We can't. Much of science has been subverted to political ends.
"The disinterested search for truth cannot be allowed in a totalitarian system. The vindication of the official views becomes the sole object . . ." - F.A. Hayek
Scientific theory is just that, theory. Facts in science can be trusted, because they represent an unbiased answer to a question. Science facts have given us a lot of good things like electricity, mobility, flight, medical advances, and communication.
The problem with science as presented today is that politics has hijacked the process, forcing outcomes for cash grants and/or the political agenda of the chief scientist.
Do not confuse real science, which is simply the process of discovery through thought and experimentation, with the climate hoax going on today.