Pollution in general is a huge problem that will lead to much more illness and death. The 'global warming" is a bit of a fluff as much of the climate change (air currents, etc.) is aggravated by increased urbanization. Concrete jungles mess up water tables (displaced due to foundations), air currents above built-up areas due to the retention or reflection of heat off of buildings, concrete and added heat from air conditioning units, etc. Yet, the urban planning specialists have been advocating building up urban areas for decades. "Concentrate infrastructure for efficiency, build transit to take cars off roads" may sound solid but it is really just a displacement, not a reduction of pollutants. In Toronto (I grew u there), as in many cities, condominiums were pushed. so, you have thousands of new units built in clumps then people wonder why traffic is congested. The experts then scream for more transit dollars and beat drivers with fees and disincentives. So, what is really warming the air? Cow farts, carbon release or a combination of issues, most of which are ignored? I dunno.