Gonna keep it simple.
Causes: Polution, and destruction of vast, oxygen producing areas of forest. The burning of fossil fuels and the conversion of large tracts of Soputh American rain forest for the sake of cattle production results in an increase of greenhouse gases, mainly CO2 and methane. in the atmosphere, giving rise to global warming. There are other causes, but these are the two that are foremost in my mind.
More CO2, less photosynthesising trees, more phaarping cows...
Impacts: Unknown. Raising of the global temperature will have dramatic climatic changes. Nobody kows for sure, because we don't fully understand the mechanism with which we are tinkering. For the UK, it could mean hurricane seasons, wetter weather, tornadoes.... Some predict that if the ice caps dilute the salinity of the arctic sea sufficiently that it will stop the engine that drives the gulf stream, and keeps the British Isles warm... which would paradoxically throw us into a new ice age.
Globally... nobody knows. Industry and the economists have used this doubt to preserve the status quo, even when empirical evidence made it blatantly obvious to everybody that there was something going wrong with the weather.
What are governments doing about it? At best, making token gesture, and trying to buy polution rights from under developed countries. The sad fact is that the most guilty parties are resolute about continuing down this path. What's even more tragic, the areas that will suffer first area places that are already poor, because the population is supported by a fragile economy, and the people are fed by ecosystems that are not abundant with argicultural potential. Screw up their weather and you end up with some serious famine.
Bleak, but there you go...
