The IPCC Special Report is here from the UN. It documents the immediate impacts on the environment that 1.5C will likely have. It warns that strong efforts would be required to prevent disastrous consequences from dangerous levels of climate change. This means that World War II was a cakewalk compared to this, all hands on deck. An analysis of the report: "The best time to start reducing emissions was 25 years ago. The second best time is today."
Johan Rockström, chief scientist at Conservation International speaks about it.“Climate change is occurring earlier and more rapidly than expected. Even at the current level of 1C warming, it is painful,” he told the Guardian. “This report is really important. It has a scientific robustness that shows 1.5C is not just a political concession. There is a growing recognition that 2C is dangerous.” In order to blunt the coming climate change at that level, it's necessary to abandon coal and other fossil fuels in the next decade or two.
Having said all that, there's immediate, large-magnitude things that can happen right away to drastically reduce emissions. Such as protecting, preserving and restoring our great forests. Such as elimination of fossil fuel subsidies by governments across the globe. Such as rapid technology advancement in wind and solar, along with the upgrading of the electrical grids and establishing many stand-alone power sources at its periphery. Transportation in all areas, such as auto, truck, rail, airlines, and especially port traffic from overseas, will need to become electrified and supplied with renewable fuels. These strategies are not difficult, and can be widely employed in all countries, which need to develop the revenue for this. Decarbonization also has possibilities in the future with the nascent carbon capture industry that's progressing now.
There are many other things that can be done by private industry and by municipalities that can contribute to the lowering of carbon emissions in the very near future. But we don't have much time, and we need to mobilize. All of us.
Update 10/8/18: Nobel Prizes are awarded and given to economists referencing ways to adapt growth to climate change.
Update 10/9/18: 2C is nowhere near safe from a climate impacts perspective; now it's 1.5C
Update 11/2/18: Absurd for society to kneel before the dictates of the marketplace and that its primacy should determine how you structure government.
Update 11/12/18: The IPCC report tells us that climate breakdown is inevitable if we continue with growth-based neo-liberal economics.