Acid rain was relatively easy to fix:
(1) Flue gas desulphurisation in coal-fired power stations (one of the biggest sources)
(2) Low-sulphur fuels (i.e. strip the sulpur from fuel before combusion)
(3) The change-over from coal (high in sulphur) to natural gas (v. low in sulphur) as a fuel for power stations, brought about by 1990s exploitation of North Sea gas reserves
All this was brought about by a mixture of international legislation, economics and the general public will to get something done about it. PLUS – it was 'solvable' issue on a practical level.
It was never going to Kill Us All as some might have sensationalised, it was just going to cause widespread ongoing damage to forests, rivers, lakes plants, wildlife – as it infact did. Bjørn Lomborg a.k.a 'The Sceptical Environmentalist', advocates de-sensationalising such environmental issues, becasue it evokes the sorts of jaded responses as seen above. I'm all for that approach.
Climate change is a more thorny problem, because unfortunately at present our economies are directly dependent on emitting CO2 to the atmosphere as a byproduct of fossil fuel combustion as a source of power – and you can't easily 'strip' the CO2 from power station chimneys in the same way you can with SO2. So without an alternative power source – other than fossil fuels – if we reduce CO2 emmisions, our economies (and standard of living) will directly suffer. This is not politically, economically or even generally publically favorable at present. Hence, we continue to increase our CO2 emmisions annualy on a global scale – and thereby increase the associated risks of Global Climate Change.
Part of the problem is this notion of 'economic growth', whereby an economy is only seen as healthy if it is 'growing'. On a gross scale, therefore, an economy will only grow if it uses ever more natural resources (and equally produces ever more waste – entropy – as a result). Unfortunately, the Earth is a finite bubble, with a limited capacity to both supply resources and also absorb all that entropic mess. The Climate Change that is starting to take place now is the fallout from the limited capacity of the atmosphere to absorb all that CO2 (and methane, and CFCs etc., etc.).