Geothermal from ocean trenches, use the power to generate hydrogen and ship/pipe it to regional power stations, this should be cheaper/cleaner than mining coal and there might be something interesting in the byproducts of electrolyzed seawater.
However for those of us without hundreds of billions of dollars getting this started might be a tad difficult, the coal lobby doesn't take kindly to opposition.
Get into the air conditioning and sunblock business. Buy houses far from the shore and wait till they're expensive beachfront till you sell. Develop how to harvest the energy of hurricanes and heat conduction (solar has always been an option.)