What is the best way to deal with those preaching climate change denial or questions asked about the validity or debate of climate change?
With patience and maturity.
As Socratic has recently launched the environmental science section, we seem to have an influx of questions along the lines of, "Is climate change real," "What proof is there of climate change," "How can we be sure these aren't natural variations," and so forth. Thus, I think it's a good idea to brainstorm how to best tackle these situations.
For starters, many of these questions are essentially duplicates of one another and you can always mark a question as a duplicate.
In extreme cases, you can also mark a question as inappropriate.
That said, I'd like to remind everyone here that the main mission of Socratic is to teach: to make concepts accessible, to make learning easier, to break concepts down into simpler parts so that learning can occur. That said, reading comments/answers/questions in which people are actively spreading false information or posing questions asking how climate change can be true is certainly frustrating. We've all been there. Don't fight fire with fire though, so to speak. Rather than getting angry, respond clearly and don't get personal.
Ask yourself what are the best facts we have that climate change is caused by humans and is happening? Then ask yourself, how can I clearly communicate those facts? I'd advise against listing ten pieces of evidence. I'd also advise against just providing a link to other websites. Instead, pick a few key pieces of evidence and explain them yourself. Use images, videos, graphs, links to other Socratic concepts, and your words to teach. Remember your basics.
Remember, many people just haven't been taught enough about the science behind climate change or they haven't been taught the concepts well. Hopefully you joined Socratic to help others learn, so try and have some patience and explain these concepts in a way that makes climate change science more accessible and less confusing.
In some cases, a person's religious beliefs conflict with climate change, and this is a really hard situation to handle. Be careful and be considerate of other people's beliefs while maintaining the science behind climate change.