What is Global Warming?

Questions:

What causes global warming?
What is the main cause in the modern warming trend?

Recent global scientific studies indicate that the Earth is entering a warming period. Throughout Earths History there have been warming periods and ice ages. We are aware that these periods in global climate change occur as a result of a slight variation of the Earths elliptical orbit in combination with a slight variation in the tilt of the Earth. Scientists have discovered that approximately every 100,000 years, the combination of these two variations has lead to an increase in intensity of radiation the Earth receives. This has been the cause in global climate changes resulting in ice ages and warming periods in Geologic history.. We know that global climate change is cyclic, however, studies over the past 100 years or so have indicated that Earth is not only entering a warming period, but that our civilization is accelerating the rate at which warming is occurring due to an increase in carbon emissions into our atmosphere since the industrial revolution had begun. Today, as we continue to add to the carbon content of the atmosphere, we are beginning to see the effects that the increase in temperature is having on Earth. Crop yields are decreasing, glacial ice is melting, sea levels are rising, and storms are intensifying. In addition, our oceans are becoming acidic, and the biodiversity of entire ecosystems is being threatened. All of these effects are interrelated, and collectively, can create a situation that can spiral out of control.