Is it our obligation to ensure adequate quality of life for every human on the entire planet? Why stop at improving their lives by reducing our CO2 emissions?

Is it our obligation to ensure adequate quality of life for every human on the entire planet? Why stop at improving their lives by reducing our CO2 emissions? Why not institute a 10% income tax on all Americans and send that money and resources to subsistence farmers in rural India? That would surely improve their lives and help their "real needs" even more. How much of your income do you donate to subsistence farmers in rural India? For many people, the answer is "none". Why is there an expectation that we are obligated to improve the lives of subsistence farmers in rural India by reducing our carbon footprint, but not an expectation that we should donate money?