While I am not 100% convinced on global warming, things like the pollution from coal power definitely do affect our environment (when you can actually track the soot in the air from China). We will never reach 100% or even 50% renewable in my lifetime, and it may not even be practical to...
However there is a very practical solution wind power.
Due to the natural process of convection, land heats up faster then water and causes a natural breeze, usually known as sea breeze.
http://www.weather-climate.org.uk/06.php This breeze is very high during the hottest parts of the day, and very low at nighttime, which follows ALL human electrical consumption. This also happens to be the most expensive time to generate electricity, which is usually 50% more then retail rates and is charged as "peak hours". For example, here in NYC we are charged approximately 17cents/kwh for these peak hours.
Now on top of this nearly 60% of human population lives near the ocean. Given this we could simply build on land wind turbines all along the coast that would create energy when we need it most, without the need of massive power transmission lines. With this we could easily cut pollution and generate significant amounts of power when we need it without having to build storage systems or transmission lines as most renewable naysayers say.