Hmm... no, there are no scientific "laws". There are "laws" of physics—which you correctly note are open to revision where a rigorous challenge can be made—but there are no "laws" in science. Everything in science is a theory, because any experiment can always be run again (which at least might result in a different outcome). This is precisely why it should be generally easy to trust science—at least the science that makes its way into our lives—because it has already proven itself reliable. Put simply, a theory needs to actually perform in reality to reach the point of being implemented in a practical solution.

So we make decisions based on the reliability of scientific theories. That's the same whether you're talking about your ED pills or your cell phone. Somewhat inconveniently, many of the theories underlying climate science are continuing to be validated, not invalidated, so as with the ED pills and the phone, we should be making decisions accordingly. Hence the consensus and concern from the climate science community. It can be much simpler than people make it out to be.

Now, there is a significant challenge with climate because there are many interconnected problems and competing theories of how to address these problems. And most solutions require global cooperation. That may be an insurmountable challenge... but hopefully we're smart enough to figure something out even in the face of willful (and usually self-interested) ignorance. I'm somewhat encouraged by the fact that green solutions have become Big Business. Though perhaps not ideal, it at least adds some motivational energy to the task.