For Americans, concern about "climate change" is inversely related to the immediacy of other other, more serious concerns. When the economy collapses, politicians wisely avoid talking about policies that could increase the cost of gasoline. When tragic events like terrorist attacks or school shootings occur, few politicians are willing to wax lyrical about the "threat" posed by the climate. One odd result of this inverse relationship is that the prevalence of news stories involving "climate change" can be used as a bellwether for American hopefulness about their future. When Americans feel secure, they have time to feel guilty about it and read stories about how their comfortable lives come at the expense of future generations.
As the economy roars along under President Donald Trump, it was inevitable that the Democratic Party would shift its focus toward the climate. The 2020 election was always going to feature Democrats expressing concern about "our future" while Republicans tout four more years of economic success. In a typical fight of this kind, the Republicans would most likely come out on top. As Clinton strategist James Carville once said, it's "the economy, stupid."
In steps Ocasio-Cortez. Before the primary season even begins, the freshman Congresswoman has brought the climate issue to the forefront of Democratic Party. Her initial proposals are so chock-full of absurd goals and progressive goodies that reasonable observers are tempted to think that she is unable to grasp political reality. But, the point of her Green New Deal is not to pass through Congress. The goal, as Andrew Sullivan picked up on in a recent article, is to redefine the term "moderate."
As Donald Trump points out in his book The Art of the Deal, you never begin negotiations by telling the other side what you really want. On the contrary, you ask for the moon. The more ridiculous what you claim to want is, the better—think "Mexico will pay for the wall." The more ridiculous your claim, the more ground you will appear to "conceded" and the more reasonable you will look when you "settle" for what you really wanted.
It is still an open question whether Ocasio's attempts to shift the Overton Window will help Democrats achieve victory in 2020. But, if not, her leadership of the party will set her up nicely for her own run in 2024.