The change of environment is always become a concern of world community. This includes the scientific community and also large part of the governmental body. The first question to be ask when dealing with environmental change such as global warming, is it natural or man made?
This question has been and currently been debated by numbers of scientist, and it seems that they still don’t have a clear cut answer to it.
First of all, our earth actually seen a decreasing rate of temperature rising. According to National Monitor, from 1951 up to 2012 the world temperature increase at the rate of 0.12 degree celcius per dacade. This rate decrease to just 0.05 degree celcius per dacade from 1998 to 2012. So, there a chance that the theory of global warming is a natural phenomenon rather than caused by humans.
Others suggest that volcanoes emit CO2 more than humans, and our current understanding about temperature rise maybe wrong. We maybe does not fully understand how nature regulate their temperature.