Government-promoted emphasis on the problem of global warming, in my view, is a desperate attempt of power players in industry and government to try to control the global market because they're scared to death of the idea of global competition. To justify global governance, there must be a public goods problem of global proportions which is so dire that nothing short of emergency intervention on the part of a global governing authority will suffice to prevent imminent annihilation. The global warming political narrative fits the bill perfectly.
As far as "scientific consensus" goes, it is better termed "academic consensus" since consensus has never been a part of the scientific method (Flood geology was once the consensus of science). That academic consensus aligns with the political ends of big industry and governments who want to control the global market is hardly surprising since Western academia is largely funded by government subsidy. The less control national governments have over the economy (as the economy becomes increasingly global), the less public revenue academia can command. Academia has a vested interest in having a "consensus" on global warming, so there is no reason to believe that such consensus reflects anything about the truth value of the propositions that global warming is caused by human action and that its consequences will be catastrophic.
Without a powerful global jurisdiction to heel the global market, national governments will increasingly be faced with the distasteful spectre of inter-governmental policy competition. Major national industry interests - in whose laps national governments ultimately sit - have every incentive to press for global cartelization lest their industrial empires be toppled by vulgar competition on the international market. Imminent environmental catastrophe is a rationale for global governance which is extremely difficult to argue against, true or not. Libertarians who oppose the trend of increasing government invasion of privacy and ever more flagrant violations of private property rights would do well to analyze the larger meta-narrative surrounding the political discourse on global warming. Even if global warming were debunked, there are a million other public goods problems which can take its place in the argument for controlling the global market place.