Going into space won’t be cheap, but it will take only a small proportion of world resources. NASA’s budget has remained roughly constant in real terms since the time of the Apollo landings, but it has decreased from .3 percent of U.S. GDP in 1970 to .12 percent now.
Even if we were to increase the international budget 20 times to make a serious effort to go into space, it would only be a small fraction of world GDP. There will be those who argue that it would be better to spend our money solving the problems of this planet, like climate change and pollution, rather than wasting it on a possibly fruitless search for a new planet. I am not denying the importance of fighting climate change and global warming, but we can do that and still spare a quarter of a percent of world GDP for space. Isn’t our future worth a quarter of percent?