It's not like global warming is stopping at + 1.5 C, it'll keep going up so long as our output is higher than the steady state temperature for the given concentration of greenhouse gases. At this point, the greenhouse gases already generated guarantee warming for some time forward, even if we stopped emitting all greenhouse gases tomorrow. Also, 1.5 C = 2.5 F. What's the difference in average temperature between plant climate zones, about 5-10 F? Entire ecosystems change on temperature changes not that far above your stated value of 1.5 C.
Finally, you equate a fossil fuel economy with economic profit, and yet there is no reason that has to be true in 5, 10, 15 years down the road. How much money has the United States of America spent on military and diplomatic expenditures in the Middle East and across the globe to protect a fluent oil supply? How much money has the United States spent on developing an oil-based economy at the expense of far smaller expenditures on other energy supplies? The oil/fossil fuel economy is mature after the benefits of massive national expenditures into it for a very, very long time (including its protection by many $trillions of dollars spent on military protection). If we put the same monetary and time investment into other energy sources, including advanced nuclear and renewable energy sources, suddenly the gaps in energy prices would decrease dramatically. There is a bigger picture here.
