It is all about politics. Climate change is the hardest political problem the world has ever had to deal with
The problem is not a technological one. The human race has almost all the tools it needs to continue leading much the sort of life it has been enjoying without causing a net increase in greenhouse-gas concentrations in the atmosphere. Industrial and agricultural processes can be changed. Electricity can be produced by wind, sunlight, biomass or nuclear reactors, and cars can be powered by biofuels and electricity. Biofuel engines for aircraft still need some work before they are suitable for long-haul flights, but should be available soon.
Nor is it a question of economics. Economists argue over the sums (see article), but broadly agree that greenhouse-gas emissions can be curbed without flattening the world economy.