There are a number of problems that all interlock. Democracies with their relatively short election cycles will naturally find it hard to deal with problems that last much longer than those election cycles and that have the bulk of the problems downstream of us. Voters are motivated by their personal issues first, local issues second and global issues dead last. Countries are going to have to collaborate in a very strict manner in order to deal with global issues.

Throw all of those in a blender and it's easy to see why democracy and global problems are not going lead to an actual solution. Individuals are going to make some minor difference but not enough to offset the larger trends as long as it isn't a solid majority doing this.