It's not so much that consensus is science, but science
needs consensus.

Science says that human life begins at conception. But scientifically prove what "human life" is.
Science can prove a definition of what "human life" is, but it can't prove what is meant by "human life."
Is "human life" some cells of a human that are living, even if most of the body is dead?
Is "human life" when the brain is still living?
Is "human life" a bunch of cells that could develop into a human body if it is in a mother's womb?
Without a consensus of what "human life" is, science cannot prove anything about it.
And remember, "consensus" is not something scientists sign up to. No one tells scientists "you must believe this." Rather, consensus is
what most scientists choose to believe. That is why I keep comparing it to a jury. A jury isn't told what to believe. Each individual comes to his or her own conclusion, and the verdict is found when they reach a consensus.
If a vast majority of scientists come to the same conclusion, not from being told what to believe but from their own reasoning, then that tells you something, much like a jury coming to a conclusion about the facts of a trial. It's not perfect, of course, but it's better than any other method we've come up with for finding what the facts are.
I'm sure some of you will say, "The experiments determine the facts." Well, guess what? Scientists use experiments as the determinate for what is factual, along with close observation and models. So when the experiments make clear what the facts are, you have a consensus. When the observations make clear what the facts are, you have a consensus. When all the models reasonably model what is happening, whether it be inside a star or a climate system, you have a consensus. Because scientists like to be right, and a majority will follow the best way to determine that.
When a majority of scientists come to a consensus about a theory, that theory is the best/most productive one we have. That is the power of consensus. Like a jury, when many minds independently study something and come to the same conclusion, it is the best bet that that conclusion is the best one we have.