This paragraph is an example of a Toulmin argument.
The Toulmin method has six elements: claim, grounds, warrant, backing, qualifier, and rebuttal. The elements are used in this paragraph are;
Claim: a statement that the author wants the audience to accept as true.
"I believe the cost of drilling is too high."
Grounds: information that the claim is based off of.
"I agree with environmentalists who fear that drilling will disturb the migration of more than 130,000 caribou."
Backing: additional support for the claim by addressing different points related to your claim.
"In addition, experts say that the oil in the area adds up to less than a six-month supply."
Rebuttal: addresses the opposing view to reinforce the original argument.
"Is such a small amount of oil worth the risk drilling poses to the animals?"