Global warming &human activity

Please answer these question:

1. Has human activity caused the world's climate to change over past 100 years?

2. Point out the differnt perspectives of people who

a) agree human activity cause the world's climate to change over past 100 years (what's their reason ?)

b) do not agree human activity cause the world's climate to change over past 100 years(what's their reason ?)


c) What point do both sides of people agree?