Can someone explain to me why we need laws in which politicians endorse scientific findings?

The following story is evidently generating indignation from left-of-center bloggers. (I believe that some man-made global warming is occurring, if you're interested, but I disagree with most policy-conclusions that people such as Al Gore support.)

House Republicans rejected amendments offered Tuesday by Democrats that called on Congress to accept the scientific consensus that climate change is occurring, it is caused in large part by human activity and it is a threat to human health.

The amendments, offered at an Energy and Commerce Committee markup of legislation to block Environmental Protection Agency climate change rules, are part of an effort by House Democrats to get Republicans on the record on climate science.

Committee ranking Democrat Rep. Henry Waxman (D-Calif.) offered an amendment Tuesday that called on Congress to agree that climate change is occurring. The amendment failed on a party-line vote of 20-31. No Republicans voted for the amendment. [...]

If Democrats devise hoops designed to threaten Republicans with the label of "anti-science," then Republicans are correct not to jump through them. (h/t: Memeorandum)