Sam Smith's chart is misleading about the similarities of the Green and Libertarian parties, because only 6 out of 19 issues on it are economic. If you plot an equal number of issues of economic liberty and civil liberty, the result is more like this:
Prof. Fred Foldvary and other geolibertarians have been pushing progressive green libertarianism for decades, and there are good prospects for the LP to become more green. Here is Foldvary in 2007 asking Does free plus green equal victory? Here is Dan Sullivan in 1992 writing Greens and Libertarians: the yin and yang of our political future. The LP and GP can agree on a broad range of civil-liberty issues, as well as on decentralization and electoral reform. The LP and GP should both support a Green Tax Shift, using market means to achieve green ends. The LP ultimately needs to move toward geolibertarianism and EcoLibertarianism, of the sort expressed in the Free Earth Manifesto.