Advocates for action on climate change are fond of arguing that costs of a few percent of GDP are really quite small in absolute terms (see image above from EDF). Here is one way to think about a 1% reduction in GDP in political terms.
Political scientist Ray Fair calculates that in historical presidential elections, every 1% decrease in GDP results in a 0.7% decrease in vote share for the incumbent party(See Table 2 in this PDF). In 2008, more than 130 million people voted in the US presidential election. In very round numbers, a 1% change in GDP has historically led to a swing of 1 million votes.
Are 1 million votes a small amount or a large amount? For selfish reasons alone, policymakers are going to be reluctant to impose any brakes on GDP, no matter how small those effects are argued to be. Climate policy will not succeed until the benefits are far more tangible and on the short term.