What could possibly be a rational basis for rejecting climate science?
If the issue is assessed on other grounds than science ones there can be rational reasons to reject climate science. e.g. if it is being assessed with respect to how addressing versus not addressing AGW impacts costs, competitiveness and profitability of specific business enterprises then rejecting climate science and encouraging other business operators as well as governments, courts and regulators to reject it, to avoid compliance costs of addressing it appears rational. The advice given by lawyers to people and companies facing lawsuits to admit no responsibility and seek to undermine the plaintiff's arguments, including questioning the veracity of expert witnesses is not irrational. Unethical perhaps, but it is not irrational.