The secret to finding articles on opposite sides of an issue are to include focus words in your search. Focus words are just words will zoom in on specific viewpoints, or look for articles that discuss controversies.
The example shows searching the topic words climate change and the focus word controversy:
Use the lists below to find focus words that looks useful for your topic and try them. Be aware that controversial topics are often tied to political opinions or agendas.
The library has specific books that cover hot topics and pro/con arguments. Search for your topic and one of the series names: