You could contribute and earn a living at the same time via capitalism, e.g. start a solar product sales / installation business. From an investment perspective

You could contribute and earn a living at the same time via capitalism, e.g. start a solar product sales / installation business. From an investment perspective it's a steadily growing industry with widespread unmet demand, rapidly decreasing prices and increasing efficiency, but still requires expertise even if the product costs nothing. From an ecological point of view such a business speeds up the displacement of carbon emitting tech. Politically it decentralizes the grid, redirecting political power from the energy industry toward your customers. And running a business that's a significant part of your income creates an incentive to keep at it religiously and relentlessly. That incentive is weaker without the profit motive, when it's about making an uncertain contribution to other people over decades.