth (Figure 1). Numerous myths regarding the "hockey stick" can be found on various non-peer reviewed websites and other non-scientific venues". If you carry this study back past 1000 years you get into the medieval warm period and the graph falls apart.
I think there is a great deal of money involved in this research and you have to go along to get the funds. If we look at this with a logical mind you have to agree that the earth has cooled and warmed many times over the millennia and will continue to do so. If an event occurred in the past and was unassociated with the point of your hypothesis then you have not met all of the requirements of the scientific method. Lastly, does CO2 contribute to global warming."Approximately 99.72% of the "greenhouse effect" is due to natural causes -- mostly water vapor and traces of other gases, which we can do nothing at all about. Eliminating human activity altogether would have little impact on climate change". CO2 levels are mostly dependant upon solar activity and the graphs comparing sun spot activity with CO2 levels mirror each other. I for one am very concerned about pollution, however, I think it's local pollution that is the problem. If we pick up after ourselves and treat this earth as a steward of what God has given us then we will all be much better off. By not acting on how we feel and instead on scientific fact is a good start. This will allow modern society to channel our efforts in a meaningful direction.