Feel like some people here are being emotionally invested thinking this study is a sort of a blame game encouraging us to berate the wealthy individuals for their investments. I can't say whether the researchers had this in mind or not but from reading the study it looks like an aim of devising this metric was to figure out a strategy of investment taxation to deter wealthy people from investing in industries that are ravaging the planet:

By linking GHG emissions with the incomes it enables our work has quantified the scale of emissions inequality in U.S. society and the extreme and growing concentration of emissions among very wealthy households. It also offers some suggestions on how accelerated decarbonization and revenue generation might occur, such as an income or shareholder-based carbon tax that reflects the GHG intensity of one’s income sources or financial assets. This is distinct from consumer facing carbon taxes that rely on individuals decarbonizing the economy by shifting their consumption to less GHG intensive goods and services and thereby encouraging companies to respond to their new preferences. A consumer-facing approach assumes individual consumers have the knowledge, financial resources, and agency to shift spending and the power to alter corporate decision making on the GHG intensity of their supply chain and operations. An alternative income or shareholder facing carbon tax puts pressure on executives and large shareholders (i.e. those with the most economic and corporate power) to act in their own self-interest and decarbonize their supply chain and operations in order to reduce taxes on their compensation and investments. Recent work has calculated that a climate inspired wealth tax could indeed be an effective tool to raise revenue for adaptation and mitigation efforts [52, 53].