How will humanity change if life expectancy is increased to 500 years?
Due to the industrial and infrastructure development, there is a lot of economic problems and international trade deficit will occur. Soon all the countries will be like India and China. Certainly the earth will be a hell. Due to the needs of the people, more inventions will ruin the world.
Individual and social life will be a challenge. Natural resources would be destroyed in a short period. Space science will be much improved. Human world will find living places at new worlds in new Galaxies.
Due to the longer life expectancy, fertility rate will achieve dynamic growth rate and ironically there is a scarcity of resources to be utilized. Hence, there will be certainly a resource war that will occur without any doubt.
And the population will reach around 30 to 40 billion in 2050. Which is a catastrophe for the very limited resources on earth.
There will be no food at all within a short span of period. Our ecosystem will be on turmoil due to the mass destruction of natural resources, space, ecosystem and environment. No longer the world will be safe soon.
Simply to say when life expectancy increases, the birth rate drops and there is no way to have a balance between mortality and birth rate. Soon there is no way of a chance to diminish the ultra-population growth.
In order to conclude, the forces of nature are always yet to balance because of the human activities till now.