The UN says that climate change increases risk and stress to water, sewer, food supplies, the world's forests, drainage and transportation systems as well as infrastructure.  That's because "these systems are more exposed to the impact of increasingly powerful hurricanes, typhoons and other natural disasters."  But the cost to avoid severe weather events won't be cheap.  There are various estimates but switching from fossil fuels to low-carbon sources of energy will cost $44 trillion between now and 2050, according to a report released last May by the International Energy Agency.  A UN report from the Intergovernmental Panel on Climate Change last April said that efforts to stabilize levels of greenhouse-gas emissions would require investments of about $13 trillion through 2030.  But a study in the Proceedings of the National Academy of Sciences estimates that damages from uncontrolled climate change—an increase of 3.4 degree celsius—could cost $12 trillion or 2.8 percent of global output by 2095.  And delaying action could increase costs by 40 percent every decade, making it ever more costly to do what what's needed.  That's causing some in the financial world to start looking at climate change in a different light, said Paula DiPerna, a special adviser, to the Carbon Disclosure Project, an environmental risk management firm.  "Banks are shying away from companies who don't know how to manage their climate change risk," she said. "And companies are getting better returns on equity over time for investing in green technology."  It's the bottom line that's creating a bigger response to climate change, said Mark Kenber, CEO of The Climate Group, a non-profit environmental organization that works with business and government partners.  Read MoreInvesting in climate change: A 25-stock index  "I think the climate change fight will accelerate going forward," he said. "We're seeing countries and companies going beyond just thinking about going green as it's more economical to do so now."  But Kaplan University's Wilson said that it "can't just be all about the money."  Wilson said that calls for increased financial investments in areas such as crop insurance and green energy projects shouldn't come at the expense of strategies like teaching farmers in drought-ridden areas how to plant crops that use less water.
Another UN climate change summit has experts wondering if anything will get done and if the right measures to stop greenhouse emissions are in place.