A great deal hinges on a worldwide agreement to reduce carbon emissions at a summit in Paris this year. Some momentum is finally building for securing unified commitments from nearly 200 countries. But to avert a climate catastrophe in time, far more will be needed from countries, beyond what a multilateral agreement alone can bring.

This is because an agreement in Paris won't come into effect until 2020, and a multilateral deal is unlikely, on its own, to be enough. So a global stand must be bolstered by country initiatives, including greater energy efficiency and a switch to low carbon-energy use, to help address the socioeconomic effects of climate change that are already being felt.

This will make economic sense as the cost of climate-related hazards — floods, storms, droughts and heat waves — are on the rise. The monsoon floods that hit Thailand's industrial center in 2011 caused some $46 billion in economic losses. The destruction from Hurricane Sandy in the U.S. in 2012 was estimated at $68 billion.