If Global Warming really exists and if it is caused mainly by our civilization's GHG emissions, then we need to tame the hype and focus on things that would actually reduce CO2 emissions without bankrupting the economy and converting most of us into paupers.
Short term, this is what would probably give us the most bang for the buck:
1. Go crazy with natural gas. Yes, between now and 2040, the EIA estimates that electricity production from natural gas will grow by 88%. That is a healthy number, but if we are in a hurry to reduce CO2 emissions, then we should go "crazy" with natural gas so it may a) replace more current coal generation and b) prevent some new coal plants from going on line to begin with. Let's remember that per kWh produced, natural gas emits ~half the CO2 as coal. This is not a footnote, this is a game changer.
2. Improve efficiency standards and implement efficiency projects all over the world. Efficiency tends to be the least painful energy (and thus CO2) reduction path. Here we are talking of insulation, air conditioners with higher SEER ratings, LED / CFL illumination, lighter cars, improvements in the internal combustion engine, hybrids, what have you.
Longer term, we have to consider*:
1. Nuclear energy. Today, nuclear is already the #2 low CO2 electricity source in the world. Although hydro is still king, its projected growth is smaller and thus eventually nuclear will take the top spot. However, if we are in a hurry to reduce CO2, then we should also go "crazy" with nuclear and increase its growth well above the 90% projected by the EIA.
2. Empower women via education and other means to be "the masters of their own fate." Yes, women all over the world should be able to decide when and how many children they will have. See "the Girl Effect" below.
Finally, a note on "renewable" or "sustainable" energy (solar and wind): ironically the subsidies for sustainable energy are not sustainable and the moment they are removed theses industries will survive only in their "natural" market which is small and thus largely irrelevant respecting curtailment of our global CO2 emissions.
In summary, "climate action" would require "going crazy" with natural gas and nuclear power while at the same time pursuing efficiency and supporting education for women globally. Let's tame the hype and focus more on reality.
* Yes, some may argue in favor of CCS or geo-engineering but these approaches are today very green (as it were).