Personally I think that global warming is caused by natural cause and history shows that. Global warming is not caused by CO2 in the atmosphere, but by an increase in atmospheric CO2. Carbon dioxide is released to the atmosphere by variety of natural sources, and over 95% of total carbon dioxide emissions would occur even if humans weren’t present on the Earth. Even though natural sources represent most carbon dioxide emission, they do not combined to the recent observed increase in the concentrations because natural sources are balanced by natural sinks that remove carbon dioxide from the atmosphere. There has historically been more CO2 in our atmosphere than exists today. History facts show that during the Cambrian Period which over 200,000 years ago, the average CO2 concentrations were about 1800 ppm or about 4.7 times higher than they are today. The highest concentration of CO2 during all of the Paleozoic Era occurred during the Cambrian Period, nearly 7000 ppm about 18 times higher than today. Today atmosphere CO2 is only 400 ppm, which is very low in comparison. Not only were CO2 levels higher than they are today the temperatures were also higher than they are today when humans did not exist. (“Global warming is not caused by humans”)
History shows us that the Earth has going through warming period before without human activities. The Earth has been warming since 1880, it has already increased globally. The 1990’s were the warmest decade in the past 1,000 years with the 20 warmest years having occurred since 1981. Current climate models predict an increase average temperature in the regions over the next 100 years. Oceans have been absorbing more than 80 percent of the heat added to the atmosphere. Sea levels have risen about 17 centimeters globally and glaciers are retreating almost everywhere around the world. (“Dr. Tapio Schneider”).
Over the many years history has showed that the Earth goes through cycles. The orbital cycle is the change in the...