Answer:
If I had to choose I think it would be humans fault.
Step-by-step explanation:
To think that we are the reason for global warming and everything would make the next person a little insulted but when you think about it a long time ago when there was not many technological advancements there was not complains of global warming or anything until recently. Temperatures are starting to rise and more and more pollution is filling our atmosphere. As it could be true that it might not be entirely our fault as humans I think we took a major part in it.
Hope this helps :)